Monday, January 22, 2018

android kotlin - Do while loop example

MainActivity.kt 

package com.cfsuman.kotlinexamples

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button
import android.widget.TextView


class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        // Get the widgets reference from xml layout
        val textView = findViewById<TextView>(R.id.text_view)
        val button = findViewById<Button>(R.id.button);
        val button2 = findViewById<Button>(R.id.button2);
        val button3 = findViewById<Button>(R.id.button3);


        // Loop through a range using do while loop
        button.setOnClickListener{
            // Initialize an integer type variable
            var i:Int = 1

            textView.text = "Loop through range 1 to 10 using do while loop \n\n"

            // Simple do while loop through a range
            do{
                textView.text = textView.text.toString() + "$i \n"
                i++ // Increment the value
            }while(i <= 10) // First execute code then check the condition
        }

        // Loop through another range using do while loop
        button2.setOnClickListener{
            // Initialize an integer type variable
            var index:Int = 15

            textView.text = "Loop range using do while loop condition fail \n\n"

            // Simple do while loop through a range
            do{
                /*
                    Do while loop at first execute the code then check the condition.
                    So the first number will be displayed in text view.
                    Because it pass before condition checking.
                 */
                textView.text = textView.text.toString() + "$index \n"
                index++ // Increment the value
            }while(index <= 10) // First execute code then check the condition
        }


        // Loop through a range using do while loop and break at number 5
        button3.setOnClickListener{
            // Initialize an integer type variable
            var i:Int = 1

            textView.text = "Loop through range 1 to 10 using do while loop and break at 5 \n\n"

            // Simple do while loop through a range
            do{
                textView.text = textView.text.toString() + "$i \n"
                if(i == 5)
                    break
                i++ // Increment the value
            }while(i <= 10) // First execute code then check the condition
        }

    }
}
activity_main.xml 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/root_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="16dp"
    >
    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Do While Loop"
        />
    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Another Do While Loop"
        />
    <Button
        android:id="@+id/button3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Do While Loop Break"
        />
    <TextView
        android:id="@+id/text_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text=""
        android:textSize="18sp"
        android:textStyle="bold"
        android:textColor="#ff191d"
        android:layout_marginTop="20dp"
        />
</LinearLayout>
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