在 TabActivity 中，一个 TabSpec 由几个 TextView 和下面的 ListView 元素组成。我想用来自外部数据库的 AsyncTask 填充 ListView。在我的应用程序的所有其他具有“标准”布局的部分中，这可以正常工作，但在这里嵌套的 ListView 似乎会产生问题。如果我将数据加载到 TabSpec 的 ListView 中，则应用程序会在 TabActivity 顶部创建一个新的“窗口”，因此“返回”按钮将我带回（空）TabSpec。
这是我的代码：
TabHost (venueview.xml):
<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@android:id/tabhost"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TabWidget
android:id="@android:id/tabs"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<FrameLayout
android:id="@android:id/tabcontent"
android:layout_width="fill_parent"
android:layout_height="fill_parent"/>
</LinearLayout>
</TabHost>
TabSpec 与 ListView (venueviewreviews.xml)：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/txtvname_r"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="txtvname" />
<RatingBar
android:id="@+id/ratingBar"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<Button
android:id="@+id/btnRatingSubmit"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<ListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
</LinearLayout>
下面是创建 TabHost 的代码：
public class VViewActivity extends TabActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.venueview);
TabHost tabHost = getTabHost();
TabSpec vinfospec = tabHost.newTabSpec("Info");
vinfospec.setIndicator("Info",
getResources().getDrawable(R.drawable.ic_info));
Intent vinfoIntent = new Intent(this, VViewBasicActivity.class);
vinfospec.setContent(vinfoIntent);
TabSpec vmapspec = tabHost.newTabSpec("Map");
vmapspec.setIndicator("Location",
getResources().getDrawable(R.drawable.ic_map));
Intent vmapIntent = new Intent(this, VViewMapActivity.class);
vmapspec.setContent(vmapIntent);
TabSpec vreviewsspec = tabHost.newTabSpec("Reviews");
vreviewsspec.setIndicator("Reviews",
getResources().getDrawable(R.drawable.ic_review));
Intent vreviewsIntent = new Intent(this, VViewReviewsActivity.class);
vreviewsspec.setContent(vreviewsIntent);
// Adding all TabSpec to the TabHost for display
tabHost.addTab(vinfospec);
tabHost.addTab(vmapspec);
tabHost.addTab(vreviewsspec);
}
}
这里是我认为问题的根源（双关语）的部分 - 设置 TabSpec 背后的代码， ListView 被正确填充和显示：
public class VViewReviewsActivity extends Activity {
private RatingBar ratingBar;
private TextView txtvname_r;
private Button btnRatingSubmit;
private ListView lvComments;
private static ListAdapter laComments;
String vid;
String vname;
String rating;
private static ArrayList<HashMap<String, String>> commentsList;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.venueviewreviews);
ListView lvComments = (ListView)findViewById(R.id.list);
Intent lc = new Intent(this, GetVenueComments.class);
lc.putExtra("vid",vid);
startActivity(lc);
}
public static class GetVenueComments extends ListActivity {
JSONParser jParser = new JSONParser();
JSONArray comments = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.venueviewreviews);
commentsList = new ArrayList<HashMap<String, String>>();
new LoadAllVenues().execute();
}
/**
* Background Async Task to Load all venues via HTTP Request
* */
class LoadAllVenues extends AsyncTask<String, String, String> {
protected String doInBackground(String... args) {
List<NameValuePair> params = new ArrayList<NameValuePair>();
Intent iCurr = getIntent();
JSONObject json = jParser.makeHttpRequest(
getString(R.string.urlVenueComments), "GET", params);
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
comments = json.getJSONArray(TAG_COMMENTS);
// looping through All Products
for (int i = 0; i < comments.length(); i++) {
JSONObject c = comments.getJSONObject(i);
// creating new HashMap
HashMap<String, String> hashmap = new HashMap<String, String>();
// adding each child node to HashMap key => value
hashmap.put(TAG_COMMENTS_ID, cid);
hashmap.put(TAG_COMMENTS_COMMENT, ctext);
// adding HashList to ArrayList
commentsList.add(hashmap);
}
} else {
// cut to save space
}
} catch (JSONException e) {
// cut to save space
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
// Updating parsed JSON data into ListView
laComments = new SimpleAdapter(
GetVenueComments.this,
commentsList,
R.layout.commentlistitem,
new String[] { TAG_COMMENTS_ID,
TAG_COMMENTS_COMMENT }, new int[] {
R.id.CommentList_id,
R.id.CommentList_comment });
// updating listview
setListAdapter(laComments);
}
});
}
}
}
}
知道我必须解决什么问题才能在 TabSpec 中而不是在单独打开的窗口/活动中显示评论 ListView 吗？