How to swap between UIViews inside a UIViewController? - ios

Question

I have created 8 UIViews, I have a UIPicker and when the user selects something with the UIPicker I run the thread though a big if statement which I am not happy about.
I would like to know if what I am doing is okay? and also if the code I am using to load the view is how it should be done.. the code is below you will see I am simply loading the UIView once, then bringing it to the front layer... I would rather reload it entirely using remove from subview... but I couldn't get that to work..
Any one of the UIViews can be loaded at one time which is what is causing me issue.
#pragma mark - Picker Delegates
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
// ReloadView
if (row == 0) {
if (my1View == nil ) {
[self DrawView1];
}
[self.view bringSubviewToFront:my1View];
} else if (row == 1) {
if (my2View == nil ) {
[self DrawView2];
}
[self.view bringSubviewToFront:my2View];
}else if (row == 2) {
if (my3View == nil ) {
[self DrawView3];
}
[self.view bringSubviewToFront:my3View];
}else if (row == 3) {
if (my4View == nil ) {
[self DrawView4];
}
[self.view bringSubviewToFront:my4View];
}else if (row == 4) {
if (my5View == nil ) {
[self DrawView5];
}
[self.view bringSubviewToFront:my5View];
}else if (row == 5) {
if (my6View == nil ) {
[self DrawView6];
}
[self.view bringSubviewToFront:my6View];
}else if (row == 6) {
if (my7View == nil ) {
[self DrawView7];
}
[self.view bringSubviewToFront:my7View];
}else if (row == 7) {
if (my8View == nil ) {
[self DrawView8];
}
[self.view bringSubviewToFront:my8View];
}
}
The only other issue is that sometimes it will get stuck on one view when no matter what I pick nothing will load over it.

Answer 1

First of all, maybe to make it more beautiful you could think about a switch statement, but in terms of performance this doesn't matter:
switch (row) {
case 0:
if (my1View == nil ) {
[self DrawView1];
}
[self.view bringSubviewToFront:my1View];
break;
case 1:
if (my1View == nil ) {
[self DrawView2];
}
[self.view bringSubviewToFront:my2View];
break;
//THE OTHER CASES HERE...
default:
break;
}
About the rest:
I would suggest you put all the views into an array or dictionary and also have a variable currentView
#property (nonatomic, strong) UIView* currentView;
#property (nonatomic, strong) NSMutableDictionary* myViews;
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
// ReloadView
UIView* myNewView =
[self.myViews objectForKey:[NSString stringWithFormat:#"%d",(int)row]];
if (myNewView!=self.currentView) {
[self.currentView removeFromSuperview];
}
if (!myNewView) {
[self drawView:row];
}
[self.view addSubview:myNewView];
self.currentView = myNewView;
}
Make sure to initiate the myViews property in your viewDidLoad (or something similar) like this:
self.myViews = [NSMutableDisctionary new];
Also you need a new method for this row: [self drawView:row];, in this one you can just call your existing methods or copy your existing methods into this one!
In order to change as little as possible, you can use:
- (void)drawView:(NSInteger)row
{
switch (row) {
case 0:
[self DrawView1];
break;
case 1:
[self DrawView2];
break;
//THE OTHER CASES HERE...
default:
break;
}
}

Answer 2

I have an app that has a place-holder UIView (self.mainView) for viewControllers to be placed based on a tab selection. Using this technique is good because then only 1 of the views is loaded at any time, and I can create a ViewController class that operates with that view instead of having a monolithic controller that needs to understand all the views that may be in that place.
Here is some sample code I use to show the appropriate viewController into that place holder.
#property (weak, nonatomic) IBOutlet UIView *mainView;
#property (strong) UIViewController *currentController;
if (self.currentController) {
[self.currentController willMoveToParentViewController:nil];
[[self.currentController view] removeFromSuperview];
[self.currentController removeFromParentViewController];
self.currentController = nil;
}
switch (row) {
case 0:
self.currentController = [self.storyboard instantiateViewControllerWithIdentifier:#"AboutViewController"];
break;
case 1: {
...
}
break;
}
if (self.currentController) {
[self addChildViewController:self.currentController];
[self.mainView addSubview:self.currentController.view];
[self.currentController didMoveToParentViewController:self];
[self adjustMainView]; // my own method to adjust some constraints base on flags
[self.view layoutIfNeeded];
}

Answer 3

I developer your project and I can't see a problem in your code. Works fine. There is no problem in the code that you are showing. Maybe you should share more code to check it.
I tried to follow your style, however I changed small things.
You can found the project I created to test your code here.