先贴代码：
NewsFragment.java
public class NewsFragment extends Fragment {
private final static String TAG = "NewsFragment";
Activity activity;
ArrayList<NewsEntity> newsList = new ArrayList<NewsEntity>();
HeadListView mListView;
NewsAdapter mAdapter;
int channel_id;
ImageView detail_loading;
public final static int SET_NEWSLIST = 0;
/** 此方法意思为fragment是否可见 ,可见时候加载数据 */
@Override
public void setUserVisibleHint(boolean isVisibleToUser) { //onCreateView之前调用的
if (isVisibleToUser) {
System.out.println("isVisibleToUser");
System.out.println(channel_id);
if (channel_id == 0) {
channel_id = 1;
}
initData();
//fragment可见时加载数据
if(newsList !=null && newsList.size() !=0){
System.out.println("newList not null");
handler.obtainMessage(SET_NEWSLIST).sendToTarget();
}else{
System.out.println("newList null");
new Thread(new Runnable() {
@Override
public void run() {
try {
Thread.sleep(2);
} catch (InterruptedException e) {
e.printStackTrace();
}
handler.obtainMessage(SET_NEWSLIST).sendToTarget();
}
}).start();
}
}else{
System.out.println("isNotVisibleToUser");
//fragment不可见时不执行操作
}
super.setUserVisibleHint(isVisibleToUser);
}
// OnPageChangeListener
@Override
public void onAttach(Activity activity) {
System.out.println("news_frag_onAttach");
this.activity = activity;
super.onAttach(activity);
}
@Override
public void onCreate(Bundle savedInstanceState) {
System.out.println("news_frag_onCreate");
Bundle args = getArguments(); //传值
// text = args != null ? args.getString("text") : "";
channel_id = args != null ? args.getInt("id", 0) : 0;
System.out.println("NewsFragment_channel_id:"+channel_id);
if (getUserVisibleHint()) {
System.out.println("onCreate_getUserVisibleHint");
}
super.onCreate(savedInstanceState);
}
@SuppressLint("InflateParams")
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
System.out.println("news_frag_onCreateView");
View view = LayoutInflater.from(getActivity()).inflate(R.layout.news_fragment, null);
mListView = (HeadListView) view.findViewById(R.id.mListView);
detail_loading = (ImageView)view.findViewById(R.id.detail_loading);
return view;
}
private void initData() {
//newsList.clear();
newsList = Constants2.getNewsList(channel_id);
}
@SuppressLint("HandlerLeak")
Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
System.out.println("handler:"+msg.what);
switch (msg.what) {
case SET_NEWSLIST:
detail_loading.setVisibility(View.GONE);
if(mAdapter == null){
mAdapter = new NewsAdapter(activity, newsList);
//判断是不是城市的频道
if(channel_id == Constants2.CHANNEL_CITY){
//是城市频道
mAdapter.setCityChannel(true);
initCityChannel();
}
}
mListView.setAdapter(mAdapter);
mListView.setOnScrollListener(mAdapter);
mListView.setPinnedHeaderView(LayoutInflater.from(activity).inflate(R.layout.list_item_section, mListView, false));
mListView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Intent intent = new Intent(activity, DetailsActivity.class);
if(channel_id == Constants2.CHANNEL_CITY){
if(position != 0){
intent.putExtra("news", mAdapter.getItem(position - 1));
startActivity(intent);
activity.overridePendingTransition(R.anim.slide_in_right, R.anim.slide_out_left);
}
}else{
intent.putExtra("news", mAdapter.getItem(position));
startActivity(intent);
activity.overridePendingTransition(R.anim.slide_in_right, R.anim.slide_out_left);
}
}
});
break;
default:
break;
}
super.handleMessage(msg);
}
};
/* 初始化选择城市的header*/
@SuppressLint("InflateParams")
public void initCityChannel() {
View headview = LayoutInflater.from(activity).inflate(R.layout.city_category_list_tip, null);
