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Exit button that can ask you "Do you want to close it"?

I'm a beginner in java and I have a question for you do you know how I can create the button of exit? This button can ask me before I close the application "Do you want to close this application? or "Are you sure to close it?" I need to do it for my project and I need help. Pls send me some code.

Your question is very broad, however, an AlertDialog is what you are looking for, this is the implementation:
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Are you sure you want to exit?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
MyActivity.this.finish();
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
AlertDialog alert = builder.create();
alert.show();

1.- Search how create a dialog on Android.
Link -> https://developer.android.com/guide/topics/ui/dialogs?hl=es-419
2.- In your view put a back button with onClickListener, insert showDialog created inside.
3.- Implement the override onBackPressed method, insert showDialogCreated inside.
Example onBackPressed
public void onBackPressed() {
var dialog = CustomDialog.newInstance();
dialog.setCancelable(false);
dialog.show(this.getSupportFragmentManager(), "TAG");
dialog.setOnClickListener((whichViewID, tag, args) => {
// Your Logic
// If is pressed positive button call super.onBackPressed else dialog.dismiss()
});
}

Android Alert Message Need Mandatory Input

I have developed an Android Service which will run in the background. The Service want to accept Yes or No confirmation from the user at an event(say when receive an SMS).
Its working fine; the Yes or No question will be shown to user. But i want the input from (press YES or NO) user without exit from the alert(exit by press on the Mobile Back button or Home button etc).
Please help me how it can be possible.
Below the code I am using;
AlertDialog.Builder builder = new AlertDialog.Builder(ctx);
//ctx is the Context
builder.setTitle("Emergency!");
String txt="Do you want to accept?";
builder.setMessage(txt);
builder.setPositiveButton("YES", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
//Do something
}
});
builder.setNegativeButton("NO", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
///dialog.dismiss();
}
});
AlertDialog alert = builder.create();
alert.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);
alert.show();

just add this in you AlertDialog
builder.setCancelable(false);
hope you are useing android.support.v7.app.AlertDialog;

You can disable back press while the dialog is shown (or possibly, send a "No" response when back button is pressed) with dialog.setOnKeyListener
dialog.setOnKeyListener(new Dialog.OnKeyListener() {
#Override
public boolean onKey(DialogInterface arg0, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
finish();
dialog.dismiss();
}
return true;
}
});
Unfortunately you can't override Home button press on Android. You can, however, react to an activity being sent to the background via Home button by implementing onUserLeaveHint in the activity hosting your dialog.
Edit: You may also want to disable dismissing the dialog by touching outside (which is the default behavior) by doing
dialog.setCanceledOnTouchOutside(false);

Android how to make ok button on dialog not all caps

For an alert dialog in Android, how do you make the positive button not have all capital letters. The text is "OK" instead of "Ok".

The accepted solution above won't work in Lollipop and above. Here's the working solution.
After showing the dialog, I'm setting the button all caps false. Make sure you do it after dialog.show(). Else, you'll get Null Pointer Exception.
AlertDialog.Builder builder = new AlertDialog.Builder(MyActivity.this);
builder.setTitle("Title");
builder.setMessage("message");
builder.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
//Do Something
}
});
AlertDialog dialog = builder.create();
dialog.show();
dialog.getButton(AlertDialog.BUTTON_POSITIVE).setAllCaps(false);

Use the DialogInterface.BUTTON_POSITIVE or DialogInterface.BUTTON_NEGATIVE to customize the action buttons.
val builder = MaterialAlertDialogBuilder(requireContext())
builder.setTitle(getString(R.string.alert_title))
builder.setMessage(getString(R.string.alert_msg))
builder.setPositiveButton(getString(R.string.action_yes)) { _, _ ->
// todo: your action
}
builder.setNegativeButton(getString(R.string.action_no), null)
val dialog = builder.create()
dialog.show()
dialog.getButton(DialogInterface.BUTTON_POSITIVE).isAllCaps = false
dialog.getButton(DialogInterface.BUTTON_NEGATIVE).isAllCaps = false

You can set it to be anything you want - Eg.:
AlertDialog.Builder builder = new AlertDialog.Builder(MyActivity.this);
builder.setTitle("Title");
builder.setMessage("message");
builder.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
return;
}
});
AlertDialog dialog = builder.create();
dialog.show();
Reference: http://developer.android.com/reference/android/app/AlertDialog.Builder.html#setPositiveButton(int, android.content.DialogInterface.OnClickListener)

Or even :
builder.setPositiveButton("Ok", null);
For the basic usage.

using androidx.appcompat.app.AalertDialog fixed for me.

Alert dialog not working correctly - android

I am using an alert dialog to ask the user for confirmation of an item addition to an array. I am printing the array size before and after the alert dialog and it seems that both printings are done before the alert dialog shows up.
Log.d("before", ""+wayPoints.length);
AlertDialog.Builder ab = new AlertDialog.Builder(getContext());
ab .setTitle("Add entry");
ab .setMessage("Are you sure you want to add this entry?");
ab .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int which)
{wayPoints = ArrayHandler.addAtIndex(wayPoints, node, 1);}
});
ab .setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// do nothing
}
});
ab.setIcon(android.R.drawable.ic_dialog_alert);
ab.show();
Log.d("after", ""+wayPoints.length);
The ArrayHandler.addAtIndex method handles the addition of a new item to the provided array.
The problem is it is printing both logging lines before the alert dialog shows up. I need the alert dialog to be done before the printing of the second log.

This is correct behavior. The show method does not wait or block until the dialog is dismissed. Code execution continues after the show method immediately after the dialog is shown. (Actually, the dialog isn't even displayed yet - that happens after you yield control).
You already have setPositiveButton and setNegativeButton handlers, just put the code you want to execute in those handlers when user presses a button.
If you want certain code to run when the dialog is closed regardless of which button is tapped, use setOnDismissListener and put your code there.

Use:
AlertDialog alert1 = ab.create();
alert.show();
Instead of:
ab.show();

Try this
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder( context);  
// set title
alertDialogBuilder.setTitle("Your Title");
  // set dialog message
alertDialogBuilder .setMessage("Click yes to exit!") .setCancelable(false) .setPositiveButton("Yes",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
// if this button is clicked, close
// current activity
MainActivity.this.finish(); }
}) .setNegativeButton("No",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
// if this button is clicked, just close
// the dialog box and do nothing
dialog.cancel();
}
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
wayPoints = ArrayHandler.addAtIndex(wayPoints, node, 1);
Log.d("after", ""+wayPoints.length);
} });
});  
// create alert dialog
AlertDialog alertDialog = alertDialogBuilder.create();  
// show it
alertDialog.show();

how do you add an item in a list if a user presses yes button in an alert dialog box and don't add it if he presses no

I am making an app in which if a user selects a
submenu item I pop up an Alert dialog which asks his confirmation
whether he wishes to save that item in his list and saves it if he
presses yes and doesn't add it if he presses no.

You can use this to show alert:
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Are you sure to do this?").setCancelable(false).setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
doSomeThing();
dialog.cancel();
}
}).setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
AlertDialog alert = builder.create();
alert.show();

You add the element you get from the dialog to the ArrayList you use to feed your Adapter then feed the cursor = new yourAdapter(YourClass.this.getBaseContext(), android.R.layout.simple_list_item_1, dataList);
Call cursor.notifyDataSetChanged(); which tells the list to repopulate with the new data;