Question

我有一个列表片段，我试图将解析后的数据显示在列表视图中。应用程序不会崩溃，解析后的数据会出现在日志中，而不会出现在设备或模拟器上。有人可以帮忙吗？

 public class FragmentOne extends ListFragment {

public static final String IMAGE_RESOURCE_ID = "iconResourceID";
public static final String ITEM_NAME = "itemName";

EditText editText;
Button   sendBtn;

// Progress Dialog
private ProgressDialog pDialog;

//Creating JSON Parser object
JSONParser jsonParser = new JSONParser();

ArrayList<HashMap<String, String>> messagesList;

//url to create new post
private static final String url_post_message =    "http://example.com/database/folder/myscript.php";

//url to get all messages
private static String url_view_post = "http://example.com/database/folder/myscript.php";

// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_PID = "pid";
private static final String TAG_MESSAGES = "messages";

//messages JSONArray
JSONArray messages = null;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle       savedInstanceState) {
View view=inflater.inflate(R.layout.fragment_layout_one,container, false);

editText = (EditText) view.findViewById(R.id.editText);
sendBtn = (Button) view.findViewById(R.id.sendBtn);

// button click event  
sendBtn.setOnClickListener(new View.OnClickListener(){

@Override
public void onClick(View v) {
// creating new post in background thread
    new Post().execute();
    }
});

return view;    
}

@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);

// Hashmap for ListView
messagesList = new ArrayList<HashMap<String, String>>();

// Loading messages in Background Thread
new ViewMessages().execute();

// Get listview
ListView lv = getListView();
lv.setOnItemClickListener(new OnItemClickListener() {

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position,
            long id) {
        // TODO Auto-generated method stub

    }});

}

 //Background Async Task to Create new post

类Post扩展了AsyncTask {

 //Before starting background thread Show Progress Dialog
@Override
protected void onPreExecute() {
    super.onPreExecute();
    pDialog = new ProgressDialog(getActivity());
    pDialog.setMessage("Posting..");
    pDialog.setIndeterminate(false);
    pDialog.setCancelable(true);
    pDialog.show();
}

 //Creating post    
 protected String doInBackground(String... args) {
    String messages = editText.getText().toString();

    // Building Parameters
    List<NameValuePair> params = new ArrayList<NameValuePair>();
    params.add(new BasicNameValuePair("messages", messages));

    // getting JSON Object
    // Note that create post url accepts POST method
    JSONObject json = jsonParser.makeHttpRequest(url_post_message,
            "POST", params);

    // check log cat for response
    Log.d("Create Response", json.toString());

    // check for success tag
    try {
        int success = json.getInt(TAG_SUCCESS);

        if (success == 1) {
            // successfully created post
        } else {
            // failed to create post
        }       
    } catch (JSONException e) {
        e.printStackTrace();
    }

    return null;
}

// After completing background task Dismiss the progress dialog   
protected void onPostExecute(String file_url) {

    // dismiss the dialog once done
    pDialog.dismiss();
}

}

/ ** * Background Async Task通过发出HTTP请求来查看所有消息 * * / class ViewMessages扩展了AsyncTask {

//getting all messages from url
protected String doInBackground(String... args) {

    // Building Parameters
    List<NameValuePair> params = new ArrayList<NameValuePair>();

    // getting JSON string from URL
    JSONObject json = jsonParser.makeHttpRequest(url_view_post, "GET", params);

    // Check your log cat for JSON reponse
    Log.d("Messages:", json.toString());

    try {
        // Checking for SUCCESS TAG
        int success = json.getInt(TAG_SUCCESS);

        if (success == 1) {
            // messages found
            // Getting Array of messages
            messages = json.getJSONArray(TAG_MESSAGES);


            // looping through all messages
            for (int i = 0; i < messages.length(); i++) {
                JSONObject c = messages.getJSONObject(i);

                // Storing each json item in variable
                String id = c.getString(TAG_PID);
                String messages = c.getString(TAG_MESSAGES);

                // creating new HashMap
                HashMap<String, String> map = new HashMap<String, String>();

                // adding each child node to HashMap key => value
                map.put(TAG_PID, id);
                map.put(TAG_MESSAGES, messages);

                // adding HashList to ArrayList
                messagesList.add(map);
            }
        } else {

        }
    } catch (JSONException e) {
        e.printStackTrace();
    }

    return null;
}

protected void onPostExecute(String file_url) {

    // updating UI from Background Thread
    runOnUiThread(new Runnable() {
        public void run() {

//Updating parsed JSON data into ListView
`ListAdapter adapter = new SimpleAdapter(getActivity(), messagesList,`     R.layout.list_item, new String[] 
        { TAG_PID, TAG_MESSAGES}, new int[] { R.id.pid, R.id.messages});

            // updating listview
            setListAdapter(adapter);
        }
    });
}

}

    <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <LinearLayout
        android:id="@+id/linearLayout1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical" >

        <ListView
        android:id="@android:id/list"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/linearLayout1"
        android:layout_marginTop="27dp" />

        <TextView
            android:id="@+id/pid"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dp"
            android:textAppearance="?android:attr/textAppearanceLarge" />

         <TextView
            android:id="@+id/messages"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dp"
            android:textAppearance="?android:attr/textAppearanceLarge" />
    </LinearLayout>

    <Button
        android:id="@+id/sendBtn"
        style="?android:attr/buttonStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:layout_marginBottom="16dp"
        android:layout_marginRight="19dp"
        android:text="Button" />

    <EditText
        android:id="@+id/editText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/sendBtn"
        android:layout_weight="1"
        android:ems="10" />

</RelativeLayout>

Answer 1

试试这个并确认我的回答谢谢你:)

将json字符串传递给此方法。它会起作用

 public JSONObject getJSONfromURL(String url)

 {
    InputStream is = null;
   JSONObject jObj = null;
    String json = "";
  try {

     // defaultHttpClient
      DefaultHttpClient httpClient = new DefaultHttpClient();
     HttpGet httpget= new HttpGet(url);
     HttpResponse httpResponse = httpClient.execute(httpget);
     HttpEntity httpEntity = httpResponse.getEntity();
          is = httpEntity.getContent();

} catch (Exception e) {
    e.printStackTrace();
}

try {
    BufferedReader reader = new BufferedReader(new InputStreamReader(is, "UTF-8"), 8);
    StringBuilder sb = new StringBuilder();
    String line = null;
    while ((line = reader.readLine()) != null) {
        sb.append(line + "\n");
    }
    is.close();
    json = sb.toString();
} catch (Exception e) {
    }

try {
    jObj = new JSONObject(json);
} catch (JSONException e) {
    Log.e("JSON Parser", "Error parsing data " + e.toString());
}

return jObj;

}

Answer 2

搞定了！问题不在于我的Json是我需要为我的数据库中的表创建一个节点名称并更改JsonArray名称和for循环以匹配。（消息实际上是我数据库的post表中的一行）

无法将Json Parsed数据显示在listfragment中

2 个答案: