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当我单击一个选项卡时，您必须链接到另一个类别。问题是它失败了。当我在我的代码中加载 json 时，它不会从我希望它返回到主类的类中加载。

这是我的Java代码：

public class Sport extends ExampleActivity {
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);




        }


    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.refresh:     
                loadData();
            break;
        }
        return true;
    }

    public void loadData() {
        Utils.init();

        progressDialog = ProgressDialog.show(Sport.this, getString(R.string.app_name), "Laden...");
        new GetDataTask().execute();
    }

    private void _showMessage(String msg) {
        Toast.makeText(Sport.this, msg, Toast.LENGTH_LONG).show();
    }

    private boolean _hasConnection() {
        ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        // test for connection
        if (cm.getActiveNetworkInfo() != null
                && cm.getActiveNetworkInfo().isAvailable()
                && cm.getActiveNetworkInfo().isConnected()) {
            return true;
        } else {
            System.out.println("Internet Connection Not Present");
            return false;
        }
    }

    private class GetDataTask extends AsyncTask<Void, Void, Integer> {

        protected Integer doInBackground(Void... params) {

    Private class GetDataTask extends AsyncTask<Void, Void, Integer> 
    {

    protected Integer doInBackground(Void... params) 
    {
     if(_hasConnection())
     {
    dataList.clear();
    System.out.println("Start loading JSON");
    JSONArray json =JSONFunctions.getJSONfromURL("http://www.example.com/report.phpcategory=sport&image=50x50&limit=40");
    System.out.println("End loading JSON");
    for (int i = 0; i < json.length(); i++) {
    try {
    JSONObject row = json.getJSONObject(i);
    HashMap<String, String> map = new HashMap<String, String>();
    map.put("id", row.getString("id"));
    map.put("title", row.getString("title"));
    map.put("image", row.getString("image"));
    map.put("date", row.getString("date"));
    dataList.add(map);
    } 
    catch (JSONException e) 
    {
    e.printStackTrace();
    }
    }
    System.out.println("End putting in dataList");

And here's is my xml code:

    <?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:layout_width="fill_parent"
                android:layout_height="fill_parent"
                android:orientation="vertical"
                android:padding="5dp" >

                <TabWidget
                    android:id="@android:id/tabs"
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content" />

           <ListView
                android:id="@+id/list_view"
                android:layout_width="fill_parent"
                android:layout_height="fill_parent" >
            </ListView>

                <FrameLayout
                    android:id="@android:id/tabcontent"
                    android:layout_width="fill_parent"
                    android:layout_height="fill_parent"
                    android:padding="5dp" >

                    <ListView
                        android:id="@+id/listView1"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content" >
                    </ListView>
                </FrameLayout>
            </LinearLayout>

        </TabHost>
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