Develop Reference

Trying to add buttons dynamically to Activity, Buttons aren't showing up until swapping activity

So right now I am trying to create a App for Android. I am already pretty far but I encountered one big issue. To understand it, I'll give some context on what the app does:
It's basically some app where a teacher can add schoolclasses, and in those school classes the teacher can add students.
When clicking the already existing button "add class", the user can input the name of the class, which then gets added as a button with the following method:
public void addButton(final String s) {
if(!existingButtons.contains(s)) {
Button button = new Button(getContext());
button.setText(s);
LinearLayout linearLayout = view.findViewById(R.id.linearlayout);
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.WRAP_CONTENT);
//linearLayout.addView(button, params);
button.setLayoutParams(params);
linearLayout.addView(button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(getActivity(), s, Toast.LENGTH_SHORT).show();
Intent intent = new Intent(getActivity(), SchoolClassActivity.class);
intent.putExtra("currentClassName", s);
Objects.requireNonNull(getActivity()).startActivity(intent);
}
});
existingButtons.add(s);
ClassesFragment test = new ClassesFragment();
}
}
Now the issue is as follows:
The button does get added upon confirming the input, but it only shows up, when I switch activity or swipe to the right most fragment (3 tabs with Viewpager, left is the page where you can add classes). I would like to know if there is any way to have the button show up, upon confirming the input, so without switching fragments/activities.
Thank you in advance

i wanted to start a new activity after pressing the three buttons ...please let me know how can i achieve this?

Hi i am creating a simple educational game in which user has to press three images in order to proceed to the next level and in next level user has to press 5 images.
i have gone through the on click but i using onIntent intent = new Intent(this.getApplicationContext(), Activity.class);
this.startActivity(intent, 0); i am only able to start new activity on single button pressed but i wanted to start new activity when user has finished pressing three image Buttons.
Thanks in advanced.

you can use global int variable and increase it every button click and if its more than your button number open new activity
public int btn = 0;
MyButton.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v)
{
if(btn >= 2) {
//open your activity
}
else{
btn++;
}
}
});

Based on my understanding of your problem,I have provided a possible simple implementation.
Use a simple data structure like queue or stack. When a image is tapped, add information about the image to the data structure. After adding the information to data structure see if number of items in data structure is equal to 3 ? if yes check data structure has info about the required three images and not just info about the same image (happens if user taps on same image more than once). If condition is met then call startActivity(). Generalize this so that you can reuse the logic in different activities, irrespective of the number of images.

Hi i finally achieved my desired activity. now with this after checking two check box app will start new activity.
`private CheckBox chkIos, chkAndroid, chkWindows;
private Button btnDisplay;
OnClickListener checkBoxListener;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
chkIos = (CheckBox) findViewById(R.id.chkIos);
chkAndroid = (CheckBox) findViewById(R.id.chkAndroid);
checkBoxListener =new OnClickListener() {
public void onClick(View v) {
if(chkIos.isChecked()&&chkAndroid.isChecked()) {
Intent i1=new Intent(getApplicationContext(), Main1.class);
startActivity(i1);
if(chkAndroid.isChecked()) {
Intent i2=new Intent(getApplicationContext(), Main1.class);
startActivity(i1);
}
}
}
};
chkIos.setOnClickListener(checkBoxListener);
chkAndroid.setOnClickListener(checkBoxListener);
}
}
`
thanks for all your answers.

