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();
}
});

}
}