Remove previous UIView before creating another on - ios

Question

I have a method were I'm creating UIView and it works fine when I call it from IBAction. But when I call the same method again it draws another view on top and I believe it's a memory leak. How do I remove previous UIView before creating another one? Thanks!
- (int)showQuestionMethod:(int)number;
{
UIView *questionView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 250)];
questionView.backgroundColor = [[UIColor alloc] initWithRed:0.93 green:0.93
blue:0.93 alpha:1.0];
[self.view addSubview:questionView];
questionView.tag = questionNumber;
UILabel *questionLabel = [[UILabel alloc] initWithFrame:CGRectMake(20, 20, 280, 0)];
questionLabel.text = question1;
[questionView addSubview:questionLabel];
CGRect frame = questionView.frame;
frame.size.height = questionHeight;
questionView.frame = frame;
questionView.tag = questionNumber;
return currentQuestion;
}
- (IBAction)nextQuestion:(id)sender {
[self showQuestionMethod:questionNumber];
}

Answer 1

Create a property which will let you reference a view:
#property(nonatomic, strong) UIView *questionView;
Then change your method to remove the old view and create a new one:
- (int)showQuestionMethod:(int)number;
{
// Remove the previous view.
[_questionView removeFromSuperview];
// Create a new view.
_questionView= [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 250)];
_questionView.backgroundColor = [[UIColor alloc] initWithRed:0.93 green:0.93
blue:0.93 alpha:1.0];
// Add the view.
[self.view addSubview:_questionView];
_questionView.tag = questionNumber;
UILabel *questionLabel = [[UILabel alloc] initWithFrame:CGRectMake(20, 20, 280, 0)];
questionLabel.text = question1;
[_questionView addSubview:questionLabel];
CGRect frame = _questionView.frame;
frame.size.height = questionHeight;
_questionView.frame = frame;
_questionView.tag = questionNumber;
return currentQuestion;
}

Answer 2

The simplest way would be to keep a reference to the view you will want to remove (a private property would work nicely). You could add the code at bottom to the top of your controllers .m file:
#interface MyUIViewController ()
#property (nonatomic, strong) UIView* questionView;
#end
Then modify your method as follows:
- (int)showQuestionMethod:(int)number;
{
[self.questionView removeFromSuperview]
self.questionView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 250)];
self.questionView.backgroundColor = [[UIColor alloc] initWithRed:0.93 green:0.93
blue:0.93 alpha:1.0];
[self.view addSubview:self.questionView];
self.questionView.tag = questionNumber;
UILabel *questionLabel = [[UILabel alloc] initWithFrame:CGRectMake(20, 20, 280, 0)];
self.questionLabel.text = question1;
[self.questionView addSubview:questionLabel];
CGRect frame = questionView.frame;
frame.size.height = questionHeight;
self.questionView.frame = frame;
self.questionView.tag = questionNumber;
return currentQuestion;
}

Answer 3

use this before creating new view
[myview removeFromSuperview];

Answer 4

You can either keep a reference to the view by adding #property (strong, nonatomic) UIView *questionView; in your #interface declaration then call [_questionView removeFromSuperview]; to remove it.
Or, better yet, keep that reference to it then have a method to reload the info on it and animate it out/back into view (perhaps by fading out, reloading the data on it, then fading it back in). That way you aren't throwing away / recreating views all the time, and instead you're just reusing the same, already created view.

Answer 5

[self.questionView removeFromSuperview];
before adding the other view, remove this from the superview!

Answer 6

Why not reuse the view?
If you'd rather delete it every time and you don't want to keep a reference to it, you can always set (dirty but simple):
questionView.tag = SOME_CONST;
And then add in the beginning of your method:
[[self.view viewWithTag:SOME_CONST] removeFromSuperview];

Answer 7

I know this question has been answered, but i want to add a precaution that you before removing a UIView or anything else you should FIRST CHECK IF IT IS ALLOCATED. So the removal should be like:
// Make property first
#property (nonatomic, strong) UIView *questionView;
- (int)showQuestionMethod:(int)number;
{
// Check it it is allocated
if(questionView)
{
[questionView removeFromSuperView];
//[questionView release]; // Un-Comment it if NOT using ARC
questionView = nil;
}
// At this point you safe to create a new UIView.
questionView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 250)];
questionView.backgroundColor = [[UIColor alloc] initWithRed:0.93 green:0.93
blue:0.93 alpha:1.0];
[self.view addSubview:questionView];
questionView.tag = questionNumber;
UILabel *questionLabel = [[UILabel alloc] initWithFrame:CGRectMake(20, 20, 280, 0)];
questionLabel.text = question1;
[questionView addSubview:questionLabel];
CGRect frame = questionView.frame;
frame.size.height = questionHeight;
questionView.frame = frame;
questionView.tag = questionNumber;
return currentQuestion;
}
Hope the snippet and comment inside makes sense.
Happy Coding!!!