我正在尝试使用以下代码在Facebook上发布图像。我在此行收到NullPointerException错误：bi.compress(Bitmap.CompressFormat.JPEG, 100, baos);
这是我的代码。怎么了？
import java.io.ByteArrayOutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.MalformedURLException;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.text.method.BaseKeyListener;
import android.util.Log;
import android.view.View;
import android.view.Window;
import android.widget.Toast;
import com.facebook.android.AsyncFacebookRunner;
import com.facebook.android.AsyncFacebookRunner.RequestListener;
import com.facebook.android.DialogError;
import com.facebook.android.Facebook;
import com.facebook.android.Facebook.DialogListener;
import com.facebook.android.FacebookError;
import com.facebook.android.Util;
/**
* The Class PublishOnFacebook posts the events on facebook profile using
* Facebook SDK
*/
public class PublishOnFacebook extends Activity {
/** The Constant APP_ID. */
private static final String APP_ID = "369797849756493";
/** The Constant PERMISSIONS. */
private static final String[] PERMISSIONS = new String[] { "publish_stream" };
/** The Constant TOKEN. */
private static final String TOKEN = "access_token";
/** The Constant EXPIRES. */
private static final String EXPIRES = "expires_in";
/** The Constant KEY. */
private static final String KEY = "facebook-credentials";
/** The facebook. */
private Facebook facebook;
/** The msg to post. */
private String msgToPost;
/** The post image. */
private String postImage;
/*
* (non-Javadoc)
*
* @see android.app.Activity#onCreate(android.os.Bundle)
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.fb_layout);
facebook = new Facebook(APP_ID);
restoreCrediential(facebook);
String facebookMessage = getIntent().getStringExtra("facebookMessage");
String imageToUpload = getIntent().getStringExtra("uploadphoto");
Log.d("ImageURL=: ", imageToUpload);
if (facebookMessage == null) {
facebookMessage = "Hello friends... Enjoy the rainy season.";
}
msgToPost = facebookMessage;
postImage = imageToUpload;
}
/**
* Do not share.
*
* @param button
* the button
*/
public void doNotShare(View button) {
finish();
}
/**
* Share the event on facebook .
*
* @param button
* the button
* @throws MalformedURLException
* the malformed url exception
* @throws IOException
* Signals that an I/O exception has occurred.
*/
public void share(final View button) throws MalformedURLException,
IOException {
if (!facebook.isSessionValid()) {
loginAndPostToWall();
} else {
postToWall(msgToPost);
postImageToWall(postImage);
}
}
/**
* Post image to wall.
*
* @param imageUrl
* the image url
*/
private void postImageToWall(String imageUrl) {
byte[] data = null;
Bitmap bi = BitmapFactory.decodeFile(imageUrl);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bi.compress(Bitmap.CompressFormat.JPEG, 100, baos);
data = baos.toByteArray();
Bundle params = new Bundle();
params.putString(Facebook.TOKEN, facebook.getAccessToken());
params.putString("method", "photos.upload");
params.putByteArray("picture", data);
AsyncFacebookRunner mAsyncRunner = new AsyncFacebookRunner(facebook);
mAsyncRunner.request(null, params, "POST", new SampleUploadListener(),
null);
}
/**
* Login and post to wall.
*/
private void loginAndPostToWall() {
facebook.authorize(this, PERMISSIONS, Facebook.FORCE_DIALOG_AUTH,
new LoginDialogListener());
}
/**
* Post to wall.
*
* @param message
* the message
*/
private void postToWall(String message) {
Bundle parameters = new Bundle();
parameters.putString("message", message);
parameters.putString("description", "topic to share");
try {
facebook.request("me");
String response = facebook.request("me/feed", parameters, "POST");
Log.d("response: ", response);
if (response == null || response.equals("")) {
response.equals("");
showToast("No Response.");
} else {
showToast("Message has been posted to your walll!.");
}
finish();
} catch (Exception e) {
showToast("Message failed to posdt on wall.");
e.printStackTrace();
finish();
}
}
/**
* Show toast.
*
* @param message
* the message
*/
private void showToast(String message) {
Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
}
/**
* Restore crediential.
*
* @param facebook
* the facebook
* @return true, if successful
*/
public boolean restoreCrediential(Facebook facebook) {
SharedPreferences sPreferences = getApplicationContext()
.getSharedPreferences(KEY, Context.MODE_PRIVATE);
facebook.setAccessToken(sPreferences.getString(TOKEN, null));
facebook.setAccessExpires(sPreferences.getLong(EXPIRES, 0));
return facebook.isSessionValid();
}
/**
* Save credientails.