Button not clicking in Portrait Mode

I have a button to which I attach an onClickListener via code. I have to to this through code because it's in a fragment.
The listener works fine when in landscape mode, but when it's in portrait it doesn't. There's no "click" sound even.
In my xml file, I set the initial visibility of the button to invisible and then make it visible later when the user clicks a radio button in the same Viewgroup as the button. The onclicklisteners of the radiobuttons are working just fine in both portrait and landscape mode.
Now if I remove the "android:visibility="invisible" code in xml, the onclickstener works fine in portrait mode! But of course I need it invisible till the user clicks a radiobutton otherwise the UI doesn't make sense. Very weird indeed.
Here's my code:
private void setOnClickForSaveButton(View v) {
Button changeFundsSave = (Button) v.findViewById(R.id.change_funds_save);
changeFundsSave.setOnClickListener(saveListener);
}
Button.OnClickListener saveListener = new Button.OnClickListener() {
#Override
public void onClick(View v) {
//Get the rootview
View rootView = v.getRootView();
EditText changeFundsEdit = (EditText) rootView.findViewById(R.id.change_funds_edit);
if(changeFundsEdit.getText().toString().equals("")) {
new AlertDialog.Builder(getActivity())
.setTitle( "" )
.setMessage( "Enter the number of units" )
.setPositiveButton( "Ok", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
}
})
.show();
return;
}
}
};
private void setOnClicksForRadioButtons(View v) {
RadioButton rb1 = (RadioButton)v.findViewById(R.id.add_units);
RadioButton rb2 = (RadioButton)v.findViewById(R.id.remove_units);
RadioButton rb3 = (RadioButton)v.findViewById(R.id.set_units);
rb1.setOnClickListener(addRemoveSetButtonListener);
rb2.setOnClickListener(addRemoveSetButtonListener);
rb3.setOnClickListener(addRemoveSetButtonListener);
}
OnClickListener addRemoveSetButtonListener = new OnClickListener() {
#Override
public void onClick(View v) {
// Since we only have the radiobutton view, we need to get the parent
View rootView = v.getRootView();
//Make the controls visible
TextView changeFundsText = (TextView) rootView.findViewById(R.id.change_funds_text);
EditText changeFundsEdit = (EditText) rootView.findViewById(R.id.change_funds_edit);
Button changeFundsSave = (Button) rootView.findViewById(R.id.change_funds_save);
changeFundsText.setVisibility(View.VISIBLE);
changeFundsEdit.setVisibility(View.VISIBLE);
changeFundsSave.setVisibility(View.VISIBLE);
}
};
}

Solved the problem! In portrait mode, like everyone else I load one fragment in a separate activity. Out of habit I was calling setContentView(something) before loading the fragment! So ultimately the two layouts were overlapping each other and the visible and invisible buttons were overlapping each other and things must have gotten messed up. Damn, I'm not sure if I like the concept of fragments at all. My first time using them. But maybe I just need to learn how to wire them up properly before I get used to them :) Thank you so much for your help

my guess is that
1) do you findViewById again for the view you passed in setOnClickForSaveButton? since the old view will be destroyed and a view will be created when you change screen orientation
2) do you have multiple ids for R.id.change_funds_save
3) add a log at the first line of onclick(v) to see if it is called but goto another branch you didnt expect.

Unless you are loading two separate xml layout files from layout-land and layout-port, there shouldn't be much difference between landscape mode and portrait mode. That being said, I'm going to take a wild guess and say that your app is probably not working correctly due to configuration changes. Let me know if this is actually true... i.e. does your app work at first, but stops working when you rotate the screen?
If this is true, you should look into how the Activity lifecycle is affecting your views and onClickListeners.

Force Close of Android Popupwindow when changing orientation to portrait at run time, why?

