I would like to give space of 10 pixel in each table view cell.
How I can do that?
Right now all cells are coming without any space
Here is my cell function
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier = #"MyOrderCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
NSLog(#"%d",indexPath.row);
if (cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
cell.backgroundColor = [UIColor clearColor];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
}
UILabel *orderid = (UILabel*)[cell.contentView viewWithTag:101];
orderid.textColor = kMaroonColor;
orderid.font = [UIFont fontWithName:kFontName size:kProductFont];
orderid.text = [NSString stringWithFormat:#"ORDER ID : %#",contentDict[#"order_id"]];
UILabel *date = (UILabel*)[cell.contentView viewWithTag:102];
date.textColor = kMaroonColor;
date.font = [UIFont fontWithName:kFontName size:kProductFont];
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"yyyy-MM-dd HH:mm:ss"];
NSDate *date1 = [dateFormat dateFromString:contentDict[#"order_date"]];
// Convert date object to desired output format
[dateFormat setDateFormat:kDateFormat1];
NSString *dateStr = [dateFormat stringFromDate:date1];
date.text = dateStr;
NSArray *products = contentDict[#"products"];
UILabel *noOfProducts = (UILabel*)[cell.contentView viewWithTag:103];
noOfProducts.textColor = kMaroonColor;
noOfProducts.font = [UIFont fontWithName:kFontName size:kProductFont];
noOfProducts.text= [NSString stringWithFormat:#"NO OF PRODUCTS : %d",products.count];
NSArray *totalArray = contentDict[#"totals"];
NSDictionary *totalDict = [totalArray objectAtIndex:0];
UILabel *price = (UILabel*)[cell.contentView viewWithTag:104];
price.textColor = [UIColor blackColor];
price.font = [UIFont fontWithName:kFontName size:kProductFont];
NSMutableAttributedString *attributeString = [[NSMutableAttributedString alloc] initWithString:[NSString stringWithFormat:#"\u20B9 %#",totalDict[#"total"]]];
[attributeString addAttribute:NSForegroundColorAttributeName
value:kGreyColor
range:NSMakeRange(0, 1)];
price.attributedText = attributeString;
UIView* shadowView = [[UIView alloc]init];
[cell setBackgroundView:shadowView];
// border radius
[shadowView.layer setCornerRadius:10.0f];
// border
[shadowView.layer setBorderColor:[UIColor lightGrayColor].CGColor];
[shadowView.layer setBorderWidth:1.5f];
// drop shadow
[shadowView.layer setShadowColor:[UIColor blackColor].CGColor];
[shadowView.layer setShadowOpacity:0.8];
[shadowView.layer setShadowRadius:3.0];
//[cell.layer setShadowOffset:CGSizeMake(5.0, 5.0)];
[tableView setSeparatorInset:UIEdgeInsetsMake(10, 10, 10, 10)];
[cell setLayoutMargins:UIEdgeInsetsMake(10, 10, 10, 10)];
// [tableView setIndentationWidth:10];
// [tableView setIndentationLevel:2];
//tableView.separatorStyle=UITableViewCellSeparatorStyleSingleLine;
return cell;
}
The most simple way would be make your cells height a bit bigger(3pt from top and 7pt from the bottom) than that of your cell's background image, and making the colour as [UIColor clearColor]. That would give the illusion that the cells have a 10 pt gap in between.
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
// number of cells or array count
return 10;
}
- (NSInteger)tableView:(UITableView *)tableViewnumberOfRowsInSection:(NSInteger)section
{
return 1;
}
-(CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
{
// space between cells
return 10;
}
-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
UIView *view = [UIView new];
[view setBackgroundColor:[UIColor clearColor]];
return view;
}
In the user interface for UITableView set Row Height Attribute value 210.
and In the user interface for UITableViewCell set Row Height Attribute value 200.
It will put 10 px space between each cell in the TableView
just make numberOfSections = "Your array count" and make each section contains only one row. And then define headerView and its height.
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return yourArry.count;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 1;
}
-(CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
{
return cellSpacingHeight;
}
-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
UIView *v = [UIView new];
[v setBackgroundColor:[UIColor clearColor]];
return v;
}
Create a container view inside UITableviewCell->ContentView. You keep all your subviews(labels,buttons,views) inside that container view. Now set container's boundaries away from the Cell's contentview by setting appropriate constraints.
UITableviewCell->ContentView->YourCustomContainerView-> (all
subviews). Set YourCustomContainerView's boundaries away from the
ContentView.
I guess the best way is to add a separator cell for each normal cell. let each kind of cell do its own job, and you can reuse the the separator and normal cell else where and need not to change their UI again. and you can customize the separator as you want, and all the calculations are easy, easy like this:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
return dataArray.count * 2;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
if (indexPath.row % 2 == 0) {
CellForData *cell = [tableView dequeueReusableCellWithIdentifier:#"dataCellID" forIndexPath:indexPath];
return cell;
}else{
CellForSeparation *cell = [tableView dequeueReusableCellWithIdentifier:#"separatorCellID" forIndexPath:indexPath];
return cell;
}
}
If for a simple solution you can create sections for all cells. Each section each row. You can add a footer height for spacing between sections.
its so simple
you can set the auto layout or adjust the Hight of the label
as well increases the hight of the cell
Increase the cell Hight.... And hide the separator and set the background view setBackgroundColor:[UIColor clearColor]]
You can achieve that by having 1 cell per section & set tableview style to Grouped.
