android 使用Service进行双进程守护，防止进程被杀

以下所用的方法只适用于防止app太久在后台太久而被系统杀死，在系统的一键清除功能下进程还是会被杀死的。

若要防止进程被系统的一键清除功能杀死，要设置允许当前app自启动。如何设置请看 跳转自启动管理页

定义MyService

public class MyService extends Service {    String msg;    public MyService() {        msg = "Msg from MyService";    }    @Override    public IBinder onBind(Intent intent) {        return new MyBinder();    }    public class MyBinder extends Binder{        public String getMsg(){            return msg;        }    }    @Override    public int onStartCommand(Intent intent, int flags, int startId) {        Intent service = new Intent(this, OtherService.class);        startService(service);        bindService(service, sc, Context.BIND_IMPORTANT);        NotificationCompat.Builder builder = new NotificationCompat.Builder(getApplicationContext());        //设置为0，通知栏不可见。设置为1，通知栏可见        startForeground(0, builder.build());        //返回此参数可以在Service因系统资源紧张被杀死的时候尝试重启        return START_STICKY;    }    private ServiceConnection sc = new ServiceConnection() {        @Override        public void onServiceConnected(ComponentName name, IBinder service) {            //由于配置之后OtherService不在同一线程，无法进行交互//            OtherService.OtherBinder otherBinder = (OtherService.OtherBinder) service;//            Toast.makeText(MyService.this, otherBinder.getMsg(), Toast.LENGTH_SHORT).show();            Toast.makeText(getApplicationContext(),"绑定MyService",Toast.LENGTH_SHORT).show();        }        @Override        public void onServiceDisconnected(ComponentName name) {            // 连接出现了异常断开了，OtherService被杀掉了            Toast.makeText(getApplicationContext(),"OtherService挂了",Toast.LENGTH_SHORT).show();            Intent service = new Intent(MyService.this, OtherService.class);            startService(service);            bindService(service, sc, Context.BIND_IMPORTANT);        }    };}

定义OtherService

public class OtherService extends Service {    String msg;    public OtherService() {        msg = "Msg from OtherService";    }    @Override    public IBinder onBind(Intent intent) {        return new OtherBinder();    }    public class OtherBinder extends Binder {        public String getMsg(){            return msg;        }    }    @Override    public int onStartCommand(Intent intent, int flags, int startId) {        Intent service = new Intent(this, MyService.class);        startService(service);        bindService(service, sc, Context.BIND_IMPORTANT);        return START_STICKY;    }    private ServiceConnection sc = new ServiceConnection() {        @Override        public void onServiceConnected(ComponentName name, IBinder service) {//            MyService.MyBinder myBinder = (MyService.MyBinder) service;//            Toast.makeText(OtherService.this,myBinder.getMsg(),Toast.LENGTH_SHORT).show();            Toast.makeText(getApplicationContext(),"绑定OtherService",Toast.LENGTH_SHORT).show();        }        @Override        public void onServiceDisconnected(ComponentName name) {            // 连接出现了异常断开了，MyService被杀掉了            Toast.makeText(getApplicationContext(),"MyService挂了",Toast.LENGTH_SHORT).show();            Intent service = new Intent(OtherService.this, MyService.class);            startService(service);            bindService(service, sc, Context.BIND_IMPORTANT);        }    };}

配置manifest

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.zero.servicetest">    <application        android:allowBackup="true"        android:icon="@mipmap/ic_launcher"        android:label="@string/app_name"        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" />        <!--运行在“:OtherService”线程，防止两个服务一起被杀死-->        <service            android:name=".OtherService"            android:enabled="true"            android:exported="false"            android:process=":OtherService"></service>    </application></manifest>

开启服务

public class MainActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        Intent intent = new Intent(this, MyService.class);        startService(intent);        Intent intent2 = new Intent(this, OtherService.class);        startService(intent2);    }    }