iphone - IOS 中的内存管理问题(收到内存警告。)

Question

我有一个空白屏幕，我在其中单击相机按钮并拍照，然后该照片作为 UIVIew 显示在我的空白屏幕上，并且我将相机中的多个图像添加到空白屏幕。问题是有时我可以在空白屏幕上添加多个图像，但有时当我捕获图像时，空白屏幕上的所有图像都会消失，只显示当前图像。 并在日志中。它显示我收到内存警告。 这是我的代码。我想我现在正在正确地释放我的对象。但是当我最后添加 [对象释放] 时，我的应用程序崩溃了。

   -(void)AddImagesToCanvasWithGesture{

    if(imageFromPicker.size.width > imageFromPicker.size.height || imageFromPicker.size.width == imageFromPicker.size.height)
    {
        holderView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 180, 160)];
    }
    else{
        holderView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 160, 240)];
    }
    UIImageView *imageview = [[[UIImageView alloc] initWithFrame:[holderView frame]];
    [imageview setImage:imageFromPicker];
    //[imageview setTag:101];
    //[holderView setTag:102];
    //NSLog(@"Tag By Default %d",(arc4random()%100)+10);
    [holderView setTag:(int)objectDelegate.tagForHolderView];
    [imageview setTag:((int)objectDelegate.tagForHolderView)+1];
    [holderView addSubview:imageview];
    //[imageview canBecomeFirstResponder];

    UIPinchGestureRecognizer *pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(scale:)];
    [pinchRecognizer setDelegate:self];
    [holderView addGestureRecognizer:pinchRecognizer];

    UIRotationGestureRecognizer *rotationRecognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotate:)];
    [rotationRecognizer setDelegate:self];
    [holderView addGestureRecognizer:rotationRecognizer];

    UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(move:)];
    [panRecognizer setMinimumNumberOfTouches:1];
    [panRecognizer setMaximumNumberOfTouches:1];
    [panRecognizer setDelegate:self];
    [holderView addGestureRecognizer:panRecognizer];

    UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapped:)];
    [tapRecognizer setNumberOfTapsRequired:1];
    [tapRecognizer setDelegate:self];
    [holderView addGestureRecognizer:tapRecognizer]; 


    UILongPressGestureRecognizer *gestureRecognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(gestureHandler:)];
    [holderView addGestureRecognizer:gestureRecognizer];

    [holderView.layer setBorderColor: [[UIColor whiteColor] CGColor]];
    [holderView.layer setBorderWidth: 3.0];
    [self.view addSubview:holderView];
    objectDelegate.tagForHolderView+=2;
    for(UIButton *b in self.view.subviews) {
        if([b isKindOfClass:[UIButton class]]) {
            [self.view bringSubviewToFront:b];
        }

        [self.view sendSubviewToBack:imageViewForBackground];
        //[holderView setHidden:YES];

    }

}

我如何释放它们以及我应该在哪里调用释放方法。

Answer 1

从上面添加的代码片段中，很明显您没有正确释放对象。您拥有 init 或 retain 或 copy 的每个对象，并且您有责任释放它们，除非您使用 ARC。 (上面的代码适用于 ARC)。

您拥有所有手势识别器和 ImageView 的所有权，一旦不再需要它们，您应该立即释放它们。例如... imageView 对象必须在

之后释放

[holderView addSubview:imageview];

和

pinchRecognizer 应在之后立即释放

[holderView addGestureRecognizer:pinchRecognizer];

其他手势识别器也是如此。

我猜您代码的其他部分也有类似的问题，最终应用程序收到内存警告。