TextView chose_city_tip = (TextView) headview.findViewById(R.id.chose_city_tip);
chose_city_tip.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(activity, CityListActivity.class);
startActivity(intent);
}
});
mListView.addHeaderView(headview);
}
/* 摧毁视图 */
@Override
public void onDestroyView() {
super.onDestroyView();
Log.d("onDestroyView", "channel_id = " + channel_id);
mAdapter = null;
}
/* 摧毁该Fragment，一般是FragmentActivity 被摧毁的时候伴随着摧毁 */
@Override
public void onDestroy() {
super.onDestroy();
Log.d(TAG, "channel_id = " + channel_id);
}
}
Contants2.java
public class Constants2 {
public static final String GET_NEWS_URL = AppApplication.NEWS_URL+"/getNewsJSON.php";
public static final String GET_Comment_URL = AppApplication.NEWS_URL+"/commentlist.php";
static ArrayList<NewsEntity> newsList = new ArrayList<NewsEntity>();
static ArrayList<CommentEntity> commentList = new ArrayList<CommentEntity>();
static JSONArray jsonArray;
static JSONArray commentJsonArray;
/*
* 获取新闻列表
*/
public static ArrayList<NewsEntity> getNewsList(int channel_id) {
AsyncHttpClient client = new AsyncHttpClient();
RequestParams params = new RequestParams();
params.add("channel_id", String.valueOf(channel_id));
System.out.println("Constants2_channel_id:"+String.valueOf(channel_id));
client.post(GET_NEWS_URL, params, new AsyncHttpResponseHandler() {
@Override
public void onSuccess(int i, Header[] handler, byte[] bytes) {
String response = new String(bytes);
Log.e("debug","response:"+response);
try {
jsonArray = new JSONArray(response);
} catch (JSONException e) {
System.err.println("newslist_jsonArray_error");
e.printStackTrace();
}
}
@Override
public void onFailure(int arg0, Header[] arg1, byte[] arg2, Throwable arg3) {
System.out.println("数据错误!!");
}
});
if (jsonArray != null) {
System.out.println("/////////////////////////");
System.out.println(jsonArray.length());
newsList.clear();
for(int i =0 ; i < jsonArray.length() ; i++){
try {
JSONObject obj = jsonArray.getJSONObject(i);
NewsEntity news = new NewsEntity();
news.setId(i);
news.setNewsId(obj.getString("newsId"));
news.setCollectStatus(false);
news.setCommentNum(i + 10);
news.setInterestedStatus(true);
news.setLikeStatus(true);
news.setReadStatus(false);
news.setNewsCategory("推荐");
news.setNewsCategoryId(1);
news.setSource_url("");
news.setTitle(obj.getString("title"));
List<String> url_list = new ArrayList<String>();
news.setPicOne(obj.getString("pic_url"));
url_list.add(obj.getString("pic_url"));
news.setPicList(url_list);
news.setReporter(obj.getString("reporter"));
news.setPublishTime(obj.getString("time"));
news.setReadStatus(false);
news.setSource("手机腾讯网");
news.setContent(obj.getString("content"));
news.setSummary("腾讯数码讯（编译：Gin）谷歌眼镜可能是目前最酷的可穿戴数码设备，你可以戴着它去任何地方（只要法律法规允许或是没有引起众怒），作为手机的第二块“增强现实显示屏”来使用。另外，虽然它仍未正式销售，但谷歌近日在美国市场举行了仅限一天的开放购买活动，价格则为1500美元（约合人民币9330元），虽然仍十分昂贵，但至少可以满足一些尝鲜者的需求，也预示着谷歌眼镜的公开大规模销售离我们越来越近了。");
news.setMark(i);
news.setIsLarge(false);
if(i == 2){
news.setComment("评论部分，说的非常好。");
}
// news.setPublishTime(Long.valueOf(obj.getString("time")));
if(i <= 2){
news.setPublishTime(DateTools.getTime());
}else if(i >2 && i <= 5){
news.setPublishTime(String.valueOf(Long.valueOf(DateTools.getTime()) - 86400));
}else{
news.setPublishTime(String.valueOf(Long.valueOf(DateTools.getTime()) - 86400 * 2));
}
newsList.add(news);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
return newsList;
}
}
流程是这样：
当前fragment可视时通过initData()加载数据，就是调用Constants2的getNewsList(channel_id) 方法，_该方法执行异步任务返回一个newsList,现在的问题是首次加载的时候数据显示，请问有什么解决方法？
