本文實(shí)例為大家分享了Android實(shí)現(xiàn)簡(jiǎn)單計(jì)時(shí)器的具體代碼，供大家參考，具體內(nèi)容如下

布局

在res/layout 下進(jìn)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; //計(jì)時(shí)狀態(tài) private boolean wasRunning = false; //保存running的狀態(tài) //app進(jìn)入后臺(tái)，暫停計(jì)時(shí) @Override protected void onStop() { super.onStop(); wasRunning = running; running = false; } //重新進(jìn)入app，開始計(jì)時(shí) @Override protected void onStart() { super.onStart(); if(wasRunning) running = true; } //失去焦點(diǎn)(如分屏)，暫停計(jì)時(shí) @Override protected void onPause() { super.onPause(); wasRunning = running; running = false; } //獲得焦點(diǎn),重新開始計(jì)時(shí) @Override protected void onResume() { super.onResume(); if(wasRunning) running = true; } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //獲取保存的狀態(tài) if(savedInstanceState!=null){ seconds = savedInstanceState.getInt('seconds'); running = savedInstanceState.getBoolean('running'); wasRunning = savedInstanceState.getBoolean('wasRunning'); } runTime(); } /** *保存狀態(tài) */ @Override public void onSaveInstanceState(Bundle saveInstanceState) { super.onSaveInstanceState(saveInstanceState); saveInstanceState.putInt('seconds',seconds); saveInstanceState.putBoolean('running',running); saveInstanceState.putBoolean('wasRunning',wasRunning); } /** * 響應(yīng)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線程不能被堵塞，因此不能在ui線程中調(diào)用sleep方法 * 只允許ui線程更新界面，不能在后臺(tái)線程更新界面 * * ** 使用ui線程的Handler定時(shí)更新 ** * 將任務(wù)封裝到 Runnable的run方法中 ，通過Handler的 * post(立即提交任務(wù))或postDelayed(實(shí)現(xiàn)定時(shí)調(diào)度)方法提交到ui線程 */ 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); } } ); }}

測(cè)試

完成

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持好吧啦網(wǎng)。