Dialogs | How to Show Alert Dialog in Android

Dialogs | Definition 

A dialog is a small window that prompts the user to make a decision or enter additional information. 

The full source code is available here.

Creating AlertDialog is very simple. In this tutorial I'll be discussing about creating Alert Dialogs with the following categories.

1. Single Button
2. Two Buttons
3. Three Buttons

1. Single Button - Alert Dialog

         The following code will be create a simple alert dialog with one button. Sometimes your application is need to indicate such as the process is completed, phone contact list is loaded, etc

In Java

	AlertDialog.Builder alertDialog = new AlertDialog.Builder(getActivity());
	//set title
	alertDialog.setTitle("Alert Dialog Demo");
	//set message
	alertDialog.setMessage(getResources().getString(R.string.title));
	//set icon
	alertDialog.setIcon(R.drawable.ic_done_black_24dp);
	//set outside focus
	alertDialog.setCancelable(false);
	//set button
	alertDialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
	@Override public void onClick(DialogInterface dialog, int which) {
	showToastMessage("You tapped OK");
	}
	});
	//show alert dialog
	alertDialog.show();

view raw JavaFragment.kt hosted with ❤ by GitHub

     

In Kotlin

	//build alert dialog
	val alertDialog = AlertDialog.Builder(activity)
	//set title
	alertDialog.setTitle("Alert Dialog Demo")
	//set message
	alertDialog.setMessage(resources.getString(R.string.title))
	//set icon
	alertDialog.setIcon(R.drawable.ic_done_black_24dp)
	//set button
	alertDialog.setPositiveButton("OK") { dialog, which ->
	showToastMessage("You tapped OK")
	}
	//show alert dialog
	alertDialog.show()

view raw KotlinFragment.kt hosted with ❤ by GitHub

This result of above code will be like following image.

2. Two Buttons - Alert Dialog

         The following code will be create a simple alert dialog with two buttons. Sometimes your application is need to ask such as remove file from the database or the file manager, etc

In Java

	AlertDialog.Builder alertDialog = new AlertDialog.Builder(getActivity());
	//set title
	alertDialog.setTitle("Confirm Remove...");
	//set description
	alertDialog.setMessage("Are you sure you want to remove this?");
	//set icon
	alertDialog.setIcon(R.drawable.ic_clear_black_24dp);
	//set positive button
	alertDialog.setPositiveButton("YES", new DialogInterface.OnClickListener() {
	public void onClick(DialogInterface dialog, int which) {
	showToastMessage("You tapped on YES");
	}
	});
	//set negative button
	alertDialog.setNegativeButton("NO", new DialogInterface.OnClickListener() {
	public void onClick(DialogInterface dialog, int which) {
	showToastMessage("You tapped on NO");
	dialog.cancel();
	}
	});
	//show dialog
	alertDialog.show();

view raw JavaFragment.kt hosted with ❤ by GitHub

In Kotlin

	val alertDialog = AlertDialog.Builder(activity)
	alertDialog.setTitle("Confirm Remove...")
	alertDialog.setMessage("Are you sure you want to remove this?")
	alertDialog.setIcon(R.drawable.ic_clear_black_24dp)
	alertDialog.setPositiveButton("YES"
	) { dialog, which ->
	showToastMessage("You tapped on YES")
	}
	alertDialog.setNegativeButton("NO"
	) { dialog, which ->
	showToastMessage("You tapped on NO")
	dialog.cancel()
	}
	alertDialog.show()

view raw KotlinFragment.kt hosted with ❤ by GitHub

This result of above code will be like following image.

3. Three Buttons - Alert Dialog

         The following code will be create a simple alert dialog with three buttons. Sometimes your application is need to ask save some file to the database.

In Java

	AlertDialog.Builder alertDialog = new AlertDialog.Builder(getActivity());
	alertDialog.setTitle("Save File...");
	alertDialog.setMessage("Do you want to save this file?");
	alertDialog.setIcon(R.drawable.ic_save_black_24dp);
	alertDialog.setPositiveButton("YES", new DialogInterface.OnClickListener() {
	public void onClick(DialogInterface dialog, int which) {
	showToastMessage("You tapped on YES");
	}
	});
	alertDialog.setNeutralButton("NO", new DialogInterface.OnClickListener() {
	public void onClick(DialogInterface dialog, int which) {
	showToastMessage("You tapped on NO");
	}
	});
	alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
	public void onClick(DialogInterface dialog, int which) {
	showToastMessage("You tapped on Cancel");
	}
	});
	alertDialog.show();

view raw JavaFragment.kt hosted with ❤ by GitHub

In Kotlin

	val alertDialog = AlertDialog.Builder(activity)
	alertDialog.setTitle("Save File...")
	alertDialog.setMessage("Do you want to save this file?")
	alertDialog.setIcon(R.drawable.ic_save_black_24dp)
	alertDialog.setPositiveButton("YES"
	) { dialog, which ->
	showToastMessage("You tapped on YES")
	}
	alertDialog.setNeutralButton("NO"
	) { dialog, which ->
	showToastMessage("You tapped on NO")
	}
	alertDialog.setNegativeButton("Cancel"
	) { dialog, which ->
	showToastMessage("You tapped on Cancel")
	}
	alertDialog.show()

view raw KotlinFragment.kt hosted with ❤ by GitHub

This result of above code will be like following image.

Showing toast function:

In Java

	private void showToastMessage(CharSequence msg) {
	Snackbar snackBar =
	Snackbar.make(getActivity().findViewById(android.R.id.content), msg, Snackbar.LENGTH_LONG);
	snackBar.show();
	}

view raw JavaFragment.kt hosted with ❤ by GitHub

In Kotlin

	private fun showToastMessage(msg: CharSequence) {
	val snackBar = activity.findViewById<View>(android.R.id.content)?.let {
	Snackbar.make(it, msg, Snackbar.LENGTH_LONG)
	}
	snackBar?.show()
	}

view raw KotlinFragment.kt hosted with ❤ by GitHub

This output of above code will display like following image

The full source code is available here.