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Output

Tutorialwing Kotlin NumberPicker Integer Output

Tutorialwing Kotlin NumberPicker String Output
Getting Started
Android NumberPicker can be defined as below –
NumberPicker is a widge that allows us to select a number from predefined range.
Different Attributes of Android NumberPicker Widget
Some of the popular attributes of android numberPicker inherited from linearLayout are –
Sr. | XML Attributes | Description |
---|---|---|
1 | android:divider | Drawable to use as a vertical divider between buttons |
2 | android:gravity | Defines how an object should be placed inside LinearLayout i.e. specifies position, CENTER, VERTICAL_CENTER, HORIZONTAL_CENTER etc. relative to the boundaries of the linearLayout |
3 | android:orientation | Defines whether linearLayout should be column or row. i.e. views inside linearLayout will be aligned as horizontally or vertically. |
4 | android:weightSum | Defines maximum weight sum |
Some of the popular attribute of android numberPicker inherited from viewGroup are –
Sr. | XML Attributes | Description |
---|---|---|
1 | android:animationCache | Specifies whether layout animation should create a drawing cache for their children |
2 | android:clipChildren | Specifies whether a child is limited to draw inside of its bounds or not |
3 | android:clipToPadding | Specifies whether the ViewGroup will clip its children and resize (but not clip) any EdgeEffect to its padding, if padding is not zero |
4 | android:layoutMode | Specifies layout mode of this viewGroup |
Some of the popular attribute of android numberPicker inherited from View are –
Sr. | XML Attributes | Description |
---|---|---|
1 | android:alpha | Specifies alpha of the view |
2 | android:background | Specifies background of the view |
3 | android:focusable | Specifies whether view can take focus or not |
4 | android:id | Specifies unique identifier of the view |
5 | android:padding | Specifies padding of view |
6 | android:visibility | Specifies whether this view is visible or not |
Example of Android NumberPicker Using Kotlin
At first, we will create android application. Then, we will use numberPicker using kotlin in the application.
1. Creating New Project in Kotlin
Follow steps below to create new project. Please ignore the steps if you have already created the project.
Step | Description |
---|---|
1. | Open Android Studio. |
2. | Go to File => New => New Project. Write application name as NumberPicker. Then, check Include Kotlin Support and click next button. |
3. | Select minimum SDK you need. However, we have selected 17 as minimum SDK. Then, click next button |
4. | Then, select Empty Activity => click next => click finish. |
5. | You will get a newly created project successfully if you have followed steps properly. |
Since we have a project now, we will modify xml and other files to use NumberPicker using kotlin in the application.
2. Modify values folder
Open res/values/strings.xml file. Then, add below code into it.
<resources> <string name="app_name">NumberPicker</string> </resources>
3. Use NumberPicker Widget in xml file
Open src/main/res/layout/activity_main.xml file and add below code into it.
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="20dp" android:orientation="horizontal"> <NumberPicker android:id="@+id/numberPicker" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="1"/> </LinearLayout>
In activity_main.xml file, we have defined numberPicker widget. Now, we will access this widget in kotlin file and perform some operations in it.
We can provide two types of data in numberPicker. They are –
a. Only Integer Values
b. Array of String values
Now, we will see how we can provide each types of data in numberPicker.
4. Show Only Integer Values in NumberPicker
Open src/main/java/com.tutorialwing.numberpicker/MainActivity.kt file and add below code into it.
package com.tutorialwing.numberpicker import android.os.Bundle import android.support.v7.app.AppCompatActivity import android.widget.NumberPicker import android.widget.Toast class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) val numberPicker = findViewById<NumberPicker>(R.id.numberPicker) if (numberPicker != null) { numberPicker.minValue = 0 numberPicker.maxValue = 10 numberPicker.wrapSelectorWheel = true numberPicker.setOnValueChangedListener { picker, oldVal, newVal -> val text = "Changed from $oldVal to $newVal" Toast.makeText(this@MainActivity, text, Toast.LENGTH_SHORT).show() } } } }
We have accessed numberPicker using kotlin file (i.e. MainActivity.kt file) widget. Then, we have set minValue, maxValue etc. in it. Note that we have set range of values using minValue and maxValue attributes. minValue is responsible to set minimum value and maxValue is responsible to set maximum value. We have also set a listener that displays toast message whenever there is change in value selection in numberPicker.
5. Show Array Of String Values in NumberPicker
Open src/main/java/com.tutorialwing.numberpicker/MainActivity.kt file and add below code into it.
package com.tutorialwing.numberpicker import android.os.Bundle import android.support.v7.app.AppCompatActivity import android.widget.NumberPicker class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) val numberPicker = findViewById<NumberPicker>(R.id.numberPicker) if (numberPicker != null) { val values = arrayOf("Blue", "Magenta", "Yellow", "Red", "Pink", "White", "Green", "Violet") numberPicker.minValue = 0 numberPicker.maxValue = values.size - 1 numberPicker.displayedValues = values numberPicker.wrapSelectorWheel = true numberPicker.setOnValueChangedListener { picker, oldVal, newVal -> val text = "Changed from " + values[oldVal] + " to " + values[newVal] Toast.makeText(this@MainActivity, text, Toast.LENGTH_SHORT).show() } } } }
Here, we have provided an array of string values as a data in numberPicker. Attribute displayedValues is responsible to set data in the numberPicker.
Since AndroidManifest.xml file is very important in any android application, we are also going to see the content inside this file.
AndroidManifest.xml file
Code inside main/AndroidManifest.xml file is as below.
<?xml version="1.0" encoding="utf-8"?> <manifest package="com.tutorialwing.numberpicker" xmlns:android="http://schemas.android.com/apk/res/android"> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN"/> <category android:name="android.intent.category.LAUNCHER"/> </intent-filter> </activity> </application> </manifest>
When we run the program, we will get output as shown above.
That’s end of our tutorial on Android NumberPicker using Kotlin.