If you want to be able to have sections and do not want to create mystery space within your cells, create a collection view instead of a table view. Collection Views can be set to vertical only and one column only = you can also set the minimum line height and interitem spacing. Apple Developer Docs for UICollectionView
Add UIView (childview) to ContentView. Add 10 pixcel spacing from top and bottom to parentView. Add your cell content in childView.
// I found this on internet hope this will help some future seeker
// This method should implement in custom class
// This for give space between row
override var frame: CGRect {
get {
return super.frame
}
set (newFrame) {
var frame = newFrame
frame.origin.y += 4
frame.size.height -= 2 * 5
super.frame = frame
}
}
I am developing an app which mostly uses 1 view controller. When the user presses a button it populates an array and uses that array to populate a hidden table view using [myTable reloadData].
Then he can press a button and the table disappears, and with another button it should do the same thing again, populate the same array with the same function and reload data.
But when I do that, the cell's sizes increase and it forces my table subview to increase in size and thus use scrolling to display all the data, while the first time it all fits inside the table subview.
I have probably made an error in the storyboard options of my app, but here's my delegation methods just in case:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"playerCell" forIndexPath:indexPath];
cell.textLabel.text = [NSMutableString stringWithFormat:#"Player %ld", (((Player *)[topPlayersArray objectAtIndex:indexPath.row]).playerID + 1)];
//display the player's poiunts
cell.detailTextLabel.text = [NSMutableString stringWithFormat:#"Points: %ld", (((Player *)[topPlayersArray objectAtIndex:indexPath.row]).playerScore)];
return cell;
}
//custom font and color for the cell
-(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
//set up the cell's font
cell.textLabel.font = [UIFont fontWithName:#"Aka-AcidGR-ScrachThis" size:34.0];
cell.detailTextLabel.font = [UIFont fontWithName:#"Aka-AcidGR-ScrachThis" size:24.0];
cell.detailTextLabel.textColor = [UIColor whiteColor];
//set the color of the label
if(indexPath.row == 0)
{
//set color to gold for first player
cell.textLabel.textColor = [UIColor colorWithRed:252.0/255.0 green:194.0/255.0 blue:0 alpha:1.0];
}
else if(indexPath.row == 1)
{
//set color to silver for second player
cell.textLabel.textColor = [UIColor colorWithRed:191.0/255.0 green:191.0/255.0 blue:191.0 alpha:1.0];
}
else
{
//set color to bronze for 3rd player
cell.textLabel.textColor = [UIColor colorWithRed:0.647 green:0.443 blue:0.392 alpha:1.0];
}
}
//return th e number of rows, should be 0 when the game starts and 2 or 3 depending on the number of players (2 for 2, 3 for 3 or more)
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [topPlayersArray count];
}
-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
//create header
-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
//create the header subview
UIView *headerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, tableView.bounds.size.width, 48)];
//create the section title label
UILabel *labelHeader = [[UILabel alloc] initWithFrame:CGRectMake (0,0,320,44)];
//set it to the scrachThis font and white color and center align the text
labelHeader.font = [UIFont fontWithName:#"Aka-AcidGR-ScrachThis" size:34.0];
labelHeader.textColor = [UIColor whiteColor];
labelHeader.textAlignment = NSTextAlignmentCenter;
//set the text and return the headerView
if(thisGame.gameHasEnded)
{
labelHeader.text = #"Winners:";
}
else
{
labelHeader.text = #"Leading Players:";
}
[headerView addSubview: labelHeader];
return headerView;
}
And yes, the table is supposed to have a maximum of 3 cells
Just use:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
And return the proper height.
I create table view cell which contains my custom text field, subclass of UITextField. When i add text field to my cell i set
textField.textAlignment = NSTextAlignmentCenter;
I have placeholder on text field. When my cell appears it's alignment is something average between left and center. Then after editing it becoming center. I need center alignment right after creating cell. Can anyone help to solve this?
