Ciao a tutti, sto scrivendo un' app che prevede l'apertura sulla MainActivity con due pulsanti: login o catalogo (si tratta di una "biblioteca online"). Premendo il pulsante login si apre l'activity LoginActivity che è quella proposta da android studio che poi pulirò da alcuni metodi di cui non necessito. Infine è presente l'activity ControlPanel (al momento con una sola textview di benvenuto) che sarà mostrata a login avvenuto.
Lanciando l'app e arrivando al login, inserisco le credenziali, ma al momento di eseguire l'intent per aprire ControlPanel, l'activity LoginActivity si chiude con l'avviso che il programma è stato arrestato e mi riporta alla MainActivity.
Allego il codice.
LoginActivity - le uniche istruzioni di codice aggiunte in onPostExecute sonocodice:Intent i = new Intent(LoginActivity.this, ControlPanel.class); startActivity(i);codice:import android.animation.Animator; import android.animation.AnimatorListenerAdapter; import android.annotation.TargetApi; import android.app.LoaderManager.LoaderCallbacks; import android.content.CursorLoader; import android.content.Intent; import android.content.Loader; import android.content.pm.PackageManager; import android.database.Cursor; import android.net.Uri; import android.os.AsyncTask; import android.os.Build; import android.os.Bundle; import android.provider.ContactsContract; import android.support.annotation.NonNull; import android.support.design.widget.Snackbar; import android.support.v7.app.AppCompatActivity; import android.text.TextUtils; import android.view.KeyEvent; import android.view.View; import android.view.View.OnClickListener; import android.view.inputmethod.EditorInfo; import android.widget.ArrayAdapter; import android.widget.AutoCompleteTextView; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; import java.util.ArrayList; import java.util.List; import static android.Manifest.permission.READ_CONTACTS; public class LoginActivity extends AppCompatActivity implements LoaderCallbacks<Cursor> { private static final int REQUEST_READ_CONTACTS = 0; private static final String[] DUMMY_CREDENTIALS = new String[]{ "foo@example.com:hello", "bar@example.com:world" }; private UserLoginTask mAuthTask = null; // UI references. private AutoCompleteTextView mEmailView; private EditText mPasswordView; private View mProgressView; private View mLoginFormView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_login); // Set up the login form. mEmailView = (AutoCompleteTextView) findViewById(R.id.email); populateAutoComplete(); mPasswordView = (EditText) findViewById(R.id.password); mPasswordView.setOnEditorActionListener(new TextView.OnEditorActionListener() { @Override public boolean onEditorAction(TextView textView, int id, KeyEvent keyEvent) { if (id == R.id.login || id == EditorInfo.IME_NULL) { attemptLogin(); return true; } return false; } }); Button mEmailSignInButton = (Button) findViewById(R.id.email_sign_in_button); mEmailSignInButton.setOnClickListener(new OnClickListener() { @Override public void onClick(View view) { attemptLogin(); } }); mLoginFormView = findViewById(R.id.login_form); mProgressView = findViewById(R.id.login_progress); } private void populateAutoComplete() { if (!mayRequestContacts()) { return; } getLoaderManager().initLoader(0, null, this); } private boolean mayRequestContacts() { if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) { return true; } if (checkSelfPermission(READ_CONTACTS) == PackageManager.PERMISSION_GRANTED) { return true; } if (shouldShowRequestPermissionRationale(READ_CONTACTS)) { Snackbar.make(mEmailView, R.string.permission_rationale, Snackbar.LENGTH_INDEFINITE) .setAction(android.R.string.ok, new View.OnClickListener() { @Override @TargetApi(Build.VERSION_CODES.M) public void onClick(View v) { requestPermissions(new String[]{READ_CONTACTS}, REQUEST_READ_CONTACTS); } }); } else { requestPermissions(new String[]{READ_CONTACTS}, REQUEST_READ_CONTACTS); } return false; } @Override public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { if (requestCode == REQUEST_READ_CONTACTS) { if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { populateAutoComplete(); } } } private void attemptLogin() { if (mAuthTask != null) { return; } // Reset errors. mEmailView.setError(null); mPasswordView.setError(null); // Store values at the time of the login attempt. String email = mEmailView.getText().toString(); String password = mPasswordView.getText().toString(); boolean cancel = false; View focusView = null; // Check for a valid password, if the user entered one. if (!TextUtils.isEmpty(password) && !isPasswordValid(password)) { mPasswordView.setError(getString(R.string.error_invalid_password)); focusView = mPasswordView; cancel = true; } // Check for a valid email address. if (TextUtils.isEmpty(email)) { mEmailView.setError(getString(R.string.error_field_required)); focusView = mEmailView; cancel = true; } else if (!isEmailValid(email)) { mEmailView.setError(getString(R.string.error_invalid_email)); focusView = mEmailView; cancel = true; } if (cancel) { // There was an error; don't attempt login and focus the first // form field with an error. focusView.requestFocus(); } else { // Show a progress spinner, and kick off a background task to // perform the user login attempt. showProgress(true); mAuthTask = new UserLoginTask(email, password); mAuthTask.execute((Void) null); } } private boolean isEmailValid(String email) { //TODO: Replace this with your own logic return email.contains("@"); } private boolean isPasswordValid(String password) { //TODO: Replace this with your own logic return password.length() > 4; } @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2) private void showProgress(final boolean show) { // On Honeycomb MR2 we have the ViewPropertyAnimator APIs, which allow // for very easy animations. If available, use these APIs to fade-in // the progress spinner. if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2) { int shortAnimTime = getResources().getInteger(android.R.integer.config_shortAnimTime); mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE); mLoginFormView.animate().setDuration(shortAnimTime).alpha( show ? 0 : 1).setListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE); } }); mProgressView.setVisibility(show ? View.VISIBLE : View.GONE); mProgressView.animate().setDuration(shortAnimTime).alpha( show ? 1 : 0).setListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { mProgressView.setVisibility(show ? View.VISIBLE : View.GONE); } }); } else { // The ViewPropertyAnimator APIs are not available, so simply show // and hide the relevant UI components. mProgressView.setVisibility(show ? View.VISIBLE : View.GONE); mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE); } } @Override public Loader<Cursor> onCreateLoader(int i, Bundle bundle) { return new CursorLoader(this, // Retrieve data rows for the device user's 'profile' contact. Uri.withAppendedPath(ContactsContract.Profile.CONTENT_URI, ContactsContract.Contacts.Data.CONTENT_DIRECTORY), ProfileQuery.PROJECTION, // Select only email addresses. ContactsContract.Contacts.Data.MIMETYPE + " = ?", new String[]{ContactsContract.CommonDataKinds.Email .CONTENT_ITEM_TYPE}, // Show primary email addresses first. Note that there won't be // a primary email address if the user hasn't specified one. ContactsContract.Contacts.Data.IS_PRIMARY + " DESC"); } @Override public void onLoadFinished(Loader<Cursor> cursorLoader, Cursor cursor) { List<String> emails = new ArrayList<>(); cursor.moveToFirst(); while (!cursor.isAfterLast()) { emails.add(cursor.getString(ProfileQuery.ADDRESS)); cursor.moveToNext(); } addEmailsToAutoComplete(emails); } @Override public void onLoaderReset(Loader<Cursor> cursorLoader) { } private void addEmailsToAutoComplete(List<String> emailAddressCollection) { //Create adapter to tell the AutoCompleteTextView what to show in its dropdown list. ArrayAdapter<String> adapter = new ArrayAdapter<>(LoginActivity.this, android.R.layout.simple_dropdown_item_1line, emailAddressCollection); mEmailView.setAdapter(adapter); } private interface ProfileQuery { String[] PROJECTION = { ContactsContract.CommonDataKinds.Email.ADDRESS, ContactsContract.CommonDataKinds.Email.IS_PRIMARY, }; int ADDRESS = 0; int IS_PRIMARY = 1; } /** * Represents an asynchronous login/registration task used to authenticate * the user. */ public class UserLoginTask extends AsyncTask<Void, Void, Boolean> { private final String mEmail; private final String mPassword; UserLoginTask(String email, String password) { mEmail = email; mPassword = password; } @Override protected Boolean doInBackground(Void... params) { // TODO: attempt authentication against a network service. try { // Simulate network access. Thread.sleep(2000); } catch (InterruptedException e) { return false; } for (String credential : DUMMY_CREDENTIALS) { String[] pieces = credential.split(":"); if (pieces[0].equals(mEmail)) { // Account exists, return true if the password matches. return pieces[1].equals(mPassword); } } // TODO: register the new account here. return true; } @Override protected void onPostExecute(final Boolean success) { mAuthTask = null; showProgress(false); if (success) { Intent i = new Intent(LoginActivity.this, ControlPanel.class); startActivity(i); finish(); } else { mPasswordView.setError(getString(R.string.error_incorrect_password)); mPasswordView.requestFocus(); } } @Override protected void onCancelled() { mAuthTask = null; showProgress(false); } } }
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Originariamente inviata da Landi
