详解iOS中UIButton的三大UIEdgeInsets属性用法
uiedgeinsets是什么
uiedgeinsets是什么?我们点进去看一下:
typedef struct uiedgeinsets { cgfloat top, left, bottom, right; // specify amount to inset (positive) for each of the edges. values can be negative to 'outset' } uiedgeinsets;
uiedgeinsets是个结构体类型。里面有四个参数,分别是:top, left, bottom, right。这四个参数表示距离上边界、左边界、下边界、右边界的距离。
哪三个uiedgeinsets属性
不知道大家发现没有,uibutton里面有三个uiedgeinsets属性,分别是:
@property(nonatomic) uiedgeinsets contentedgeinsets ui_appearance_selector; // default is uiedgeinsetszero @property(nonatomic) uiedgeinsets titleedgeinsets; // default is uiedgeinsetszero @property(nonatomic) uiedgeinsets imageedgeinsets; // default is uiedgeinsetszero
contentedgeinsets后面有个ui_appearance_selector是什么意思呢?
提示:ui_appearance_selector标记的属性都支持通过外观代理来定制。
举例,设置uibutton的contentedgeinsets属性,可以直接调用:
[[uibutton appearance] settitleedgeinsets:uiedgeinsetsmake(0, 0, 0, 0)];
创建uibutton:
uibutton *button = [[uibutton alloc] init]; button.frame = cgrectmake(50, 200, 200, 50); [button settitle:@"我是uibutton" forstate:uicontrolstatenormal]; [button settitlecolor:[uicolor bluecolor] forstate:uicontrolstatenormal]; [button setbackgroundcolor:[uicolor orangecolor]]; button.titlelabel.textalignment = nstextalignmentleft; button.contenthorizontalalignment = uicontrolcontenthorizontalalignmentleft; [self.view addsubview:button];
创建一个button,让button的title居左,以便观察:
uibutton的contentedgeinsets属性
@property(nonatomic) uiedgeinsets contentedgeinsets ui_appearance_selector; // default is uiedgeinsetszero
contentedgeinsets里有一个content应该指的就是uibutton的title。
参数含义:
上面我们讲了uiedgeinsets是个结构体类型。里面有四个参数,分别是:top, left, bottom, right。这四个参数表示距离上边界、左边界、下边界、右边界的距离。
这四个参数的值可以为正值,也可以为负值。拿left举例:
left = 10; //代表以当前位置为基准,向右移动10个像素 left = -10; //代表以当前位置为基准,向左移动10个像素
向右移动20个像素
button.contentedgeinsets = uiedgeinsetsmake(0, 20, 0, 0);
向右移动20个像素,left = 20,就可以了。
向左移动20个像素
button.contentedgeinsets = uiedgeinsetsmake(0, -20, 0, 0);
uibutton的titleedgeinsets属性
titleedgeinsets和contentedgeinsets的作用差不多。我们及设置contentedgeinsets,又设置titleedgeinsets,会怎样呢?
button.titleedgeinsets = uiedgeinsetsmake(0, 20, 0, 0); button.contentedgeinsets = uiedgeinsetsmake(0, 20 , 0, 0);
看一下效果:
uibutton的imageedgeinsets属性
创建一个带照片的button:
uibutton *button = [[uibutton alloc] init]; button.frame = cgrectmake(50, 200, 200, 200); [button settitlecolor:[uicolor bluecolor] forstate:uicontrolstatenormal]; [button setbackgroundcolor:[uicolor orangecolor]]; [button setimage:[uiimage imagenamed:@"test"] forstate:uicontrolstatenormal]; [self.view addsubview:button];
运行一下:
向右移动50个像素
button.imageedgeinsets = uiedgeinsetsmake(0, 50, 0, 0);
看看效果:
向左移动50个像素
button.imageedgeinsets = uiedgeinsetsmake(0, -50, 0, 0);
看看效果:
大家可以自行设置其他三个参数看看效果是怎样的,自己动手便于理解。