觀察者類,觀察目標(biāo)的生命周期

import android.arch.lifecycle.Lifecycle;
import android.arch.lifecycle.LifecycleObserver;
import android.arch.lifecycle.OnLifecycleEvent;

public class MyObserver implements LifecycleObserver {

    private MyObserver() {

    }

    private static MyObserver m;

    public static MyObserver instance() {
        synchronized (MyObserver.class) {
            if (null == m) {
                synchronized (MyObserver.class) {
                    m = new MyObserver();
                }
            }
        }

        return m;
    }

    @OnLifecycleEvent( Lifecycle.Event.ON_CREATE )
    public void ON_CREATE() {
        System.out.println("MyObserver:ON_CREATE");
    }

    @OnLifecycleEvent( Lifecycle.Event.ON_START )
    public void ON_START() {
        System.out.println("MyObserver:ON_START");
    }

    @OnLifecycleEvent( Lifecycle.Event.ON_RESUME )
    public void ON_RESUME() {
        System.out.println("@@@@@@@@MyObserver:ON_RESUME");
    }

    @OnLifecycleEvent( Lifecycle.Event.ON_PAUSE )
    public void ON_PAUSE() {
        System.out.println("MyObserver:ON_PAUSE");
    }

    @OnLifecycleEvent( Lifecycle.Event.ON_STOP )
    public void ON_STOP() {
        System.out.println("MyObserver:ON_STOP");
    }

    @OnLifecycleEvent( Lifecycle.Event.ON_DESTROY )
    public void ON_DESTROY() {
        System.out.println("MyObserver:ON_DESTROY");
    }


}

被觀察的類,一般是activity或fragment

//實現(xiàn) LifecycleOwner接口
//重寫
LifecycleRegistry mLifecycleRegistry = new LifecycleRegistry(this);
    @NonNull
    @Override
    public Lifecycle getLifecycle() {
        return mLifecycleRegistry;
    }

手動標(biāo)記生命周期

@Override
    public void onStart() {
        super.onStart();
        //標(biāo)記狀態(tài)
        mLifecycleRegistry.markState(Lifecycle.State.STARTED);
    }

    @Override
    protected void onResume() {
        super.onResume();
        //標(biāo)記狀態(tài)
        mLifecycleRegistry.markState(Lifecycle.State.RESUMED);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        //標(biāo)記狀態(tài)
        mLifecycleRegistry.markState(Lifecycle.State.DESTROYED);
    }