前言

在android開發(fā)中我們都會(huì)遇到一個(gè)需求忱叭，那就是退出應(yīng)用眉尸，那么我們都會(huì)退出所有的activity寺旺。
我們一般常用的方式有下面幾種：

第一種方式

我們寫一個(gè)BaseActivity燕少，在activity的創(chuàng)建的時(shí)候添加當(dāng)前activity到集合中，在activity銷毀的時(shí)候把當(dāng)前activity移除出activity集合盆赤。退出應(yīng)用時(shí)直接遍歷activity集合贾富，然后分別調(diào)用activity的finish()方法。

package com.huangjie.exitapplication;

import android.app.Activity;

import java.util.ArrayList;

/**
 * 應(yīng)用管理類
 */

public class ActivityManager {
    private static ArrayList<Activity> mActivityList;

    private ActivityManager() {
    }

    /**
     * 添加activity
     *
     * @param activity
     */
    public static void addActivity(Activity activity) {
        if (mActivityList == null) {
            mActivityList = new ArrayList<>();
        }
        mActivityList.add(activity);
    }

    /**
     * 移除activity
     *
     * @param activity
     */
    public static void removeActivity(Activity activity) {
        mActivityList.remove(activity);
    }

    /**
     * 退出應(yīng)用
     */
    public static void exit() {
        for (Activity activity : mActivityList) {
            activity.finish();
        }
        mActivityList.clear();
    }
}

package com.huangjie.exitapplication;

import android.app.Activity;
import android.os.Bundle;
import android.support.annotation.Nullable;

/**
 * Activity基類
 */

public class BaseActivity extends Activity {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ActivityManager.addActivity(this);
    }

    @Override
    protected void onDestroy() {
        ActivityManager.removeActivity(this);
        super.onDestroy();
    }
}

第二種方式廣播式

BaseActivity中注冊(cè)一個(gè)廣播接收器牺六，在廣播接收器中finish掉當(dāng)前activity颤枪。所有的Activity繼承BaseActivity。

package com.huangjie.exitapplication;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.support.annotation.Nullable;


public class BaseActivity extends Activity {
    private static String ACTION = "activity_exit";

    private BroadcastReceiver mExitReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            finish();
        }
    };

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        IntentFilter filter = new IntentFilter();
        filter.addAction(ACTION);
        registerReceiver(mExitReceiver, filter);
    }

    @Override
    protected void onDestroy() {
        unregisterReceiver(mExitReceiver);
        super.onDestroy();
    }
}

還有殺進(jìn)程的方式兔乞。拋異常方式等等汇鞭，這些都不夠優(yōu)雅，第一種方式如果當(dāng)一個(gè)activity異常退出庸追，是不會(huì)回掉onDestroy()方法霍骄，也就意味我們靜態(tài)Activity集合無法移除當(dāng)前activity，會(huì)導(dǎo)致內(nèi)存泄漏淡溯。android 系統(tǒng)為每個(gè)應(yīng)用分配的內(nèi)存都是有限的读整，如果內(nèi)存泄漏到一定程度就會(huì)導(dǎo)致應(yīng)用崩潰。

第三種方式

ActivityLifecycleCallbacks 這個(gè)接口看著名字大概都能猜出來他是activity生命周期回掉接口咱娶。

public interface ActivityLifecycleCallbacks {
        void onActivityCreated(Activity activity, Bundle savedInstanceState);
        void onActivityStarted(Activity activity);
        void onActivityResumed(Activity activity);
        void onActivityPaused(Activity activity);
        void onActivityStopped(Activity activity);
        void onActivitySaveInstanceState(Activity activity, Bundle outState);
        void onActivityDestroyed(Activity activity);
    }

當(dāng)我們一旦給應(yīng)用注冊(cè)了ActivityLifecycleCallbacks米间，那么上面接口中對(duì)應(yīng)的方法都是應(yīng)用中所有activity的生命周期都會(huì)回掉的方法。不管是我們寫的activity膘侮，還是我們引用的第三方庫中activity的生命周期都會(huì)回掉這些方法屈糊。那么我們我們可以在這里做處理。

package com.huangjie.exitapplication;

import android.app.Activity;
import android.app.Application;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import java.util.ArrayList;



public class MyApplication extends Application {
    private ActivityLifecycleCallbacks mcallBack;
    private static ArrayList<Activity> mActiivtyList;

    @Override
    public void onCreate() {
        super.onCreate();
        initLifeCallBack();
        registerActivityLifecycleCallbacks(mcallBack);
    }


    private void initLifeCallBack() {
        mcallBack = new ActivityLifecycleCallbacks() {
            @Override
            public void onActivityCreated(Activity activity, Bundle bundle) {
                if (mActiivtyList == null) {
                    mActiivtyList = new ArrayList<>();
                }
                mActiivtyList.add(activity);
            }

            @Override
            public void onActivityStarted(Activity activity) {

            }

            @Override
            public void onActivityResumed(Activity activity) {

            }

            @Override
            public void onActivityPaused(Activity activity) {

            }

            @Override
            public void onActivityStopped(Activity activity) {

            }

            @Override
            public void onActivitySaveInstanceState(Activity activity, Bundle bundle) {

            }

            @Override
            public void onActivityDestroyed(Activity activity) {
                mActiivtyList.remove(activity);
            }
        };
    }


    /**
     * 退出應(yīng)用程序
     */
    public static void exit() {
        for (Activity activity : mActiivtyList) {
            activity.finish();
        }
        mActiivtyList.clear();
    }

}