UIButton中的**EdgeInsets是做什么用的?

UIButton中的**EdgeInsets是做什么用的?

UIEdgeInsetsMake

Creates an edge inset for a button or view.
An inset is a margin around the drawing rectangle where each side (left, right, top, and bottom) can have a different value.

给一个button或者view创建一个嵌入的边缘.

inset是一个矩形view页边空白,每一边都可以设定一个不同的值.

图片素材: [e-mail]

- (void)viewDidLoad
{
    [super viewDidLoad];

    UIButton *normalButton = nil;
    UIButton *edgeButton   = nil;

    // normalButton
    {
        // 初始化按钮
        normalButton = [[UIButton alloc] initWithFrame:CGRectMake(, , , )];
        normalButton.backgroundColor = [UIColor blackColor];

        // 按钮图片
        [normalButton setImage:[UIImage imageNamed:@""] forState:UIControlStateNormal];
    }

    // EdgeButton
    {
        // 初始化按钮
        edgeButton = [[UIButton alloc] initWithFrame:CGRectMake(, , , )];
        edgeButton.backgroundColor = [UIColor blackColor];

        // 按钮图片
        [edgeButton setImage:[UIImage imageNamed:@""] forState:UIControlStateNormal];

        // 设置图片间距
        edgeButton.imageEdgeInsets = UIEdgeInsetsMake(, , , );
    }

    [self.view addSubview:normalButton];
    [self.view addSubview:edgeButton];
}

viewDidLoad

以下是模拟器显示结果:

从结果中可以看到,设置了图片的imageEdgeInsets后,图片显示被缩放了哦.

再来测试文本的titleEdgeInsets

- (void)viewDidLoad
{
    [super viewDidLoad];

    UIButton *normalButton = nil;
    UIButton *edgeButton   = nil;

    // normalButton
    {
        // 初始化按钮
        normalButton = [[UIButton alloc] initWithFrame:CGRectMake(, , , )];
        normalButton.backgroundColor = [UIColor blackColor];

        [normalButton setTitle:@"Y.X." forState:UIControlStateNormal];
        [normalButton setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
    }

    // EdgeButton
    {
        // 初始化按钮
        edgeButton = [[UIButton alloc] initWithFrame:CGRectMake(, , , )];
        edgeButton.backgroundColor = [UIColor blackColor];

        [edgeButton setTitle:@"Y.X." forState:UIControlStateNormal];
        [edgeButton setTitleColor:[UIColor redColor] forState:UIControlStateNormal];

        edgeButton.titleEdgeInsets = UIEdgeInsetsMake(, , , );
    }

    [self.view addSubview:normalButton];
    [self.view addSubview:edgeButton];
}

viewDidLoad

以下是运行结果:

文本并没有缩放的说,再试试这么设置:

UIButton还有一个属性叫contentEdgeInsets.

Use this property to resize and reposition the effective drawing rectangle for the button content. The content comprises the button image and button title.

实际上,这个contentEdgeInsets是用来同时设置imageEdgeInsets与titleEdgeInsets的,没什么特别的,就不举例子了:)