Android - Spinner, onItemSelected(…) not being called

问题

Here's the code:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.json.JSONArray;
import org.json.JSONObject;
import com.project.locationapp.model.Device;
import android.os.AsyncTask;
import android.os.Bundle;
import android.provider.Settings.Secure;
import android.app.Activity;
import android.content.Intent;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;


public class SelectDevice extends Activity implements OnItemSelectedListener {

private Spinner deviceSpinner;
private List<Device> deviceList;
private ArrayAdapter<Device> deviceAdapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_select_device);
    deviceList = new ArrayList<Device>();


    try {
        deviceSpinner = (Spinner) findViewById(R.id.select_device_spinner);
        deviceAdapter = new DeviceAdapter(this, android.R.layout.simple_spinner_dropdown_item, deviceList);
        deviceSpinner.setAdapter(deviceAdapter);
        deviceSpinner.setOnItemSelectedListener(this);

        DataAsyncTask loadDevices = new DataAsyncTask();
        loadDevices.execute(new String[] { WebServiceURL.WEB_SERVICE + WebServiceURL.DEVICES + WebServiceURL.ALL });




    } catch (Exception e){
        Log.e(TAG, e.getLocalizedMessage(), e);
    }
}

@Override
public void onItemSelected(AdapterView<?> a, View v, int position,
        long id) {

    Log.d(TAG, "called!");  
    Intent intent = new Intent(this, ViewTrips.class);
    intent.putExtra("device_id", deviceAdapter.getItem(position).getId());
    startActivity(intent);

}
}

DeviceAdapter class:

import java.util.List;
import com.project.locationapp.model.Device;
import android.content.Context;
import android.widget.ArrayAdapter;

public class DeviceAdapter extends ArrayAdapter<Device> {

public DeviceAdapter(Context context, int textViewResourceId,
        List<Device> objects) {
    super(context, textViewResourceId, objects);
}
}

Activity layout xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".SelectDevice" >


<TextView
    android:id="@+id/instructions_device_select"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:text="@string/select_device_instructions"
    android:layout_marginTop="10dp"
    android:layout_marginBottom="10dp"
    android:layout_marginRight="15dp"
    android:layout_marginLeft="15dp" />

<Button
    android:id="@+id/start_service_button"
    android:layout_below="@id/instructions_device_select"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:onClick="thisDevice"
    android:text="@string/this_device"
    android:layout_marginTop="10dp"
    android:layout_marginRight="40dp"
    android:layout_marginLeft="40dp" />

<Spinner
    android:id="@+id/select_device_spinner"
    android:layout_below="@id/start_service_button"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:prompt="@string/select_device"
    android:layout_marginTop="20dp"
    android:layout_marginLeft="5dp"
    android:drawSelectorOnTop = "true" />

</RelativeLayout>

I am waiting to get this working properly, then I am going to customise DeviceAdapter further.

The Activity implements OnItemSelectedListener, hence the override of onItemSelected(...), which isn't being called at all. No errors in LogCat. Spinner is defined in the Activity's layout xml and displays and populates fine. Any advice to fix this would be great.

Thank you.

回答1:

It might be the spinner layouts, I can see you didn't set a dropdown view for the adapter. Could you try to initialize your spinner like this:

deviceAdapter = new DeviceAdapter(this, android.R.layout.simple_spinner_item, deviceList);
deviceSpinner.setAdapter(deviceAdapter);
deviceAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
deviceSpinner.setOnItemSelectedListener(this);

回答2:

I was facing the same problem today. Then I realized I am testing on emulator. When I tested the same app it worked. I am posting this if someone is trying to get call back for spinner over emulator it did not work for me. you may also check the same. It works on real device

来源：https://stackoverflow.com/questions/15110369/android-spinner-onitemselected-not-being-called

标签

android

spinner