使用lifecycle解耦页面和组件
对于一个需要在activity生命周期的某个阶段执行响应操作的组件，可以让其实现LifecycleObserver接口，并通过注解的方式，在响应的阶段进行操作：
public class MyChronometer extends Chronometer implements LifecycleObserver { private long elapsedTime; public MyChronometer(Context context, AttributeSet attrs) { super(context, attrs); } @OnLifecycleEvent(Lifecycle.Event.ON_RESUME) private void startMeter(){ setBase(SystemClock.elapsedRealtime() - elapsedTime); start(); } @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE) private void stopMeter(){ elapsedTime = SystemClock.elapsedRealtime()-getBase(); stop(); }}并在activity中注册：
public class MainActivity extends AppCompatActivity {
ActivityMainBinding binding;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
binding= DataBindingUtil.setContentView(this,R.layout.activity_main);
getLifecycle().addObserver(binding.chronometer);
}
}使用LifecycleService解耦Service与组件
执行的操作放在一个实现了LifecycleObserver接口的观察者中：
public class MyLocationObserver implements LifecycleObserver { private Context context; private MyLocationListener listener; private LocationManager locationManager; private static String TAG="shopkeepertag"; public MyLocationObserver(Context context) { this.context = context; } @OnLifecycleEvent(Lifecycle.Event.ON_CREATE) private void startGetLocation() { Log.d(TAG, "startGetLocation: "); locationManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE); listener = new MyLocationListener(); if (ActivityCompat.checkSelfPermission(context, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(context, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) { return; } locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 3000, 1, listener); } @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY) private void stopGetLocation(){ Log.d(TAG, "stopGetLocation: "); locationManager.removeUpdates(listener); } static class MyLocationListener implements LocationListener{ @Override public void onLocationChanged(@NonNull Location location) { Log.d(TAG, "onLocationChanged: "+location.toString()); } }}service要继承自LifecycleService，并注册一个观察者：
public class MyLocationService extends LifecycleService { public MyLocationService() { Log.d("sk", "MyLocationService: "); MyLocationObserver observer=new MyLocationObserver(this); getLifecycle().addObserver(observer); }}在activity中启动或者关闭服务时，观察者类就能自动执行操作。
使用ProcessLifecycleOwner监听应用程序生命周期
在Application的不同生命周期要执行的操作用注解的方式放在一个实现了LifecycleObserver接口的观察者中：
public class ApplicationObserver implements LifecycleObserver { private static String TAG="shopkeepertag"; @OnLifecycleEvent(Lifecycle.Event.ON_CREATE) public void onCreated(){ Log.d(TAG, "onCreated: "); } @OnLifecycleEvent(Lifecycle.Event.ON_START) public void onStart(){ Log.d(TAG, "onStart: "); } @OnLifecycleEvent(Lifecycle.Event.ON_RESUME) public void onResume(){ Log.d(TAG, "onResume: "); } @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE) public void onPause(){ Log.d(TAG, "onPause: "); } @OnLifecycleEvent(Lifecycle.Event.ON_STOP) public void onStop(){ Log.d(TAG, "onStop: "); } @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY) public void onDestroy(){ Log.d(TAG, "onDestroy: "); }}在application通过ProcessLifecycleOwner注册一个观察者：
public class MyApplication extends Application { @Override public void onCreate() { super.onCreate(); ProcessLifecycleOwner.get().getLifecycle() .addObserver(new ApplicationObserver()); }}