LayoutParams are used by views to tell their parents how they want to be laid out. See ViewGroup Layout Attributes for a list of all child view attributes that this class supports.
LayoutParams布局参数是用来保存当前view在父控件中的布局参数，如位置，长，宽等。
The base LayoutParams class just describes how big the view wants to be for both width and height. For each dimension, it can specify one of:
- FILL_PARENT (renamed MATCH_PARENT in API Level 8 and higher), which means that the view wants to be as big as its parent (minus padding)
- WRAP_CONTENT, which means that the view wants to be just big enough to enclose its content (plus padding)
- an exact number
There are subclasses of LayoutParams for different subclasses of ViewGroup. For example, AbsoluteLayout has its own subclass of LayoutParams which adds an X and Y value.
布局参数是一系列类，不同布局都有它的布局参数类，不可乱用，如 LinearLayout.LayoutParams.