adding UIView to UIViewController - iphone

I need to add a Button or a label to a UIView and add it to my UIViewController. I did the following but it only crashed the program.
UIView *myview = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 0, 300)] ;
[myview addSubview:myButton];
[self.view addSubview:myView];
The code crashes. Why is that?

You set your myview's width to 0.
You sure you created "myButton"?
You create myview but you add my*V*iew as subview. Is there any warning?

The first step you need to take is:
Make Sure you have allocated & initialized UIButton object with "initWithFrame" method.
provide a width to your UIView in "initWithframe" method, So that it can be seen.
Now use your [self.view addSubview:myView];
Please let me know if it is useful.

Use:
//Assuming that myview should have the size of the main view:
UIView *myview = [[UIView alloc] initWithFrame:self.view.bounds];
[myview addSubview:myButton]; //Whatever ...
[self.view addSubview:myview]; //There was a typo in this line

If this code block is in the init or loadView of viewcontroller, this will crash.
Make sure you have created a view for view controller in this case before adding views to self.view
UIView *aView = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
self.view = aView;
[aView release];
myButton = [[UIButton alloc] init....
.....
UIView *myView = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 0, 300)] ;
[myView addSubview:myButton];
[self.view addSubview:myView];

Try updating the view with the following:
[myview setNeedsDisplay];
and remove the second call to addSubView (which is probably causing the crash):
[self.view addSubview:myView];

Related

Adding UIScrollView to view and sending it to the back

I have added few UI components using Storyboard (UILabel, UIImageView). I am trying to put UIScrollView in this view, below all other elements:
Here is my code right at the end of -viewWillAppear method (code from my View Controller):
UIScrollView *scroll = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
scroll.contentSize = CGSizeMake(320, 480);
scroll.showsVerticalScrollIndicator = YES;
[self.view addSubview:scroll];
[self.view sendSubviewToBack:scroll];
The reason why I need a UIScrollView is large amount of text in detailsLabel - I'm attaching code I use for handling this label programatically:
detailsLabel.text = #"Some long text taken from databse";
[detailsLabel sizeToFit];
detailsLabel.numberOfLines = 0;
detailsLabel.lineBreakMode = UILineBreakModeWordWrap;
What I am doing wrong? How do I put UIScrollView below all other elements of my main view?
Try this:
UIScrollView *scroll = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
scroll.contentSize = CGSizeMake(320, 480);
scroll.showsVerticalScrollIndicator = YES;
[self.view insertSubview:scroll atIndex:0];
...
[self.view insertSubview:detailsLabel atIndex:1];
Put your code in ViewDidLoad . Then add the labels after you have added the UIScrollView to the self.View in the ViewDidLoad itself. So by default the UIScrollView would be added on the self.View and then your label. Now you can either add the label on the scrollview or onto the self.view .
I've followed the instructions in this answer and it worked great: I've changed the Custom Class in Identity Inspector from UIView to UIScrollView and added this line to my -viewDidLoad in the View Controller file:
[(UIScrollView *)self.view setContentSize:CGSizeMake(320, 700)];
Option One:
Declare detailsLabel in .h:
IBOutlet UILabel * detailsLabel; // MAP IT WITH NIB or STORYBOARD
give it property and Synthesise in .m.
here in viewDidLoad declare:
UIScrollView *scroll = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
scroll.contentSize = CGSizeMake(320, 480);
scroll.showsVerticalScrollIndicator = YES;
[self.view addSubview:scroll];
[self.view sendSubviewToBack:scroll];
[scroll addSubview:detailsLabel];
// IT SHOULD WORK.
Option two:
If you have large amount of text to display, then you can also use UITextView, it has inbuilt scrollview. And you can also set its text edit property.

