android退出所有Actiivty的实例方法

import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.app.Application;

public class MyApplication extends Application {
	private List<Activity> activityList = new ArrayList<Activity>();
	private static MyApplication instance;

	private MyApplication() {

	}

	// 单列模式获取唯一MyApplication的实例
	static MyApplication getinstance() {
		if (instance == null) {
			instance = new MyApplication();
		}
		return instance;
	}

	// 添加Activity到容器中
	public void addActivity(Activity acivity) {
		activityList.add(acivity);
	}

	// 遍历所有的Activity并fanish
	public void closeAllActiivty() {
		for (int i = 0; i < activityList.size(); i++) {
			Activity activity = activityList.get(i);
			activity.finish();
		}
		System.exit(0);
	}

}

在Activity 的Oncreate（）的方法中执行：
	MyApplication.getinstance().addActivity(FirstActivity.this);

在退出所有的Activity执行：
MyApplication.getinstance().closeAllActiivty();