Service

Service生命周期

知識點:
Service中的onBind方法,返回IBinder接口,如果直接實現(xiàn),方法數(shù)太多,因此返回自定義MyBinder繼承Binder類

@Override
public IBinder onBind(Intent intent) {
    return new IBinder() {
        @Override
        public String getInterfaceDescriptor() throws RemoteException {
            return null;
        }
        @Override
        public boolean pingBinder() {
            return false;
        }
        @Override
        public boolean isBinderAlive() {
            return false;
        }

合理的寫法

@Override
public IBinder onBind(Intent intent) {
    Log.i("zhang","服務(wù) onBind");
    return new MyBinder();
}
public class MyBinder extends Binder {
    //自定義方法
    //比如 我要獲取這個service
    public MyService getService() {
        return MyService.this;
    }
}

綁定服務(wù)會隨著Activity結(jié)束而結(jié)束,啟動服務(wù)則不受activity影響

MainActivity

    private ServiceConnection mConnection=new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            Log.i("zhang","服務(wù) mConnection onServiceConnected");
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            Log.i("zhang","服務(wù) mConnection disConnected");
        }
    };

    @butterknife.OnClick({R.id.start, R.id.stop, R.id.bind, R.id.unbind})
    public void onViewClicked(View view) {
        switch (view.getId()) {
            case R.id.start:
                Intent intent = new Intent(MainActivity.this, MyService.class);
                startService(intent);
                break;
            case R.id.stop:
                stopService(new Intent(MainActivity.this, MyService.class));
                break;
            case R.id.bind:
                Intent bindintent = new Intent(MainActivity.this, MyService.class);
                bindService(bindintent,mConnection,BIND_AUTO_CREATE);
                break;
            case R.id.unbind:
                unbindService(mConnection);
                break;
        }
    }

MyService

    @Override
    public IBinder onBind(Intent intent) {
        Log.i("zhang","服務(wù) onBind");
        return new MyBinder();
    }

    @Override
    public void onCreate() {
        super.onCreate();
        Log.i("zhang","服務(wù) onCreate");
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.i("zhang","服務(wù) onStartCommand");
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.i("zhang","服務(wù) onDestroy");
    }

    @Override
    public boolean onUnbind(Intent intent) {
        Log.i("zhang","服務(wù) onUnbind");
        return super.onUnbind(intent);
    }

    public class MyBinder extends Binder {
        //自定義方法
        //比如 我要獲取這個service
        public MyService getService() {
            return MyService.this;
        }
    }

AndroidManifest

        <service
            android:name=".MyService">
        </service>

運行

1. start -> stop

說明啟動service,一定會調(diào)用onStartCommand方法

2. start -> start

重復(fù)啟動service,只會調(diào)用一次onCreate方法,onStartCommand可多次調(diào)用

3. bind -> unbind

bind也能創(chuàng)建service,執(zhí)行onCreate方法

4. bind -> start

bind之后start service,不會重新onCreate,只會執(zhí)行onStartCommond

5. bind -> start -> stop

6. bind -> start -> unbind

bind創(chuàng)建的Service,start之后,unbind只能解綁,不能銷毀

7.bind -> start -> unbind ->stop

同上5,6,7對比,說明bind創(chuàng)建的Service,start之后,如果要銷毀service,必須先unbind,然后stop,才能銷毀

8. bind -> bind

重復(fù)bind并未執(zhí)行任何方法

9. bind -> start ->unbind ->bind

若要執(zhí)行ServiceConnection的方法,必須先unbind,然后bind調(diào)用
即可獲得值service中的值,達到實時監(jiān)控service中的值方法

10. bind -> 點擊返回鍵

activity銷毀之后,bind的service也unbind,銷毀

11. bind -> start ->點擊返回鍵

中間加了start步驟,即使activity銷毀之后,service也不會被銷毀,只會解綁

案例:

耗時操作放在onStartCommond中執(zhí)行
實時獲取線程中的值,需要bind
bind之后,start執(zhí)行,然后重復(fù)unbind bind操作,就可以通過serviceConn中的方法獲取值