我正在创建一个Android应用程序，在用户登录应用程序后使用片段使用intent显示第二个活动。但问题是申请会在登录后强制关闭。
有人可以帮我解决错误吗？
ackage com.exercise.AndroidNavigationTabs;
import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentTransaction;
import android.os.Bundle;
public class AndroidNavigationTabsActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
Tab tabA = actionBar.newTab();
tabA.setText("Tab A");
tabA.setTabListener(new TabListener<MyFragmentA>(this, "Tag A", MyFragmentA.class));
actionBar.addTab(tabA);
Tab tabB = actionBar.newTab();
tabB.setText("Tab B");
tabB.setTabListener(new TabListener<MyFragmentB>(this, "Tag B", MyFragmentB.class));
actionBar.addTab(tabB);
Tab tabC = actionBar.newTab();
tabC.setText("Tab C");
tabC.setTabListener(new TabListener<MyFragmentC>(this, "Tag C", MyFragmentC.class));
actionBar.addTab(tabC);
if (savedInstanceState != null) {
int savedIndex = savedInstanceState.getInt("SAVED_INDEX");
getActionBar().setSelectedNavigationItem(savedIndex);
}
}
@Override
protected void onSaveInstanceState(Bundle outState) {
// TODO Auto-generated method stub
super.onSaveInstanceState(outState);
outState.putInt("SAVED_INDEX", getActionBar().getSelectedNavigationIndex());
}
public static class TabListener<T extends Fragment>
implements ActionBar.TabListener{
private final Activity myActivity;
private final String myTag;
private final Class<T> myClass;
public TabListener(Activity activity, String tag, Class<T> cls) {
myActivity = activity;
myTag = tag;
myClass = cls;
}
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
Fragment myFragment = myActivity.getFragmentManager().findFragmentByTag(myTag);
// Check if the fragment is already initialized
if (myFragment == null) {
// If not, instantiate and add it to the activity
myFragment = Fragment.instantiate(myActivity, myClass.getName());
ft.add(android.R.id.content, myFragment, myTag);
} else {
// If it exists, simply attach it in order to show it
ft.attach(myFragment);
}
}
@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
Fragment myFragment = myActivity.getFragmentManager().findFragmentByTag(myTag);
if (myFragment != null) {
// Detach the fragment, because another one is being attached
ft.detach(myFragment);
}
}
@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// TODO Auto-generated method stub
}
}
}
package com.exercise.AndroidNavigationTabs;
import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.View;
import android.view.inputmethod.EditorInfo;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
/**
* Activity which displays a login screen to the user, offering registration as
* well.
*/
public class LoginActivity extends Activity {
/**
* A dummy authentication store containing known user names and passwords.
* TODO: remove after connecting to a real authentication system.
*/
private static final String[] DUMMY_CREDENTIALS = new String[] {
"foo@example.com:hello", "bar@example.com:world" };
/**
* The default email to populate the email field with.
*/
public static final String EXTRA_EMAIL = "com.example.android.authenticatordemo.extra.EMAIL";
/**
* Keep track of the login task to ensure we can cancel it if requested.
*/
private UserLoginTask mAuthTask = null;
// Values for email and password at the time of the login attempt.
private String mEmail = "jamil@jamil.com";
private String mPassword = "jamil123";
// UI references.
private EditText mEmailView;
private EditText mPasswordView;
private View mLoginFormView;
private View mLoginStatusView;
private TextView mLoginStatusMessageView;
private TextView mRegister;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
// Set up the login form.
mEmail = getIntent().getStringExtra(EXTRA_EMAIL);
mEmailView = (EditText) findViewById(R.id.email);
mEmailView.setText(mEmail);
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;
}
});
mLoginFormView = findViewById(R.id.login_form);
mLoginStatusView = findViewById(R.id.login_status);
mLoginStatusMessageView = (TextView) findViewById(R.id.login_status_message);
findViewById(R.id.sign_in_button).setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View view) {
attemptLogin();
}
});
// Register link
mRegister = (TextView) findViewById(R.id.txt_register);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
getMenuInflater().inflate(R.menu.login, menu);
return true;
}
/**
* Attempts to sign in or register the account specified by the login form.
* If there are form errors (invalid email, missing fields, etc.), the
* errors are presented and no actual login attempt is made.
*/
public void attemptLogin() {
if (mAuthTask != null) {
// if everything go well the application will send the user to the
// second page
Intent intent = new Intent(this, MyFragmentA.class);
startActivity(intent);
Toast.makeText(this, "the system will display the second page",
Toast.LENGTH_SHORT).show();
return;
}
// Reset errors.
mEmailView.setError(null);
mPasswordView.setError(null);
// Store values at the time of the login attempt.
mEmail = mEmailView.getText().toString();
mPassword = mPasswordView.getText().toString();
boolean cancel = false;
View focusView = null;
// Check for a valid password.
if (TextUtils.isEmpty(mPassword)) {
mPasswordView.setError(getString(R.string.error_field_required));
focusView = mPasswordView;
cancel = true;
} else if (mPassword.length() < 6) {
mPasswordView.setError(getString(R.string.error_invalid_password));
focusView = mPasswordView;
cancel = true;
}
// Check for a valid email address.
if (TextUtils.isEmpty(mEmail)) {
mEmailView.setError(getString(R.string.error_field_required));
focusView = mEmailView;
cancel = true;
} else if (!mEmail.contains("@")) {
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.
mLoginStatusMessageView.setText(R.string.login_progress_signing_in);
showProgress(true);
mAuthTask = new UserLoginTask();
mAuthTask.execute((Void) null);
}
}
/**
* Shows the progress UI and hides the login form.
