如何在列表视图中获取所选项目ID

Question

我想在列表视图中获取所选项目的ID，其中数据来自服务器。一切正常但我无法获取ID发送到下一个活动以显示所选项目内容。我用过这一行：

String number_of_keys = (lv.getItemAtPosition(position).toString());

但它返回行中的所有项目:(这是我的代码谢谢。

import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.HashMap;

public class MainActivity2 extends AppCompatActivity implements TextWatcher {
    public String number_of_keys;

    private String TAG = MainActivity2.class.getSimpleName();

    private ProgressDialog pDialog;
    private ListView lv;
    private String id;


    // URL to get contacts JSON
    private static String url = "http://farazjou.com/mobile/drugstore";

    ArrayList<HashMap<String, String>> drugstoreList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        drugstoreList = new ArrayList<>();

        lv = (ListView) findViewById(R.id.list);

        new GetDrugs().execute();
        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {


                Intent i = new Intent(getApplicationContext(), SecondActivity.class);
                String number_of_keys = (lv.getItemAtPosition(position).toString());

               i.putExtra("number_of_keys", number_of_keys);

                startActivity(i);

            }
        });
    }

    @Override
    public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

    }

    @Override
    public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {

    }

    @Override
    public void afterTextChanged(Editable editable) {

    }

    /**
     * Async task class to get json by making HTTP call
     */
    private class GetDrugs extends AsyncTask<Void, Void, Void> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            // Showing progress dialog
            pDialog = new ProgressDialog(MainActivity2.this);
            pDialog.setMessage("Please wait...");
            pDialog.setCancelable(false);
            pDialog.show();

        }

        @Override
        public Void doInBackground(Void... arg0) {
            HttpHandler sh = new HttpHandler();

            // Making a request to url and getting response
            String jsonStr = sh.makeServiceCall(url);

            Log.e(TAG, "Response from url: " + jsonStr);

            if (jsonStr != null) {
                try {
                    JSONObject jsonObj = new JSONObject(jsonStr);

                    // Getting JSON Array node
                    JSONArray drugstore = jsonObj.getJSONArray("drugstore");

                    // looping through All Contacts
                    for (int i = 0; i < drugstore.length(); i++) {
                        JSONObject c = drugstore.getJSONObject(i);

                         id = c.getString("id");
                        String post_title = c.getString("post_title");
                        String public_title = c.getString("public_title");


                        HashMap<String, String> drug = new HashMap<>();


                        drug.put("id", id);
                        drug.put("post_title", post_title);
                        drug.put("public_title", public_title);
                        drugstoreList.add(drug);
                    }
                } catch (final JSONException e) {
                    Log.e(TAG, "Json parsing error: " + e.getMessage());
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Toast.makeText(getApplicationContext(),
                                    "Json parsing error: " + e.getMessage(),
                                    Toast.LENGTH_LONG)
                                    .show();
                        }
                    });

                }
            } else {
                Log.e(TAG, "Couldn't get json from server.");
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Toast.makeText(getApplicationContext(),
                                "Couldn't get json from server. Check LogCat for possible errors!",
                                Toast.LENGTH_LONG)
                                .show();
                    }
                });

            }

            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            super.onPostExecute(result);
            // Dismiss the progress dialog
            if (pDialog.isShowing())
                pDialog.dismiss();
            /**
             * Updating parsed JSON data into ListView
             * */
            ListAdapter adapter = new SimpleAdapter(
                    MainActivity2.this, drugstoreList,
                    R.layout.list_item2, new String[]{"post_title", "public_title", "id"}
                    , new int[]{R.id.post_title, R.id.public_title , R.id.public_id});



            lv.setAdapter(adapter);



        }

    }
}

Answer 1

您正在实现Click Handler而不是Select Handler。默认情况下，列表不会选择。

按照以下方式尝试，

public void onItemClick(AdapterView<?> adapter, View v, int position, long id) {
    MyClass item = (MyClass) adapter.getItem(position);
}