Question

问题是在我按下2个按钮后，应用程序崩溃，我无法找出原因

Button1连接到button1 Button2连接到button2 ... Button5连接到button5

我做错了什么？

基本上我想检查＃的序列是否正确打孔（55235）

在我的AppDelegate.H文件中，我定义了一个名为

的变量

NSString * myEasterEgg;

在AppDelegate.M中，我有5个正确连线的按钮，每个按钮都有自己的方法

-(IBAction)button1:(id)sender
{
if(CFStringCompare((CFStringRef)myEasterEgg, (CFStringRef)@"52235", 1) == 0)
{
myEasterEgg = @"";
} else {
myEasterEgg = [myEasterEgg stringByAppendingString:@"1"];
}
}

-(IBAction)button2:(id)sender
{
if(CFStringCompare((CFStringRef)myEasterEgg, (CFStringRef)@"52235", 1) == 0)
{
myEasterEgg = @"";
} else {
myEasterEgg = [myEasterEgg stringByAppendingString:@"2"];
}
}

-(IBAction)button3:(id)sender
{
if(CFStringCompare((CFStringRef)myEasterEgg, (CFStringRef)@"52235", 1) == 0)
{
myEasterEgg = @"";
} else {
myEasterEgg = [myEasterEgg stringByAppendingString:@"3"];
}
}

-(IBAction)button4:(id)sender
{
if(CFStringCompare((CFStringRef)myEasterEgg, (CFStringRef)@"52235", 1) == 0)
{
myEasterEgg = @"";
} else {
myEasterEgg = [myEasterEgg stringByAppendingString:@"4"];
}
}

-(IBAction)button5:(id)sender
{
if(CFStringCompare((CFStringRef)myEasterEgg, (CFStringRef)@"52235", 1) == 0)
{
myEasterEgg = @"";
} else {
myEasterEgg = [myEasterEgg stringByAppendingString:@"5"];
}
}

-(void)viewDidLoad
{
myEasterEgg = [[NSString alloc] initWithString:@""];
}

Answer 1

您正在泄漏原始字符串，并将其替换为新值而不保留它们。发生崩溃的原因是你在悬空指针上调用[myEasterEgg stringByAppendingString:…]，即一个不再引用任何对象的变量。有关详细信息，请参阅Memory Management Programming Guide。

关于NSString的一个重要问题

1 个答案: