objective-c - cocoa：多按钮设置图片，标签效果

Question

有几个按钮，点击其中一个，改变这个按钮的图片，其他按钮设置另一个图片。下面的代码哪里出错了？

NSButton *button = (NSButton *)sender;
NSInteger tag = button.tag;
[button setImage:[NSImage imageNamed:@"menuBtnHover.png"]];
for (int i = 5; i <= 8; i++) {
    if (tag != i) {
        button =[(NSButton *)[self contentView] viewWithTag:i];
        [button setImage:[NSImage imageNamed:@"menuBtn.png"]];
    }
}

添加测试，<code>按钮＝null

NSLog(@"button tag: %ld %d %@", tag,i ,button);

Answer 1

使用此代码

 NSButton *button = (NSButton *)sender;
NSInteger tag = button.tag;
[button setImage:[NSImage imageNamed:@"menuBtnHover.png"]];
for (int i = 5; i <= 8; i++) {
if (tag != i) { button =[(NSButton *)[self contentView] viewWithTag:i];                

   if(button)[button setImage:[NSImage imageNamed:@"menuBtn.png"]];}
  }