Android TextSwitcher的使用

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
	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="TextSwitcher" />
	<Button android:text="ok" android:id="@+id/Button01"
		android:layout_width="wrap_content"
		android:layout_height="wrap_content">
	</Button>
	<TextSwitcher android:id="@+id/TextSwitcher01"
		android:layout_width="wrap_content"
		android:layout_height="wrap_content">
	</TextSwitcher>
	<TextView android:text="@+id/TextView01"
		android:id="@+id/TextView01" android:layout_width="wrap_content"
		android:layout_height="wrap_content">
	</TextView>
</LinearLayout>

package com.Aina.Android;

import java.util.Random;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.TextSwitcher;
import android.widget.TextView;
import android.widget.ViewSwitcher;

public class Test_TextSwitcher extends Activity implements ViewSwitcher.ViewFactory{
    /** Called when the activity is first created. */
	TextSwitcher ts;
	TextView tv2;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Button btn = (Button) this.findViewById(R.id.Button01);
        ts = (TextSwitcher) this.findViewById(R.id.TextSwitcher01);
        tv2 = (TextView) this.findViewById(R.id.TextView01);
        tv2.setTextSize(36);
        ts.setFactory(this);// 指定转换器的 ViewSwitcher.ViewFactory
        // 设置淡入和淡出的动画效果
        Animation in = AnimationUtils.loadAnimation(this, android.R.anim.fade_in);
        Animation out = AnimationUtils.loadAnimation(this, android.R.anim.fade_out);
        ts.setInAnimation(in);
        ts.setOutAnimation(out);
        btn.setOnClickListener(new Button.OnClickListener(){

			public void onClick(View v) {
				String str = String.valueOf(new Random().nextInt());
				ts.setText(str);
				tv2.setText(str);
			}
        	
        });
    }
      // 重写 ViewSwitcher.ViewFactory 的 makeView()，返回一个 View
	public View makeView() {
		TextView tv = new TextView(this);
		tv.setTextSize(36);
		return tv;
	}
}