转载请加入链接,谢谢:http://blog.csdn.net/u013173289/article/details/44002371
上次写了一个问答项目,用的fragment+viewpager架构,后来发现,划了几次之后,再划回来,会重新加载布局,重新获取数据,这样整个程序和卡,并且占用太多的网络资源。
当时的解决办法是,自己重写view,用最基本的Basepageradapder,算是不是很优雅的解决了问题。
当时知道是重新调用onCreateView方法原因,但是没有好的解决办法,现在知道了,这里记载一下。
我实验了viewpager加载四个fragment:
第一次进入的时候:
<span style="font-size:18px;">03-01 13:50:16.151 22667-22667/com.graypn.modelproject I/onCreate1﹕ onCreate 03-01 13:50:16.151 22667-22667/com.graypn.modelproject I/onCreateView1﹕ onCreateView 03-01 13:50:16.161 22667-22667/com.graypn.modelproject I/onActivityCreated1﹕ onActivityCreated 03-01 13:50:16.161 22667-22667/com.graypn.modelproject I/onCreate2﹕ onCreate 03-01 13:50:16.161 22667-22667/com.graypn.modelproject I/onCreateView2﹕ onCreateView 03-01 13:50:16.161 22667-22667/com.graypn.modelproject I/onActivityCreated2﹕ onActivityCreated</span>往右滑动到第二个界面:
<span style="font-size:18px;">03-01 13:51:22.391 22667-22667/com.graypn.modelproject I/onCreate3﹕ onCreate 03-01 13:51:22.391 22667-22667/com.graypn.modelproject I/onCreateView3﹕ onCreateView 03-01 13:51:22.401 22667-22667/com.graypn.modelproject I/onActivityCreated3﹕ onActivityCreated</span>往右滑动到第三个界面:
03-01 13:55:24.351 24165-24165/com.graypn.modelproject I/onDestroyView1﹕ onDestroyView 03-01 13:55:24.351 24165-24165/com.graypn.modelproject I/onCreate4﹕ onCreate 03-01 13:55:24.351 24165-24165/com.graypn.modelproject I/onCreateView4﹕ onCreateView 03-01 13:55:24.361 24165-24165/com.graypn.modelproject I/onActivityCreated4﹕ onActivityCreated往右滑动到第四个界面:
03-01 13:56:22.021 24165-24165/com.graypn.modelproject I/onDestroyView2﹕ onDestroyView往左划到第三个界面:
03-01 13:58:09.541 24165-24165/com.graypn.modelproject I/onCreateView2﹕ onCreateView 03-01 13:58:09.541 24165-24165/com.graypn.modelproject I/onActivityCreated2﹕ onActivityCreated结论:viewpager会加载和当前页面相连的两个fragment,会销毁相邻第三个页面的view,再次调用是会重新oncreateview和onactivityreate。
我们需要优化自己的fragment,如下时我优化后的类:
<span style="font-size:18px;">/** * 提供了fragment的封装后基类,提供context给子类使用 * * @author Graypn */ public abstract class BaseFragment extends Fragment { //根部view private View rootView; protected Context context; private Boolean hasInitData = false; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); context = getActivity(); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { if (rootView == null) { rootView = initView(inflater); } return rootView; } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); if (!hasInitData) { initData(); hasInitData = true; } } @Override public void onDestroyView() { super.onDestroyView(); ((ViewGroup) rootView.getParent()).removeView(rootView); } /** * 子类实现初始化View操作 */ protected abstract View initView(LayoutInflater inflater); /** * 子类实现初始化数据操作(子类自己调用) */ public abstract void initData(); /** * 封装从网络下载数据 */ protected void loadData(HttpRequest.HttpMethod method, String url, RequestParams params, RequestCallBack<String> callback) { if (0 == NetUtils.isNetworkAvailable(getActivity())) { new CustomToast(getActivity(), "无网络,请检查网络连接!", 0).show(); } else { NetUtils.loadData(method, url, params, callback); } } }</span>
加入判断是否已经加载数据完成的标志变量,如果已经加载了数据,就不重新加载数据。
算是优雅的解决了优化的问题,希望能帮到有同样问题的同学。
原文地址:http://blog.csdn.net/u013173289/article/details/44002371