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我想在我的android應用程序中擴展另一個不是活動。但是當我在清單文件中初始化它後運行應用程序時，它顯示異常class cannot be cast to android.app.activity我該如何解決這個問題？ 編輯： 這是我的類文件SessionLoginSampleActivity.java這就要求FacebookSignIn例外：類不能轉換爲android.app.activity
public class SessionLoginSampleActivity extends Activity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Settings.addLoggingBehavior(LoggingBehavior.INCLUDE_ACCESS_TOKENS);
Session session = Session.getActiveSession();
if (session == null) {
if (savedInstanceState != null) {
session = Session.restoreSession(this, null, statusCallback, savedInstanceState);
}
if (session == null) {
session = new Session(this);
}
Session.setActiveSession(session);
if (session.getState().equals(SessionState.CREATED_TOKEN_LOADED)) {
session.openForRead(new Session.OpenRequest(this).setCallback(statusCallback));
} }
updateView();
}
@Override
public void onStart() {
super.onStart();
Session.getActiveSession().addCallback(statusCallback);
}
@Override
public void onStop() {
super.onStop();
Session.getActiveSession().removeCallback(statusCallback);
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
Session.getActiveSession().onActivityResult(this, requestCode, resultCode, data);
}
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
Session session = Session.getActiveSession();
Session.saveSession(session, outState);
}
private void updateView() {
Session session = Session.getActiveSession();
if (session.isOpened()) {
startActivityForResult(new Intent(SessionLoginSampleActivity.this, FacebookSignIn.class), 100);
}
else{
onClickLogin(); } }
private void onClickLogin() {
Session session = Session.getActiveSession();
if (!session.isOpened() && !session.isClosed()) {
session.openForRead(new Session.OpenRequest(this).setCallback(statusCallback));
} else {
Session.openActiveSession(this, true, statusCallback);
} }
private void onClickLogout() {
Session session = Session.getActiveSession();
if (!session.isClosed()) {
session.closeAndClearTokenInformation();
} }
@Override
protected void onResume() {
super.onResume();
}
private class SessionStatusCallback implements Session.StatusCallback {
@Override
public void call(Session session, SessionState state, Exception exception) {
updateView();
} } }
FacebookSignIn.java
public class FacebookSignIn extends FacebookFragment{
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
fetchUserInfo();
if(databaseExists()!=false)
{
if(!checkValidUser()!=true){
Intent intent = new Intent(getActivity(),UserAccount.class);
startActivity(intent);
/*Sending some arguments*/
Bundle bundle = new Bundle();
bundle.putString("UserName",strUserName);
bundle.putString("Id", strEmailId);
intent.putExtras(bundle);
this.startActivity(intent);
}}}
private boolean databaseExists(){
SQLiteDatabase checkDB = null;
try {
String myPath = DB_PATH + DATABASE_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null,SQLiteDatabase.OPEN_READONLY);
if(checkDB != null){
System.out.println("DataBase Exists");
checkDB.close();
return true;
}else{
//database does not exist
return false;
}
} catch (Exception e){
//database does not exist
return false;
}}
private Boolean checkValidUser(){
Cursor cursor = null;
try{
cursor = database.rawQuery("SELECT loginId, emailAddress FROM UserDetails WHERE loginId = '"+NAME+"' AND emailAddress = '"+ID+"'", null);
if (cursor != null) {
if (cursor.moveToFirst()){
strUserName = cursor.getString(cursor.getColumnIndex("loginId"));
strEmailId = cursor.getString(cursor.getColumnIndex("emailAddress"));
}}
}catch (Exception e) {
Log.e(getClass().getSimpleName(), "Could not create or Open the database");
}finally {
if(cursor != null && !cursor.isClosed()) cursor.close();
}
return true;
}
private void fetchUserInfo() {
final Session currentSession = getSession();
if (currentSession != null && currentSession.isOpened()) {
if (currentSession != userInfoSession) {
Request request = Request.newMeRequest(currentSession, new Request.GraphUserCallback() {
@Override
public void onCompleted(GraphUser me, Response response) {
if (currentSession == getSession()) {
user = me;
updateUI();
}
if (response.getError() != null) {
//loginButton.handleError(response.getError().getException());
}}});
Bundle parameters = new Bundle();
parameters.putString(FIELDS, REQUEST_FIELDS);
request.setParameters(parameters);
Request.executeBatchAsync(request);
userInfoSession = currentSession;
}
} else {
user = null;
}}
private void updateUI() {
if (!isAdded()) {
return;
}
if (isSessionOpen()) {
// connectedStateLabel.setTextColor(getResources().getColor(R.color.com_facebook_usersettingsfragment_connected_text_color));
// connectedStateLabel.setShadowLayer(1f, 0f, -1f,
// getResources().getColor(R.color.com_facebook_usersettingsfragment_connected_shadow_color));
if (user != null) {
ImageRequest request = getImageRequest();
if (request != null) {
URI requestUrl = request.getImageUri();
// Do we already have the right picture? If so, leave it alone.
//if (!requestUrl.equals(connectedStateLabel.getTag())) {
if (user.getId().equals(userProfilePicID)) {
} else {
ImageDownloader.downloadAsync(request);
}}}}}
private ImageRequest getImageRequest() {
ImageRequest request = null;
try {
ImageRequest.Builder requestBuilder = new ImageRequest.Builder(
getActivity(),
ImageRequest.getProfilePictureUrl(
user.getId(),
getResources().getDimensionPixelSize(R.dimen.com_facebook_usersettingsfragment_profile_picture_width),
getResources().getDimensionPixelSize(R.dimen.com_facebook_usersettingsfragment_profile_picture_height)));
request = requestBuilder.setCallerTag(this)
.setCallback(
new ImageRequest.Callback() {
@Override
public void onCompleted(ImageResponse response) {
processImageResponse(user.getId(), response);
}})
.build();
} catch (URISyntaxException e) {
}
return request;
}
private void processImageResponse(String id, ImageResponse response) {
if (response != null) {
Bitmap bitmap = response.getBitmap();
if (bitmap != null) {
BitmapDrawable drawable = new BitmapDrawable(FacebookSignIn.this.getResources(), bitmap);
drawable.setBounds(0, 0,
getResources().getDimensionPixelSize(R.dimen.com_facebook_usersettingsfragment_profile_picture_width),
getResources().getDimensionPixelSize(R.dimen.com_facebook_usersettingsfragment_profile_picture_height));
userProfilePic = drawable;
userProfilePicID = id;
} } }}
您正在使用您的課程作爲一項活動。但事實並非如此。如果你沒有向我們展示代碼，就不可能說你在哪裏出錯，但基本上它應該是顯而易見的，如果你按照你使用某個活動的方式使用某些東西，那麼它可能只是一個（或者是其中一個孩子） – Nanne
你確定「UserAccount」是你的活動？你並沒有試圖將FacebookSignIn添加到你的清單文件中。 – Piyush
不，引發異常當我在SessionLoginSampleActivity中調用FacebookSignIn – Robert