问题
I follow
this link
site to integrate Twitter on Android.
But the problem is my consumer key and secret have some problem because when I run my application it gives the Sorry! your application has stopped unexpectedly error
and when I checked in logcat it's giving null pointer exception
my logcat result is
07-07 11:06:50.962: ERROR/AndroidRuntime(323): java.lang.RuntimeException: Unable to resume activity {com.ecs.android.sample.twitter/com.ecs.android.sample.twitter.AndroidTwitterSample}: java.lang.NullPointerException
07-07 11:06:50.962: ERROR/AndroidRuntime(323): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3128)
07-07 11:06:50.962: ERROR/AndroidRuntime(323): at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3143)
07-07 11:06:50.962: ERROR/AndroidRuntime(323): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2684)
07-07 11:06:50.962: ERROR/AndroidRuntime(323): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
07-07 11:06:50.962: ERROR/AndroidRuntime(323): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
07-07 11:06:50.962: ERROR/AndroidRuntime(323): at android.os.Handler.dispatchMessage(Handler.java:99)
07-07 11:06:50.962: ERROR/AndroidRuntime(323): Caused by: java.lang.NullPointerException
07-07 11:06:50.962: ERROR/AndroidRuntime(323): at com.ecs.android.sample.twitter.TwitterUtils.isAuthenticated(TwitterUtils.java:18)
07-07 11:06:50.962: ERROR/AndroidRuntime(323): at com.ecs.android.sample.twitter.AndroidTwitterSample.updateLoginStatus(AndroidTwitterSample.java:67)
07-07 11:06:50.962: ERROR/AndroidRuntime(323): at com.ecs.android.sample.twitter.AndroidTwitterSample.onResume(AndroidTwitterSample.java:63)
07-07 11:06:50.962: ERROR/AndroidRuntime(323): at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1149)
07-07 11:06:50.962: ERROR/AndroidRuntime(323): at android.app.Activity.performResume(Activity.java:3823)
07-07 11:06:50.962: ERROR/AndroidRuntime(323): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3118)
Please tell me what is the mistake I am making?
And the whole code with 5 classes is:
Constants class- package com.ecs.android.sample.twitter;
package com.ecs.android.sample.twitter;
public class Constants {
public static final String CONSUMER_KEY = "consumer key";
public static final String CONSUMER_SECRET= "consumer secret key";
public static final String REQUEST_URL = "http://api.twitter.com/oauth/request_token";
public static final String ACCESS_URL = "http://api.twitter.com/oauth/access_token";
public static final String AUTHORIZE_URL = "http://api.twitter.com/oauth/authorize";
public static final String CALLBACK_SCHEME = "x-oauthflow-twitter";
public static final String CALLBACK_HOST = "callback";
public static final String CALLBACK_URL = CALLBACK_SCHEME + "://" + CALLBACK_HOST;
}
AndroidTwitterSample Class -
public class AndroidTwitterSample extends Activity {
private SharedPreferences prefs;
private final Handler mTwitterHandler = new Handler();
private TextView loginStatus;
final Runnable mUpdateTwitterNotification = new Runnable() {
public void run() {
Toast.makeText(getBaseContext(), "Tweet sent !", Toast.LENGTH_LONG).show();
}
};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
this.prefs = PreferenceManager.getDefaultSharedPreferences(this);
loginStatus = (TextView)findViewById(R.id.login_status);
Button tweet = (Button) findViewById(R.id.btn_tweet);
Button clearCredentials = (Button) findViewById(R.id.btn_clear_credentials);
tweet.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (TwitterUtils.isAuthenticated(prefs)) {
sendTweet();
} else {
Intent i = new Intent(getApplicationContext(), PrepareRequestTokenActivity.class);
i.putExtra("tweet_msg",getTweetMsg());
startActivity(i);
}
}
});
clearCredentials.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
clearCredentials();
updateLoginStatus();
}
});
}
@Override
protected void onResume() {
super.onResume();
updateLoginStatus();
}
public void updateLoginStatus() {
loginStatus.setText("Logged into Twitter : " + TwitterUtils.isAuthenticated(prefs));
}
private String getTweetMsg() {
return "Tweeting from Android App at " + new Date().toLocaleString();
}
public void sendTweet() {
Thread t = new Thread() {
@Override
public void run() {
try {
