First, i have a slide application, there i have a tableview.
By tapping a cell "CellInMainMenu" in the main menu, application opens tableview "TV1" by push, and cells in this tableview("TV1") fill with data by an array. When i slide this tableview("TV1") to side, and tapps again on a cell "CellInMainMenu", application opens again tableview("TV1"), but! Tableview("TV1") starts AGAIN to fill cells with information! How to make application load all data by once at starting application?
(I'm really sorry for my English, because it's not my language)
Can somebody help me?
Code in "TV1":
- (void)viewDidLoad
{
[super viewDidLoad];
daoDS = [[SampleDataDAO alloc] init];
self.ds = daoDS.PopulateDataSource;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"TV1CellId";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if(cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier];
}
SampleData *sample = [self.ds objectAtIndex:indexPath.row];
cell.textLabel.text = sample.HeroesName;
cell.textLabel.textColor = [UIColor whiteColor];
cell.textLabel.font = [UIFont fontWithName:#"Trajan-Regular" size:18.0f];
return cell;
}
(All appliction works fine, i just want to know how to make just one load but not every time)
The problem is not your table view code, but how you push it. If you invoke a segue, it will always create a new one.
Instead you could only push it the first time, keep a reference to it and then update it based on a selection of your menu. Some custom delegate #protocol is likely the best pattern for this.
Related
I am doing using some code that I have seen work before. Essentially a user answers yes or no on a post with some buttons. Pressing yes or no updates the database, which is working correctly, and it also updates the visible UI, which is not working. This UI updates the buttons so they one is selected, other is highlighted and both are disabled for user interaction. Also it makes changes to two UILabels. The method that these buttons calls needs to update the database and retrieve the buttons from the tableViewCell and update the changes I have the methods working in another ViewController so I can not understand the difference here. Here is my cellForRowAtIndexPath
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *simpleTableIdentifier = [NSString stringWithFormat:#"%ld,%ld",(long)indexPath.section,(long)indexPath.row];
NSLog(#" simple: %#",simpleTableIdentifier);
if (indexPath.row==0) {
ProfileFirstCell *cell = [self.tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];
if (cell == nil)
{
cell = [[ProfileFirstCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:simpleTableIdentifier];
}
cell = [self createProfileCell:cell];
return cell;
}else{
YesNoCell *cell =[self.tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];
if (cell==nil) {
cell=[[YesNoCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:simpleTableIdentifier];
}
cell = [self createYesNoCell:cell:indexPath];
return cell;
}
}
Essentially what this does is create the users profile in the first cell, and load all the questions that user asks. This is the major difference I see between the old tableView and this tableView. In createYesNoCell I create the UIElements and create tags as follows
cell.yesVoteButton.tag=indexPath.row+ yesVoteButtonTag1;
cell.noVoteButton.tag=indexPath.row+ noVoteButtonTag1;
cell.yesCountLabel.tag=indexPath.row+ yesCountLabelTag1;
cell.noCountLabel.tag=indexPath.row+ noCountLabelTag1;
The buttons have the selector that initiates a number of things. It finds which button was pressed by the following.
NSInteger index;
if(sender.tag>=yesVoteButtonTag1){
NSLog(#"Yes button pressed");
votedYes=true;
index=sender.tag-yesVoteButtonTag1;
}else{
NSLog(#"No button Pressed");
votedYes=false;
index=sender.tag-noVoteButtonTag1;
}
UILabel *yesLabel = (UILabel*) [self.tableView viewWithTag:index+yesCountLabelTag1]; // you get your label reference here
UIButton *yesButton=(UIButton *)[self.tableView viewWithTag:index+1+yesVoteButtonTag1];
NSLog(#"Tag IN METHOD: %ld",index+yesVoteButtonTag1);
UILabel *noLabel = (UILabel*) [self.tableView viewWithTag:index+1+noCountLabelTag1]; // you get your label reference here
UIButton *noButton=(UIButton *)[self.tableView viewWithTag:index+noVoteButtonTag1];
These viewWithTag calls are nil when I look at them. The only difference that I can see from my earlier implementation is that the old one had sections and one row, while this one is all rows and one section. So replacing the indexPath.section with indexPath.row should account for that. Also I checked that the tag made in cellForRowAtIndexPath is the same as the row recovered in the yes/no vote method, because it is displaced by one because of the profile cell being created at indexPath.row==0. I tried passing the cell to the yes/no vote method and tried to recover the buttons and labels with contentView as some suggestions made on similar posts. However this didn't seem to solve my problem. Really would appreciate some insight on this.
have you call the '[tableView reload]' method to update the UITableView, it may helps.
