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Android Math quiz (Thread manipulation)

I need to make a math quiz. Here is workflow:
On button click(Start) i need to show a question e.g. 5+5, which stays on screen for 2 seconds after which a dialog i shown asking for result of previous operation. And i need to repeat that for e.g. 5 times. At the end I need to show to user number of correct answers.
I have Java experience but I'm new to Android. I have read various articles and examples regarding Android threading but haven't found solution to this workflow.
As far as I know I cannot block or pause main/UI thread, but the problem is that i should repeat questions for e.g. 5 times and after each one(after 2 sec.) I should pause activity to show Dialog and then go back to showing another question.
Thanks in advance!
EDIT:
Here is my code for now. The number is shown on screen and after 2 seconds alert dialog is shown asking to enter that number. But the problem is that the application doesn't wait for user input but continues to show new random number an opens new alert dialog every 2 seconds.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_questions);
tv = (TextView) findViewById(R.id.questionText);
handler = new Handler();
Runnable r = new Runnable() {
public void run() {
tv.setText(String.valueOf(rand.nextInt(50) + 1));
createDialog();
handler.postDelayed(this, 2000);
}
};
handler.postDelayed(r, 2000);
}
protected void createDialog() {
LayoutInflater li = LayoutInflater.from(context);
View promptsView = li.inflate(R.layout.activity_answer_dialog, null);
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context);
// set prompts.xml to alertdialog builder
alertDialogBuilder.setView(promptsView);
final EditText userInput = (EditText) promptsView.findViewById(R.id.editTextDialogUserInput);
// set dialog message
alertDialogBuilder
.setCancelable(false)
.setPositiveButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
// get user input and set it to result
// edit text
result.setText(userInput.getText());
}
})
.setNegativeButton("Cancel",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
dialog.cancel();
}
});
// create alert dialog
AlertDialog alertDialog = alertDialogBuilder.create();
// show it
alertDialog.show();
}
PS. Also I tried to create separate Activity for dialog and added this line to Manifest:
android:theme="#android:style/Theme.Dialog"
but the same thing happens.

You use event driven programming and timers. To show the dialog after 2 seconds, the easiest way is to post a runnable to a handler using postDelayed, which will call your runnable in N milliseconds. Then display the dialog box.
You don't need to pause the activity to show the dialog box, just show it. Any code that you want to run after the dialog is finished with should be put in the handler for the dialog's ok button. In other words, your code is called in response to the event of a button being pressed.

