Question

I’m stuck at how to declare the uibutton in uiview:

- (void)viewWillAppear:(BOOL)animated {

NSLog(@"Added holderView.");
UIView *holderView = [[UIView alloc] initWithFrame:CGRectMake(0, 50, _imagePicker.selectedImage.size.width, _imagePicker.selectedImage.size.height)];
UIImageView *imageView = [[UIImageView alloc] initWithFrame:[holderView frame]];
[imageView setImage:_imagePicker.selectedImage];
[holderView addSubview:imageView];

UIButton *removeSticker = [UIButton buttonWithType:UIButtonTypeCustom];
removeSticker.frame = CGRectMake(0, 0, 100, 100);
[removeSticker setImage:[UIImage imageNamed:@"cancel-disabled.png"] forState:UIControlStateNormal];
[removeSticker addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
[holderView addSubview: removeSticker];
[removeSticker setHidden: YES];

UIPinchGestureRecognizer *pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(scale:)];
[pinchRecognizer setDelegate:self];
[holderView addGestureRecognizer:pinchRecognizer];

UIRotationGestureRecognizer *rotationRecognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotate:)];
[rotationRecognizer setDelegate:self];
[holderView addGestureRecognizer:rotationRecognizer];

UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(move:)];
[panRecognizer setMinimumNumberOfTouches:1];
[panRecognizer setMaximumNumberOfTouches:1];
[panRecognizer setDelegate:self];
[holderView addGestureRecognizer:panRecognizer];

UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapped:)];
[tapRecognizer setNumberOfTapsRequired:1];
[tapRecognizer setDelegate:self];
[holderView addGestureRecognizer:tapRecognizer];

UILongPressGestureRecognizer *longPressRecognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPress:)];
[longPressRecognizer setDelegate:self];
[holderView addGestureRecognizer:longPressRecognizer];

[stickerView addSubview:holderView];

}

- (void)buttonClicked:(id)sender {
UIView *holderView = [(UIButton *)sender superview]; [holderView removeFromSuperview];
}

Here I want to make the uibutton *removeSticker visible to be able to do buttonClicked, however it said undeclared identifier *holderView:

-(void)longPress:(id)sender {

for(UIButton *removeSticker in holderView.subviews)[removeSticker setHidden: NO];

}

How should I write this line? Please help, thanks a lot.

Answer 1

Just this

 -(void)longPress:(id)sender {
    [removeSticker setHidden:NO];
 }

The reason you get that error is that the scope for holderView is limited to the block it is declared in. For future reference, if you want it to have scope across your entire class, it should be an ivar or property.

You also want to make removeSticker an ivar for the same reason.

To make it an ivar, put the declaration in the header file:

UIButton *removeSticker;

Then in your viewWillAppear code you change this line

UIButton *removeSticker = [UIButton buttonWithType:UIButtonTypeCustom];

to this

removeSticker = [UIButton buttonWithType:UIButtonTypeCustom];

But barley has it right in his answer, too. sender is already pointing to the removeSticker object, whether you declare it as an ivar or not.