Here's my MAIN ACTIVITY
public static boolean popupStatus=false;
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
if (savedInstanceState != null){
popupStatus = savedInstanceState.getBoolean("Open");
}
setContentView(R.layout.main);
public void onSaveInstanceState(Bundle savedInstanceState) {
savedInstanceState.putBoolean("Open", DateTimePicker.openPopup);
super.onSaveInstanceState(savedInstanceState);
}
I have DateTimePicker.java class which has 1 button and 1 Textview. Clicking on button, my another class Calendar.java get populated in PopupWindow and this Popup window displays my class Calendar.java . I have created different layouts of my Calendar.java class for portrait and landscape mode. Here's DateTimePicker.java some snippet of code,
public static boolean openPopup = false;
textView = new TextView(this.getContext());
this.addView(textView, layoutParams);
button = new Button(this.getContext());
button.setText("C");
this.addView(button, layoutParams1);
button.setOnClickListener(this);
if(Main.popupStatus){
button.performClick();
}
public void onClick(View v) {
if(Main.popupStatus){
new Handler().postDelayed(new Runnable() {
public void run() {
openCalendar();
}
}, 100);
}
else{
openCalendar();
}
private void openCalendar() {
Calendar calendar = new Calendar(this.getContext());
if(portrait.equals(orientation)){
pw = new PopupWindow(calendarLayout, 245, 284, true);
}
else{
pw = new PopupWindow(calendarLayout, 295, 240, true);
}
pw.setOutsideTouchable(false);
pw.showAtLocation(this, Gravity.NO_GRAVITY, 10, 80);
openPopup = true;
}
public void closeCalendar(){
pw.dismiss();
openPopup = false;
}
Main.XML contain DateTimePicker .
Actually I wanted my Popup window to be opened up even when orientation gets changed at run time, so I have done it through setting flag openPopup = true; in openCalendar() method and if it is opened and orientation gets changed at run time, this flag will be saved in onSaveInstanceState() method. After orientation will change, it will be checked in onCreate() and popup will be opened up for respective orientation mode. I hope you got my point.
PROBLEM: Initially When I click on button in Portrait mode, popup window pops up for portrait layout. then without dismissing popup window, I change the orientation to landscape. And after changing, I can see my popup window as intact and appears on screen of landscape layout. Till now it works fine. But IF popup window is opened up in landscape mode and then I change the orientation to portrait, popup window of portrait layout didn't come up and I see FORCE CLOSE message:/ Please help since I am working behind it so long and getting no clue. I would be very grateful to you all. Thanks!
P.S.: Changing orientation means I am pressing ctrl+F11 and changing orientation of Emulator

The emulator has an odd feature (some consider it a bug) in which changing from landscape to portrait in the emulator causes two configuration changes and two restarts of your activity. (One configuration change is the orientation and the other is an emulated change in the keyboard state.) The timing of the configuration changes frequently causes crashes like this. Try adding this attribute:
android:configChanges="keyboard|keyboardHidden"
to your <activity> tag in the manifest. See if that improves the situation.

Make sure you have your layout defined in layout-land folder and ensure onCreate is not called again and again. android:configChanges="keyboard|keyboardHidden" Put this in your manifest file so that the state is retained when you change orientation

In Android: How do you show layout twice using intent?

Let's pretend this was my Java Class...
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button ScreentwoGameButton = (Button) findViewById(R.id.screentwo);
ScreentwoGameButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Intent ScreentwoGameIntent = new Intent(Main.this, Screentwo.class);
startActivity(StartGameIntent);
}
});
How do i use this code below but the right way like.
So let's put an example if I click screentwo button the screentwo.xml will show and it will allow me to click inside if any buttons are available. Instead just stare what's in the layout.
I don't want to use the Activity to activity cause the whole point is i'm trying to avoid the flashing looking feel going to another java class.
If you look at the moron test game on Android it says example: press the blue button then red and then green, so if u press the blue button the screen will remain and not flash at all but the image of the blue button will disappear and I'm allowed to click the red and then green.
Hope that helped.
Thanks
Wahid
Button ScreentwoButton = (Button) findViewById(R.id.screentwo);
ScreentwoButton.setOnClickListener(new OnClickListener() {
private Uri Uri;
#Override
public void onClick(View v) {
setContentView(R.layout.Screentwo);
Uri uri=Uri;
Intent i=new Intent(Intent.ACTION_VIEW, uri);
mSoundManager.playSound(1);
}
});

try to use:
setContentView(R.layout.next layout); in your button click.

You could use the viewflipper class and add the different layouts as childs to the viewflipper
and set the active child. Using setcontentView will be trouble some when you use findViewById for a old layout. As findViewById will look in the layout that is specified by setContentView