Android中退出多个Activity的两个经典方法

一种把每个activity用集合记住，然后逐一干掉；另一种思路是使用广播。

方法一、用list保存activity实例，然后逐一干掉

创建一个外部类继承Application用来存放activity

public class MyActvity extends Application {
    //创建一个集合，用来存放activity的对象
    ArrayList<Activity>list=new ArrayList<>();
    //声明一个本类的对象
    private static MyActvity instance;
    public MyActvity() {
    }
    //创建一个方法，用来初始化MyActivity的对象，并且初始化的对像的返回
    public synchronized static MyActvity getInstance(){
        if (instance==null){
            instance=new MyActvity();
        }
        return instance;
    }
    //调用此方法用来向集合当中添加activity对象
    public void addActivity(Activity activity){
        list.add(activity);
    }
    //判断activity是否已经在集合当中
    public boolean isexitlist(Activity activity){
        if (list.contains(activity)){
            return true;
        }
        return false;
    }
    //当调用此方法的时候，关闭所有的activity
    public void exit(){
        for (Activity activity:list){
            activity.finish();
        }
        //退出当前的MyActivity
        System.exit(0);
    }

    @Override
    public void onLowMemory() {
        super.onLowMemory();
        //当系统的存储空间不够的时候，调用系统的垃圾回收期，清理里面的垃圾
        System.gc();
    }
}

Activity1代码：

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //调用存放activity类
        MyActvity instance = MyActvity.getInstance();
        //判断存放activity类是否存放该activity，不存在加入类
        if (!instance.isexitlist(this)){
            instance.addActivity(this);
        }
        Intent intent = new Intent(this, Main2Activity.class);
        startActivity(intent);
    }
}

Activity2代码：

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) {
            //调用exit（）方法销毁里面所有activity
                instance.exit();
            }
        });

    }
}

方法二、使用广播在activity里注册广播，销毁时启动广播

MainActivity里注册广播：

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);
        //注册广播
        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：启动广播

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();
            }
        });

    }
}