Android xmlns 的作用及其自定义实例详解

package kexc.myView;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.widget.TextView;
public class MyView extends TextView { 
 private String mString = "Welcome to Kesion's blog";
 
 public MyView(Context context, AttributeSet attrs) {
 super(context, attrs);
 TypedArray a = context.obtainStyledAttributes(attrs, 
    R.styleable.MyView);
 int textColor = a.getColor(R.styleable.MyView_textColor, 
    0XFFFFFFFF); 
  float textSize = a.getDimension(R.styleable.MyView_textSize, 36); 
  mString = a.getString(R.styleable.MyView_title);
 setText(mString);
 setTextSize(textSize);
 setTextColor(textColor);
 }
}

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout 
 xmlns:android="http://schemas.android.com/apk/res/android" 
 xmlns:test="http://schemas.android.com/apk/res/kexc.myView"
 android:orientation="vertical" 
 android:layout_width="fill_parent" 
 android:layout_height="fill_parent"> 
 <TextView 
  android:layout_width="fill_parent" 
  android:layout_height="wrap_content" 
  android:text="@string/hello" 
  /> 
 <kexc.myView.MyView 
  android:layout_width="fill_parent" 
  android:layout_height="fill_parent"
  test:title="wo shi text"
  test:textSize="20px" 
  test:textColor="#fff" 
 />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<resources>
 <declare-styleable name="MyView"> 
  <attr name="textColor" format="color"/> 
 <attr name="textSize" format="dimension" /> 
 <attr name="title" format="string"/>
 </declare-styleable>
</resources>