addTarget不适用于iOS中的UIButtons，视图被遮盖

Question

I have two UIButtons I am creating programmatically and setting targets. If I add these buttons to a main view, everything works beautifully. However when I add the to a subview first and add this subview to the main view, touch events don't work. I'm guessing these buttons are being covered up.

How can I uncover these buttons while keeping them inside the subview?

Here is my code:

// Create button panel here
UIImage *buttonPanel = [UIImage imageNamed:@"left_button_background"];
UIImageView *buttonPanelView = [[UIImageView alloc] initWithImage:buttonPanel];
[buttonPanelView setFrame:CGRectMake(20, 186, 363, 345)];

// Populate the panel with buttons
UIButton *cmsButton = [[UIButton alloc] initWithFrame:CGRectMake(10, 10, 351, 142)];
[cmsButton setImage:[UIImage imageNamed:@"BTN_MATLIB"] forState:UIControlStateNormal];
[cmsButton addTarget:self action:@selector(loadCMS) forControlEvents:UIControlEventTouchDown];
[buttonPanelView addSubview:cmsButton];
[self setCms:cmsButton];

UIButton *calcButton = [[UIButton alloc] initWithFrame:CGRectMake(10, 196, 351, 142)];
[calcButton setImage:[UIImage imageNamed:@"BTN_MORE_RESOURCES"] forState:UIControlStateNormal];
[calcButton addTarget:self action:@selector(loadCalc) forControlEvents:UIControlEventTouchDown];
[buttonPanelView addSubview:calcButton];
[self setCalc:calc];

[[self view] addSubview:buttonPanelView];

Answer 1

默认情况下，图像视图未启用用户交互，这意味着它们的子视图都不能接收用户交互。

buttonPanelView.userInteractionEnabled = YES;