Edit
My CellForRowAtIndexPath method:
- (CTKMultiColumnTableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *reuseIdentifier = [NSString stringWithFormat:#"cell%d",indexPath.section];
CTKMultiColumnTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:reuseIdentifier];
if (cell == nil) {
cell = [[CTKMultiColumnTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:reuseIdentifier];
[cell setFrameWithRect:CGRectMake(0, 0, tableView.frame.size.width, 34)];
}
cell.textField.placeholder = [_placeholders objectAtIndex:tableView.tag];
cell.delegate = self;
cell.relatedTableView = tableView;
return cell;
}
and part of willDisplayCell method
- (void)tableView:(UITableView *)tableView willDisplayCell:(CTKMultiColumnTableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
switch (tableView.tag) {
case 4:
cell.textField.leftView = nil;
cell.textField.rightView = nil;
cell.textField.textAlignment = NSTextAlignmentCenter;
cell.textField.keyboardType = UIKeyboardTypeNumberPad;
cell.isPickable = NO;
cell.valueLimitMin = 0;
cell.valueLimitMax = 1000;
if (((CTKRoom *)[_roomsArray objectAtIndex:indexPath.section]).heatedArea) {
cell.textField.text = [NSString stringWithFormat:#"%#", ((CTKRoom *)[_roomsArray objectAtIndex:indexPath.section]).heatedArea];
}
else cell.textField.text = #"";
break;
}
this part is example of setting properties to my cell
I solved my problem. The reason was
myTextField.rightViewMode = UITextFieldViewModeAlways;
In my case right view was necessary, so in case when it wasn't needed i set
myTextField.rightView.frame = CGRectMake(0, 0, 1, 0);
This is my solution for setting custom grouped table view cell backgrounds:
- (UIView *)top
{
if (_top) {
return _top;
}
_top = [[UIView alloc] init];
[_top setBackgroundColor:[UIColor blueColor]];
return _top;
}
// dot dot dot
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
NSInteger section = [indexPath section];
NSInteger row = [indexPath row];
NSInteger maxRow = [tableView numberOfRowsInSection:section] - 1;
if (maxRow == 0) {
[cell setBackgroundView:[self lonely]];
} else if (row == 0) {
[cell setBackgroundView:[self top]];
} else if (row == maxRow) {
[cell setBackgroundView:[self bottom]];
} else {
[cell setBackgroundView:[self middle]];
}
}
Obviously it doesn't work as expected which brings me here, but it does work when I don't use cached views:
UIView *background = [[UIView alloc] init];
if (maxRow == 0) {
[background setBackgroundColor:[UIColor redColor]];
} else if (row == 0) {
[background setBackgroundColor:[UIColor blueColor]];
} else if (row == maxRow) {
[background setBackgroundColor:[UIColor yellowColor]];
} else {
[background setBackgroundColor:[UIColor greenColor]];
}
[cell setBackgroundView:background];
UPDATE: After Jonathan pointed out that I can't use the same view for more than one cell, I decided to follow the table view model where it has a queue of reusable cells. For my implementation, I have a queue of reusable background views (_backgroundViewPool):
#implementation RootViewController {
NSMutableSet *_backgroundViewPool;
}
- (id)initWithStyle:(UITableViewStyle)style
{
if (self = [super initWithStyle:style]) {
_backgroundViewPool = [[NSMutableSet alloc] init];
UITableView *tableView = [self tableView];
[tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:#"Cell"];
}
return self;
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
// Return the number of sections.
return 6;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
if (section == 0) {
return 1;
}
return 10;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
[[cell textLabel] setText:[NSString stringWithFormat:#"[%d, %d]", [indexPath section], [indexPath row]]];
return cell;
}
#pragma mark - Table view delegate
- (void)tableView:(UITableView *)tableView didEndDisplayingCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
UIView *backgroundView = [cell backgroundView];
[_backgroundViewPool addObject:backgroundView];
}
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
NSInteger section = [indexPath section];
NSInteger row = [indexPath row];
NSInteger maxRow = [tableView numberOfRowsInSection:section] - 1;
UIColor *color = nil;
if (maxRow == 0) {
// single cell
color = [UIColor blueColor];
} else if (row == 0) {
// top cell
color = [UIColor redColor];
} else if (row == maxRow) {
// bottom cell
color = [UIColor greenColor];
} else {
// middle cell
color = [UIColor yellowColor];
}
UIView *backgroundView = nil;
for (UIView *bg in _backgroundViewPool) {
if (color == [bg backgroundColor]) {
backgroundView = bg;
break;
}
}
if (backgroundView) {
[backgroundView retain];
[_backgroundViewPool removeObject:backgroundView];
} else {
backgroundView = [[UIView alloc] init];
[backgroundView setBackgroundColor:color];
}
[cell setBackgroundView:[backgroundView autorelease]];
}
It works except when you scroll really fast. Some of the background views disappear! I suspect the background views are still being used in more than one cell, but I really don't know what's going on because the background views are supposed to be removed from the queue once it's reused making it impossible for the background view to be used in more than one visible cell.
I've been looking into this since I have posted this question. The current solutions for custom background views for grouped table view cells online are unsatisfactory, they don't used cached views. Additionally, I don't want to have use the solution proposed by XJones and jszumski because it's gonna get hairy once reusable custom cells (e.g., text field cell, switch cell, slider cell) are taken into account.
Have you considered using 4 separate cell identifiers for the "lonely, "top", "bottom", and "middle" cases and setting the backgroundView only once when initializing the cell? Doing it that way lets you leverage UITableView's own caching and reuse without having to write an implementation on top of it.