Firstly, the table reuse identifier should be used for types of cells, not one for each cell. You have two types, so you should use two fixed reuse identifiers.
ProfileFirstCell *cell = [self.tableView dequeueReusableCellWithIdentifier:#"ProfileCell"];
if (cell == nil) {
cell = [[ProfileFirstCell alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:#"ProfileCell"];
}
and
YesNoCell *cell =[self.tableView dequeueReusableCellWithIdentifier:#"YesNoCell"];
if (cell==nil) {
cell=[[YesNoCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"YesNoCell"];
}
Secondly, rather than trying to get a reference to a cell after creating the table, which isn't working for you, you should initialize the cells completely when they are created. (TableView won't create cells unless they're visible, so you shouldn't rely on their existing at all.)
createProfileCell should really be called initializeProfileCell, because you're not creating the cell in it - you already did that in the line above, or recovered an old one.
Then your call to initializeProfileCell can take a flag specifying whether it is a Yes or No cell and set its properties accordingly.
cell = [self initializeProfileCell:cell isYes:(indexPath.section==0)];
Similarly with createYesNoCell --> initializeYesNoCell.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"YOURCELL_IDENTIFIER";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
UILabel *title = (UILabel*) [cell viewWithTag:5];
UILabel *vensu =(UILabel*) [cell viewWithTag:7];
vensu.text = #"YOUR TEXT";
title.text = #"YOUR TEXT";
return cell;
}
I'm learning The development of iOS ,and I have a question .I can't debug it ,Google can’t give me answer.
Maybe I did not find a right way.
This question is when I create UITableViewCell objects and I reuse them ,and these cells are stored in a MutableArray, when I reuse cells from Buffer pool ,and get the value from the MutableArray, but the value of textLable.text is not right .
my code :
-(UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
static NSString * timeRing = #"ring";
UITableViewCell * cell = [tableView dequeueReusableCellWithIdentifier:timeRing];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:timeRing];
}else{
while ([cell.contentView.subviews lastObject]!=nil) {
[[cell.contentView.subviews lastObject] removeFromSuperview];
}
}
cell.accessoryType = UITableViewCellAccessoryNone;
if (self.cellArray.count<self.ringArray.count) {
self.timeRingItem = self.ringArray[indexPath.row];
cell.tintColor = [UIColor redColor];
cell.textLabel.text= self.timeRingItem.ringName;
[self.cellArray addObject:cell];
}
else{
cell = self.cellArray[indexPath.row];
}
return cell;
}
when the code run to cell = self.cellArray[indexPath.row]; ,the cell.textLable.text is wrong
so why? thanks for giving me answer.
The nature of a tableview means that cells will be re-used. When the user scrolls, it's going to take the top cell that just disappeared, and use it for the new cell. If you want to reference data, you need to keep the data in a separate array that's independent from the cells.
Edit 1
To be clear, [self loadObjects] is not my method it is a method on the PFQueryTableViewController class supplied by parse to pull in new data.
I suspect this might be being caused by the table drawing code, as the tablecellview is configured to be auto-adjust it's height.
Here is the table drawing code:
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
object:(PFObject *)object
{
//Setup estimated heights and auto row height
self.tableView.estimatedRowHeight = 68.0;
self.tableView.rowHeight = UITableViewAutomaticDimension;
//Give the cell a static identifier
static NSString *cellIdentifier;
socialPost* post = object;
//Check to see what sort of cell we should be creating, text, image or video
if (object[#"hasImage"] != nil) {
cellIdentifier = #"posts_with_image";
} else {
cellIdentifier = #"posts_no_image";
}
//Create cell if needed
hashtagLiveCellView *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (!cell) {
cell = [[hashtagLiveCellView alloc] initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:cellIdentifier];
}
// Configure the cell to show our imformation, loading video and images if needed
cell.postTitle.text = [NSString stringWithFormat:#"#%#",object[#"userName"]];
cell.postText.text = [NSString stringWithFormat:#"%#",
object[#"text"]];
[cell.userImage setImageWithURL:[NSURL URLWithString:post.userImageURL]];
[cell.postImage setImageWithURL:[NSURL URLWithString:post.imageURL]];
//Set ID's on the custom buttons so we know what object to work with when a button is pressed
cell.approveButtonOutlet.stringID = object.objectId;
[cell.approveButtonOutlet addTarget:self action:#selector(approvePostCallback:) forControlEvents:UIControlEventTouchUpInside];
cell.deletButtonOutlet.stringID = object.objectId;
[cell.deletButtonOutlet addTarget:self action:#selector(deletePostCallback:) forControlEvents:UIControlEventTouchUpInside];
return cell;
}
Original
I have a PFQueryTableViewController that i am loading with object from parse.
