objective-c - UIButton 调用选择器会使应用程序崩溃

Question

在我的应用程序中，我有一个按钮，它是已在 .h 文件中声明的实例变量。现在，在为其分配目标并实际按下按钮后，应用程序崩溃，在调试器中给出以下输出:

-[__NSCFString handleActionSheet:]: unrecognized selector sent to instance 0x9090330
2012-05-04 17:51:02.646 financeAppV2[2595:f803] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString handleActionSheet:]: unrecognized selector sent to instance 0x9090330'
*** First throw call stack:
(0x13d1022 0x1562cd6 0x13d2cbd 0x1337ed0 0x1337cb2 0x13d2e99 0x1e14e 0x1e0e6 0xc4ade 0xc4fa7 0xc3d8a 0x2dfa1a 0x13a599e 0x133c640 0x13084c6 0x1307d84 0x1307c9b 0x12ba7d8 0x12ba88a 0x1b626 0x29dd 0x2945)
terminate called throwing an exceptionCurrent language:  auto; currently objective-c

我的代码如下所示:

saveButton=[UIButton buttonWithType:UIButtonTypeCustom];
[saveButton setBackgroundImage:[UIImage imageNamed:@"intervalbutton"] forState:UIControlStateNormal];
[saveButton setBackgroundImage:[UIImage imageNamed:@"intervalbuttonpressed"] forState:UIControlStateHighlighted];
saveButton.alpha=.8;
saveButton.frame= frame;
UILabel* label=[[UILabel alloc]initWithFrame:CGRectMake(0, 2, saveButton.frame.size.width, 21)];
[saveButton addSubview:label];

[saveButton addTarget:self action:@selector(handleActionSheet:) forControlEvents:UIControlEventTouchDown];

[self.view addSubview:saveButton];


-(void)handleActionSheet:(id)sender{
NSLog(@"working");

}

知道应用程序可能崩溃的原因吗？

Answer 1

如果没有看到代码的其余部分，很难具体说明，但 self 没有被正确保留。

您正确设置了按钮(据我所知)并将目标指向self。不幸的是，当您按下按钮时，self 已经超出了范围，并且 NSString 使用了相同的内存。当您发送字符串 handleActionSheet: 消息时，iOS 会感到惊讶。