Android中的setLayoutParams是给父控件看的

 setLayoutParams()是给其父控件看的 

 These supply parameters to the parent of this view specifying how it 

should be arranged

其实这也好理解:只有父类可以改变子View的位置布局.而不是说子View可以随意按照自己的想法摆放自己的位置,而不受父控件控制  。

例子：

RelativeLayout.LayoutParams layoutParams  
//           =new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.FILL_PARENT, RelativeLayout.LayoutParams.FILL_PARENT);  
//           layoutParams.setMargins(280, 0, 0, 0);  
//           mTextView.setLayoutParams(layoutParams); 

 

<span style="font-size:18px;">RelativeLayout.LayoutParams layoutParams= 
            new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT); 
            layoutParams.addRule(RelativeLayout.CENTER_IN_PARENT); 
            mTextView.setLayoutParams(layoutParams); 
        </span>