java - android listview 的详细 View

Question

我有一个显示属性名称的listView，它运行良好，但在显示每个公告的详细 View 时遇到问题。当您单击 listView 中的项目时，我收到空的 Activity_details，并且调试器中出现以下错误:

W/System.err: org.json.JSONException: Value No of type java.lang.String cannot be converted to JSONArray
W/System.err:     at org.json.JSON.typeMismatch(JSON.java:111)
W/System.err:     at org.json.JSONArray.<init>(JSONArray.java:96)
W/System.err:     at org.json.JSONArray.<init>(JSONArray.java:108)
W/System.err:     at com.example.said.populate.DetailsActivity$GetHttpResponse.doInBackground(DetailsActivity.java:205)
W/System.err:     at com.example.said.populate.DetailsActivity$GetHttpResponse.doInBackground(DetailsActivity.java:180)
W/System.err:     at android.os.AsyncTask$2.call(AsyncTask.java:288)
W/System.err:     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
W/System.err:     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
W/System.err:     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
W/System.err:     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
W/System.err:     at java.lang.Thread.run(Thread.java:831)
Disconnected from the target VM, address: 'localhost:8600', transport: 'socket'

这是用于连接的 PHP 文件:

 <?php

if($_SERVER['REQUEST_METHOD']=='POST'){

include 'DatabaseConfig.php';

 $StudentID= $_POST['propertyid'];

// Create connection
$conn = new mysqli($HostName, $HostUser, $HostPass, $DatabaseName);

if ($conn->connect_error) {

 die("Connection failed: " . $conn->connect_error);
}

$sql = "SELECT * FROM estate2 where id = '$propertyid'" ;

$result = $conn->query($sql);

if ($result->num_rows >0) {


 while($row[] = $result->fetch_assoc()) {

 $tem = $row;

 $json = json_encode($tem);

 }

} else {
 echo "No Results Found.";
}
 echo $json;

$conn->close();
}
?>

下面是我的详细信息 Activity :

public class DetailsActivity extends AppCompatActivity {

    HttpParse httpParse = new HttpParse();
    ProgressDialog pDialog;

    // Http Url For Filter Student Data from Id Sent from previous activity.
    String HttpURL = "https://sultonkhuja1111.000webhostapp.com/MobApp/detail.php";


    String finalResult ;
    HashMap<String,String> hashMap = new HashMap<>();
    String ParseResult ;
    HashMap<String,String> ResultHash = new HashMap<>();
    String FinalJSonObject ;
    TextView NAME,PHONE_NUMBER,CLASS;
    String NameHolder, NumberHolder, ClassHolder;
    Button UpdateButton, DeleteButton;
    String TempItem;
    ProgressDialog progressDialog2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_details);

        NAME = (TextView)findViewById(R.id.textName);
        PHONE_NUMBER = (TextView)findViewById(R.id.textPhone);
        CLASS = (TextView)findViewById(R.id.textClass);

        UpdateButton = (Button)findViewById(R.id.buttonUpdate);
        DeleteButton = (Button)findViewById(R.id.buttonDelete);

        //Receiving the ListView Clicked item value send by previous activity.
        TempItem = getIntent().getStringExtra("ListViewValue");

        //Calling method to filter Student Record and open selected record.
        HttpWebCall(TempItem);

    }


    //Method to show current record Current Selected Record
    public void HttpWebCall(final String PreviousListViewClickedItem){

        class HttpWebCallFunction extends AsyncTask<String,Void,String> {

            @Override
            protected void onPreExecute() {
                super.onPreExecute();

                pDialog = ProgressDialog.show(DetailsActivity.this,"Loading Data",null,true,true);
            }

            @Override
            protected void onPostExecute(String httpResponseMsg) {

                super.onPostExecute(httpResponseMsg);

                pDialog.dismiss();

                //Storing Complete JSon Object into String Variable.
                FinalJSonObject = httpResponseMsg ;

                //Parsing the Stored JSOn String to GetHttpResponse Method.
                new GetHttpResponse(DetailsActivity.this).execute();

            }

            @Override
            protected String doInBackground(String... params) {

                ResultHash.put("propertyid",params[0]);

                ParseResult = httpParse.postRequest(ResultHash, HttpURL);

                return ParseResult;
            }
        }

        HttpWebCallFunction httpWebCallFunction = new HttpWebCallFunction();

        httpWebCallFunction.execute(PreviousListViewClickedItem);
    }


    // Parsing Complete JSON Object.
    private class GetHttpResponse extends AsyncTask<Void, Void, Void>
    {
        public Context context;

        public GetHttpResponse(Context context)
        {
            this.context = context;
        }

        @Override
        protected void onPreExecute()
        {
            super.onPreExecute();
        }

