Monday, August 31, 2020

android kotlin - EditText limit number range

MainActivity.kt

package com.example.jetpack

import android.content.Context
import android.content.Context.INPUT_METHOD_SERVICE
import android.graphics.BlendMode
import android.graphics.BlendModeColorFilter
import android.graphics.Color
import android.graphics.PorterDuff
import android.os.Build
import android.os.Bundle
import android.text.InputFilter
import android.text.Spanned
import android.view.View
import android.view.inputmethod.EditorInfo
import android.view.inputmethod.InputMethodManager
import android.widget.EditText
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.activity_main.*


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

        // apply edit text input filter number range
        editText.inputFilterNumberRange(6..90)

        // show the rule
        textView.text = "Input number range 6 to 90"
        textView.append("\n\nIf user put less than minimum then it set to minimum.")
    }
}


// extension function to filter edit text number range
fun EditText.inputFilterNumberRange(range: IntRange){
    filterMin(range.first)
    filters = arrayOf<InputFilter>(InputFilterMax(range.last))
}


// class to input filter maximum number
class InputFilterMax(private var max: Int) : InputFilter {
    override fun filter(
        p0: CharSequence,p1: Int,p2: Int,p3: Spanned?,p4: Int,p5: Int
    ): CharSequence? {
        try {
            val replacement = p0.subSequence(p1, p2).toString()
            val newVal = p3.toString().substring(0, p4) + replacement + p3.toString()
                .substring(p5, p3.toString().length)
            val input = newVal.toInt()
            if (input <= max) return null
        } catch (e: NumberFormatException) { }
        return ""
    }
}


// extension function to filter edit text minimum number
fun EditText.filterMin(min: Int){
    onFocusChangeListener = View.OnFocusChangeListener { view, b ->
        if (!b) {
            // set minimum number if inputted number less than minimum
            setTextMin(min)
            // hide soft keyboard on edit text lost focus
            context.hideSoftKeyboard(this)
        }
    }

    setOnEditorActionListener { v, actionId, event ->
        if (actionId == EditorInfo.IME_ACTION_DONE) {
            // set minimum number if inputted number less than minimum
            setTextMin(min)

            // hide soft keyboard on press action done
            context.hideSoftKeyboard(this)
        }
        false
    }
}


// extension function to set edit text minimum number
fun EditText.setTextMin(min: Int){
    try {
        val value = text.toString().toInt()
        setUnderlineColor(Color.GREEN)
        if (value < min){
            setText("$min")
            setUnderlineColor(Color.RED)
        }
    }catch (e: Exception){
        setUnderlineColor(Color.RED)
        setText("$min")
    }
}


// extension function to hide soft keyboard programmatically
fun Context.hideSoftKeyboard(editText: EditText){
    (getSystemService(INPUT_METHOD_SERVICE) as InputMethodManager).apply {
        hideSoftInputFromWindow(editText.windowToken, 0)
    }
}


// extension function to set/change edit text underline color
fun EditText.setUnderlineColor(color: Int){
    background.mutate().apply {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q){
            colorFilter = BlendModeColorFilter(color, BlendMode.SRC_IN)
        }else{
            setColorFilter(color, PorterDuff.Mode.SRC_IN)
        }
    }
}
activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/constraintLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FEFEFA"
    android:clickable="true"
    android:focusable="true"
    android:focusableInTouchMode="true"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/editText"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="12dp"
        android:layout_marginEnd="12dp"
        android:inputType="number"
        android:padding="12dp"
        android:textSize="30sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.12" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="12dp"
        android:fontFamily="sans-serif-condensed-medium"
        android:gravity="center"
        android:padding="8dp"
        android:textColor="#4F42B5"
        android:textSize="25sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editText"
        tools:text="TextView" />

</androidx.constraintlayout.widget.ConstraintLayout>