Learn Mobile App Development: Use Prompt Dialog in Android

A Prompt Dialog box can be used to prompt the user to enter an input. In this tutorial, we shall enhance the AlertDialog example illustrated previously to enable it to accept user input. This is precisely a custom AlertDialog example.

We shall follow the following steps :
i. Create a prompt dialog layout in XML
ii. Attach the prompt dialog layout to AlertDialog.Builder
iii. Attach the AlertDialog.Builder to AlertDialog

1. XML layout files

We shall use two files- main.xml and custom.xml to display the dialog box, the earlier file shall display the main screen and the latter shall display the prompt dialog.

File : res/layout/main.xml


<?xml version="1.0" encoding="utf-8"?>


<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"



    android:layout_width="fill_parent"



    android:layout_height="fill_parent"



    android:gravity="center"



    android:orientation="vertical">

   
<Button android:id="@+id/buttonPrompt"



        android:layout_width="wrap_content"



        android:layout_height="wrap_content"



        android:text="Show Prompt Dialog" />


<EditText android:id="@+id/editTextResult"



        android:layout_marginTop="15dp"



        android:layout_width="match_parent"



        android:layout_height="wrap_content" >


</EditText>


</LinearLayout>

File : res/layout/prompt.xml


<?xml version="1.0" encoding="utf-8"?>


<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"



    android:id="@+id/layout_root"



    android:layout_width="fill_parent"



    android:layout_height="fill_parent"



    android:orientation="vertical"



    android:padding="10dp" >

   
<TextView android:id="@+id/textView1"



        android:layout_width="wrap_content"



        android:layout_height="wrap_content"



        android:text="Enter Your Message : "



        android:textAppearance="?android:attr/textAppearanceLarge" />

   
<EditText android:id="@+id/editTextDialogUserInput"



        android:layout_width="match_parent"



        android:layout_height="wrap_content" >




<requestFocus />




</EditText>




</LinearLayout>

2. Java Code

We shall add a listener to the button and set the dialog message.

File: Main.java


package com.endeavour.tutorial;



import android.app.Activity;

import android.app.AlertDialog;

import android.content.Context;

import android.content.DialogInterface;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.EditText;

public class Main extends Activity {

       final Context context = this;

       private Button button;

       private EditText result;

       public void onCreate(Bundle savedInstanceState) {

              super.onCreate(savedInstanceState);

              setContentView(R.layout.main);

              // components from main.xml

              button = (Button) findViewById(R.id.buttonPrompt);

              result = (EditText) findViewById(R.id.editTextResult);



              // add button listener

              button.setOnClickListener(new OnClickListener() {



                     @Override

                     public void onClick(View arg0) {




                           // get prompts.xml view

                           LayoutInflater li = LayoutInflater.from(context);

                           View promptsView = li.inflate(R.layout.prompt, null);

                           AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context);



                           // set prompt.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();



                     }

              });

       }

}