正在使用AsyncTaskLoader时间。当手机被解锁，重复加载数据，码，如以下：

	static class CouponShopQueryLoader extends

			AsyncTaskLoader<List<CouponStore>> {

		private int couponId;

		public CouponShopQueryLoader(Context context, int couponId) {

			super(context);

			this.couponId = couponId;

		}

		@Override

		protected void onStartLoading() {

			forceLoad();

		}

		@Override

		public List<CouponStore> loadInBackground() {

			//查询数据载入

		}

	}

这时候，非常奇怪的现象就出来了，每次手机解锁后，数据都会反复了，反复载入。经查阅CursorLoader源代码后发现，原来还是自己太嫩了，loader使用时。没有严格遵守android官方帮助文档demo的使用方式。

经改动后：

	static class CouponShopQueryLoader2 extends

			AsyncTaskLoader<List<CouponStore>> {

		private List<CouponStore> mData;

		private int couponId;

		public CouponShopQueryLoader2(Context context, int couponId) {

			super(context);

			this.couponId = couponId;

		}

		// final ForceLoadContentObserver mObserver;

		/* Runs on a worker thread */

		@Override

		public List<CouponStore> loadInBackground() {

			mData = ds.queryShopByCoupon(couponId, pageNo, PAGE_SIZE);

			return mData;

		}

		/* Runs on the UI thread */

		@Override

		public void deliverResult(List<CouponStore> data) {

			if (isReset()) {

				return;

			}

			if (isStarted()) {

				super.deliverResult(data);

			}

		}

		/**

		 * Starts an asynchronous load of the contacts list data. When the

		 * result is ready the callbacks will be called on the UI thread. If a

		 * previous load has been completed and is still valid the result may be

		 * passed to the callbacks immediately.

		 *

		 * Must be called from the UI thread

		 */

		@Override

		protected void onStartLoading() {

			if (mData != null) {

				deliverResult(mData);

			}

			if (takeContentChanged() || mData == null) {

				forceLoad();

			}

		}

		/**

		 * Must be called from the UI thread

		 */

		@Override

		protected void onStopLoading() {

			Log.d("sss", "onStopLoading");

			// Attempt to cancel the current load task if possible.

			cancelLoad();

		}

		@Override

		public void onCanceled(List<CouponStore> cursor) {

			Log.d("sss", "onCanceled");

		}

		@Override

		protected void onReset() {

			super.onReset();

			Log.d("sss", "onReset");

			// Ensure the loader is stopped

			onStopLoading();

			mData = null;

		}

	}

改动后。反复载入的现象攻克了，究其原因是没有重写

	/**

		 * Must be called from the UI thread

		 */

		@Override

		protected void onStopLoading() {

			Log.d("sss", "onStopLoading");

			// Attempt to cancel the current load task if possible.

			cancelLoad();

		}

当手机屏幕关闭时，会调用onStopLoading（）方法，此时应该将loader取消掉，当屏幕解锁时，会去运行onStartLoading（）方法，在onStartLoading方法中依据数据是否须要又一次载入进行推断。而假设不在onStartLoading进行loader状态推断的话。就导致了数据反复载入的问题！ ok---攻克了！

提示：在学习android开发中。官方文档事实上是非常好的，遵守他们的编写规范，能够使自己少走好多弯路。