How do I display an alert dialog on Android?

Question

I want to display a dialog/popup window with a message to the user that shows \"Are you sure you want to delete this entry?\" with one button that says \'Delete\'. When

Answer 1

   new AlertDialog.Builder(v.getContext()).setMessage("msg to display!").show();

Answer 2

This is definitely help for you. Try this code: On click of a button, you can put one, two or three buttons with an alert dialog...

SingleButtton.setOnClickListener(new View.OnClickListener() {

    public void onClick(View arg0) {
        // Creating alert Dialog with one Button

        AlertDialog alertDialog = new AlertDialog.Builder(AlertDialogActivity.this).create();

        // Setting Dialog Title
        alertDialog.setTitle("Alert Dialog");

        // Setting Dialog Message
        alertDialog.setMessage("Welcome to Android Application");

        // Setting Icon to Dialog
        alertDialog.setIcon(R.drawable.tick);

        // Setting OK Button
        alertDialog.setButton("OK", new DialogInterface.OnClickListener() {

            public void onClick(DialogInterface dialog,int which)
            {
                // Write your code here to execute after dialog    closed
                Toast.makeText(getApplicationContext(),"You clicked on OK", Toast.LENGTH_SHORT).show();
            }
        });

        // Showing Alert Message
        alertDialog.show();
    }
});

btnAlertTwoBtns.setOnClickListener(new View.OnClickListener() {

    public void onClick(View arg0) {
        // Creating alert Dialog with two Buttons

        AlertDialog.Builder alertDialog = new AlertDialog.Builder(AlertDialogActivity.this);

        // Setting Dialog Title
        alertDialog.setTitle("Confirm Delete...");

        // Setting Dialog Message
        alertDialog.setMessage("Are you sure you want delete this?");

        // Setting Icon to Dialog
        alertDialog.setIcon(R.drawable.delete);

        // Setting Positive "Yes" Button
        alertDialog.setPositiveButton("YES",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog,int which) {
                        // Write your code here to execute after dialog
                        Toast.makeText(getApplicationContext(), "You clicked on YES", Toast.LENGTH_SHORT).show();
                    }
                });

        // Setting Negative "NO" Button
        alertDialog.setNegativeButton("NO",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog,    int which) {
                        // Write your code here to execute after dialog
                        Toast.makeText(getApplicationContext(), "You clicked on NO", Toast.LENGTH_SHORT).show();
                        dialog.cancel();
                    }
                });

        // Showing Alert Message
        alertDialog.show();
    }
});

btnAlertThreeBtns.setOnClickListener(new View.OnClickListener() {

    public void onClick(View arg0) {
        // Creating alert Dialog with three Buttons

        AlertDialog.Builder alertDialog = new AlertDialog.Builder(
                AlertDialogActivity.this);

        // Setting Dialog Title
        alertDialog.setTitle("Save File...");

        // Setting Dialog Message
        alertDialog.setMessage("Do you want to save this file?");

        // Setting Icon to Dialog
        alertDialog.setIcon(R.drawable.save);

        // Setting Positive Yes Button
        alertDialog.setPositiveButton("YES",
            new DialogInterface.OnClickListener() {

                public void onClick(DialogInterface dialog,
                        int which) {
                    // User pressed Cancel button. Write Logic Here
                    Toast.makeText(getApplicationContext(),
                            "You clicked on YES",
                            Toast.LENGTH_SHORT).show();
                }
            });

        // Setting Negative No Button... Neutral means in between yes and cancel button
        alertDialog.setNeutralButton("NO",
            new DialogInterface.OnClickListener() {

                public void onClick(DialogInterface dialog,
                        int which) {
                    // User pressed No button. Write Logic Here
                    Toast.makeText(getApplicationContext(),
                            "You clicked on NO", Toast.LENGTH_SHORT)
                            .show();
                }
            });

        // Setting Positive "Cancel" Button
        alertDialog.setNegativeButton("Cancel",
            new DialogInterface.OnClickListener() {

                public void onClick(DialogInterface dialog,
                        int which) {
                    // User pressed Cancel button. Write Logic Here
                    Toast.makeText(getApplicationContext(),
                            "You clicked on Cancel",
                            Toast.LENGTH_SHORT).show();
                }
            });
        // Showing Alert Message
        alertDialog.show();
    }
});

Answer 3

I'd like to add on David Hedlund great answer by sharing a more dynamic method than what he posted so it can be used when you do have a negative action to perform and when you don't, i hope it helps.

private void showAlertDialog(@NonNull Context context, @NonNull String alertDialogTitle, @NonNull String alertDialogMessage, @NonNull String positiveButtonText, @Nullable String negativeButtonText, @NonNull final int positiveAction, @Nullable final Integer negativeAction, @NonNull boolean hasNegativeAction)
{
    AlertDialog.Builder builder;
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        builder = new AlertDialog.Builder(context, android.R.style.Theme_Material_Dialog_Alert);
    } else {
        builder = new AlertDialog.Builder(context);
    }
    builder.setTitle(alertDialogTitle)
            .setMessage(alertDialogMessage)
            .setPositiveButton(positiveButtonText, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    switch (positiveAction)
                    {
                        case 1:
                            //TODO:Do your positive action here 
                            break;
                    }
                }
            });
            if(hasNegativeAction || negativeAction!=null || negativeButtonText!=null)
            {
            builder.setNegativeButton(negativeButtonText, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    switch (negativeAction)
                    {
                        case 1:
                            //TODO:Do your negative action here
                            break;
                        //TODO: add cases when needed
                    }
                }
            });
            }
            builder.setIcon(android.R.drawable.ic_dialog_alert);
            builder.show();
}

Answer 4

The code which David Hedlund has posted gave me the error:

Unable to add window — token null is not valid

If you are getting the same error use the below code. It works!!

runOnUiThread(new Runnable() {
    @Override
    public void run() {

        if (!isFinishing()){
            new AlertDialog.Builder(YourActivity.this)
              .setTitle("Your Alert")
              .setMessage("Your Message")
              .setCancelable(false)
              .setPositiveButton("ok", new OnClickListener() {
                  @Override
                  public void onClick(DialogInterface dialog, int which) {
                      // Whatever...
                  }
              }).show();
        }
    }
});

Answer 5

This is done in kotlin

val builder: AlertDialog.Builder = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            AlertDialog.Builder(this, android.R.style.Theme_Material_Dialog_Alert)
        } else {
            AlertDialog.Builder(this)
        }
        builder.setTitle("Delete Alert!")
                .setMessage("Are you want to delete this entry?")
                .setPositiveButton("YES") { dialog, which ->

                }
                .setNegativeButton("NO") { dialog, which ->

                }
                .setIcon(R.drawable.ic_launcher_foreground)
                .show()

Answer 6

You could use an AlertDialog for this and construct one using its Builder class. The example below uses the default constructor that only takes in a Context since the dialog will inherit the proper theme from the Context you pass in, but there's also a constructor that allows you to specify a specific theme resource as the second parameter if you desire to do so.

new AlertDialog.Builder(context)
    .setTitle("Delete entry")
    .setMessage("Are you sure you want to delete this entry?")

    // Specifying a listener allows you to take an action before dismissing the dialog.
    // The dialog is automatically dismissed when a dialog button is clicked.
    .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int which) { 
            // Continue with delete operation
        }
     })

    // A null listener allows the button to dismiss the dialog and take no further action.
    .setNegativeButton(android.R.string.no, null)
    .setIcon(android.R.drawable.ic_dialog_alert)
    .show();