cocoa-touch - cocoa touch : Creating and Adding Custom View

Question

我在 cocoa touch 中创建了一个由 UIView 父类(super class)的自定义 View ，并在我的主 Controller 中初始化它，然后将它作为 subview 添加到主 View 中，但是当我将它添加到主 View 时，它再次调用我的初始化方法并导致一个无限循环。我要创建我的自定义 View 错误吗？
这是主 View

- (void)loadView {
    UIImage* tempImage = [UIImage imageNamed: @"image1.jpg"];
    CustomImageContainer *testImage = [[CustomImageContainer alloc] initWithImage: tempImage andLabel: @"test image" onTop: true atX: 10 atY: 10];
    [self.view addSubview: testImage];
}

和 CustomImageContainer

-(CustomImageContainer *) initWithImage: (UIImage *)imageToAdd andLabel: (NSString *)text onTop: (BOOL) top atX: (int) x_cord atY: (int) y_cord{
    UIImageView *imageview_to_add = [[UIImageView alloc] initWithImage: imageToAdd];
    imageview_to_add.frame = CGRectMake(0, 0, imageToAdd.size.width, imageToAdd.size.height);
    UILabel *label_to_add = [[UILabel alloc] init];
    label_to_add.text = text;
    label_to_add.alpha = 50;
    label_to_add.backgroundColor = [UIColor blackColor];
    label_to_add.textColor = [UIColor whiteColor];
    [self addSubview: imageview_to_add];
    self.frame = CGRectMake(x_cord, y_cord, imageToAdd.size.width, imageToAdd.size.height);
    if (top) {
        label_to_add.frame = CGRectMake(0, 0, imageview_to_add.frame.size.width, imageview_to_add.frame.size.height);
        //[self addSubview: label_to_add];
    }
    else {
        label_to_add.frame = CGRectMake(0,.2 * imageview_to_add.frame.size.height, imageview_to_add.frame.size.width, imageview_to_add.frame.size.height);
    }
    [self addSubview: label_to_add];
    [super  init];
    return self;
}

Answer 1

你为什么把[super init]初始化程序末尾的语句？子类化时，通常将此语句放在方法的开头。

对于 UIView子类，代码中创建 View 时指定的初始化器是initWithFrame: ，所以你应该在添加标签和图像之前调用它。您可以使用图像来计算自定义 View 所需的帧。

-(CustomImageContainer *) initWithImage: (UIImage *)imageToAdd andLabel: (NSString *)text onTop: (BOOL) top atX: (int) x_cord atY: (int) y_cord{
    // The view will gets its frame to the size of the image
    UIImageView *imageview_to_add = [[UIImageView alloc] initWithImage: imageToAdd];

    // Call the designated initializer
    CGRect frame = CGRectMake(x_cord, y_cord, imageToAdd.size.width, imageToAdd.size.height);
    self = [super initWithFrame:frame];

    [self addSubview: imageview_to_add];

    UILabel *label_to_add = [[UILabel alloc] init];
    label_to_add.text = text;
    label_to_add.alpha = 50;
    label_to_add.backgroundColor = [UIColor blackColor];
    label_to_add.textColor = [UIColor whiteColor];

    if (top) {
        label_to_add.frame = CGRectMake(0, 0, imageview_to_add.frame.size.width, imageview_to_add.frame.size.height);
    }
    else {
        label_to_add.frame = CGRectMake(0,.2 * imageview_to_add.frame.size.height, imageview_to_add.frame.size.width, imageview_to_add.frame.size.height);
    }
    [self addSubview: label_to_add];

    return self;
}

如果仍然存在无限循环，请暂停调试器并在堆栈跟踪中搜索循环方法模式。此模式将告诉您代码进入无限循环的位置。