Hello! In this tutorial, we will learn how to develop Android apps using Kotlin.
Specifically, we will implement a KakaoTalk password verification screen and get acquainted with various techniques,
such as UI composition, event handling, and applying simple animations.
Table of Contents
- Environment Setup
- Project Creation
- UI Design
- Implementing Password Verification Logic
- Adding Animation
- Final Result Check
1. Environment Setup
Before developing Android apps, you need to set up the appropriate development environment.
It is necessary to install Android Studio along with the Android SDK and related tools.
Once the installation is complete, run Android Studio to create a new project.
2. Project Creation
Please follow the steps below to create a new project.
- Open Android Studio and click on “Start a new Android Studio project”.
- Select “Empty Activity” and click “Next”.
- Enter the project name, set the package name and storage location, then click “Finish”.
3. UI Design
Once the project is created, it’s time to design the UI.
We will modify the `activity_main.xml` file to create the password input screen.
Here is the basic XML code.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="16dp">
<TextView
android:id="@+id/textViewTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Password Verification"
android:textSize="24sp"
android:layout_centerHorizontal="true"
android:layout_marginBottom="32dp"/>
<EditText
android:id="@+id/editTextPassword"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Enter Password"
android:inputType="textPassword"
android:layout_below="@id/textViewTitle"
android:layout_marginBottom="16dp"/>
<Button
android:id="@+id/buttonConfirm"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Confirm"
android:layout_below="@id/editTextPassword"/>
</RelativeLayout>
The above code constructs a simple password input screen.
The TextView displays the screen title, the EditText allows the user to enter a password,
and the Button is used to perform the password verification function.
4. Implementing Password Verification Logic
With the UI ready, let’s implement the password verification logic.
We handle the click event of the password verification button in the `MainActivity.kt` file.
package com.example.passwordcheck
import android.os.Bundle
import android.widget.Button
import android.widget.EditText
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val editTextPassword = findViewById<EditText>(R.id.editTextPassword)
val buttonConfirm = findViewById<Button>(R.id.buttonConfirm)
buttonConfirm.setOnClickListener {
val password = editTextPassword.text.toString()
if (password == "KotlinPassword") { // Change to actual password.
Toast.makeText(this, "Password has been verified!", Toast.LENGTH_SHORT).show()
} else {
Toast.makeText(this, "Incorrect password.", Toast.LENGTH_SHORT).show()
}
}
}
}
The above code implements the password verification logic. It checks if the password entered by the user matches
“KotlinPassword” and displays an appropriate message via a toast depending on whether it matches or not.
5. Adding Animation
To improve user experience, let’s add an animation when the button is clicked.
We can give a slight press effect to the button whenever the user clicks it.
For this, we will add animation resources to the XML file.
<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<scale
android:fromXScale="1.0"
android:toXScale="0.9"
android:fromYScale="1.0"
android:toYScale="0.9"
android:pivotX="50%"
android:pivotY="50%"
android:duration="100"
android:repeatCount="1"
android:repeatMode="reverse"/>
</set>
Save the animation XML file in the `res/anim` folder as shown above.
Then, apply this animation in the `MainActivity.kt` file when the button is clicked.
// ... Existing code omitted ...
val buttonConfirm = findViewById<Button>(R.id.buttonConfirm)
val animation = AnimationUtils.loadAnimation(this, R.anim.button_click)
buttonConfirm.setOnClickListener {
buttonConfirm.startAnimation(animation)
// ... Existing password verification logic ...
}
6. Final Result Check
Once all the code is ready, let’s run the project to check the final result.
Test whether the KakaoTalk password verification screen is functioning properly.
When you enter a password and click the “Confirm” button, a message will be displayed
depending on whether the entered password is correct or not.
Conclusion
In this tutorial, we learned how to create a KakaoTalk password verification screen using Kotlin.
We explored UI composition, password verification logic, and applied animation effects to build
a user-friendly interface.
Keep developing more diverse apps to enhance your skills in the future!