Android实现简单计时器功能

本文实例为大家分享了Android实现简单计时器的具体代码，供大家参考，具体内容如下

布局

在res/layout 下进行布局

<?xml version='1.0' encoding='utf-8'?><android.support.constraint.ConstraintLayout xmlns:android='http://schemas.android.com/apk/res/android' xmlns:tools='http://schemas.android.com/tools' xmlns:app='http://schemas.android.com/apk/res-auto' android:layout_width='match_parent' android:layout_height='match_parent' tools:context='.MainActivity'> <LinearLayout android:orientation='vertical' android:layout_width='match_parent' android:layout_height='match_parent' tools:layout_editor_absoluteY='0dp' tools:layout_editor_absoluteX='0dp'> <TextView android:text='00:00:00' android:textSize='60sp' android:gravity='center' android:layout_width='match_parent' android:layout_height='wrap_content' android: /> <Button android:text='start' android:onClick='onClickStart' android:layout_width='match_parent' android:layout_height='wrap_content' android: /> <Button android:text='stop' android:onClick='onClickStop' android:layout_width='match_parent' android:layout_height='wrap_content' android: /> <Button android:text='reset' android:onClick='onClickReset' android:layout_width='match_parent' android:layout_height='wrap_content' android: /> </LinearLayout></android.support.constraint.ConstraintLayout>

MainActivity

package com.test;import android.os.Handler;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.TextView;public class MainActivity extends AppCompatActivity { private int seconds = 0; private boolean running = false; //计时状态 private boolean wasRunning = false; //保存running的状态 //app进入后台，暂停计时 @Override protected void onStop() { super.onStop(); wasRunning = running; running = false; } //重新进入app，开始计时 @Override protected void onStart() { super.onStart(); if(wasRunning) running = true; } //失去焦点(如分屏)，暂停计时 @Override protected void onPause() { super.onPause(); wasRunning = running; running = false; } //获得焦点,重新开始计时 @Override protected void onResume() { super.onResume(); if(wasRunning) running = true; } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //获取保存的状态 if(savedInstanceState!=null){ seconds = savedInstanceState.getInt('seconds'); running = savedInstanceState.getBoolean('running'); wasRunning = savedInstanceState.getBoolean('wasRunning'); } runTime(); } /** *保存状态 */ @Override public void onSaveInstanceState(Bundle saveInstanceState) { super.onSaveInstanceState(saveInstanceState); saveInstanceState.putInt('seconds',seconds); saveInstanceState.putBoolean('running',running); saveInstanceState.putBoolean('wasRunning',wasRunning); } /** * 响应button的onClick事件 * 方法名和onClick的值一致 */ public void onClickStart(View button){ running = true; } public void onClickStop(View button){ running = false; } public void onClickReset(View button){ running = false; seconds = 0; } /** * 注意 ui线程不能被堵塞，因此不能在ui线程中调用sleep方法 * 只允许ui线程更新界面，不能在后台线程更新界面 * * ** 使用ui线程的Handler定时更新 ** * 将任务封装到 Runnable的run方法中 ，通过Handler的 * post(立即提交任务)或postDelayed(实现定时调度)方法提交到ui线程 */ private void runTime(){ final Handler handler = new Handler(); handler.post(new Runnable() { @Override public void run() { final TextView textView = findViewById(R.id.timeView); int hour = seconds /3600%24; int minute = seconds%3600/60; String time = String.format('%02d:%02d:%02d',hour,minute,seconds%60); textView.setText(time); if(running) seconds++; handler.postDelayed(this,1000); } } ); }}

测试

完成

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