setImage:forState: 在 iOS 3.2 中不起作用
预期的行为是在单击播放操作时更改图像（从播放到暂停以及从暂停到播放）。这在 4.x 版本中按预期工作。在版本 3.2 中，setImage 不起作用，这意味着 setImage 不设置图像。在 3.2 版本中，调用 imageForState:UIControlStateNormal 返回 null。有什么想法吗？
@interface TestViewController : UIViewController {
IBOutlet UIButton *playButton;
BOOL play;
}
- (IBAction) play:(id)sender;
@end
@implementation TestViewController
- (IBAction) play:(id)sender {
if (play == YES) {
[playButton setImage:[UIImage imageNamed:@"pause"] forState:UIControlStateNormal];
play = NO;
} else {
[playButton setImage:[UIImage imageNamed:@"play"] forState:UIControlStateNormal];
play = YES;
}
//[playButton imageForState:UIControlStateNormal]
}
@end
The expected behavior is to change the image (from play to pause and from pause to play) when the play action is clicked. This works as expected in version 4.x. In version 3.2 the setImage does not work meaning the setImage does not set the image. Call to imageForState:UIControlStateNormal returns null in 3.2 version. Any ideas?
@interface TestViewController : UIViewController {
IBOutlet UIButton *playButton;
BOOL play;
}
- (IBAction) play:(id)sender;
@end
@implementation TestViewController
- (IBAction) play:(id)sender {
if (play == YES) {
[playButton setImage:[UIImage imageNamed:@"pause"] forState:UIControlStateNormal];
play = NO;
} else {
[playButton setImage:[UIImage imageNamed:@"play"] forState:UIControlStateNormal];
play = YES;
}
//[playButton imageForState:UIControlStateNormal]
}
@end
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评论（2）
您的代码看起来正确，您是否检查过是否在 XIB 文件中为按钮连接了 IBOutlet？
Your code looks correct, have you checked that you connected up the IBOutlet in your XIB file for your button?
UIImage的imageNamed接受带有扩展名的图像名称，即如果您将代码更改为
您的代码将按照您的期望工作。
UIImage'simageNamedtakes in a image name with extension i.e if you change your codeto
your code will work as per your expectations.