-2 
  public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.artistname);

    Bundle extras = getIntent().getExtras(); 
    String val = extras.getString("artistname");

    //Toast.makeText(getApplicationContext(), val, Toast.LENGTH_LONG).show();


    String result = null;
    InputStream is = null;
    StringBuilder sb = null;

    ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();

    try{

    //http post
    HttpClient httpclient = new DefaultHttpClient();
    //HttpPost httppost = new HttpPost("http://192.168.0.5/staging/android/get_search_result.php?keyword=Chinna_Mani&format=json");

HttpPost httppost = new HttpPost("http://192.168.0.5/staging/android/get_search_result.php?keyword="+val+"&format=json&flg=1");

    //HttpPost httppost = new HttpPost("http://192.168.0.5/staging/android/ilaiyarajawebservice.php?format=xml");
    httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
    HttpResponse response = httpclient.execute(httppost);
    HttpEntity entity = response.getEntity();
    is = entity.getContent();
    }
    catch(Exception e){
        Toast.makeText(getBaseContext(),e.toString() ,Toast.LENGTH_LONG).show();
   }

    //Convert response to string  
    try
    {
      BufferedReader reader = new BufferedReader(new InputStreamReader(is,"UTF-8"));

      sb = new StringBuilder();

      String line = null;

      while ((line = reader.readLine()) != null) 
      {
         sb.append(line + "\n");
      }

      is.close();

      result = sb.toString();
    }
    catch(Exception e)
    {
        Toast.makeText(getBaseContext(),e.toString() ,Toast.LENGTH_LONG).show();
    }
    //END Convert response to string   
    try{
            JSONArray jArray = new JSONArray(result);
            JSONObject json_data=null;
            for(int i=0;i<jArray.length();i++)
            {
               json_data = jArray.getJSONObject(i);


               r.add(json_data.getString("artistfirstname"));


              // r.add(json_data.getString("file_name")+json_data.getString("artist_name") +json_data.getString("album_name"));

            }                                              
        }                            



    catch (JSONException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }

            finally {      



        Cursor cursor = getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null, null, null);



         if(null != cursor)
        {

                 cursor.moveToFirst();

                setListAdapter(new ArrayAdapter<String>(this,R.layout.custom_list_item, r));

             }
             else{

//我想要这样我在这里开发警报消息未找到播放列表

                 System.out.println("playlist not  found");

        }
        }
            }

如果值r有内容然后显示，我需要帮助，如果没有内容，那么我想设置警报“未找到列表”我该如何实现？我尝试使用其他但没有成功。

4

4 回答 4

1 
if(null != cursor && cursor.getCount()>0 )//check cursor is not null and having atleast 1 data
 {
    cursor.moveToFirst();
    setListAdapter(new ArrayAdapter<String>(this,R.layout.custom_list_item, r));        

    //do your operation with content
 }
else
  //show alert here i.e. no list found
于 2012-06-22T06:46:31.587 回答
0 
if(null != cursor)
{
    //other work......

    if (cursor.getCount () > 0 )
    {        
         //show alert 

    } 
    else
    {
        cursor.moveToFirst();
        setListAdapter(new ArrayAdapter<String>(this,R.layout.custom_list_item, r));
    }
于 2012-06-22T06:45:57.950 回答
0

您只需要检查游标，如果游标至少有一个数据然后尝试移动到第一条记录，如果有第一条记录则cursor.moveToFirst()返回boolean值然后为真否则为假，您可以直接使用它来检查游标是否已获取数据或不如下。

if(cursor.moveToFirst())
{
   //Populate Contents
}
else
{
  //No Contents Found
}
于 2012-06-22T06:48:33.113 回答
0 
if(r.size()>0){    
 Cursor cursor = getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null, null, null);

     if(null != cursor)
     {
        cursor.moveToFirst();
    setListAdapter(new ArrayAdapter<String>(this,R.layout.custom_list_item, r));        
//here I need help the value are having content means display, if not have content means I want set alert no list found how? I will try else but not success.



   }
}else{

您可以通过创建对话框来向她显示警报并告诉用户该列表为空以创建对话框您可以参考最佳链接..

   }

刚刚添加了检查 arraylist 是否包含元素，如果没有，那么您可以通过 Toast 或对话框显示警报，因为我为其提供了链接。--------------------------这是您的问题解决方案------------------- ----------------------

public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.artistname);

    Bundle extras = getIntent().getExtras(); 
    String val = extras.getString("artistname");

    //Toast.makeText(getApplicationContext(), val, Toast.LENGTH_LONG).show();


    String result = null;
    InputStream is = null;
    StringBuilder sb = null;

    ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();

    try{

    //http post
    HttpClient httpclient = new DefaultHttpClient();
    //HttpPost httppost = new HttpPost("http://192.168.0.5/staging/android/get_search_result.php?keyword=Chinna_Mani&format=json");
HttpPost httppost = new HttpPost("http://192.168.0.5/staging/android/get_search_result.php?keyword="+val+"&format=json&flg=1");

    //HttpPost httppost = new HttpPost("http://192.168.0.5/staging/android/ilaiyarajawebservice.php?format=xml");
    httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
    HttpResponse response = httpclient.execute(httppost);
    HttpEntity entity = response.getEntity();
    is = entity.getContent();
    }
    catch(Exception e){
        Toast.makeText(getBaseContext(),e.toString() ,Toast.LENGTH_LONG).show();
   }

    //Convert response to string  
    try
    {
      BufferedReader reader = new BufferedReader(new InputStreamReader(is,"UTF-8"));

      sb = new StringBuilder();

      String line = null;

      while ((line = reader.readLine()) != null) 
      {
         sb.append(line + "\n");
      }

      is.close();

      result = sb.toString();
    }
    catch(Exception e)
    {
        Toast.makeText(getBaseContext(),e.toString() ,Toast.LENGTH_LONG).show();
    }
    //END Convert response to string   
    try{
            JSONArray jArray = new JSONArray(result);
            JSONObject json_data=null;
            for(int i=0;i<jArray.length();i++)
            {
               json_data = jArray.getJSONObject(i);


               r.add(json_data.getString("artistfirstname"));


              // r.add(json_data.getString("file_name")+json_data.getString("artist_name") +json_data.getString("album_name"));

            }                                              
        }                            



    catch (JSONException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }

            finally {      

if(r.size()>0){

        Cursor cursor = getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null, null, null);



         if(null != cursor)
        {

                 cursor.moveToFirst();

                setListAdapter(new ArrayAdapter<String>(this,R.layout.custom_list_item, r));

             }
}else{

Toast.makeToast(getApplicationcontext(),"no Records ...", Toast.SHORT).show();

        }

        }
            }

希望这个解释对你有用..感谢

于 2012-06-22T06:49:26.983 回答