        @Override
        protected Void doInBackground(Void... arg0)
        {
            try
            {
                if(FinalJSonObject != null)
                {
                    JSONArray jsonArray = null;

                    try {
                        jsonArray = new JSONArray(FinalJSonObject);

                        JSONObject jsonObject;

                        for(int i=0; i<jsonArray.length(); i++)
                        {
                            jsonObject = jsonArray.getJSONObject(i);

                            // Storing Student Name, Phone Number, Class into Variables.
                            NameHolder = jsonObject.getString("property_name").toString() ;
                            NumberHolder = jsonObject.getString("price").toString() ;
                            ClassHolder = jsonObject.getString("description").toString() ;

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

        @Override
        protected void onPostExecute(Void result)
        {

            // Setting Student Name, Phone Number, Class into TextView after done all process .
            NAME.setText(NameHolder);
            PHONE_NUMBER.setText(NumberHolder);
            CLASS.setText(ClassHolder);

        }
    }

}

并显示AllEstatesActivity:

public class ShowingAllEstatesActivity extends AppCompatActivity {

    ListView SubjectListView;
    ProgressBar progressBarSubject;
    String ServerURL = "http://sultonkhuja1111.000webhostapp.com/MobApp/Estate.php";
    List<String> IdList = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_showing_all_estates);

        SubjectListView = (ListView)findViewById(R.id.listview1);

        progressBarSubject = (ProgressBar)findViewById(R.id.progressBar);

        new GetHttpResponse(ShowingAllEstatesActivity.this).execute();

        //Adding ListView Item click Listener.
        SubjectListView.setOnItemClickListener(new AdapterView.OnItemClickListener()
        {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                // TODO Auto-generated method stub

                Intent intent = new Intent(ShowingAllEstatesActivity.this, DetailsActivity.class);

                // Sending ListView clicked value using intent.
                intent.putExtra("ListViewValue", IdList.get(position).toString());

                startActivity(intent);

                //Finishing current activity after open next activity.
                finish();

            }
        });

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_listing, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        switch (item.getItemId()){
            case R.id.addNew:
                startActivity(new Intent(this, AddPropertyActivity.class));
                break;
        }
        return true;
    }

    private class GetHttpResponse extends AsyncTask<Void, Void, Void>
    {
        public Context context;

        String ResultHolder;

        List<subjects> subjectsList;

        public GetHttpResponse(Context context)
        {
            this.context = context;
        }

        @Override
        protected void onPreExecute()
        {
            super.onPreExecute();
        }

        @Override
        protected Void doInBackground(Void... arg0)
        {
            HttpServicesClass httpServiceObject = new HttpServicesClass(ServerURL);
            try
            {
                httpServiceObject.ExecutePostRequest();

                if(httpServiceObject.getResponseCode() == 200)
                {
                    ResultHolder = httpServiceObject.getResponse();

                    if(ResultHolder != null)
                    {
                        JSONArray jsonArray = null;

                        try {
                            jsonArray = new JSONArray(ResultHolder);

                            JSONObject jsonObject;

                            subjects subjects;

                            subjectsList = new ArrayList<subjects>();

                            for(int i=0; i<jsonArray.length(); i++)
                            {
                                subjects = new subjects();

                                jsonObject = jsonArray.getJSONObject(i);

                                IdList.add(jsonObject.getString("propertyid").toString());

                                subjects.SubjectName = jsonObject.getString("property_name");

                                subjectsList.add(subjects);
                            }
                        }
                        catch (JSONException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        }
                    }
                }
                else
                {
                    Toast.makeText(context, httpServiceObject.getErrorMessage(), Toast.LENGTH_SHORT).show();
                }
            }
            catch (Exception e)
            {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void result)

        {
            progressBarSubject.setVisibility(View.GONE);

            SubjectListView.setVisibility(View.VISIBLE);

            if(subjectsList != null)
            {
                ListAdapter adapter = new ListAdapter(subjectsList, context);

                SubjectListView.setAdapter(adapter);
            }
        }
    }

}

这是获取 HttpUrl、detail.php 的代码:

<?php

if($_SERVER['REQUEST_METHOD']=='POST'){

include 'DatabaseConfig.php';

 $propertyid= $_POST['propertyid'];

// Create connection
$conn = new mysqli($HostName, $HostUser, $HostPass, $DatabaseName);

if ($conn->connect_error) {

 die("Connection failed: " . $conn->connect_error);
}

$sql = "SELECT * FROM estate2 where propertyid = '$propertyid'";

$result = $conn->query($sql);

if ($result->num_rows >0) {


 while($row[] = $result->fetch_assoc()) {

 $tem = $row;

 $json = json_encode($tem);

 }

} else {
 echo "No Results Found.";
}
 echo $json;

$conn->close();
}
?>

Answer 1

我认为您的 HttpURL 看起来不太好。如果此 url 未给出 JSON 响应，则会产生相同的问题。