DialogFragment not visible but selectable

I have a very strange problem on Android using DialogFragments.
I have a FrameLayout with no content and the OnClickListener set to open a FragmentDialog where the user can choose what type of content he wants to add.
If I choose an image from the gallery, this image will be loaded and an image view inside the Frame-Layout is created and the image is shown. If the user clicks again on the layout the selection dialog should open again and the user can select a new image and the old one would be replaced.
This works quite well on my device with Android 4.1. But if I test it on Android 2.3 something strange happens:
The first dialog appears and the user can choose an image from the gallery. But if the user clicks again the dialog is not shown again. But the display becomes darker as if the dialog would be there but is not shown. If I click on the position where the selection dialog should be the gallery is started again. So the dialog is definitely there, but it is simply not shown.
I have tried almost everything that came to my mind(and what I found in the internet) to fix this issue, but it does not help anything. Of course I am using the support library to import the Fragment and DialogFragment.
I start this dialog from a Fragment which is embedded in a ViewPager. So it is basically a tabbed view. What's interesting: I I run into this bug and the display is just getting darker but no dialog is visible, I can cancel the invisible dialog and just drag the ViewPager a bit to left or right(to the next fragment) and if I get back and click on the content again the dialog is shown again.
But if I am dragging the ViewPager around there are no log messages so I have no idea why the dialog is suddenly visible again if I firstly move the page(only a bit is enough).
Here is some of my code:
in the onCreateView method I do the following:
rootView = inflater.inflate(args.getInt(ARG_OBJECT_TYPE), container, false);
editorActivity = ((NoteEditorActivity) EditorSectionFragment.this.getActivity());
// ...
if( fragmentId == R.layout.fragment_note_preferences_editor ){
// the other page
else if( fragmentId == R.layout.fragment_note_editor ) {
final View addLeftElement = rootView.findViewById( R.id.addLeftElement );
final View addRightElement = rootView.findViewById( R.id.addRightElement );
final View addTopElement = rootView.findViewById( R.id.addTopElement );
final View addBottomElement = rootView.findViewById( R.id.addBottomElement );
final FrameLayout contentLayout = (FrameLayout) rootView.findViewById( R.id.contentLayout );
showNavigation(editorActivity, contentLayout, editorActivity.currentPosition.x, editorActivity.currentPosition.y);
contentLayout.setOnClickListener( new OnClickListener() {
#Override
public void onClick(View v) {
Log.i("CONTENT CREATOR", "create new element at " + editorActivity.currentPosition);
//((NoteEditorActivity) EditorSectionFragment.this.getActivity()).showContentSelectionDialog();
((NoteEditorActivity) EditorSectionFragment.this.getActivity()).showCameraChooseDialog();
}
});
}
showCameraChoose(I also did it without the FragmentTransaction, but this didn't work either)
protected void showCameraChooseDialog() {
getSupportFragmentManager().executePendingTransactions();
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
Fragment prev = getSupportFragmentManager().findFragmentByTag("cameraChoose");
if( prev != null ){
Log.i("PREVIOUS", "Remove previous dialog");
ft.remove(prev);
}
(new CameraSelectionDialog()).show( ft, "cameraChoose");
}
CameraSelectionDialog:
public static class CameraSelectionDialog extends DialogFragment {
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
final CharSequence[] items = {"Camera", "Gallery"};
AlertDialog.Builder builder = new AlertDialog.Builder( this.getActivity() );
builder.setTitle("Choose how to get the image!");
builder.setItems(items, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
if( which == 0){
((NoteEditorActivity)(getActivity())).startCamera();
CameraSelectionDialog.this.dismiss();
}
else{
((NoteEditorActivity)(getActivity())).startGallery();
CameraSelectionDialog.this.dismiss();
}
}
});
return builder.create();
}
}
The startGallery method simply starts an gallery intent:
protected void startGallery() {
Intent pickPhoto = new Intent(Intent.ACTION_PICK,
android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(pickPhoto , ActionCodes.GALLERY_ACTION_CODE);
}
This image is handled in the onActivityResult method. But it does not matter what I choose to do in the onActivityResult method. Even if I don't create the image, the problem occurs.
I have no idea what I can do to solve this problem and I hope that maybe you can think of a reason for this strange bug. I am grateful for any advice or hint what could be wrong.
Thank you in advance!

Disabled back button and time Handler

I have a game quiz, and if a user's answer is wrong a popup screen pops up and stays on screen for 3 seconds. I do this with Handler. Since the game is time limited, they come up with solution to press back button to remove popup from the screen :) and move along. So I disabled the back button for that popup activity. BUT, now I have another problem. It seems that my Handler count time from the last click, so if I click back button on that popup screen Handler count time from that click. If I click it again, it starts from beggining. I've tried to click it 10-12 times and my popup screen was on for half a minute. :) And that's not good. How to make my popup be on for 3 seconds no metter if click back button or not during his time on?
My popup class:
public class WrongAnswer extends Activity{
TextView wrong;
String correctAnswer, correct;
public final int delayTime = 3000;
private Handler myHandler = new Handler();
public void onUserInteraction(){
myHandler.removeCallbacks(closePopup);
myHandler.postDelayed(closePopup, delayTime);
}
private Runnable closePopup = new Runnable(){
public void run(){
finish();
}
};
#Override
public void onBackPressed() {
//do nothing
}
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.wrong);
Bundle extras = getIntent().getExtras();
if(extras !=null) {
correct = extras.getString("correctAnswer");
}
inicijalizujVarijable();
myHandler.postDelayed(closePopup, delayTime);
}
private void inicijalizujVarijable() {
wrong = (TextView) findViewById(R.id.tvWrong);
Typeface pogresanFont = Typeface.createFromAsset(getAssets(), "Bebas.ttf");
wrong.setTypeface(pogresanFont);
Wrong.setText("Wrong answer!\nCorrect answer is:\n\n" + correct);
}
}

Remove this:
public void onUserInteraction(){
myHandler.removeCallbacks(closePopup);
myHandler.postDelayed(closePopup, delayTime);
}
It's resetting your handler on any interaction, which results in the behaviour you describe.
As a side note, it seems rather heavy to dedicate an Activity to this functionality, I think you'd be better off using a Dialog or similar.