Update: An implementation for a grouped UITableViewController subclass that reuses background views with a minimal number of cell reuse identifiers (Espresso's use case). tableView:willDisplayCell:forRowAtIndexPath: and tableView:didDisplayCell:forRowAtIndexPath: do the heavy lifting to apply or reclaim each background view, and the pooling logic is handled in backgroundViewForStyle:.
typedef NS_ENUM(NSInteger, JSCellBackgroundStyle) {
JSCellBackgroundStyleTop = 0,
JSCellBackgroundStyleMiddle,
JSCellBackgroundStyleBottom,
JSCellBackgroundStyleSolitary
};
#implementation JSMasterViewController {
NSArray *backgroundViewPool;
}
- (void)viewDidLoad {
[super viewDidLoad];
// these mutable arrays will be indexed by JSCellBackgroundStyle values
backgroundViewPool = #[[NSMutableArray array], // for JSCellBackgroundStyleTop
[NSMutableArray array], // for JSCellBackgroundStyleMiddle
[NSMutableArray array], // for JSCellBackgroundStyleBottom
[NSMutableArray array]]; // for JSCellBackgroundStyleSolitary
}
#pragma mark - Table View
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 5;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
if (section == 2) {
return 1;
} else if (section == 3) {
return 0;
}
return 5;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
NSInteger section = indexPath.section;
NSInteger row = indexPath.row;
static NSString *switchCellIdentifier = #"switchCell";
static NSString *textFieldCellIdentifier = #"fieldCell";
static NSString *textCellIdentifier = #"textCell";
UITableViewCell *cell = nil;
// apply a cached cell type (you would use your own logic to choose types of course)
if (row % 3 == 0) {
cell = [tableView dequeueReusableCellWithIdentifier:switchCellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:switchCellIdentifier];
UISwitch *someSwitch = [[UISwitch alloc] init];
cell.accessoryView = someSwitch;
cell.textLabel.text = #"Switch Cell";
}
} else if (row % 3 == 1) {
cell = [tableView dequeueReusableCellWithIdentifier:textFieldCellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:textFieldCellIdentifier];
UITextField *someField = [[UITextField alloc] initWithFrame:CGRectMake(0, 0, 80, 30)];
someField.borderStyle = UITextBorderStyleRoundedRect;
cell.accessoryView = someField;
cell.textLabel.text = #"Field Cell";
}
} else {
cell = [tableView dequeueReusableCellWithIdentifier:textCellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:textCellIdentifier];
cell.textLabel.text = #"Generic Label Cell";
}
}
cell.selectionStyle = UITableViewCellSelectionStyleNone;
cell.textLabel.backgroundColor = [UIColor clearColor];
cell.detailTextLabel.text = [NSString stringWithFormat:#"[%d, %d]", section, row];
cell.detailTextLabel.backgroundColor = [UIColor clearColor];
return cell;
}
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
// apply a cached background view
JSCellBackgroundStyle backgroundStyle = [self backgroundStyleForIndexPath:indexPath tableView:tableView];
cell.backgroundView = [self backgroundViewForStyle:backgroundStyle];
}
- (void)tableView:(UITableView *)tableView didEndDisplayingCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
JSCellBackgroundStyle backgroundStyle = [self backgroundStyleForIndexPath:indexPath tableView:tableView];
NSMutableArray *stylePool = backgroundViewPool[backgroundStyle];
// reclaim the background view for the reuse pool
[cell.backgroundView removeFromSuperview];
if (cell.backgroundView != nil) {
[stylePool addObject:cell.backgroundView];
}
cell.backgroundView = nil; // omitting this line will cause some rows to appear without a background because they try to be in two superviews at once
}
- (JSCellBackgroundStyle)backgroundStyleForIndexPath:(NSIndexPath*)indexPath tableView:(UITableView*)tableView {
NSInteger maxRow = MAX(0, [tableView numberOfRowsInSection:indexPath.section] - 1); // catch the case of a section with 0 rows
if (maxRow == 0) {
return JSCellBackgroundStyleSolitary;
} else if (indexPath.row == 0) {
return JSCellBackgroundStyleTop;
} else if (indexPath.row == maxRow) {
return JSCellBackgroundStyleBottom;
} else {
return JSCellBackgroundStyleMiddle;
}
}
- (UIView*)backgroundViewForStyle:(JSCellBackgroundStyle)style {
NSMutableArray *stylePool = backgroundViewPool[style];
// if we have a reusable view available, remove it from the pool and return it
if ([stylePool count] > 0) {
UIView *reusableView = stylePool[0];
[stylePool removeObject:reusableView];
return reusableView;
// if we don't have any reusable views, make a new one and return it
} else {
UIView *newView = [[UIView alloc] init];
NSLog(#"Created a new view for style %i", style);
switch (style) {
case JSCellBackgroundStyleTop:
newView.backgroundColor = [UIColor blueColor];
break;
case JSCellBackgroundStyleMiddle:
newView.backgroundColor = [UIColor greenColor];
break;
case JSCellBackgroundStyleBottom:
newView.backgroundColor = [UIColor yellowColor];
break;
case JSCellBackgroundStyleSolitary:
newView.backgroundColor = [UIColor redColor];
break;
}
return newView;
}
}
#end
Although you could very easily get away with dumping all views into one reuse pool, it complicates some of the looping logic and this way is easier to comprehend.
