I'm struggling in a little problem that i can not find! In my main activity i want to display an AlertDialog and have a checkbox if the user do not want display the dialog again.
I can make the dialog appear with the checkbox, etc.. but for some reason when I try to add a OnCheckedChangeListener to the CheckBox my application closes before it starts :(
Here is the relevant parts of my code:
Initializing the variables for the SharedPreferences:
public final static String WEL_PREF = "Welcome Dialog Preference";
public static int welcomeChecked = 0;
Inside OnCreate:
SharedPreferences welcomePref = getSharedPreferences(WEL_PREF, MODE_PRIVATE);
welcomeChecked = welcomePref.getInt("tut", 0);
...
if(welcomeChecked == 1) {
showAlertDialog();
}
the showAlertDialog() function:
private void showAlertDialog() {
final Intent tutorial = new Intent(MainActivity.this, TutorialActivity.class);
View checkBoxView = View.inflate(this, R.layout.welcome_checkbox, null);
CheckBox welcomeCheck = (CheckBox) findViewById(R.id.tutCheck);
welcomeCheck.setOnCheckedChangeListener(new OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
SharedPreferences welcomePref = getSharedPreferences(WEL_PREF, MODE_PRIVATE);
SharedPreferences.Editor editor = welcomePref.edit();
if(isChecked) {
editor.putInt("tut", 1);
editor.commit();
} else {
editor.putInt("tut", 0);
editor.commit();
}
}
});
AlertDialog.Builder welcomeDialog = new AlertDialog.Builder(this);
welcomeDialog.setTitle("Welcome");
welcomeDialog.setMessage("Welcome to Formula Calculator, if you want to know how to use my features " +
"click in the Tutorial button.");
welcomeDialog.setView(checkBoxView);
welcomeDialog.setCancelable(false);
welcomeDialog.setPositiveButton("Tutorial", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
startActivity(tutorial);
}
});
welcomeDialog.setNegativeButton("Close", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
AlertDialog welDialog = welcomeDialog.create();
welDialog.show();
}
Thank you very much for your help! I can not find the solution why the application closes.!
Here is the logcat if helps:
05-19 15:37:55.807: W/ActivityThread(8009): Application com.gabilheri.marcuscalculatorv2 can be
debugged on port 8100...
05-19 15:37:56.127: D/AndroidRuntime(8009): Shutting down VM
05-19 15:37:56.127: W/dalvikvm(8009): threadid=1: thread exiting with uncaught exception (group=0x40c32930)
05-19 15:37:56.137: E/AndroidRuntime(8009): FATAL EXCEPTION: main
05-19 15:37:56.137: E/AndroidRuntime(8009): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.gabilheri.marcuscalculatorv2/com.gabilheri.marcuscalculatorv2.MainActivity}: java.lang.NullPointerException
05-19 15:37:56.137: E/AndroidRuntime(8009): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
05-19 15:37:56.137: E/AndroidRuntime(8009): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
05-19 15:37:56.137: E/AndroidRuntime(8009): at android.app.ActivityThread.access$600(ActivityThread.java:141)
05-19 15:37:56.137: E/AndroidRuntime(8009): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
05-19 15:37:56.137: E/AndroidRuntime(8009): at android.os.Handler.dispatchMessage(Handler.java:99)
05-19 15:37:56.137: E/AndroidRuntime(8009): at android.os.Looper.loop(Looper.java:137)
05-19 15:37:56.137: E/AndroidRuntime(8009): at android.app.ActivityThread.main(ActivityThread.java:5041)
05-19 15:37:56.137: E/AndroidRuntime(8009): at java.lang.reflect.Method.invokeNative(Native Method)
05-19 15:37:56.137: E/AndroidRuntime(8009): at java.lang.reflect.Method.invoke(Method.java:511)
05-19 15:37:56.137: E/AndroidRuntime(8009): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
05-19 15:37:56.137: E/AndroidRuntime(8009): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
05-19 15:37:56.137: E/AndroidRuntime(8009): at dalvik.system.NativeStart.main(Native Method)
05-19 15:37:56.137: E/AndroidRuntime(8009): Caused by: java.lang.NullPointerException
05-19 15:37:56.137: E/AndroidRuntime(8009): at com.gabilheri.marcuscalculatorv2.MainActivity.showAlertDialog(MainActivity.java:744)
05-19 15:37:56.137: E/AndroidRuntime(8009): at com.gabilheri.marcuscalculatorv2.MainActivity.onCreate(MainActivity.java:171)
05-19 15:37:56.137: E/AndroidRuntime(8009): at android.app.Activity.performCreate(Activity.java:5104)
05-19 15:37:56.137: E/AndroidRuntime(8009): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
05-19 15:37:56.137: E/AndroidRuntime(8009): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
05-19 15:37:56.137: E/AndroidRuntime(8009): ... 11 more
05-19 15:37:56.187: D/dalvikvm(8009): GC_CONCURRENT freed 219K, 5% free 7518K/7864K, paused 14ms+2ms, total 80ms
if tutCheck CheckBox is in Dialog Layout then initialize it as:
View checkBoxView = View.inflate(this, R.layout.welcome_checkbox, null);
CheckBox welcomeCheck = (CheckBox)checkBoxView.findViewById(R.id.tutCheck);