Question

我有一个名为imgBall的NSArray，它包含一个临时变量名imgView，当用户触摸屏幕上的某个点时，它会在屏幕上显示一个图像。

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {

    UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectMake(40, 40, 40, 40)];
    imgView.image = [UIImage imageNamed:@"ball.png"];
    [self.view addSubview:imgView];
    imgView.center = [myTouch locationInView:self.view];
    [imgBall addObject:imgView];
}

用户可以通过触摸屏幕上的任意位置来创建多个实例。可能意味着阵列中有5个，10个或20个不同的球。

现在，我有一个按钮需要“清除”屏幕并删除所有imgView实例。我尝试过以下方法：

 for (UIImageView *imgView in imgBall) {
    [self.view removeFromSuperview:imgView]; 
}

和

    for (UIImageView *imgView in imgBall) {
    [imgBall removeObject:imgView];
}

但他们都产生SIGABRT并抛出异常：

Terminating app due to uncaught exception 'NSGenericException', reason: 
'*** Collection     <__NSArrayM: 0x735f4a0> was mutated while being enumerated.'

如果没有每次都抛出SIGABRT，我该怎样做？

Answer 1

我想你想要：

for (UIImageView *imgView in imgBall) {
    [imgView removeFromSuperview]; 
    [imgBall removeObject:imgView];
}

在touchesEnded中创建[imgBall addObject：imgView]后，还需要执行[imgView release] ，否则会泄漏内存。

Answer 2

这样做：

for (UIImageView *imgView in imgBall)
{
[imgView removeFromSuperview];
}

然后不要忘记释放并将数组imgBall设置为nil以避免内存问题。如果它是NSMutableArray，只需调用removeAllObjects。

Answer 3

你应该这样做......

for (UIImageView *imgView in imgBall) {
    [imgView removeFromSuperview];
}
[imgBall removeAllObjects];

iOS：删除由NSArray创建的UIImageView实例？

3 个答案: