Question

我在可可触摸中创建了一个自定义视图，它被UIView超级化，在我的主控制器中我初始化它然后将它作为子视图添加到主视图中，但是当我将它添加到主视图时它调用我的初始化方法再次导致无限循环。我是否打算创建自定义视图？这是mainView

- (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

为什么将[super init]语句放在初始化程序的末尾？在子类化时，通常将此语句放在方法的开头。

对于UIView子类，在代码中创建视图时指定的初始值设定项为initWithFrame:，因此您应在添加标签和图像之前调用它。您可以使用该图像计算自定义视图所需的帧。

-(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;
}

如果仍有无限循环，请暂停调试器并在堆栈跟踪中搜索循环方法模式。此模式将为您提供代码进入无限循环的位置。

Cocoa Touch：创建和添加自定义视图

1 个答案: