android实现淡入淡出欢迎界面

本例子会实现想手机QQ和酷狗那样的淡入淡出的欢迎界面

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.view.Window;
import android.view.WindowManager;

import com.dapp.R;

public class Welcome extends Activity{
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		requestWindowFeature(Window.FEATURE_NO_TITLE);
		getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
				WindowManager.LayoutParams.FLAG_FULLSCREEN);
		super.onCreate(savedInstanceState);
		setContentView(R.layout.welcome);
		
		new CountDownTimer(2000,1000) {
			
			@Override
			public void onTick(long millisUntilFinished) {
			}
			@Override
			public void onFinish() {
				Intent intent = new Intent();
				intent.setClass(Welcome.this, MainGroup.class);
				startActivity(intent);
				
				int VERSION=Integer.parseInt(android.os.Build.VERSION.SDK);
				if(VERSION >= 5){
					Welcome.this.overridePendingTransition(R.anim.alpha_in, R.anim.alpha_out);
				}
				finish();
			}
		}.start();
	}
}

淡入XML代码清单：

<?xml version="1.0" encoding="UTF-8"?>
<set
	xmlns:android="http://schemas.android.com/apk/res/android">
	<alpha
		android:fromAlpha="0.0"
		android:toAlpha="1.0"
		android:duration="2000" />
</set>

淡出XML代码清单：

<?xml version="1.0" encoding="UTF-8"?>
<set
	xmlns:android="http://schemas.android.com/apk/res/android">
	<alpha
		android:fromAlpha="1.0"
		android:toAlpha="0.0"
		android:duration="2000" />
</set>