UIActivityIndicatorView in an UIScrollview

I have a full screen UIScrollView to display my image. An UIActivityIndicatorView is added to the UIScrollView, it spinning well, but how could i make it always spinning in the middle of the screen while I am scrolling, zooming, rotating?
If you add the UIActivityIndicatorView directly to the scroll view it will scroll with the scroll view. But, if you add it to the parent of the scroll view it will remain where it was placed. So, the solution is to add it to the parent of the scroll view.
Notes:
I would recommend having a UIViewController in your window, and then adding these both to the UIViewController.
See the discussion here about adding views directly to your window:
View Controller being sent a message even though it has been deallocated
In ur .h file
UIView *primaryImage;
UIView *secondaryImage;
UIActivityIndicatorView *indicator;
In ur .m file
-(void)indicatorView
{
primaryImage = [[UIView alloc] initWithFrame:CGRectMake(0,0,320,480)];
primaryImage.backgroundColor = [UIColor blackColor];
primaryImage.alpha =0.5;
//[self.view.superview insertSubview:primaryImage aboveSubview:self.view.superview];
//[theTableView addSubview:primaryImage];
[self.view addSubview:primaryImage];
secondaryImage = [[UIView alloc] initWithFrame:CGRectMake(127.50,215,65,50)];
secondaryImage.backgroundColor = [UIColor blackColor];
secondaryImage.alpha = 0.9;
secondaryImage.layer.cornerRadius = 12;
[primaryImage addSubview:secondaryImage];
indicator = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(30, 25, 25, 25)];
indicator.center = CGPointMake(32, 25);
//[indicator hidesWhenStopped];
[indicator startAnimating];
[secondaryImage addSubview:indicator];
}
-(void)dismissCoverImageView {
[indicator stopAnimating];
[indicator removeFromSuperview];
[secondaryImage removeFromSuperview];
[primaryImage removeFromSuperview];
}
and after that you can call [self indicatorView];
and [self dismissCoverImageView];
Define the UIScrollViewDelegate of your UIScrollView. And in the delegate method –(void)scrollViewDidScroll:(UIScrollView *)scrollView change the frame of UIActivityIndicator object.

Subviews in UIView Hierarchy not displaying subviews

When this Action is executed it displays totally black view screen with toolbar
- (void)displayviewsAction:(id)sender
{
self.view = [[[UIView alloc] initWithFrame:[[UIScreen mainScreen] bounds]]autorelease];
self.view.frame = CGRectMake(0, 0, 320, 480);
[self.view addSubview:toolbar];
UIView *viewController = [[UIView alloc] init];
UIView *secondController = [[UIView alloc] init];
[self.view insertSubview:viewController atIndex:1];
[self.view insertSubview:secondController atIndex:2];
NSLog(#"%d", [[self.view subviews] indexOfObject:viewController]); // Is 1
NSLog(#"%d", [[self.view subviews] indexOfObject:secondController]); // Is 2
[self.view bringSubviewToFront:viewController];
NSLog(#"%d", [[self.view subviews] indexOfObject:viewController]);
[self.view sendSubviewToBack:viewController];
NSLog(#"%d", [[self.view subviews] indexOfObject:viewController]);
[self.view bringSubviewToFront:secondController];
NSLog(#"%d", [[self.view subviews] indexOfObject:secondController]);
SecondViewController * secondController = [[[SecondViewController alloc] init]autorelease];
secondController.view.frame = CGRectMake(0, 0, 320, 480);
[self.view addSubview:secondController.view];
[self.view addSubview:toolbar];
}
Any ideas why the view is appearing as totally black with toolbar.
The default background color of views is nil, which is a transparent background.
If you have nothing in any of the views and set no background color for any of them, the default background of the window or the device will show through. I didn't see it in the documentation, but I am assuming it is black.
Also, you have defined UIView pointers, but named them with the word "controller". This can contribute to mistakes since a UIViewController is an entirely different object. The UIViewController contains a UIView and interacts with it, but it is not a UIView, nor does it inherit from one.

Why am i getting a black frame and not the picker?