First and foremost, I would check why this kind of caching is necessary. If it's a performance problem, I would check that the problem is indeed the views, and not something else like too many blended layers!
Regarding the caching, there are several approaches. At least three come to mind:
For each of the four backgrounds, register an own cell reuse identifier. Then set the background view depending on the reuse identifier.
Use an own cache for the background views, and reuse background views from there.
Use the same class for background views on all cells, and set the content on them only.
The first solution is quite easy to implement, but it holds the risk that the UITableView ends up holding lots of cells for reusing that are not needed. Also, if you need more types of cells, you would have to provide cells for each type/background combination.
While the second solution reuses cell backgrounds, you have to write an own cache for those, and to set/unset backgrounds where necessary.
The third solution only works if the background view can be configured to show the background for the respective cell. It would reuse the content only, not the background views themselves.
Here is an early screenshot of a test for the second solution:
Here is the implementation:
#implementation RootViewController
{
NSMutableDictionary *_backgroundViews;
}
- (void)viewDidLoad
{
_backgroundViews = [NSMutableDictionary dictionary];
[self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:#"Cell"];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 100;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return section / 10 + 1;
}
- (void)tableView:(UITableView *)tableView didEndDisplayingCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
cell.backgroundView = nil;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
cell.textLabel.backgroundColor = [UIColor clearColor];
if (!cell.backgroundView || ![cell.backgroundView isKindOfClass:[UIImageView class]]) {
NSInteger section = [indexPath section];
NSInteger row = [indexPath row];
NSInteger maxRow = [tableView numberOfRowsInSection:section] - 1;
NSString *imageName = nil;
UIEdgeInsets insets = UIEdgeInsetsZero;
if (maxRow == 0) {
// single cell
imageName = #"singlebackground";
insets = UIEdgeInsetsMake(12, 12, 12, 12);
} else if (row == 0) {
// top cell
imageName = #"topbackground";
insets = UIEdgeInsetsMake(12, 12, 0, 12);
} else if (row == maxRow) {
// bottom cell
imageName = #"bottombackground";
insets = UIEdgeInsetsMake(0, 12, 12, 12);
} else {
// middle cell
imageName = #"middlebackground";
insets = UIEdgeInsetsMake(0, 12, 0, 12);
}
NSMutableSet *backgrounds = [_backgroundViews objectForKey:imageName];
if (backgrounds == nil) {
backgrounds = [NSMutableSet set];
[_backgroundViews setObject:backgrounds forKey:imageName];
}
UIImageView *backgroundView = nil;
for (UIImageView *candidate in backgrounds) {
if (candidate.superview == nil) {
backgroundView = candidate;
break;
}
}
if (backgroundView == nil) {
backgroundView = [[UIImageView alloc] init];
backgroundView.image = [[UIImage imageNamed:imageName] resizableImageWithCapInsets:insets];
backgroundView.backgroundColor = [UIColor whiteColor];
backgroundView.opaque = YES;
}
cell.backgroundView = backgroundView;
}
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
[[cell textLabel] setText:[NSString stringWithFormat:#"[%d, %d]", [indexPath section], [indexPath row]]];
return cell;
}
If you would like to check it out, here are the images I used (non-retina only and too big, but hey, it's only an example):
singlebackground.png:
topbackground.png:
middlebackground.png:
bottombackground.png:
EDIT - using images as a background view
Given your comments on my answer it seems like you want to display images in the background view of your cells. It is not clear if these images are compiled into your app as resources or downloaded from a service. Regardless, you can use the same UIImage instance in multiple UIImageView instances. So as you create your cells, you can create a new UIImageView on the fly for use as the background view and then set the image property to the appropriate UIImage based on the cell's indexPath.
If the images are compiled into your app then [UIImage imageNamed:#""] uses an iOS implemented cache and will perform well. If you are downloading images (presumably on a background thread) then you will need to implement a disk and/or memory cache for your image data.
ORIGINAL ANSWER
When you configure your cell in tableView:cellForRowAtIndexPath: use the cell identifier to use the built-in caching of the tableView to cache cells with the various background views for you.
Something like:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *singleCellID = #"single";
static NSString *firstCellID = #"first";
static NSString *middleCellID = #"middle";
static NSString *lastCellID = #"last";
NSString *cellID = nil;
NSInteger section = [indexPath section];
NSInteger row = [indexPath row];
NSInteger maxRow = [tableView numberOfRowsInSection:section] - 1;
UIColor *color = nil;
if (maxRow == 0) {
// single cell
cellID = singleCellID;
} else if (row == 0) {
// top cell
cellID = firstCellID;
} else if (row == maxRow) {
// bottom cell
cellID = lastCellID;
} else {
// middle cell
cellID = middleCellID;
}
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellID forIndexPath:indexPath];
if (cell == nil) {
if (cellID == singleCellID) {
// create single cell
cell = ...
cell.backgroundView = ...
