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:id="@+id/timeView"/> <Button android:text="start" android:onClick="onClickStart" android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/start"/> <Button android:text="stop" android:onClick="onClickStop" android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/stop"/> <Button android:text="reset" android:onClick="onClickReset" android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/reset"/> </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

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。