I have a scheduled task set to run every 20 seconds that calls:
[self loadObjects]
To fetch any new objects, or any changed to objects that have happened.
That all works fine, however if i am scrolled halfway down the tableview when the loadObjects is called the page jumps back to the top. Even if there are no new or changed data available.
Is there an easy way around this, before i start looking into hacky ways to catch the reload and force the table to stay where it is.
Thanks
Gareth
When you're calling loadObjects you load the objects from start. And there for you get the first results again.
Try to change [self loadObjects]; to [self.tableView reloadData];.
I have a custom class that extends UITableViewCell. It has two labels and a UISegmentedControl.
Here is the cellForRowAtIndexPath() that I configured. When I inspect "cell" in the debugger it has all the data I'm providing. But somehow that data never gets applied.
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"MyCell";
CustomGameCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (!cell) {
cell = [[CustomGameCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
MyData *my_data = [rows objectAtIndex:indexPath.row];
UILabel *my_date = [[UILabel alloc] init];
my_date.text = my_data.myDate;
[cell setMyDateLabel:my_date];
UILabel *my_question = [[UILabel alloc] init];
my_question.text = my.question;
[cell setMyQuestionLabel:my_question];
UISegmentedControl *my_choices = [[UISegmentedControl alloc]
initWithItems:[NSArray arrayWithObjects:my.firstChoice, my.secondChoice, nil]];
[my_choices setSelectedSegmentIndex:my.choice];
[cell setMyChoiceSegments:my_choices];
return cell
}
The data that I want displayed is currently in an array I create in viewDidLoad() which is accessible to cellForRowAtIndexPath() through the "rows" var.
When I run the code in the simulator I get three rows in the table representing the three elements in the array I created in viewDidLoad(). However, the content of those rows look exactly like what I defined in the storyboard.
What am I missing?
Where are you defining the layout of your cell? In a NIB? In your storyboard? Programmatically in your initWithStyle of CustomGameCell? The implementation details vary a little based upon which approach you use, but you definitely need to either define NIB or prototype cell in your storyboard, or programmatically create the controls, set their frames, perform addSubview so they're included in the cell, etc.
Your code is adding new UILabel objects, not adding them as a subview to anything, doing it regardless if you're using a dequeued cell or not, etc. So there are numerous problems here. To see examples of how you might properly use a custom cell, see Customizing Cells in the Table View Programming Guide. But, like I said, the details vary a bit based upon how you're designing your subclassed UITableViewCell layout, so I hesitate to propose any code until you specify how you're designing your user interface.
You must have added the labels and segmentcontrol in the cells content view of the cell, if not then please do so.
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"MyCell";
CustomGameCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (!cell) {
cell = [[CustomGameCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
MyData *my_data = [rows objectAtIndex:indexPath.row];
cell.myDateLabel.text = my_data.myDate;
cell.myQuestionLabel.text = my.question;
[cell.myChoiceSegments setSelectedSegmentIndex:my.choice];
[cell autorelease];
return cell
}
Also use autorelease for the memory management.
Hi Guys I am creating a iOS(Universal) application.
My problem is that in my application there is a UITableView that works fine if the application doesn't goes to background(By pressing home button or by clicking a URL link).
If the application goes into the background, when it gets active, reloading a cell or the whole table view crashes the whole application.
Any Solution???
Is removing the dequeueReusableCellWithIdentifier: will make some difference??
The code is :
- (UITableViewCell *)tableView:(UITableView *)tableView1 cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *identifier = #"Cell";
UITableViewCell *cell = [tableView1 dequeueReusableCellWithIdentifier:identifier];
if(cell == nil){
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identifier];
}
Animation *animation = [animationArray objectAtIndex:indexPath.row];
cell.textLabel.text = animation.title;
if(animation.isAnimationEnabled){
cell.imageView.image = OnImage;
}else {
cell.imageView.image = OffImage;
}
return cell;
}
You have to make sure all the view controllers in your app can survive arbitrary number of cycles of view load/view unload. Check whether you remove something in viewDidUnload that is used in viewDidLoad.