I am new to this android. Whenever I click the login button, it says "unfortunately, your app has stopped".
There is no compile time error..
I am uploading my MainActivity.java, LoginActivity.java and manifest.xml files..
Please tell me whats the problem or am i doing something wrong?
//MainActivity.java
package com.satty002.swag;
import java.util.Locale;
import android.app.ActionBar;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.content.Intent;
import android.os.Bundle;
import android.support.v13.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import com.parse.ParseAnalytics;
import com.parse.ParseUser;
public class MainActivity extends Activity implements ActionBar.TabListener {
public static final String TAG = MainActivity.class.getSimpleName();
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link FragmentPagerAdapter} derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* {@link android.support.v13.app.FragmentStatePagerAdapter}.
*/
SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ParseAnalytics.trackAppOpened(getIntent());
ParseUser currentUser = ParseUser.getCurrentUser();
if (currentUser == null) {
navigateToLogin();
} else {
Log.i(TAG, currentUser.getUsername());
}
// Set up the action bar.
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
// When swiping between different sections, select the corresponding
// tab. We can also use ActionBar.Tab#select() to do this if we have
// a reference to the Tab.
mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
// For each of the sections in the app, add a tab to the action bar.
for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
// Create a tab with text corresponding to the page title defined by
// the adapter. Also specify this Activity object, which implements
// the TabListener interface, as the callback (listener) for when
// this tab is selected.
actionBar.addTab(
actionBar.newTab()
.setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
}
private void navigateToLogin() {
Intent intent = new Intent(this, LoginActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_logout) {
ParseUser.logOut();
navigateToLogin();
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
// When the given tab is selected, switch to the corresponding page in
// the ViewPager.
mViewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a PlaceholderFragment (defined as a static inner class below).
return PlaceholderFragment.newInstance(position + 1);
}
@Override
public int getCount() {
// Show 3 total pages.
return 3;
}
@Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position) {
case 0:
return getString(R.string.title_section1).toUpperCase(l);
case 1:
return getString(R.string.title_section2).toUpperCase(l);
case 2:
return getString(R.string.title_section3).toUpperCase(l);
}
return null;
}
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
}
}
//LoginActivity.java
package com.satty002.swag;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import com.parse.LogInCallback;
import com.parse.ParseException;
import com.parse.ParseUser;
public class LoginActivity extends Activity {
protected EditText mUsername;
protected EditText mPassword;
protected Button mLoginButton;
protected TextView mSignUpTextView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
mSignUpTextView = (TextView) findViewById(R.id.SignupText);
mSignUpTextView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(LoginActivity.this, SignupActivity.class);
startActivity(intent);
}
});
mUsername = (EditText) findViewById(R.id.usernameField);
mPassword = (EditText) findViewById(R.id.passwordFiled);
mLoginButton = (Button) findViewById(R.id.loginButton);
mLoginButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String username = mUsername.getText().toString();
String password = mPassword.getText().toString();
username.trim();
password.trim();
if(username.isEmpty() || password.isEmpty() )
{
AlertDialog.Builder builder = new AlertDialog.Builder(LoginActivity.this);
builder.setMessage(R.string.login_error_message)
.setTitle(R.string.login_error_title)
.setPositiveButton(android.R.string.ok, null);
AlertDialog dialog = builder.create();
dialog.show();
}
else
{
ParseUser.logInInBackground(username, password, new LogInCallback() {
@Override
public void done(ParseUser user, ParseException e) {
if(e == null)
{
//success
Intent intent = new Intent(LoginActivity.this, MainActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);
}
else
{
AlertDialog.Builder builder = new AlertDialog.Builder(LoginActivity.this);
builder.setMessage(R.string.login_error_message)