I have this very simple code or at least i think it's simple.
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
CGRect rect = CGRectMake(0.0f, 20.0f, 320.0f, 216.0f);
UIPickerView *myPickerView = [[UIPickerView alloc] initWithFrame:rect];
self.view = myPickerView;
[myPickerView release];
}
I am running a general View Based template with XCode. I can see the loadView getting called but i get an black frame instead of the UIPickerView.
What am i doing wrong ?
/donnib
Have you implemented the picker's datasource methods? You need it otherwise it won't show.
Link to Apple Documentation here: http://developer.apple.com/library/ios/#DOCUMENTATION/iPhone/Reference/UIPickerViewDataSource_Protocol/Reference/Reference.html#//apple_ref/occ/intf/UIPickerViewDataSource
You've forgotten to set the UIPickerView's delegate to your current view. Add:
myPickerView.delegate = self;
...following your initialization and before your view. And of course, make sure you set up your header file as a UIPickerView delegate and implement the dataSource methods.
Try this:
UIView *contentView = [[UIView alloc] initWithFrame: [[UIScreen mainscreen] bounds]];
UIPickerView *pickerView = [[UIPickerView alloc] initWithFrame: CGRectZero];
CGSize pickerSize = [pickerView sizeThatFits: CGSizeZero];
pickerView.frame = [self pickerFrameWithSize: pickerSize];
[pickerView setShowsSelectionIndicator: YES];
[contentView addSubview: pickerView];
[pickerView release];
[self setView: contentView];
[contentView release];
Instead of overriding -loadView, you should override -viewDidLoad. Once the view has loaded you'll create the picker and add it as a subview of the view owned by the view controller.
- (void)viewDidLoad
{
[super viewDidLoad];
CGRect rect = CGRectMake(0.0f, 20.0f, 320.0f, 216.0f);
UIPickerView *myPickerView = [[UIPickerView alloc] initWithFrame:rect];
[self.view addSubview:myPickerView];
[myPickerView release];
}

Why does this code from iPhone Developer's Cookbook work?

I've been trying out some of the view code from Erica Sadun's book "The iPhone Developer's Cookbook" and found some code I don't understand. Here's the code for a loadView method:
- (void)loadView
{
// Create the main view
UIView *contentView = [[UIView alloc] initWithFrame:
[[UIScreen mainScreen] applicationFrame]];
contentView.backgroundColor = [UIColor whiteColor];
self.view = contentView;
[contentView release];
// Get the view bounds as our starting point
CGRect apprect = [contentView bounds];
// Add each inset subview
UIView *subview = [[UIView alloc]
initWithFrame:CGRectInset(apprect, 32.0f, 32.0f)];
subview.backgroundColor = [UIColor lightGrayColor];
[contentView addSubview:subview];
[subview release];
}
My question is why does she release contentView, but then use it again in [contentView addSubview:subview]? Has self.view = contentView retained contentView?
If you look in the documentation for UIViewController, you'll see that the view property is declared as:
#property(nonatomic, retain) UIView *view;
This means that when you use the setView: method (or use .view on the left hand side of the =), then whatever value you pass in will be retained. So, if you go through the code and look at retain counts, you'll get this:
- (void)loadView {
// Create the main view
UIView *contentView = [[UIView alloc] initWithFrame:
[[UIScreen mainScreen] applicationFrame]]; //retain count +1
contentView.backgroundColor = [UIColor whiteColor]; //retain count +1
self.view = contentView; //retain count +2
[contentView release]; //retain count +1
// Get the view bounds as our starting point
CGRect apprect = [contentView bounds];
// Add each inset subview
UIView *subview = [[UIView alloc]
initWithFrame:CGRectInset(apprect, 32.0f, 32.0f)];
subview.backgroundColor = [UIColor lightGrayColor];
[contentView addSubview:subview];
[subview release];
}
I'd say that the really interesting thing is that after releasing contentView, we can still send messages to it, because the object living at the end of contentView's pointer still exists (since it was retained by calling setView:).
If u declare ur property like so
#property(nonatomic,retain) ...
TheN yes the property is retained when assigned. that is probably what's going on