Android使用Timer编写倒计时程序

摘要: Android使用Timer编写倒计时程序

开篇大家可以先看看Timer的基础用法，以及简单的原理。http://my.oschina.net/zhengweishan/blog/493891 Java之Timer使用。这里我要说的是Android使用Timer编写一个倒计时程序。

需求：实现简单的倒计时程序。要求可以根据用户的输入实现倒计时，时间到的时候有友好的提示。

分析：首先要实现这个功能，我想到的第一个方法就是使用Timer这个类。然后就是分析用户界面怎么设计，由于这个是简单程序，所以就采用Android原生的一些UI组件Button TextView EditText来设计基本的页面。友好提示我打算使用Toast这种机制。这里打算让用户输入分秒。

源码下载地址：https://git.oschina.net/zhengweishan/AndroidTimer

Activity代码：

import java.util.Timer;

import java.util.TimerTask;

import android.app.Activity;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.EditText;

import android.widget.TextView;

import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener {

private Button startButton;

private Button stopButton;

private EditText minuteText;

private EditText secondText;

private TextView myTime;

private int minute = 0;

private int second = 0;

private Timer timer = null;

private TimerTask task = null;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

initView();

}

private void initView() {

startButton = (Button) findViewById(R.id.startBtn);

stopButton = (Button) findViewById(R.id.stopBtn);

minuteText = (EditText) findViewById(R.id.minute);

secondText = (EditText) findViewById(R.id.second);

myTime = (TextView) findViewById(R.id.myTime);

startButton.setOnClickListener(this);

stopButton.setOnClickListener(this);

}

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

switch (v.getId()) {

case R.id.startBtn:

start();

break;

case R.id.stopBtn:

stop();

break;

}

}

public void start() {

if (!minuteText.getText().toString().equals("")) {

minute = Integer.parseInt(minuteText.getText().toString());

}

if (!secondText.getText().toString().equals("")) {

second = Integer.parseInt(secondText.getText().toString());

}

myTime.setText(minute + ":" + second);

task = new TimerTask() {

@Override

public void run() {

Message msg = new Message();

msg.what = 0;

mHandler.sendMessage(msg);

}

};

timer = new Timer();

timer.schedule(task, 0, 1000);

}

public void stop() {

timer.cancel();

}

public void timeProcess(){

if (minute == 0) {

if (second == 0) {

//myTime.setText("Time out!");

Toast.makeText(getApplicationContext(), "Time out!",5);

if (timer != null) {

timer.cancel();

timer = null;

}

if (task != null) {

task = null;

}

} else {

second--;

if (second >= 10) {

myTime.setText("0" + minute + ":" + second);

} else {

myTime.setText("0" + minute + ":0" + second);

}

}

} else {

if (second == 0) {

second = 59;

minute--;

if (minute >= 10) {

myTime.setText(minute + ":" + second);

} else {

myTime.setText("0" + minute + ":" + second);

}

} else {

second--;

if (second >= 10) {

if (minute >= 10) {

myTime.setText(minute + ":" + second);

} else {

myTime.setText("0" + minute + ":" + second);

}

} else {

if (minute >= 10) {

myTime.setText(minute + ":0" + second);

} else {

myTime.setText("0" + minute + ":0" + second);

}

}

}

}

}

private Handler mHandler = new Handler() {

public void handleMessage(Message msg) {

timeProcess();

};

};

}

xml布局文件：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

tools:context="com.example.androidtimer.MainActivity" >

<TextView

android:id="@+id/lable"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentLeft="true"

android:layout_alignParentTop="true"

android:text="@string/lable" />

<EditText

android:id="@+id/minute"

android:layout_width="100dp"

android:layout_height="wrap_content"

android:layout_alignLeft="@+id/lable"

android:layout_below="@+id/lable"

android:layout_marginTop="40dp"

android:ems="10" />

<TextView

android:id="@+id/textView2"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignBottom="@+id/minute"

android:layout_toRightOf="@+id/minute"

android:text="@string/minute" />

<EditText

android:id="@+id/second"

android:layout_width="100dp"

android:layout_height="wrap_content"

android:layout_toRightOf="@+id/textView2"

android:layout_below="@+id/lable"

android:layout_marginTop="40dp"

android:ems="10" />

<TextView

android:id="@+id/textView3"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_toRightOf="@+id/second"

android:layout_alignBottom="@+id/second"

android:text="@string/second" />

<TextView

android:id="@+id/myTime"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:layout_above="@+id/startBtn"

android:layout_alignRight="@+id/textView3"

android:layout_margin="30dp"

android:gravity="center"

android:textColor="#FF0000"

android:textSize="60sp"

android:textStyle="bold" />

<Button

android:id="@+id/startBtn"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignLeft="@+id/minute"

android:layout_alignParentBottom="true"

android:text="@string/startBtn" />

<Button

android:id="@+id/stopBtn"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignBottom="@+id/startBtn"

android:layout_toRightOf="@+id/startBtn"

android:layout_alignRight="@+id/textView3"

android:layout_marginRight="40dp"

android:text="@string/stopBtn" />

</RelativeLayout>

string.xml文件：

<?xml version="1.0" encoding="utf-8"?>

<resources>

<string name="app_name">AndroidTimer</string>

<string name="hello_world">Hello world!</string>

<string name="action_settings">Settings</string>

<string name="lable">请设置时间:</string>

<string name="minute">分:</string>

<string name="second">秒</string>

<string name="startBtn">开始计时</string>

<string name="stopBtn">停止计时</string>

</resources>