Android实现倒计时跳转Activity

现在的APP大部分打开时的欢迎界面都有广告，倒计时结束进入主界面，今天就自己试试实现了一下，主要用到有：

Intent：意图，实现页面跳转

CountDownTimer：倒计时器，不言而喻

Handler:消息处理类，将跳转意图发送到消息队列，可以设置延迟

完整代码如下：

package com.example.sharedpreferences;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.os.Handler;
import android.view.Window;
import android.view.WindowManager;
import android.widget.TextView;

public class Welcome extends Activity {
	private static final String MY_DB_FirstCheck = "my_db";
	private TextView countdown;

	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		this.requestWindowFeature(Window.FEATURE_NO_TITLE);
		this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
				WindowManager.LayoutParams.FLAG_FULLSCREEN);
		setContentView(R.layout.welcome_layout);
		countdown = (TextView) findViewById(R.id.TView_countdown);

		final SharedPreferences sharedpreferences = getSharedPreferences(
				MY_DB_FirstCheck, Context.MODE_PRIVATE);

		/**
		 * Check if this is user's first visit;
		 */

		final boolean hasVisited = sharedpreferences.getBoolean("hasVisited",
				false);
		/**
		 * Default preference is 'false',if 'sharedpreferences' hasn't the
		 * String 'hasVisited'.
		 */

		countdowntimer = new MyCountdownTimer(3000, 1000);
		countdowntimer.start();
		handler.postDelayed(new Runnable() {

			@Override
			public void run() {
				if (!hasVisited) {
					/**
					 * Show Login Activity.
					 */
					Intent intent = new Intent();
					intent.setClass(Welcome.this, Login.class);
					startActivity(intent);
					/**
					 * Commit change: change state to 'true'.
					 */
					Editor edit = sharedpreferences.edit();
					edit.putBoolean("hasVisited", true);
					edit.commit();
				} else {
					Intent intent = new Intent();
					intent.setClass(Welcome.this, MainActivity.class);
					startActivity(intent);
				}
				finish();
			}
		}, 3000);
	}

	private Handler handler = new Handler();
	private MyCountdownTimer countdowntimer;

	/**
	 * Rewrite 'CountDownTimer' method.
	 * 
	 * @param millisInFuture
	 *            倒计时总数，单位为毫秒。
	 * @param countDownInterval
	 *            每隔多久调用onTick一次
	 * @author DaiZhenWei
	 * 
	 */
	protected class MyCountdownTimer extends CountDownTimer {

		public MyCountdownTimer(long millisInFuture, long countDownInterval) {
			super(millisInFuture, countDownInterval);
		}

		@Override
		public void onTick(long millisUntilFinished) {
			countdown.setText("Close(" + millisUntilFinished / 1000 + ")");
		}

		@Override
		public void onFinish() {
			countdown.setText("Turning");
		}

	}
}

注意：finish()必须写在Runnable()中，写在方法外围会造成欢迎界面闪退，之后直接进入主界面

今天就写到这里，明天准备把倒计时那里加上点击事件，实现跳过等待时间的过程，暂时还没有想法，明天继续！