}
else if (cellID == firstCellID) {
// create first cell
cell = ...
cell.backgroundView = ...
}
else if (cellID == lastCellID) {
// create last cell
cell = ...
cell.backgroundView = ...
}
else {
// create middle cell
cell = ...
cell.backgroundView = ...
}
}
}
[EDIT]
Ok, so, as far as you use custom background view, I think you should assign your background view to cell's .backgroundView property in the tableView:cellForRowAtIndexPath: method and do not use your own views caching mechanism, because table view caches entire cell with all it's subviews - you assign background view when you create cell and later just update it's backgroundColor with proper value (in your case, based on index path).
Also, this is just a suggestion, your background view might be obscured with cell's other content (e.g. you added something to .contentView) - try setting cell / contentView .alpha value to 0.5 to be able to see through it. Code is still related - this method is called every time UITableView needs new cell to display on the screen
- (UITableViewCell*) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell* cell = nil;
static NSString* identifer = #"Cell";
cell = [tableView dequeueReusableCellWithIdentifier:identifer];
if(cell==nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identifer];
cell.backgroundView = [YourCustomView new];//assign your custom background view here
}
cell.textLabel.text = [NSString stringWithFormat:#"%d",indexPath.row];
//update background view's color based on index path row
if(indexPath.row==0)
cell.backgroundView.backgroundColor = [UIColor redColor];
else if(indexPath.row==1)
cell.backgroundView.backgroundColor = [UIColor yellowColor];
else
cell.backgroundView.backgroundColor = [UIColor blueColor];
return cell;
}
you can not use a view twice at the same time, which would occure when you have more than 3 cells. The reuising mechanism of the table should be sufficient enough.
I am not sure why u want to handle the backgroundViews seperatly from the cells.
Anyways, i altered your code so that there is no bug with missing backgroundViews:
NOTE! i did use ARC.
static NSString *identifierSingle = #"single";
static NSString *identifierTop = #"top";
static NSString *identifierBtm = #"btm";
static NSString *identifierMid = #"mid";
#implementation RootViewController {
NSMutableDictionary *_backgroundViewPool;
}
- (id)initWithStyle:(UITableViewStyle)style
{
if (self = [super initWithStyle:style]) {
_backgroundViewPool = [[NSMutableDictionary alloc] init];
UITableView *tableView = [self tableView];
[tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:#"cell"];
}
return self;
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
// Return the number of sections.
return 6;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
if (section == 0) {
return 1;
}
return 10;
}
- (NSString *)tableView:(UITableView *)tableView identifierForRowAtIndexPath:(NSIndexPath *)indexPath {
NSInteger section = [indexPath section];
NSInteger row = [indexPath row];
NSInteger maxRow = [tableView numberOfRowsInSection:section] - 1;
if (maxRow == 0) {
// single cell
return identifierSingle;
} else if (row == 0) {
// top cell
return identifierTop;
} else if (row == maxRow) {
// bottom cell
return identifierBtm;
} else {
// middle cell
return identifierMid;
}
}
- (UIColor *)tableView:(UITableView *)tableView colorForRowAtIndexPath:(NSIndexPath *)indexPath {
NSInteger section = [indexPath section];
NSInteger row = [indexPath row];
NSInteger maxRow = [tableView numberOfRowsInSection:section] - 1;
UIColor *color = nil;
if (maxRow == 0) {
// single cell
color = [UIColor blueColor];
} else if (row == 0) {
// top cell
color = [UIColor redColor];
} else if (row == maxRow) {
// bottom cell
color = [UIColor greenColor];
} else {
// middle cell
color = [UIColor yellowColor];
}
return color;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *colorIdentifier = [self tableView:tableView identifierForRowAtIndexPath:indexPath];
NSString *CellIdentifier = #"cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
[[cell textLabel] setText:[NSString stringWithFormat:#"[%d, %d]", [indexPath section], [indexPath row]]];
[[cell textLabel] setBackgroundColor:[UIColor clearColor]];
NSMutableSet *set = [self backgroundPoolForIdentifier:colorIdentifier];
UIView *backgroundView = [set anyObject];;
if (backgroundView) {
[set removeObject:backgroundView];
} else {
backgroundView = [[UIView alloc] init];
[backgroundView setBackgroundColor:[self tableView:tableView colorForRowAtIndexPath:indexPath]];
}
[cell setBackgroundView:backgroundView];
return cell;
}
#pragma mark - Table view delegate
- (NSMutableSet *)backgroundPoolForIdentifier:(NSString *)identifier {
NSMutableSet *set = [_backgroundViewPool valueForKey:identifier];
if (!set) {
set = [[NSMutableSet alloc] init];
[_backgroundViewPool setValue:set forKey:identifier];
}
return set;
}
- (void)tableView:(UITableView *)tableView didEndDisplayingCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
[[self backgroundPoolForIdentifier:cell.reuseIdentifier] addObject:cell.backgroundView];
}
#end
Your original implementation didnt work because in cellForRowAtIndexPath: you sometimes returning a nil object. UITableView framework then passes that *cell object to willDisplayCell:(UITableViewCell*).
ie:
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
....
return cell;
// cell maybe nil
If you do indeed perfer using your own caching mechanism, you can simply return a plain UITableViewCell object, dequeued if available or create a new one if none is available for reuse.
ie:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
return [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath]
|| [UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier]
;
}
Then, there is the "view can only be added to 1 superview limit" causing your cached view to appear jumping.
