iOS UIButton在设置背景图像为零后消失

Question

我有一个没有标题或初始背景图像的UIButton。按下后，按钮背景图像会改变，再次按下时，它将被设置为零。现在使用iOS 6.x，该按钮完全消失。这里是我的代码：

- (IBAction)resetAll: (id) sender { 
[self reset]; 

for (UIView *view in self.view.subviews) { 

    if ([[[view class] description] isEqualToString:@"UIRoundedRectButton"]) { 
     UIButton *theButton = (UIButton *)view;   

     int nTag = theButton.tag; 

     switch (nTag) { 
      case 11: { 
       theButton.tag = 10; 
       [theButton setBackgroundImage:nil forState:UIControlStateNormal]; 
       break; 
      } 
      case 21: { 
       theButton.tag = 20; 
       [theButton setBackgroundImage:nil forState:UIControlStateNormal]; 
       [theButton setEnabled:YES]; 
       break; 
      } 
      case 31: { 
       theButton.tag = 30; 
       [theButton setBackgroundImage:nil forState:UIControlStateNormal]; 
       [theButton setEnabled:YES]; 
       break; 
      } 
      case 41: { 
       theButton.tag = 40; 
       [theButton setBackgroundImage:nil forState:UIControlStateNormal]; 
       [theButton setEnabled:YES]; 
       break; 
      } 
      case 51: { 
       theButton.tag = 50; 
       [theButton setBackgroundImage:nil forState:UIControlStateNormal]; 
       [theButton setEnabled:YES]; 
       break; 
      } 
     } 
    } 
} 
return; 

此代码工作正常：

- (IBAction)ButtonClicked: (id) sender { 
UIButton *btn = (UIButton *)sender; 

// Get the current tag value 
int currentTag = [sender tag]; 

// Toggle the check buttons 
if (currentTag == 10 || currentTag == 20 || currentTag == 30 || currentTag == 40 || currentTag == 50) { 
     [btn setBackgroundImage:[UIImage imageNamed:@"check.png"] forState:UIControlStateNormal]; 
     btn.tag = ++currentTag; 
} 

else 
    if (currentTag == 11 || currentTag == 21 || currentTag == 31 || currentTag == 41 || currentTag == 51) { 
     [btn setBackgroundImage:nil forState:UIControlStateNormal]; 
     btn.tag = --currentTag; 
} 

[self calculate]; 

任何建议或帮助将不胜感激！

Answer 1

而不是更改UIControlStateNormal中的按钮的背景图像，而不是改变按钮的状态？ 如果您创建的按钮编程，你只需要添加

[btn setBackgroundImage:[UIImage imageNamed:@"check.png"] forState:UIControlStateSelected]; 

然后，按下，当你希望它是箭头图像的行：

[btn setSelected:YES]; 

，并设置它回默认外观：

[btn setSelected:NO]; 

如果您在厦门国际银行所做的按钮，就可以通过改变状态配置所选择的设定状态的图像和设置图像那里。

Answer 2

这是实现DOC答案的最终代码。我设置界面生成器的默认设置，选中状态：

- (IBAction)ButtonClicked: (id) sender { 
UIButton *btn = (UIButton *)sender; 

if ([btn isSelected ]) { 
    [btn setSelected:NO]; 
} else { 
    [btn setSelected:YES]; 
} 

[self calculate]; 
} 


- (IBAction)resetAll: (id) sender { 
[self reset]; 

for (UIView *view in self.view.subviews) { 

    if ([[[view class] description] isEqualToString:@"UIRoundedRectButton"]) { 
     UIButton *theButton = (UIButton *)view;   

     [theButton setSelected:NO]; 

    } 
} 

Answer 3

的情况下，只是一个附加的应答（比如我）已经有按钮周围的选定状态逻辑的一个良好的金额（父类提供了状态到基于这个观点）。如果您需要按钮以非选择状态启动图像，并将状态更改为使用无图像进行选择，则可以将生成的空白图像添加到选定状态，如此。

  //Make a stupid blank image because setting to nil on a state doesn't work. 
      UIGraphicsBeginImageContextWithOptions(CGSizeMake(23, 23), NO, 0.0); 
      UIImage *blank = UIGraphicsGetImageFromCurrentImageContext(); 
      UIGraphicsEndImageContext(); 

      UIImage *buttonNonSelectedImage = [UIImage imageNamed:@"video-slomo"]; 
      [self.myButton setBackgroundImage:buttonNonSelectedImage forState:UIControlStateNormal]; 
      [self.mybutton setBackgroundImage:blank forState:UIControlStateSelected]; 
      [self.myButton addTarget:self 
            action:@selector(onMyButtonPress) 
          forControlEvents:UIControlEventTouchUpInside]; 
      self.myButton.titleLabel.font = [UIFont boldSystemFontOfSize:14]; 
      [self.playRateButton setTitleColor:[UIColor whiteColor] forState:UIControlStateSelected]; 
      [self.view addSubview:self.myButton]; 

然后，在你的按钮动作中，你可以改变状态（在我的情况下添加文本）。

- (void)onMyButtonPress 
{ 
    if (self.myButton.isSelected) { 
     [self.myButton setSelected:NO]; 
    } 
    else { 
     [self.myButton setTitle:@"Selected"] 
           forState:UIControlStateSelected]; 
     [self.myButton setSelected:YES]; 
    } 
} 

接受的答案在大多数情况下起作用，我只需要其他跟踪信息的选定状态。快乐编程。