1、public static class
ViewGroup.LayoutParams
extends Object
| java.lang.Object | |
| ↳ | android.view.ViewGroup.LayoutParams |
Class Overview
LayoutParams are used by views to tell their parents how they want to be laid out.
LayoutParams是ViewGroup的一个内部类, 每个不同的ViewGroup都有自己的LayoutParams子类
DEMO:
//创建一个线性布局
private LinearLayout mLayout;
mLayout = (LinearLayout) findViewById(R.id.layout);
//现在要往mLayout里边添加一个TextView TextView textView = new TextView(Activity01.this);
textView.setText("Text View " );
//这里是设置 这个textView的布局 FILL_PARENT WRAP_CONTENT 和在xml文件里边设置是一样的如
/**<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Text View"/>*///第一个参数为宽的设置，第二个参数为高的设置。
LinearLayout.LayoutParams p = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.FILL_PARENT,
LinearLayout.LayoutParams.WRAP_CONTENT
);
//调用addView()方法增加一个TextView到线性布局中
mLayout.addView(textView, p);
//比较简单的一个例子
LayoutParams继承于Android.View.ViewGroup.LayoutParams.
LayoutParams相当于一个Layout的信息包，它封装了Layout的位置、高、宽等信息。假设在屏幕上一块区域是由一个Layout占领的，如果将一个View添加到一个Layout中，最好告诉Layout用户期望的布局方式，也就是将一个认可的layoutParams传递进去。
可以这样去形容LayoutParams，在象棋的棋盘上，每个棋子都占据一个位置，也就是每个棋子都有一个位置的信息，如这个棋子在4行4列，这里的“4行4列”就是棋子的LayoutParams。
但LayoutParams类也只是简单的描述了宽高，宽和高都可以设置成三种值：
1，一个确定的值；
2，FILL_PARENT
3，WRAP_CONTENT
2、addRule()
public classRelativeLayout
extends ViewGroup
| java.lang.Object | |||
| ↳ | android.view.View | ||
| ↳ | android.view.ViewGroup | ||
| ↳ | android.widget.RelativeLayout | ||
| java.lang.Object | |||
| ↳ | android.view.View | ||
| ↳ | android.view.ViewGroup | ||
| ↳ | android.widget.RelativeLayout | ||
void android.widget.RelativeLayout.LayoutParams.addRule(int verb, int anchor)
public void addRule (int verb, int anchor) 设置控件的相对位置
Added in API level 1
Adds a layout rule to be interpreted by the RelativeLayout. Use this for verbs that take a target, such as a sibling (ALIGN_RIGHT) or a boolean value (VISIBLE).
Parameters
| verb | One of the verbs defined by RelativeLayout, such as ALIGN_WITH_PARENT_LEFT. |
|---|---|
| anchor | The id of another view to use as an anchor, or a boolean value(represented as TRUE) for true or 0 for false). For verbs that don't refer to another sibling (for example, ALIGN_WITH_PARENT_BOTTOM) just use -1. |
package sunny.example.layoutparamstaddrule;import android.content.Context;
import android.util.AttributeSet;
import android.widget.Button;
import android.widget.RelativeLayout;
import android.widget.RelativeLayout.LayoutParams;
import android.widget.TextView;public class TestView extends RelativeLayout{private LayoutParams mLayoutParams_1,mLayoutParams_2;Button mButton;TextView mTextView;public TestView(Context context) {super(context);// TODO Auto-generated constructor stubmButton = new Button(context);mTextView = new TextView(context);init();}public TestView(Context context, AttributeSet attrs) {super(context, attrs);// TODO Auto-generated constructor stubmButton = new Button(context);mTextView = new TextView(context);init();}public TestView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);// TODO Auto-generated constructor stubmButton = new Button(context);mTextView = new TextView(context);init();}public void init(){mLayoutParams_1 = new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT);mLayoutParams_1.addRule(RelativeLayout.ALIGN_TOP); addView(mButton,mLayoutParams_1);mLayoutParams_2 = new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT);mLayoutParams_2.addRule(RelativeLayout.BELOW, TRUE);mTextView.setText("Hey");addView(mTextView,mLayoutParams_2);}
}
Thanks to 泡在网上的日子
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