Activity全局管理類

public class ActivityManager{
       private static WeakReference<Activity> curAct;
       private static WeakHashMap<Activity, Object> acList = new WeakHashMap<>();

     /**
      * 設置當前activity
     *
     * @param act
    */
   public static void setCurActivity(Activity act) {
     curAct = new WeakReference<>(act);
     acList.put(act, null);
  }

 public static Activity getCurActivity() {
     if (acList == null || acList.isEmpty())
        return null;
    WeakReference<Activity> wr = curAct;
    if (wr != null) {
        return wr.get();
    }
    return null;
}

public static void clearCurActivity(Activity act) {
    Object remove = acList.remove(act);
    if (remove != null && TextUtils
        .equals(remove.getClass().getSimpleName(), curAct.get().getClass().getSimpleName())) {

    }
}

public static void destroyAllActivity() {
    if (null != acList && !acList.isEmpty()) {
        Object[] keys = acList.keySet().toArray();
        for (Object obj : keys) {
            Activity act = (Activity)obj;
            if (act != null) {
                act.finish();
            }
        }
    }
}
public static void closeActivity(String  activity) {
    if (null != acList && !acList.isEmpty()) {
        Object[] keys = acList.keySet().toArray();
        for (Object obj : keys) {
            if (obj != null && activity != null && TextUtils.equals(obj.getClass().getSimpleName(),activity)) {
                Activity act = (Activity)obj;
                act.finish();
            }
        }
    }
}