Android 監聽各個Acitivity的生命週期

在Application註冊對該應用Activity的監聽

package com.example.test.app;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.Application;
import android.os.Bundle;

public class MyApplication extends Application
{
    @SuppressLint("NewApi") @Override
    public void onCreate()
    {
        super.onCreate();
        registerActivityLifecycleCallbacks(new ActivityLifecycleCallbacks()
        {

            @Override
            public void onActivityStopped(Activity activity)
            {
                System.out.println("======>>>>>>" + activity.getClass().getCanonicalName() + " onActivityStopped");
            }

            @Override
            public void onActivityStarted(Activity activity)
            {
                System.out.println("======>>>>>>" + activity.getClass().getCanonicalName() + " onActivityStarted");

            }

            @Override
            public void onActivitySaveInstanceState(Activity activity, Bundle outState)
            {
                System.out.println("======>>>>>>" + activity.getClass().getCanonicalName() + " onActivitySaveInstanceState");

            }

            @Override
            public void onActivityResumed(Activity activity)
            {
                System.out.println("======>>>>>>" + activity.getClass().getCanonicalName() + " onActivityResumed");

            }

            @Override
            public void onActivityPaused(Activity activity)
            {
                System.out.println("======>>>>>>" + activity.getClass().getCanonicalName() + " onActivityPaused");

            }

            @Override
            public void onActivityDestroyed(Activity activity)
            {
                System.out.println("======>>>>>>" + activity.getClass().getCanonicalName() + " onActivityDestroyed");

            }

            @Override
            public void onActivityCreated(Activity activity, Bundle savedInstanceState)
            {
                System.out.println("======>>>>>>" + activity.getClass().getCanonicalName() + " onActivityCreated");
            }
        });
    }
}

兩個Activity

package com.example.test;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;

public class MainActivity extends Activity
{

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        startActivity(new Intent(this, SecondActivity.class));
    }
}

package com.example.test;

import android.app.Activity;
import android.os.Bundle;

public class SecondActivity extends Activity
{
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
    }
}

打開應用MainActivity然後進入SecondActivity,生命週期的監聽打印如下:

03-21 15:09:53.225: I/System.out(4289): ======>>>>>>com.example.test.MainActivity onActivityCreated
03-21 15:09:53.245: I/System.out(4289): ======>>>>>>com.example.test.MainActivity onActivityStarted
03-21 15:09:53.245: I/System.out(4289): ======>>>>>>com.example.test.MainActivity onActivityResumed
03-21 15:09:53.275: I/System.out(4289): ======>>>>>>com.example.test.MainActivity onActivityPaused
03-21 15:09:53.315: I/System.out(4289): ======>>>>>>com.example.test.SecondActivity onActivityCreated
03-21 15:09:53.315: I/System.out(4289): ======>>>>>>com.example.test.SecondActivity onActivityStarted
03-21 15:09:53.315: I/System.out(4289): ======>>>>>>com.example.test.SecondActivity onActivityResumed
03-21 15:09:53.590: I/System.out(4289): ======>>>>>>com.example.test.MainActivity onActivitySaveInstanceState
03-21 15:09:53.590: I/System.out(4289): ======>>>>>>com.example.test.MainActivity onActivityStopped

可以在通過監聽各個Activity做一些統計性的工作，比如多少個Activity處於resume狀態，統計Acitivity使用情況等。再比如每個Activity在每個onCreate時候將其放進集合，在要退出程序的時候，通過掃描集合，挨個finish()
square leakcanary工具即使用onActivityDestroyed回調+weakRefence+refrenceQueue判斷Activity有沒有泄露。（PS：這個是聽別人說的，想想確實能做到）