MessagesActivity.java
package org.example.fbapp;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.MalformedURLException;
import java.util.ArrayList;
import java.util.HashMap;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import com.facebook.android.AsyncFacebookRunner;
import com.facebook.android.Facebook;
import com.facebook.android.FacebookError;
import com.facebook.android.AsyncFacebookRunner.RequestListener;
import android.app.ListActivity;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;
public class MessagesActivity extends ListActivity {
// Your Facebook APP ID
private static String APP_ID = "5496*******054";
// JSON Node names
private static final String TAG_DATA = "data";
private static final String TAG_MESSAGE = "message";
// data JSONArray
JSONArray data = null;
// Instance of Facebook Class
@SuppressWarnings("deprecation")
private Facebook facebook = new Facebook(APP_ID);
@SuppressWarnings("deprecation")
private AsyncFacebookRunner mAsyncRunner;
String FILENAME = "AndroidSSO_data";
private SharedPreferences mPrefs;
// Hashmap for ListView
ArrayList<HashMap<String, String>> messages = new ArrayList<HashMap<String, String>>();
private ListView lv;
ListView mylistview;
ArrayList<String> array_months;
ArrayAdapter<String> listAdapter;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.contacts_view);
ListAdapter adapter = createAdapter();
setListAdapter(adapter);
}
/**
* Creates and returns a list adapter for the current list activity
*
* @return
*/
@SuppressWarnings("deprecation")
protected ListAdapter createAdapter()
{
mAsyncRunner.request("203153109726651/feed", new RequestListener() {
@Override
public void onComplete(String response, Object state) {
Log.d("GET POSTS", response);
String json = response;
try {
// Facebook Profile JSON data
JSONObject obj = new JSONObject(json);
JSONArray finalObj = obj.getJSONArray("data");
array_months = new ArrayList<String>();
for (int i = 0; i < finalObj.length(); i++) {
final String message = finalObj.getJSONObject(i)
.getString("message");
array_months.add(message);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
@Override
public void onIOException(IOException e, Object state) {
}
@Override
public void onFileNotFoundException(FileNotFoundException e,
Object state) {
}
@Override
public void onMalformedURLException(MalformedURLException e,
Object state) {
}
@Override
public void onFacebookError(FacebookError e, Object state) {
}
});
// Create a simple array adapter (of type string) with the test values
//ListAdapter adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, adapter);
ListAdapter adapter = new ArrayAdapter<String>(MessagesActivity.this,
android.R.layout.simple_list_item_1, array_months);
//setListAdapter(listAdapter);
return adapter;
}
}
从我的主要活动中单击按钮
/**
* Get Posts from Group
* */
btnGetPost.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// getGroupPosts();
//getGPosts();
startActivity(new Intent(FBAppActivity.this, MessagesActivity.class));
}
});
当我单击按钮时，我收到此错误
10-28 01:48:28.585: E/AndroidRuntime(1299): FATAL EXCEPTION: main
10-28 01:48:28.585: E/AndroidRuntime(1299): java.lang.RuntimeException: Unable to start activity ComponentInfo{org.example.fbapp/org.example.fbapp.MessagesActivity}: java.lang.NullPointerException
10-28 01:48:28.585: E/AndroidRuntime(1299): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2306)
10-28 01:48:28.585: E/AndroidRuntime(1299): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2358)
10-28 01:48:28.585: E/AndroidRuntime(1299): at android.app.ActivityThread.access$600(ActivityThread.java:156)
10-28 01:48:28.585: E/AndroidRuntime(1299): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1340)
10-28 01:48:28.585: E/AndroidRuntime(1299): at android.os.Handler.dispatchMessage(Handler.java:99)
10-28 01:48:28.585: E/AndroidRuntime(1299): at android.os.Looper.loop(Looper.java:153)
10-28 01:48:28.585: E/AndroidRuntime(1299): at android.app.ActivityThread.main(ActivityThread.java:5297)
10-28 01:48:28.585: E/AndroidRuntime(1299): at java.lang.reflect.Method.invokeNative(Native Method)
10-28 01:48:28.585: E/AndroidRuntime(1299): at java.lang.reflect.Method.invoke(Method.java:511)
10-28 01:48:28.585: E/AndroidRuntime(1299): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
10-28 01:48:28.585: E/AndroidRuntime(1299): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
10-28 01:48:28.585: E/AndroidRuntime(1299): at dalvik.system.NativeStart.main(Native Method)
10-28 01:48:28.585: E/AndroidRuntime(1299): Caused by: java.lang.NullPointerException
10-28 01:48:28.585: E/AndroidRuntime(1299): at org.example.fbapp.MessagesActivity.createAdapter(MessagesActivity.java:74)
10-28 01:48:28.585: E/AndroidRuntime(1299): at org.example.fbapp.MessagesActivity.onCreate(MessagesActivity.java:62)
10-28 01:48:28.585: E/AndroidRuntime(1299): at android.app.Activity.performCreate(Activity.java:5122)
10-28 01:48:28.585: E/AndroidRuntime(1299): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1081)
10-28 01:48:28.585: E/AndroidRuntime(1299): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2270)
10-28 01:48:28.585: E/AndroidRuntime(1299): ... 11 more
任何指针为什么？