*
* @param facebook
* the facebook
* @return true, if successful
*/
public boolean saveCredientails(Facebook facebook) {
Editor editor = getApplicationContext().getSharedPreferences(KEY,
Context.MODE_PRIVATE).edit();
editor.putString(TOKEN, facebook.getAccessToken());
editor.putLong(EXPIRES, facebook.getAccessExpires());
return editor.commit();
}
/**
* The listener interface for receiving loginDialog events. The class that
* is interested in processing a loginDialog event implements this
* interface, and the object created with that class is registered with a
* component using the component's
* <code>addLoginDialogListener<code> method. When
* the loginDialog event occurs, that object's appropriate
* method is invoked.
*
* @see LoginDialogEvent
*/
public class LoginDialogListener implements DialogListener {
/*
* (non-Javadoc)
*
* @see
* com.facebook.android.Facebook.DialogListener#onComplete(android.os
* .Bundle)
*/
public void onComplete(Bundle values) {
saveCredientails(facebook);
if (msgToPost != null) {
postToWall(msgToPost);
}
postImageToWall(values.getString(Facebook.TOKEN));
}
/*
* (non-Javadoc)
*
* @see
* com.facebook.android.Facebook.DialogListener#onFacebookError(com.
* facebook.android.FacebookError)
*/
public void onFacebookError(FacebookError e) {
showToast("Auntication with facebook failed");
finish();
}
/*
* (non-Javadoc)
*
* @see
* com.facebook.android.Facebook.DialogListener#onError(com.facebook
* .android.DialogError)
*/
public void onError(DialogError e) {
showToast("Auntication with facebbok failed");
finish();
}
/*
* (non-Javadoc)
*
* @see com.facebook.android.Facebook.DialogListener#onCancel()
*/
public void onCancel() {
showToast("Aunticaton with facebbok failed");
finish();
}
}
/**
* The listener interface for receiving sampleUpload events. The class that
* is interested in processing a sampleUpload event implements this
* interface, and the object created with that class is registered with a
* component using the component's
* <code>addSampleUploadListener<code> method. When
* the sampleUpload event occurs, that object's appropriate
* method is invoked.
*
* @see SampleUploadEvent
*/
public class SampleUploadListener extends BaseKeyListener implements
RequestListener {
/*
* (non-Javadoc)
*
* @see
* com.facebook.android.AsyncFacebookRunner.RequestListener#onComplete
* (java.lang.String, java.lang.Object)
*/
public void onComplete(final String response, final Object state) {
try {
// process the response here: (executed in background thread)
Log.d("Facebook-Example", "Response: " + response.toString());
JSONObject json = Util.parseJson(response);
final String src = json.getString("src");
// then post the processed result back to the UI thread
// if we do not do this, an runtime exception will be generated
// e.g. "CalledFromWrongThreadException: Only the original
// thread that created a view hierarchy can touch its views."
} catch (JSONException e) {
Log.w("Facebook-Example", "JSON Error in response");
} catch (FacebookError e) {
Log.w("Facebook-Example", "Facebook Error: " + e.getMessage());
}
}
/*
* (non-Javadoc)
*
* @see
* com.facebook.android.AsyncFacebookRunner.RequestListener#onFacebookError
* (com.facebook.android.FacebookError, java.lang.Object)
*/
public void onFacebookError(FacebookError e, Object state) {
}
/**
* Gets the input type.
*
* @param img
* the img
* @return the input type
*/
public Bitmap getInputType(Bitmap img) {
return img;
}
/*
* (non-Javadoc)
*
* @see android.text.method.KeyListener#getInputType()
*/
public int getInputType() {
return 0;
}
/*
* (non-Javadoc)
*
* @see
* com.facebook.android.AsyncFacebookRunner.RequestListener#onIOException
* (java.io.IOException, java.lang.Object)
*/
public void onIOException(IOException e, Object state) {
}
/*
* (non-Javadoc)
*
* @see com.facebook.android.AsyncFacebookRunner.RequestListener#
* onFileNotFoundException(java.io.FileNotFoundException,
* java.lang.Object)
*/
public void onFileNotFoundException(FileNotFoundException e,
Object state) {
}
/*
* (non-Javadoc)
*
* @see com.facebook.android.AsyncFacebookRunner.RequestListener#
* onMalformedURLException(java.net.MalformedURLException,
* java.lang.Object)
*/
public void onMalformedURLException(MalformedURLException e,
Object state) {
}
}
}
答案 0 :(得分：1)
如果您查看BitmapFactory.decodeFile（String pathName）的文档，您会看到：
将文件路径解码为位图。如果指定的文件名为null， 或者无法解码为位图，该函数返回null。
我建议您查看尝试从中获取位图的网址。
/ toffer