Android中退出多個Activity的兩個經典方法

用list保存activity實例，然後逐一干掉

上代碼：

import java.util.LinkedList;
import java.util.List;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Application;
import android.content.DialogInterface;
import android.content.Intent;

public class SysApplication extends Application {
private List<Activity> mList = new LinkedList<Activity>();
private static SysApplication instance;

private SysApplication() {
}

public synchronized static SysApplication getInstance() {
   if (null == instance) {
         instance = new SysApplication();
      }
         return instance;
      }

// add Activity
public void addActivity(Activity activity) {
      mList.add(activity);
}

    public void exit() {
        try {
           for (Activity activity : mList) {
              if (activity != null)
                 activity.finish();
                 }
             } catch (Exception e) {
                 e.printStackTrace();
             } finally {
                System.exit(0);
             }
}

@Override
public void onLowMemory() {
    super.onLowMemory();
      System.gc();
}

}
在每個Activity的onCreate方法中添加類似代碼：

[java] public void onCreate(Bundle savedInstanceState) {
             super.onCreate(savedInstanceState);
                SysApplication.getInstance().addActivity(this);
            }
       public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            SysApplication.getInstance().addActivity(this);
        }

在需要退出程序的時候，調用：

SysApplication.getInstance().exit();
SysApplication.getInstance().exit();

簡而言之，通過單例模式把每個Activity 的引用添加到一個全局鏈表中，每次退出程序調用System.exit(0)時，先調用鏈表中Activity 的finish方法