一種把每個activity用集合記住，然後逐一干掉；另一種思路是使用廣播。

方法一、用list儲存activity例項，然後逐一干掉

建立一個外部類繼承Application用來存放activity

public class MyActvity extends Application {
    //建立一個集合，用來存放activity的物件
    ArrayList<Activity>list=new ArrayList<>();
    //宣告一個本類的物件
    private static MyActvity instance;
    public
 
 MyActvity() {
    }
    //建立一個方法，用來初始化MyActivity的物件，並且初始化的對像的返回
    public synchronized static MyActvity getInstance(){
        if (instance==null){
            instance=new MyActvity();
        }
        return instance;
    }
    //呼叫此方法用來向集合當中新增activity物件
    public void addActivity(Activity activity){
        list.add(activity);
    }
    //判斷activity是否已經在集合當中
 

    public boolean isexitlist(Activity activity){
        if (list.contains(activity)){
            return true;
        }
        return false;
    }
    //當呼叫此方法的時候，關閉所有的activity
    public void exit(){
        for (Activity activity:list){
            activity.finish();
        }
        //退出當前的MyActivity
 

        System.exit(0);
    }

    @Override
    public void onLowMemory() {
        super.onLowMemory();
        //當系統的儲存空間不夠的時候，呼叫系統的垃圾回收期，清理裡面的垃圾
        System.gc();
    }
}

Activity1程式碼：

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //呼叫存放activity類
        MyActvity instance = MyActvity.getInstance();
        //判斷存放activity類是否存放該activity，不存在加入類
        if (!instance.isexitlist(this)){
            instance.addActivity(this);
        }
        Intent intent = new Intent(this, Main2Activity.class);
        startActivity(intent);
    }
}

Activity2程式碼：

public class Main2Activity extends Activity {

    private MyActvity instance;

    /**
     * Called when the activity is first created.
     */

    @Override+
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sdfa);
        Button bt= (Button) findViewById(R.id.bt);
        instance = MyActvity.getInstance();
        if (!instance.isexitlist(this)){
            instance.addActivity(this);
        }
        bt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
            //呼叫exit（）方法銷燬裡面所有activity
                instance.exit();
            }
        });

    }
}

方法二、使用廣播在activity裡註冊廣播，銷燬時啟動廣播

MainActivity裡註冊廣播：

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Intent intent = new Intent(this, Main2Activity.class);
        startActivity(intent);
        //註冊廣播
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction(Define.PAHNAME);
        registerReceiver(new MyReceiver(),intentFilter);
    }
    class MyReceiver extends BroadcastReceiver{

        @Override
        public void onReceive(Context context, Intent intent) {
            unregisterReceiver(this);
            ((Activity)context).finish();
        }
    }
}

activity2：啟動廣播

public class Main2Activity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sdfa);
        Button bt= (Button) findViewById(R.id.bt);
        bt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(Define.PAHNAME);
                sendBroadcast(intent);
                finish();
            }
        });

    }
}