Android中使用Handler及Countdowntimer实现包含倒计时的闪屏页面

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:id="@+id/activity_splash"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:background="@mipmap/background_login"
 tools:context="com.mly.panhouye.handlerdemo.SplashActivity">
 <TextView
 android:gravity="right"
 android:id="@+id/tv_time"
 android:textColor="@color/colorAccent"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:text="SS"
 android:textSize="30sp"/>
</RelativeLayout>

package com.mly.panhouye.handlerdemo;
import android.content.Intent;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.Window;
import android.view.WindowManager;
import android.widget.TextView;
public class SplashActivity extends AppCompatActivity {
 private MyHandler myHandler = new MyHandler();
 private TextView tv_time;
 private MyCountDownTimer mc;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 //设置Activity为全屏
 getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
 WindowManager.LayoutParams.FLAG_FULLSCREEN);
 //去标题状态栏
 requestWindowFeature(Window.FEATURE_NO_TITLE);
 setContentView(R.layout.activity_splash);
 tv_time = (TextView) findViewById(R.id.tv_time);
 mc = new MyCountDownTimer(5000, 1000);
 mc.start();
 /**
 * 使用handler的postDelayed延迟5秒执行页面跳转
 * （与CountDownTimer的millisInFuture一致）
 */
 myHandler.postDelayed(new Runnable() {
 @Override
 public void run() {
 startMainActivity();
 }
 },5000);
 }
 //将Handler声明为静态内部类
 private static class MyHandler extends Handler {
 @Override
 public void handleMessage(Message msg) {
 super.handleMessage(msg);
 }
 }
 //页面跳转的方法
 private void startMainActivity(){
 Intent intent = new Intent(this,Main3Activity.class);
 startActivity(intent);
 finish();//完成跳转后销毁闪屏页（从栈内移除）
 }
 class MyCountDownTimer extends CountDownTimer {
 /**
 * @param millisInFuture
 * 表示以毫秒为单位 倒计时的总数
 * 例如 millisInFuture=1000 表示1秒
 * @param countDownInterval
 * 表示 间隔 多少微秒 调用一次 onTick 方法
 * 例如: countDownInterval =1000 ; 表示每1000毫秒调用一次onTick()
 */
 public MyCountDownTimer(long millisInFuture, long countDownInterval) {
 super(millisInFuture, countDownInterval);
 }
 public void onFinish() {
 tv_time.setText("正在跳转");
 }
 public void onTick(long millisUntilFinished) {
 tv_time.setText("倒计时(" + millisUntilFinished / 1000 + ")");
 Log.i("tag","倒计时"+millisUntilFinished / 1000);
 }
 }
 @Override
 protected void onDestroy() {
 super.onDestroy();
 //闪屏页销毁时将消息对象从消息队列移除并结束倒计时
 myHandler.removeCallbacksAndMessages(null);
 mc.cancel();
 Log.i("tag","destory");
 }
}