Android四大组件之Service示例

深藏阁楼爱情的钟 2022-05-18 01:12 260阅读 0赞

一个很简单的service示例，没有太多要讲解的。

有一个地方需要注意的是getRunningServices 已经被google标记为deprecated, 所以对于27（oreo）及以后的版本，如果要达到类似效果，可以使用isMyServiceRunning来代替isRunning()，如例子中所标记的那样。

我这里使用的是stopService来停止service，作为示例，其中也使用了stopSelf。

使用stopSelf(startId)的话，startID就是onStartCommand所传进来的那个。在service创建实例之后，每startService一次，这个startID就会+1。当stopService->onDestroy运行之后，不管有多少个Thread在运行，全部都会终止，如下图所示，

![70][]

下面是本例全部的源码，

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.spacesoftwares.servicedemo">
    
        <application
            android:allowBackup="true"
            android:icon="@mipmap/ic_launcher"
            android:label="@string/app_name"
            android:roundIcon="@mipmap/ic_launcher_round"
            android:supportsRtl="true"
            android:theme="@style/AppTheme">
            <activity android:name=".MainActivity">
                <intent-filter>
                    <action android:name="android.intent.action.MAIN" />
    
                    <category android:name="android.intent.category.LAUNCHER" />
                </intent-filter>
            </activity>
    
            <service
                android:name=".MyService"
                android:enabled="true"
                android:exported="true"></service>
        </application>
    
    </manifest>

activity\_main.xml

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="20dp"
        android:orientation="vertical"
        tools:context=".MainActivity">
    
        <Button
            android:id="@+id/bt_start"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/start_service"/>
    
        <Button
            android:id="@+id/bt_stop"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/stop_service"/>
    </LinearLayout>

MainActivity.java

package com.spacesoftwares.servicedemo;
    
    import android.content.Intent;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    
    public class MainActivity extends AppCompatActivity {
    
        private Button mBtnStart;
        private Button mBtnStop;
        private Intent intent;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            mBtnStart = findViewById(R.id.bt_start);
            mBtnStop = findViewById(R.id.bt_stop);
            setListener();
        }
    
        private void setListener(){
            OnClick onClick = new OnClick();
            mBtnStart.setOnClickListener(onClick);
            mBtnStop.setOnClickListener(onClick);
        }
    
        private class  OnClick implements View.OnClickListener{
    
            @Override
            public void onClick(View view) {
                int view_id = view.getId();
    
                if(view_id == R.id.bt_start){
                    if(null == intent)
                        intent = new Intent(MainActivity.this, MyService.class);
                    startService(intent);
                    MyService.isMyServiceRunning = true;
                }else if(view_id == R.id.bt_stop){
                    if(null != intent){
                        stopService(intent);
                        MyService.isMyServiceRunning = false;
                    }
                }
            }
        }
    }

MyService.java

package com.spacesoftwares.servicedemo;
    
    import android.app.Activity;
    import android.app.ActivityManager;
    import android.app.Service;
    import android.content.Context;
    import android.content.Intent;
    import android.os.IBinder;
    import android.util.Log;
    
    import java.util.ArrayList;
    
    public class MyService extends Service {
    
        public static boolean isMyServiceRunning = false;
    
        public MyService() {
        }
    
        private String TAG = "MyService";
        @Override
        public void onCreate() {
            super.onCreate();
            Log.i(TAG, "service created");
        }
    
        @Override
        public int onStartCommand(Intent intent, int flags, int startId) {
            Log.i(TAG, "service start command");
            new Thread(new Runnable() {
                @Override
                public void run() {
                    int i = 0;
    
                    while(isRunning()) // or, you can use while(isMyServiceRunning) here instead of isRunning
                    {
                        Log.i(TAG, "SERVICE IS RUNNING for " + String.valueOf(i++) + " seconds");
                        try {
                            Thread.sleep(1000);
                        }catch (InterruptedException e){
                            e.printStackTrace();
                        }
                    }
                }
            }).start();
            return super.onStartCommand(intent, flags, startId);
        }
    
        @Override
        public void onDestroy() {
            super.onDestroy();
            Log.i(TAG, "service destroyed");
        }
    
        @Override
        public IBinder onBind(Intent intent) {
            // TODO: Return the communication channel to the service.
            throw new UnsupportedOperationException("Not yet implemented");
        }
    
        // 请注意getRunningServices 已经标记为deprecated, 如果要达到类似效果，请使用isMyServiceRunning来代替isRunning()
        public boolean isRunning(){
            ActivityManager activityManager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
            ArrayList<ActivityManager.RunningServiceInfo> runningService =
                    (ArrayList<ActivityManager.RunningServiceInfo>) activityManager.getRunningServices(40);
            for(int i=0; i<runningService.size();i++){
                String name = runningService.get(i).service.getClassName().toString();
                if(name.equals("com.spacesoftwares.servicedemo.MyService")){
                    return true;
                }
            }
            return  false;
        }
    }

res->values->strings.xml

<resources>
        <string name="app_name">ServiceDemo</string>
        <string name="start_service">StartServiceDemo</string>
        <string name="stop_service">StopServiceDemo</string>
    </resources>

[70]: /images/20220518/5f38398f19944a50b9d49025fa1b7f68.png