*/
@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);
mLoginStatusView.setVisibility(View.VISIBLE);
mLoginStatusView.animate().setDuration(shortAnimTime)
.alpha(show ? 1 : 0)
.setListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
mLoginStatusView.setVisibility(show ? View.VISIBLE
: View.GONE);
}
});
mLoginFormView.setVisibility(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);
}
});
} else {
// The ViewPropertyAnimator APIs are not available, so simply show
// and hide the relevant UI components.
mLoginStatusView.setVisibility(show ? View.VISIBLE : View.GONE);
mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE);
}
}
/**
* Represents an asynchronous login/registration task used to authenticate
* the user.
*/
public class UserLoginTask extends AsyncTask<Void, Void, Boolean> {
@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) {
finish();
} else {
mPasswordView
.setError(getString(R.string.error_incorrect_password));
mPasswordView.requestFocus();
}
}
@Override
protected void onCancelled() {
mAuthTask = null;
showProgress(false);
}
}
}
package com.exercise.AndroidNavigationTabs;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class MyFragmentA extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View myFragmentView = inflater.inflate(R.layout.fragment_a, container, false);
return myFragmentView;
}
}
10-21 10:32:58.146: D/AndroidRuntime(784): CheckJNI is ON
10-21 10:32:58.976: D/AndroidRuntime(784): Calling main entry com.android.commands.am.Am
10-21 10:32:59.006: I/ActivityManager(89): START {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.exercise.AndroidNavigationTabs/.LoginActivity} from pid 784
10-21 10:32:59.006: W/WindowManager(89): Failure taking screenshot for (180x300) to layer 21005
10-21 10:32:59.136: W/NetworkManagementSocketTagger(89): setKernelCountSet(10047, 1) failed with errno -2
10-21 10:32:59.136: D/AndroidRuntime(784): Shutting down VM
10-21 10:32:59.186: D/dalvikvm(784): GC_CONCURRENT freed 102K, 77% free 485K/2048K, paused 0ms+1ms
10-21 10:32:59.196: D/dalvikvm(784): Debugger has detached; object registry had 1 entries
10-21 10:32:59.206: I/AndroidRuntime(784): NOTE: attach of thread 'Binder Thread #3' failed
10-21 10:32:59.627: I/Process(89): Sending signal. PID: 726 SIG: 3
10-21 10:32:59.627: I/dalvikvm(726): threadid=3: reacting to signal 3
10-21 10:32:59.716: I/dalvikvm(726): Wrote stack traces to '/data/anr/traces.txt'
10-21 10:33:00.196: D/dalvikvm(89): GC_CONCURRENT freed 404K, 12% free 11366K/12871K, paused 7ms+76ms
10-21 10:33:00.216: I/Process(89): Sending signal. PID: 726 SIG: 3
10-21 10:33:00.216: I/dalvikvm(726): threadid=3: reacting to signal 3
10-21 10:33:00.246: I/dalvikvm(726): Wrote stack traces to '/data/anr/traces.txt'
10-21 10:33:00.446: I/ActivityManager(89): Displayed com.exercise.AndroidNavigationTabs/.LoginActivity: +1s326ms
10-21 10:33:00.766: W/NetworkManagementSocketTagger(89): setKernelCountSet(10013, 0) failed with errno -2
10-21 10:33:01.067: D/dalvikvm(144): GC_CONCURRENT freed 295K, 29% free 9990K/13959K, paused 5ms+6ms
10-21 10:33:18.656: D/dalvikvm(175): GC_CONCURRENT freed 384K, 6% free 9534K/10119K, paused 5ms+5ms
10-21 10:33:28.957: D/InputEventConsistencyVerifier(726): KeyEvent: ACTION_UP but key was not down.
10-21 10:33:28.957: D/InputEventConsistencyVerifier(726): in android.widget.EditText@412bc250
10-21 10:33:28.957: D/InputEventConsistencyVerifier(726): 0: sent at 1906974000000, KeyEvent { action=ACTION_UP, keyCode=KEYCODE_TAB, scanCode=15, metaState=0, flags=0x8, repeatCount=0, eventTime=1906974, downTime=1906890, deviceId=0, source=0x101 }
10-21 10:33:40.476: W/WindowManager(89): Failure taking screenshot for (180x300) to layer 21010
10-21 10:33:40.596: W/NetworkManagementSocketTagger(89): setKernelCountSet(10013, 1) failed with errno -2
10-21 10:33:40.826: W/InputManagerService(89): Starting input on non-focused client com.android.internal.view.IInputMethodClient$Stub$Proxy@413a0168 (uid=10047 pid=726)
10-21 10:33:40.836: W/IInputConnectionWrapper(726): showStatusIcon on inactive InputConnection
10-21 10:33:41.576: W/NetworkManagementSocketTagger(89): setKernelCountSet(10047, 0) failed with errno -2
10-21 10:33:41.646: D/dalvikvm(144): GC_CONCURRENT freed 586K, 30% free 9867K/13959K, paused 5ms+37ms