You can show popup as Dialog and setCancelable() to false.
http://developer.android.com/reference/android/app/Dialog.html#setCancelable(boolean)

How to set font size for text of dialog buttons

I have an android app that uses some custom dialogs which are inflated from XML layouts. The contents of the dialog's view come from the XML layout, but the actual positive and negative buttons are added by calling the builder's setPositiveButton and setNegativeButton methods, so I have no control over (or at least don't know how to control) the styling of the buttons themselves.
See the onCreateDialog method below from my LoginConfirmationDialog.java file which extends DialogFragment. It basically pops a very simple dialog up that asks for confirmation of who is logging in (i.e. "Are you Joe Schmoe?", with Yes and No buttons).
The XML layout in this case has just a single TextView, and to make this easy (because the users will be construction workers with big knobby dirty fingers who need large text and large buttons), I made the font for the TextView pretty big. The two buttons though have much smaller font for their text, and since they aren't part of my layout and are added with the setPositiveButton and setNegativeButton methods, how do I control the font size?
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
Bundle args = this.getArguments();
String empName = args.getString("empName");
// Use the Builder class for convenient dialog construction
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
View view = getActivity().getLayoutInflater().inflate(R.layout.dialog_login_confirmation, null);
TextView message = (TextView)view.findViewById(R.id.txtLoginConfirmationMessage);
message.setText("Are you " + empName + "?");
builder.setView(view);
builder.setPositiveButton("Yes",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
mListener.onEmpConfirmPositiveClick(LoginConfirmationDialog.this);
}
});
builder.setNegativeButton("No",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
mListener.onEmpConfirmNegativeClick(LoginConfirmationDialog.this);
}
});
// Create the AlertDialog object and return it
return builder.create();
}

Instead of returning builder.create(), try this.-
final AlertDialog alert = builder.create();
alert.setOnShowListener(new DialogInterface.OnShowListener() {
#Override
public void onShow(DialogInterface dialog) {
Button btnPositive = alert.getButton(Dialog.BUTTON_POSITIVE);
btnPositive.setTextSize(TEXT_SIZE);
Button btnNegative = alert.getButton(Dialog.BUTTON_NEGATIVE);
btnNegative.setTextSize(TEXT_SIZE);
}
});
return alert;

Took me a while, to integrate Asok's answer, since I used anonymous inner classes for buttons, so I needed to get a handle on the button references. This works. Make sure it goes after the messageDialog.show() line:
messageDialog.show();
messageDialog.getButton(AlertDialog.BUTTON_POSITIVE).setTextSize(TypedValue.COMPLEX_UNIT_SP, 25.0f);
messageDialog.getButton(AlertDialog.BUTTON_NEUTRAL).setTextSize(TypedValue.COMPLEX_UNIT_SP, 25.0f);
Note: It's recommended to use sp as a unit for text size. Unlike px, it is device density independent.

You can try this:
AlertDialog.Builder builder = new AlertDialog.Builder(CompQuestionsActivity.this);
builder.setMessage("Message");
builder.setPositiveButton("Yes", dialogClickListener);
builder.setNegativeButton("No", dialogClickListener);
AlertDialog alertDialog = builder.create();
alertDialog.show();
//For positive button:
Button button1 = alertDialog.findViewById(android.R.id.button1);
button1.setTextSize(25);
//For negative button:
Button button2 = alertDialog.findViewById(android.R.id.button2);
button2.setTextSize(25);

