Zestaw SDK dla iPhone: nieprzejrzyste subviews w widoku przezroczystym

Question

Mam subview, który został dodany do mojego UIView. Chodzi o to, że podgląd jest panelem z uibuttonami. W widoku podrzędnym podano wartość 0.2, ponieważ użytkownik musi być w stanie zobaczyć, co za tym stoi.

Problem polega na tym, że kiedy dodaję uibuttons do subview, dziedziczą alfa z subview (chcę, aby przyciski były nieprzezroczyste i mają alfa 1.0). Próbowałem rozwiązać ten problem przez iterowanie przez uibuttons i ustawienie ich alfa z powrotem do wersji 1.0 bez powodzenia. Rozwiązania?

// Create the subview and add it to the view 
    topHoverView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 50)]; 
    topHoverView.backgroundColor = [UIColor blackColor]; 
    [topHoverView setAlpha:0.2]; 
    [self.view addSubview:topHoverView]; 

    // Add button 1 
    button1 = [UIButton buttonWithType:UIButtonTypeRoundedRect]; 
    [button1 setFrame:CGRectMake(20, 10, 80, 30)]; 
    [button1 setTitle:@"New" forState:UIControlStateNormal]; 
    [button1 addTarget:self action:@selector(button1Action:) forControlEvents:UIControlEventTouchUpInside]; 
    [topHoverView addSubview:button1]; 

    // Add button 2 
    button2 = [UIButton buttonWithType:UIButtonTypeRoundedRect]; 
    [button2 setFrame:CGRectMake(120, 10, 80, 30)]; 
    [button2 setTitle:@"Clear" forState:UIControlStateNormal]; 
    [button2 addTarget:self action:@selector(button2Action:) forControlEvents:UIControlEventTouchUpInside]; 
    [topHoverView addSubview:button2]; 

    // Add button 3 
    button3 = [UIButton buttonWithType:UIButtonTypeRoundedRect]; 
    [button3 setFrame:CGRectMake(220, 10, 80, 30)]; 
    [button3 setTitle:@"Delete" forState:UIControlStateNormal]; 
    [button3 addTarget:self action:@selector(button3Action:) forControlEvents:UIControlEventTouchUpInside]; 
    [topHoverView addSubview:d button3]; 

    // Attempt to iterate through the subviews (buttons) to set their transparency back to 1.0 
    for (UIView *subView in topHoverView.subviews) { 
     subView.alpha = 1.0; 
    } 

Answer 1

Powinieneś stworzyć topHoverView z alpha 1.0 i przezroczystym kolorem tła. Następnie dodać podrzędny z czarnym tle, który obejmuje kompletny widok z alfa 0,2, a następnie dodać przyciski do topHoverView:

// Create the subview and add it to the view 
topHoverView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 50)]; 
topHoverView.backgroundColor = [UIColor transparentColor]; 
[topHoverView setAlpha:1.0]; 
[self.view addSubview:topHoverView]; 

canvasView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 50)]; 
canvasView.backgroundColor = [UIColor blackColor]; 
[canvasViewView setAlpha:0.2]; 
[topHoverView.view addSubview:canvasView]; 

// Add button 1 
button1 = [UIButton buttonWithType:UIButtonTypeRoundedRect]; 
[button1 setFrame:CGRectMake(20, 10, 80, 30)]; 
[button1 setTitle:@"New" forState:UIControlStateNormal]; 
[button1 addTarget:self action:@selector(button1Action:) forControlEvents:UIControlEventTouchUpInside]; 
[topHoverView addSubview:button1]; 

// Add button 2 
button2 = [UIButton buttonWithType:UIButtonTypeRoundedRect]; 
[button2 setFrame:CGRectMake(120, 10, 80, 30)]; 
[button2 setTitle:@"Clear" forState:UIControlStateNormal]; 
[button2 addTarget:self action:@selector(button2Action:) forControlEvents:UIControlEventTouchUpInside]; 
[topHoverView addSubview:button2]; 

// Add button 3 
button3 = [UIButton buttonWithType:UIButtonTypeRoundedRect]; 
[button3 setFrame:CGRectMake(220, 10, 80, 30)]; 
[button3 setTitle:@"Delete" forState:UIControlStateNormal]; 
[button3 addTarget:self action:@selector(button3Action:) forControlEvents:UIControlEventTouchUpInside]; 
[topHoverView addSubview:d button3]; 

// Attempt to iterate through the subviews (buttons) to set their transparency back to 1.0 
for (UIView *subView in topHoverView.subviews) { 
    subView.alpha = 1.0; 
} 

Answer 2

Zamiast

topHoverView.backgroundColor = [UIColor transparentColor]; 

poniższy kod ma rację.

topHoverView.backgroundColor = [UIColor clearColor];