.setTitle(R.string.login_error_title)
.setPositiveButton(android.R.string.ok, null);
AlertDialog dialog = builder.create();
dialog.show();
}
}
});
}
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.login, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
//manifest.xml
android:versionCode="1"
android:versionName="1.0" >
android:targetSdkVersion="21" />
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" android:name="SwagApplication">
android:label="@string/app_name"
android:screenOrientation="portrait" >
android:label="@string/app_name"
android:screenOrientation="portrait" >
android:label="@string/app_name"
android:parentActivityName=".LoginActivity">
//Activity_login.xml
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.satty002.swag.LoginActivity" >
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="@string/signup_text" />
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:ems="10"
android:hint="@string/username_hint" >
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/usernameField"
android:layout_below="@+id/usernameField"
android:ems="10"
android:hint="@string/password_hint"
android:inputType="textPassword" />
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/PasswordField"
android:layout_below="@+id/PasswordField"
android:text="@string/login_button_label" />
//logcat
07-25 17:52:52.332: E/Trace(1627): error opening trace file: No such file or directory (2)
07-25 17:52:54.393: D/dalvikvm(1627): GC_CONCURRENT freed 274K, 7% free 6132K/6535K, paused 14ms+110ms, total 330ms
07-25 17:52:55.083: D/libEGL(1627): loaded /system/lib/egl/libEGL_emulation.so
07-25 17:52:55.093: D/(1627): HostConnection::get() New Host Connection established 0xb8462cf0, tid 1627
07-25 17:52:55.123: D/libEGL(1627): loaded /system/lib/egl/libGLESv1_CM_emulation.so
07-25 17:52:55.153: D/libEGL(1627): loaded /system/lib/egl/libGLESv2_emulation.so
07-25 17:52:55.363: W/EGL_emulation(1627): eglSurfaceAttrib not implemented
07-25 17:52:55.423: D/OpenGLRenderer(1627): Enabling debug mode 0
07-25 17:52:56.833: W/EGL_emulation(1627): eglSurfaceAttrib not implemented
07-25 17:52:56.833: I/Choreographer(1627): Skipped 37 frames! The application may be doing too much work on its main thread.
07-25 17:52:57.283: D/dalvikvm(1627): GC_CONCURRENT freed 189K, 5% free 6342K/6663K, paused 18ms+101ms, total 151ms
07-25 17:53:19.003: D/AndroidRuntime(1627): Shutting down VM
07-25 17:53:19.003: W/dalvikvm(1627): threadid=1: thread exiting with uncaught exception (group=0xb5f03288)
07-25 17:53:19.014: E/AndroidRuntime(1627): FATAL EXCEPTION: main
07-25 17:53:19.014: E/AndroidRuntime(1627): java.lang.NullPointerException
07-25 17:53:19.014: E/AndroidRuntime(1627): at com.satty002.swag.LoginActivity$2.onClick(LoginActivity.java:50)
07-25 17:53:19.014: E/AndroidRuntime(1627): at android.view.View.performClick(View.java:4084)
07-25 17:53:19.014: E/AndroidRuntime(1627): at android.view.View$PerformClick.run(View.java:16966)
07-25 17:53:19.014: E/AndroidRuntime(1627): at android.os.Handler.handleCallback(Handler.java:615)
07-25 17:53:19.014: E/AndroidRuntime(1627): at android.os.Handler.dispatchMessage(Handler.java:92)
07-25 17:53:19.014: E/AndroidRuntime(1627): at android.os.Looper.loop(Looper.java:137)
07-25 17:53:19.014: E/AndroidRuntime(1627): at android.app.ActivityThread.main(ActivityThread.java:4745)
07-25 17:53:19.014: E/AndroidRuntime(1627): at java.lang.reflect.Method.invokeNative(Native Method)
07-25 17:53:19.014: E/AndroidRuntime(1627): at java.lang.reflect.Method.invoke(Method.java:511)
07-25 17:53:19.014: E/AndroidRuntime(1627): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
07-25 17:53:19.014: E/AndroidRuntime(1627): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
07-25 17:53:19.014: E/AndroidRuntime(1627): at dalvik.system.NativeStart.main(Native Method)
Answer
I am going to guess that there is a null pointer somewhere in your onClick for your login activity. you should be able to figure this out by looking at your logcat which should tell you the exact line of code that is causing this crash. probably referencing an object that is not initialized / null
Edit
As stated you have a null reference on line 50 of LoginActivity:
java.lang.NullPointerException
07-25 17:53:19.014: E/AndroidRuntime(1627): at com.satty002.swag.LoginActivity$2.onClick(LoginActivity.java:50
you misspelled the password field reference:
mPassword = (EditText) findViewById(R.id.passwordFiled);
should be
mPassword = (EditText) findViewById(R.id.passwordField);
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