TwitterUtils.sendTweet(prefs,getTweetMsg());
mTwitterHandler.post(mUpdateTwitterNotification);
} catch (Exception ex) {
ex.printStackTrace();
}
}
};
t.start();
}
private void clearCredentials() {
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
final Editor edit = prefs.edit();
edit.remove(OAuth.OAUTH_TOKEN);
edit.remove(OAuth.OAUTH_TOKEN_SECRET);
edit.commit();
}
}
Twitter Utils Class -
import oauth.signpost.OAuth;
import twitter4j.Twitter;
import twitter4j.TwitterFactory;
import twitter4j.http.AccessToken;
import android.content.SharedPreferences;
public class TwitterUtils {
public static boolean isAuthenticated(SharedPreferences prefs) {
String token = prefs.getString(OAuth.OAUTH_TOKEN, "");
String secret = prefs.getString(OAuth.OAUTH_TOKEN_SECRET, "");
AccessToken a = new AccessToken(token,secret);
Twitter twitter = new TwitterFactory().getInstance();
twitter.setOAuthConsumer(Constants.CONSUMER_KEY, Constants.CONSUMER_SECRET);
twitter.setOAuthAccessToken(a);
try {
twitter.getAccountSettings();
return true;
} catch (Exception e) {
return false;
}
}
public static void sendTweet(SharedPreferences prefs,String msg) throws Exception {
String token = prefs.getString(OAuth.OAUTH_TOKEN, "");
String secret = prefs.getString(OAuth.OAUTH_TOKEN_SECRET, "");
AccessToken a = new AccessToken(token,secret);
Twitter twitter = new TwitterFactory().getInstance();
twitter.setOAuthConsumer(Constants.CONSUMER_KEY, Constants.CONSUMER_SECRET);
twitter.setOAuthAccessToken(a);
twitter.updateStatus(msg);
}
}
OAuthRequestToken Class-
public class OAuthRequestTokenTask extends AsyncTask<Void, Void, Void> {
final String TAG = getClass().getName();
private Context context;
private OAuthProvider provider;
private OAuthConsumer consumer;
public OAuthRequestTokenTask(Context context,OAuthConsumer consumer,OAuthProvider provider) {
this.context = context;
this.consumer = consumer;
this.provider = provider;
}
public OAuthRequestTokenTask(PrepareRequestTokenActivity context2,
CommonsHttpOAuthConsumer consumer2,
CommonsHttpOAuthProvider provider2) {
// TODO Auto-generated constructor stub
}
@Override
protected Void doInBackground(Void... params) {
try {
Log.i(TAG, "Retrieving request token from Google servers");
final String url = provider.retrieveRequestToken(consumer, Constants.CALLBACK_URL);
Log.i(TAG, "Popping a browser with the authorize URL : " + url);
Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url)).setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP |
Intent.FLAG_ACTIVITY_NO_HISTORY | Intent.FLAG_FROM_BACKGROUND);
context.startActivity(intent);
} catch (Exception e) {
Log.e(TAG, "Error during OAUth retrieve request token", e);
}
return null;
}
}
PrepareRequestTokenActivity Class-
public class OAuthRequestTokenTask extends AsyncTask<Void, Void, Void> {
final String TAG = getClass().getName();
private Context context;
private OAuthProvider provider;
private OAuthConsumer consumer;
public OAuthRequestTokenTask(Context context,OAuthConsumer consumer,OAuthProvider provider) {
this.context = context;
this.consumer = consumer;
this.provider = provider;
}
public OAuthRequestTokenTask(PrepareRequestTokenActivity context2,
CommonsHttpOAuthConsumer consumer2,
CommonsHttpOAuthProvider provider2) {
// TODO Auto-generated constructor stub
}
@Override
protected Void doInBackground(Void... params) {
try {
Log.i(TAG, "Retrieving request token from Google servers");
final String url = provider.retrieveRequestToken(consumer, Constants.CALLBACK_URL);
Log.i(TAG, "Popping a browser with the authorize URL : " + url);
Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url)).setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP |
Intent.FLAG_ACTIVITY_NO_HISTORY | Intent.FLAG_FROM_BACKGROUND);
context.startActivity(intent);
} catch (Exception e) {
Log.e(TAG, "Error during OAUth retrieve request token", e);
}
return null;
}
}
回答1:
You have to put CONSUMER_KEY = "enter consumer key here" and CONSUMER_SECRET="enter consumer secret here" in your Constants class. For that you have to register your application in Twitter. To register your app, visit https://dev.twitter.com/user . After that it will give you those keys.
来源：https://stackoverflow.com/questions/6606678/problem-in-twitter-integration-on-android