我想创建一个从数据库中检索数据的微调器，但OnItemSelectedListener不起作用。它一直建议使用adapterview.OnclickListener，但编码需要OnClickListenerOnly。
package com.example.win7.fyp;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.AsyncTask;
import android.os.Bundle;
import android.provider.Settings;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.List;
public class student_register extends Activity implements OnItemSelectedListener {
Toolbar toolbar;
private ProgressDialog progressDialog;
JsonParser jParser = new JsonParser();
private static String URL_TO_PASS = "http://arcafyp.xyz/chat/register_student.php";
SharedPreferences pref;
EditText username5, password5 ,advisorName5;
TextView advReg;
String username1;
String AndroidId;
private ArrayList<Category> categoriesList;
ProgressDialog pDialog;
private Spinner spinnerFood;
// Url to get all categories
private String URL_CATEGORIES = "http://ekinidris.site40.net/chat/advisorName.php";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_student_register);
pref = getApplicationContext().getSharedPreferences("MyPref", 0);// 0 - for private mode
username5 = (EditText)findViewById(R.id.register_matrixno);
password5 = (EditText) findViewById(R.id.register_ic);
advisorName5 = (EditText) findViewById(R.id.advName);
spinnerFood.setOnItemSelectedListener(this);
spinnerFood = (Spinner) findViewById(R.id.spinFood);
categoriesList = new ArrayList<Category>();
// Add new category click event
new GetCategories().execute();
}
private class GetCategories extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(student_register.this);
pDialog.setMessage("Fetching advisor name..");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
ServiceHandler jsonParser = new ServiceHandler();
String json = jsonParser.makeServiceCall(URL_CATEGORIES, ServiceHandler.GET);
Log.e("Response: ", "> " + json);
if (json != null) {
try {
JSONObject jsonObj = new JSONObject(json);
if (jsonObj != null) {
JSONArray categories = jsonObj
.getJSONArray("categories");
for (int i = 0; i < categories.length(); i++) {
JSONObject catObj = (JSONObject) categories.get(i);
Category cat = new Category(catObj.getInt("phone_id"),
catObj.getString("name"));
categoriesList.add(cat);
}
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("JSON Data", "Didn't receive any data from server!");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
if (pDialog.isShowing())
pDialog.dismiss();
//populateSpinner();
}
}
/**
* Adding spinner data
* */
private void populateSpinner() {
List<String> lables = new ArrayList<String>();
advisorName5.setText("");
for (int i = 0; i < categoriesList.size(); i++) {
lables.add(categoriesList.get(i).getName());
}
// Creating adapter for spinner
ArrayAdapter<String> spinnerAdapter = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_item, lables);
// Drop down layout style - list view with radio button
spinnerAdapter
.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
// attaching data adapter to spinner
spinnerFood.setAdapter(spinnerAdapter);
}
@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_student_register, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.register_send) {
new registerUser().execute();
String newCategory = advisorName5.getText().toString();
return true;
}
return super.onOptionsItemSelected(item);
}
class registerUser extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
Intent i = getIntent();
String studentPhone_id = i.getStringExtra("phone_id").toString();
String studentUsername = username5.getText().toString();
progressDialog = new ProgressDialog(student_register.this);
progressDialog.setMessage("Processing Data" + studentPhone_id + studentUsername);
progressDialog.setIndeterminate(false);
progressDialog.setCancelable(true);
progressDialog.show();
}
@Override
protected String doInBackground(String... strings) {
String studentUsername = username5.getText().toString(); // matrix no
String studentPassword = password5.getText().toString(); //cgpa
String studentAdvName = advisorName5.getText().toString(); //advisor name
Intent i = getIntent();
String studentPhone_id = i.getStringExtra("phone_id").toString();
List<NameValuePair> param = new ArrayList<NameValuePair>();
param.add(new BasicNameValuePair("username",studentUsername));
param.add(new BasicNameValuePair("phone_id",studentPhone_id));
param.add(new BasicNameValuePair("password", studentPassword));
param.add(new BasicNameValuePair("advisorName", studentAdvName));
JSONObject json = jParser.makeHttpRequest("http://ekinidris.site40.net/chat/register_student.php","POST",param);
SharedPreferences.Editor editor = pref.edit();
Log.d("data", json.toString());
try {
int result = json.getInt("success");
if(result == 1) {
editor.putString("phone_id",studentPhone_id);
editor.commit();
Intent intent = new Intent(student_register.this, MainActivity.class);
intent.putExtra("phone_id", studentPhone_id);
intent.putExtra("username",studentUsername);
intent.putExtra("advisorName",studentAdvName);
startActivity(intent);
finish();
progressDialog.dismiss();
}else{
To be edited.....
put some action refreshing the page
}
}catch (JSONException e){
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
progressDialog.dismiss();
finish();
}
}
}
logcat的
11-06 16:43:02.289 22071-22071/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.win7.fyp/com.example.win7.fyp.student_register}: java.lang.ClassCastException: com.example.win7.fyp.student_register cannot be cast to android.view.View$OnClickListener
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1968)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1993)
at android.app.ActivityThread.access$600(ActivityThread.java:127)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1159)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4507)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:980)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:747)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.ClassCastException: com.example.win7.fyp.student_register cannot be cast to android.view.View$OnClickListener
at com.example.win7.fyp.student_register.onCreate(student_register.java:78)
at android.app.Activity.performCreate(Activity.java:4465)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1052)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1932)
答案 0 :(得分：0)
遵循此代码 -
spinner1.setOnItemSelectedListener(new OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> arg0, View arg1,
int arg2, long arg3) {
// TODO Auto-generated method stub
String msupplier=supplier.getSelectedItem().toString();
Log.e("Selected item : ",msupplier);
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
});
答案 1 :(得分：0)
我使用了sud回答的相同内容，但进行了少许修改却有效
spinner1.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view,
int pos, long id) {
// TODO Auto-generated method stub
// String msupplier=supplier.getSelectedItem().toString(); instead used below
Log.e("Selected item : ", (String) parent.getItemAtPosition(pos));
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
// TODO Auto-generated method stub
}
});