AlertDialog Extensions

Custom AlertDialog

This is custom AlertDialog which can easily invoke from Activity or from Fragment.

```kotlin tab="AlertDialogExtensions.kt"

import android.annotation.SuppressLint import android.app.Activity import android.content.Context import android.view.LayoutInflater import android.view.View import android.widget.Button import android.widget.TextView import androidx.annotation.StringRes import androidx.appcompat.app.AlertDialog import androidx.fragment.app.Fragment import au.com.elegantmedia.presentation.R

/* * Created by Chathura Wijesinghe * cdanasiri@gmail.com /

inline fun Activity.alert(title: CharSequence? = null, message: CharSequence? = null, func: AlertDialogHelper.() -> Unit): AlertDialog { return AlertDialogHelper(this, title, message).apply { func() }.create() }

inline fun Activity.alert(titleResource: Int = 0, messageResource: Int = 0, func: AlertDialogHelper.() -> Unit): AlertDialog { val title = if (titleResource == 0) null else getString(titleResource) val message = if (messageResource == 0) null else getString(messageResource) return AlertDialogHelper(this, title, message).apply { func() }.create() }

inline fun Fragment.alert(title: CharSequence? = null, message: CharSequence? = null, func: AlertDialogHelper.() -> Unit): AlertDialog { return AlertDialogHelper(this.context!!, title, message).apply { func() }.create() }

inline fun Fragment.alert(titleResource: Int = 0, messageResource: Int = 0, func: AlertDialogHelper.() -> Unit): AlertDialog { val title = if (titleResource == 0) null else getString(titleResource) val message = if (messageResource == 0) null else getString(messageResource) return AlertDialogHelper(this.context!!, title, message).apply { func() }.create() }

@SuppressLint("InflateParams") class AlertDialogHelper(context: Context, title: CharSequence?, message: CharSequence?) {

private val dialogView: View by lazyFast {
    LayoutInflater.from(context).inflate(R.layout.dialog_info, null)
}

private val builder: AlertDialog.Builder = AlertDialog.Builder(context)
    .setView(dialogView)

private val title: TextView by lazyFast {
    dialogView.findViewById<TextView>(R.id.dialogInfoTitleTextView)
}

private val message: TextView by lazyFast {
    dialogView.findViewById<TextView>(R.id.dialogInfoMessageTextView)
}

private val positiveButton: Button by lazyFast {
    dialogView.findViewById<Button>(R.id.dialogInfoPositiveButton)
}

private val negativeButton: Button by lazyFast {
    dialogView.findViewById<Button>(R.id.dialogInfoNegativeButton)
}

private var dialog: AlertDialog? = null

var cancelable: Boolean = true

init {
    this.title.text = title
    this.message.text = message
}

fun positiveButton(@StringRes textResource: Int, func: (() -> Unit)? = null) {
    with(positiveButton) {
        text = builder.context.getString(textResource)
        setClickListenerToDialogButton(func)
    }
}

fun positiveButton(text: CharSequence, func: (() -> Unit)? = null) {
    with(positiveButton) {
        this.text = text
        setClickListenerToDialogButton(func)
    }
}

fun negativeButton(@StringRes textResource: Int, func: (() -> Unit)? = null) {
    with(negativeButton) {
        text = builder.context.getString(textResource)
        setClickListenerToDialogButton(func)
    }
}

fun negativeButton(text: CharSequence, func: (() -> Unit)? = null) {
    with(negativeButton) {
        this.text = text
        setClickListenerToDialogButton(func)
    }
}

fun onCancel(func: () -> Unit) {
    builder.setOnCancelListener { func() }
}

fun create(): AlertDialog {
    title.goneIfTextEmpty()
    message.goneIfTextEmpty()
    positiveButton.goneIfTextEmpty()
    negativeButton.goneIfTextEmpty()

    dialog = builder
        .setCancelable(cancelable)
        .create()
    return dialog!!
}

private fun TextView.goneIfTextEmpty() {
    visibility = if (text.isNullOrEmpty()) {
        View.GONE
    } else {
        View.VISIBLE
    }
}

private fun Button.setClickListenerToDialogButton(func: (() -> Unit)?) {
    setOnClickListener {
        func?.invoke()
        dialog?.dismiss()
    }
}

}

/* * Implementation of lazy that is not thread safe. Useful when you know what thread you will be * executing on and are not worried about synchronization. / fun lazyFast(operation: () -> T): Lazy = lazy(LazyThreadSafetyMode.NONE) { operation() }

```xml tab="dialog_info.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:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:elevation="8dp"
        android:minWidth="300dp"
        android:orientation="vertical"
        android:padding="16dp">

    <TextView
            android:id="@+id/dialogInfoTitleTextView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="0.5"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"/>

    <TextView
            android:id="@+id/dialogInfoMessageTextView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="16dp"
            app:layout_constraintTop_toBottomOf="@+id/dialogInfoTitleTextView"
            app:layout_constraintEnd_toEndOf="@+id/dialogInfoTitleTextView"
            app:layout_constraintStart_toStartOf="@+id/dialogInfoTitleTextView"/>
    <Button
            android:layout_width="wrap_content"
            android:layout_height="0dp"
            android:id="@+id/dialogInfoPositiveButton"
            app:layout_constraintTop_toBottomOf="@+id/dialogInfoMessageTextView" android:layout_marginTop="64dp"
            app:layout_constraintEnd_toEndOf="parent"/>
    <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/dialogInfoNegativeButton"
            app:layout_constraintEnd_toStartOf="@+id/dialogInfoPositiveButton" android:layout_marginEnd="16dp"
            app:layout_constraintBottom_toBottomOf="@+id/dialogInfoPositiveButton"
            app:layout_constraintTop_toTopOf="@+id/dialogInfoPositiveButton"/>


</androidx.constraintlayout.widget.ConstraintLayout>

Usage

```kotlin tab="String" alert("Title", "Message: Are you sure") { positiveButton("Ok") { // Do positive stuff here } negativeButton("Cancel"){ // Do negative stuff here } }.show()

```kotlin tab="String Resource"
 alert(R.string.title, R.string.message) {
     positiveButton(R.string.ok) {
         // Do positive stuff here 
     }
     negativeButton(R.string.cancel){
         // Do negative stuff here 
     }
 }.show()

kotlin tab="Single acction" alert(R.string.title, R.string.message) { positiveButton(R.string.ok) { // Do positive stuff here } }.show()