Activity管理类

public class AppManager {    private static AppManager instance;    private Stack<Activity> activityStack;    /**     * 私有的构造函数     */    private AppManager() {        if (null == activityStack) {            activityStack = new Stack<>();        }    }    public static AppManager getInstance() {        if (null == instance) {            instance = new AppManager();        }        return instance;    }    /**     * 添加Activity到堆栈     */    public void addActivity(Activity activity) {        activityStack.add(activity);    }    /**     * 获取当前Activity（堆栈中最后一个压入的）     */    public Activity currentActivity() {        return activityStack.lastElement();    }    /**     * 结束当前Activity（堆栈中最后一个压入的）     */    public void finishCurrentActivity() {        finishActivity(activityStack.lastElement());    }    /**     * 结束指定的Activity     */    public void finishActivity(Activity activity) {        if (null != activity) {            activityStack.remove(activity);            activity.finish();            activity = null;        }    }    /**     * 结束指定类名的Activity     */    public void finishActivity(Class<?> cls) {        for (Activity activity : activityStack) {            if (activity.getClass().equals(cls)) {                finishActivity(activity);            }        }    }    /**     * 结束所有Activity     */    public void finishAllActivity() {        for (int i = 0, size = activityStack.size(); i < size; i++) {            if (null != activityStack.get(i)) {                activityStack.get(i).finish();            }        }        activityStack.clear();    }    /**     * 退出应用程序     */    public void AppExit(Context context) {        try {            finishAllActivity();            ActivityManager activityMgr = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);            activityMgr.killBackgroundProcesses(context.getPackageName());            System.exit(0);        } catch (Exception e) {        }    }    /**     * 是否退出了     *     * @return     */    public boolean isAppExit() {        return null == activityStack || activityStack.isEmpty();    }    /**     * 某个Activity是否存在     *     * @param cls     * @return     */    public boolean isExistActivity(Class<?> cls) {        for (Activity activity : activityStack) {            if (activity.getLocalClassName().contains(cls.getSimpleName())) {                return true;            }        }        return false;    }    /**     * 除了cls,结束所有的Activity     * @param cls     */    public void finishAllActivityExcept(Class<?> cls) {        for (Activity activity : activityStack) {            if (!activity.getClass().equals(cls)) {                finishActivity(activity);            }        }    }}