Tried several things to do this but finally got satisfied on this very basic solutions, i know it's not really a charming one but it gave me smooth scrolling, you can try this if you like:
NSMutableArray *_viewArray;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
#define kTotalNoOfRows 1000
_viewArray = [[NSMutableArray alloc] initWithCapacity:kTotalNoOfRows];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
for (int i = 0; i < kTotalNoOfRows; i++) {
UIView * backGroundView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];
if (kTotalNoOfRows == 0)
[backGroundView setBackgroundColor:[UIColor redColor]];
else if (i == 0)
[backGroundView setBackgroundColor:[UIColor greenColor]];
else if (i == (kTotalNoOfRows - 1))
[backGroundView setBackgroundColor:[UIColor blueColor]];
else
[backGroundView setBackgroundColor:[UIColor yellowColor]];
[_viewArray addObject:backGroundView];
}
return kTotalNoOfRows;
}
- (UITableViewCell*) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell* cell = nil;
static NSString* middleCell = #"middleCell";
cell = [tableView dequeueReusableCellWithIdentifier:middleCell];
if(cell==nil) {
NSInteger maxRow = [tableView numberOfRowsInSection:indexPath.section] - 1;
if (maxRow != 0 && indexPath.row != 0 && indexPath.row != maxRow) {
middleCell = nil;
}
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:middleCell];
cell.backgroundView = [_viewArray objectAtIndex:indexPath.row];//assign your custom background view here
[cell.textLabel setBackgroundColor:[UIColor clearColor]];
}
cell.textLabel.text = [NSString stringWithFormat:#"%d",indexPath.row];
return cell;
}
Also I would like to mention my journey towards here; So what I have tried is
created a dictionary of Views:
UIView * _topView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];
UIView * _bottomView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];
UIView * _middleView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];
UIView * _lonelyView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];
[_topView setBackgroundColor:[UIColor redColor]];
[_bottomView setBackgroundColor:[UIColor greenColor]];
[_middleView setBackgroundColor:[UIColor blueColor]];
[_lonelyView setBackgroundColor:[UIColor yellowColor]];
_viewDictionary = [NSDictionary dictionaryWithObjectsAndKeys:
_topView, #"topView",
_bottomView, #"bottomView",
_middleView, #"middleView",
_lonelyView, #"lonelyView", nil];
returned copy of these view with unarchiver
- (UIView *) getBackgroundViewWith : (NSInteger) maxRow currentRow : (NSInteger) row{
if (maxRow == 0) {
return (UIView *)[NSKeyedUnarchiver unarchiveObjectWithData:[NSKeyedArchiver archivedDataWithRootObject:[_viewDictionary valueForKey:#"lonelyView"]]];//[[_viewDictionary valueForKey:#"lonelyView"] copy];
} else if (row == 0) {
return (UIView *)[NSKeyedUnarchiver unarchiveObjectWithData:[NSKeyedArchiver archivedDataWithRootObject:[_viewDictionary valueForKey:#"topView"]]];//[[_viewDictionary valueForKey:#"topView"] copy];
} else if (row == maxRow) {
return (UIView *)[NSKeyedUnarchiver unarchiveObjectWithData:[NSKeyedArchiver archivedDataWithRootObject:[_viewDictionary valueForKey:#"bottomView"]]];//[[_viewDictionary valueForKey:#"bottomView"] copy];
} else {
return (UIView *)[NSKeyedUnarchiver unarchiveObjectWithData:[NSKeyedArchiver archivedDataWithRootObject:[_viewDictionary valueForKey:#"middleView"]]];//[[_viewDictionary valueForKey:#"middleView"] copy];
}
return nil;
}
But it crash, while scrolling table with SIGBART. Thus gave up with this.
It's been a while since I've worked with tableviews, but I vaguely recall running into this problem. I believe the calls to the tableView:willDisplayCell:forRowAtIndexPath: method are threaded. When the user scrolls very fast multiple calls can get out simultaneously. In that case, given your current code, it is possible for multiple cells to get assigned the same view which will then cause the blank spaces.
If you use #synchronized(anObject){} to prevent multiple threads from running the same code simultaneously, you should be able to prevent the problem.