Since you are already using an xml file for the dialog why not just include the two buttons in the layout and set the onClick handlers in the dialog creation, something like this should work. I am using something similar.
Here is a quick example:
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
View view = getActivity().getLayoutInflater().inflate(R.layout.dialog_login_confirmation, null);
TextView message = (TextView)view.findViewById(R.id.txtLoginConfirmationMessage);
message.setText("Are you " + empName + "?");
Button positiveBtn = (Button) view.findViewById(R.id.dialogButtonPositive);
// Set size of button in relation to screen size
positiveBtn.setTextSize(TypedValue.COMPLEX_UNIT_PX, (float) 25);
positiveBtn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
mListener.onEmpConfirmPositiveClick(LoginConfirmationDialog.this);
}
});
Button negativeBtn = (Button) view.findViewById(R.id.dialogButtonNeg);
// Set size of button in relation to screen size
negativeBtn.setTextSize(TypedValue.COMPLEX_UNIT_PX, (float) 25);
negativeBtn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
mListener.onEmpConfirmNegativeClick(LoginConfirmationDialog.this);
}
});
builder.setView(view);
return builder.create();
I am also quite fond of using the following for setting text sizes, this allows for various screen sizes to get a different size of text (You can play with the float value to suit your needs):
.setTextSize(TypedValue.COMPLEX_UNIT_PX, (float) 25);

You should check out the following answer:
In Dialog.java (Android src) a ContextThemeWrapper is used. So you could copy the idea and do something
You just have to change the following line of code:
<item name="android:textSize">10sp</item> to your desired size.
And don't forget to check the comments of the answer also.
Best of luck.

I have tried many devices using setOnShowListener . But it did not work for all devices. In the end I come to a decision that the most easiest way is to using a Theme for your alertDialog.
Add this to the style file.
<style name="MyAlertDialogTheme" parent="Theme.AppCompat.Light.Dialog.Alert">
<item name="android:textSize">10sp</item>
</style>
Now Use this in your AlertDialog
val dialog = AlertDialog.Builder(requireActivity(),R.style.MyAlertDialogTheme)
Thats all.

My approach is to obtain the buttons in onResume() and configure them there
public class LoginConfirmationDialog extends DialogFragment {
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
// your code here remains unchanged
}
#Override
public void onResume() {
super.onResume();
Button positiveButton = ((AlertDialog) getDialog()).getButton(AlertDialog.BUTTON_POSITIVE);
positiveButton.setTextSize(TypedValue.COMPLEX_UNIT_SP, 20);
Button negativeButton = ((AlertDialog) getDialog()).getButton(AlertDialog.BUTTON_NEGATIVE);
negativeButton.setTextSize(TypedValue.COMPLEX_UNIT_SP, 20);
}
}

Progress bar inside alert dialog containing webview

I have created an activity in which, on clicking a particular button, an alert dialog will open containing a WebView.
Everything is working fine, except when the url of the WebView is getting loaded. While loading the content of the WebView, the alert dialog's tile and button is shown, which looks a bit weird.
This is the screenshot of the alert dialog while loading the webpage for the webview inside it:
After successfully loading the content of the webview, it looks like this:
What I want is while loading the webview's content, a progress bar will be shown or a fixed background image will be show. How to achieve that?
The method which I am using to create this alert is:
//method to zoom images
public void zoomImage(String imageUrl)
{
AlertDialog.Builder alert = new AlertDialog.Builder(this);
alert.setTitle("Zoomed Image");
WebView wv = new WebView(this);
wv.setBackgroundColor(Color.WHITE);
wv.getSettings().setBuiltInZoomControls(true);
wv.setInitialScale(400);
wv.loadUrl(imageUrl);
wv.setWebViewClient(new WebViewClient()
{
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url)
{
view.loadUrl(url);
return true;
}
});
alert.setView(wv);
alert.setNegativeButton("Close", new DialogInterface.OnClickListener()
{
#Override
public void onClick(DialogInterface dialog, int id)
{
}
});
alert.show();
}
Thanks in advance!

You can take a progress bar in your alert dialog custom layout, and make the visibility gone in
the OnPageFinishedMethod.
you can create your custom alert dialog like this:
LayoutInflater inflater = getLayoutInflater();
View dialoglayout = inflater.inflate(R.layout.big_east, (ViewGroup) getCurrentFocus());
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setView(dialoglayout);
builder.setTitle("Zoomed Image");
and you should override two methods just like "shouldOverrideUrlLoading".
Methods are "OnPageStart" and "OnPageFinished".
In OnPageStart show the dialog and in OnPageFinish make the progress bar gone.
Hope it helps.

You can use a WebView.PictureListener (it is deprecated, but still works. Not sure if there is a usable alternative for it):
wv.setPictureListener(new WebView.PictureListener() {
#Override
public void newPicture(WebView view, Picture arg1) {
alert.show();
}
}