[Java for Android App Development] Sandy||Striker:
help needed

public void onClick(View arg0) {
// TODO Auto-generated method stub
switch (arg0.getId()){
case R.id.bgo2:

try{

username=et1.getText().toString();
password=et2.getText().toString();
ParseUser signup = new ParseUser();
signup.setUsername(username);
signup.setPassword(password);
signup.signUpInBackground(new SignUpCallback() {
public void done(ParseException e) {
if (e == null) {
// Hooray! Let them use the app now.
Intent i = new Intent(MainActivity.this,Slider.class);
startActivity(i);
} else {
// Sign up didn't succeed. Look at the ParseException
// to figure out what went wrong
Toast.makeText(MainActivity.this, "something wrong" , Toast.LENGTH_SHORT).show();
}
}
});
} catch (IllegalArgumentException IO) {
// The user didn't type in anything, I suggest using a Toast to notify him
Toast.makeText(MainActivity.this, "Please type something" , Toast.LENGTH_SHORT).show();
}

this is my code for signup on click of a button. everything is setup. but nothing happens when i click on sighn up button. and when i click on sigh in.. the app exits with an error. logcat says:-

06-03 11:55:41.761: E/SpannableStringBuilder(15340): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
06-03 11:55:41.761: E/SpannableStringBuilder(15340): SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
06-03 11:55:42.178: E/NativeCrypto(15340): ssl=0x52f7c578 cert_verify_callback x509_store_ctx=0x52112a80 arg=0x0
06-03 11:55:42.178: E/NativeCrypto(15340): ssl=0x52f7c578 cert_verify_callback calling verifyCertificateChain authMethod=RSA
06-03 11:55:50.001: E/AndroidRuntime(15340): FATAL EXCEPTION: main
06-03 11:55:50.001: E/AndroidRuntime(15340): java.lang.IllegalArgumentException: Must specify a username for the user to log in with
06-03 11:55:50.001: E/AndroidRuntime(15340):	at com.parse.ParseUser.logInAsync(ParseUser.java:655)
06-03 11:55:50.001: E/AndroidRuntime(15340):	at com.parse.ParseUser.logInInBackground(ParseUser.java:715)
06-03 11:55:50.001: E/AndroidRuntime(15340):	at com.sandy.letsfixthat.MainActivity.onClick(MainActivity.java:98)
06-03 11:55:50.001: E/AndroidRuntime(15340):	at android.view.View.performClick(View.java:4091)
06-03 11:55:50.001: E/AndroidRuntime(15340):	at android.view.View$PerformClick.run(View.java:17072)
06-03 11:55:50.001: E/AndroidRuntime(15340):	at android.os.Handler.handleCallback(Handler.java:615)
06-03 11:55:50.001: E/AndroidRuntime(15340):	at android.os.Handler.dispatchMessage(Handler.java:92)
06-03 11:55:50.001: E/AndroidRuntime(15340):	at android.os.Looper.loop(Looper.java:153)
06-03 11:55:50.001: E/AndroidRuntime(15340):	at android.app.ActivityThread.main(ActivityThread.java:5086)
06-03 11:55:50.001: E/AndroidRuntime(15340):	at java.lang.reflect.Method.invokeNative(Native Method)
06-03 11:55:50.001: E/AndroidRuntime(15340):	at java.lang.reflect.Method.invoke(Method.java:511)
06-03 11:55:50.001: E/AndroidRuntime(15340):	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:821)
06-03 11:55:50.001: E/AndroidRuntime(15340):	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:584)
06-03 11:55:50.001: E/AndroidRuntime(15340):	at dalvik.system.NativeStart.main(Native Method)
06-03 11:55:56.435: E/Trace(15377): error opening trace file: No such file or directory (2)
06-03 11:55:56.452: E/com.parse.PushService(15377): The Parse push service cannot start because Parse.initialize has not yet been called.
If you call Parse.initialize from an Activity's onCreate, that call should instead be in the Application.onCreate.
Be sure your Application class is registered in your AndroidManifest.xml with the android:name property of your <application> tag.

push notification working fine for me.