#synchronized (self) {
UIView *backgroundView = nil;
for (UIView *bg in _backgroundViewPool) {
if (color == [bg backgroundColor]) {
backgroundView = bg;
break;
}
}
if (backgroundView) {
[backgroundView retain];
[_backgroundViewPool removeObject:backgroundView];
} else {
backgroundView = [[UIView alloc] init];
[backgroundView setBackgroundColor:color];
}
}
According to my understanding of apple docs, when a cell is dequeued, it still has all it's views and settings you previously set.
Therefore, if you set a background view to cell it would still be there when it's dequeued and if it's a new cell it won't have background view.
I believe you don't need the background view pool since the OS handles that for you, so you can just reuse the BG view as you reuse the cell and do something like that in willDisplayCell: only
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
NSInteger section = [indexPath section];
NSInteger row = [indexPath row];
NSInteger maxRow = [tableView numberOfRowsInSection:section] - 1;
UIColor *color = nil;
if (maxRow == 0) {
// single cell
color = [UIColor blueColor];
} else if (row == 0) {
// top cell
color = [UIColor redColor];
} else if (row == maxRow) {
// bottom cell
color = [UIColor greenColor];
} else {
// middle cell
color = [UIColor yellowColor];
}
UIView *backgroundView = nil;
//***This is the different part***//
if (cell.backgroundView != nil) {
NSLog(#"Old Cell, reuse BG View");
backgroundView = cell.backgroundView;
} else {
NSLog(#"New Cell, Create New BG View");
backgroundView = [[UIView alloc] init];
[cell setBackgroundView:[backgroundView autorelease]];
}
[backgroundView setBackgroundColor:color];
}
Like that there is no need for the code didEndDisplayingCell: as well.
I want to create a view like this in my iPhone App:
I do not know exactly what is this control in iOS, that maybe I can set an icon and text in the left side and that small sign in the right side.
I have implemented a TableView, there I was able to set these stuff, like this:
[[cell textLabel] setText:customer.name];
[[cell textLabel] setTextColor:[UIColor blackColor]];
[[cell imageView] setImage:[UIImage imageNamed:#"icon.png"]];
//[[cell detailTextLabel] setText:#"Awsome weather idag"];
cell.accessoryView = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
But how can I make it works like that view in the picture?
It is pretty simple, follow the steps below and in case of doubts check out the UITableView documentation:
1. Create a grouped table view:
Programmatically:
CGRect tableFrame = CGRectMake(0, 0, 200, 200);
UITableView *tableView = [[UITableView alloc] initWithFrame:tableFrame style:UITableViewGroupedStyle];
tableView.delegate = self;
tableView.dataSource = self;
[self.view addSubview:tableView];
Allocating a UITableViewController subclass (common case):
MyTableViewController *controller [[MyTableViewController alloc] initWithStyle: UITableViewGroupedStyle];
[self.navigationController pushViewController:controller animated:NO];
Through Interface Build:
Expand the Utilities Menu (top right corner icon);
Select your table view (click on it);
Click on the attributes inspector (top right corner fourth icon);
Under Table View, click on the style dropdown and select grouped.
2. Implement the UITableViewDataSource protocol:
Basically add this three functions to your controller.
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
// Return the number of sections.
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
// Return the number of rows in a given section.
return 5;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
// Configure the cells.
return cell;
}
3. Configuring the cells:
The default style of a UITableViewCell has an image view (UIImageView), a title label (UILabel) and an accessory view (UIView). All you need to replicate the table view in the image you provided.
So, you're looking for something like this in tableView:cellForRowAtIndexPath::
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString * const cellIdentifierDefault = #"default";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifierAccount];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifierAccount];
}
if (indexPath.section == 0) {
cell.imageView.image = [UIImage imageName:#"bluetooth_icon"];
cell.textLabel.text = #"Bluetooth";
// Additional setup explained later.
}else{
if (indexPath.row == 0) {
cell.imageView.image = [UIImage imageName:#"general_icon"];
cell.textLabel.text = #"General";
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
}else{
cell.imageView.image = [UIImage imageName:#"privacy_icon"];
cell.textLabel.text = #"Privacy";
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
}
}
return cell;
}
The property accessoryType defines what is going to appear on the right side of a cell, a list of accessory types can be found here.
In the first cell (bluetooth), you'll need to create a custom accessory view and assign it to the cell's accessoryView property. A very naive example of how to achieve this is given below:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString * const cellIdentifierDefault = #"default";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifierAccount];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifierAccount];
label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 100, 44)];
label.textAlignment = NSTextAlignmentRight;
cell.accessoryView = label;
}else{
label = (UILabel *) cell.accessoryView;
}
cell.imageView.image = [UIImage imageName:#"bluetooth_icon"];
cell.textLabel.text = #"Bluetooth";
label.text = #"Off";
return cell;
}
Hope this helps, Mateus
For fast output, you can use some library like
https://github.com/escoz/QuickDialog
protip, in my experience, solutions like this leaves you more tangled when Changes come in.
Some times you only want to change one specific label on once specific view, thats not gona be easy in any ready-made solution.
Look into UITableView Sections. That is what separates the groups apart.