Converted DialogUtil to Kotlin (#3621)

* Converted DialogUtil to Kotlin

* Kotlin syntax and standard changes

* Removed ;

* Added missing null

* Added missing null

* Removed unnecessary code

* Reduced functions

* added let to customView

* reverted "let" changes

* reverted "let" changes

* removed if-statements

* replaced with "it"

* fixed overflow error

* Function rename

* Used named arguments

* Fix Typo

* single lined

* Update DialogUtil.kt

* changed default value

Author: madhurgupta10

app/src/main/java/fr/free/nrw/commons/utils/DialogUtil.java

@@ -0,0 +1,161 @@
+package fr.free.nrw.commons.utils
+
+import android.app.Activity
+import android.app.AlertDialog
+import android.app.Dialog
+import android.view.View
+import fr.free.nrw.commons.R
+import timber.log.Timber
+
+object DialogUtil {
+    /**
+     * Shows a dialog safely.
+     * @param activity the activity
+     * @param dialog the dialog to be shown
+     */
+    private fun showSafely(activity: Activity?, dialog: Dialog?) {
+
+        if (activity == null || dialog == null) {
+            Timber.d("Show called with null activity / dialog. Ignoring.")
+            return
+        }
+
+        if (activity.isFinishing || activity.isDestroyed) {
+            Timber.e("Activity is not running. Could not show dialog. ")
+            return
+        }
+        try {
+            dialog.show()
+        } catch (e: IllegalStateException) {
+            Timber.e(e, "Could not show dialog.")
+        }
+    }
+
+    @JvmStatic
+    fun showAlertDialog(
+        activity: Activity,
+        title: String,
+        message: String,
+        onPositiveBtnClick: Runnable?,
+        onNegativeBtnClick: Runnable?
+    ) {
+        createAndShowDialogSafely(
+            activity = activity,
+            title = title,
+            message = message,
+            positiveButtonText = activity.getString(R.string.yes),
+            negativeButtonText = activity.getString(R.string.no),
+            onPositiveBtnClick = onPositiveBtnClick,
+            onNegativeBtnClick = onNegativeBtnClick
+        )
+    }
+
+    @JvmStatic
+    fun showAlertDialog(
+        activity: Activity,
+        title: String,
+        message: String,
+        positiveButtonText: String?,
+        negativeButtonText: String?,
+        onPositiveBtnClick: Runnable?,
+        onNegativeBtnClick: Runnable?
+    ) {
+        createAndShowDialogSafely(
+            activity = activity,
+            title = title,
+            message = message,
+            positiveButtonText = positiveButtonText,
+            negativeButtonText = negativeButtonText,
+            onPositiveBtnClick = onPositiveBtnClick,
+            onNegativeBtnClick = onNegativeBtnClick
+        )
+    }
+
+    @JvmStatic
+    fun showAlertDialog(
+        activity: Activity,
+        title: String,
+        message: String,
+        onPositiveBtnClick: Runnable?,
+        onNegativeBtnClick: Runnable?,
+        customView: View?,
+        cancelable: Boolean
+    ) {
+        createAndShowDialogSafely(
+            activity = activity,
+            title = title,
+            message = message,
+            positiveButtonText = activity.getString(R.string.yes),
+            negativeButtonText = activity.getString(R.string.no),
+            onPositiveBtnClick = onPositiveBtnClick,
+            onNegativeBtnClick = onNegativeBtnClick,
+            customView = customView,
+            cancelable = cancelable
+        )
+    }
+
+    @JvmStatic
+    fun showAlertDialog(
+        activity: Activity,
+        title: String,
+        message: String,
+        positiveButtonText: String?,
+        onPositiveBtnClick: Runnable?,
+        cancelable: Boolean
+    ) {
+        createAndShowDialogSafely(
+            activity = activity,
+            title = title,
+            message = message,
+            positiveButtonText = positiveButtonText,
+            onPositiveBtnClick = onPositiveBtnClick,
+            cancelable = cancelable
+        )
+    }
+
+    /**
+     * show a dialog
+     * @param activity
+     * @param title
+     * @param message
+     * @param positiveButtonText
+     * @param negativeButtonText
+     * @param onPositiveBtnClick
+     * @param onNegativeBtnClick
+     * @param customView
+     * @param cancelable
+     */
+    private fun createAndShowDialogSafely(
+        activity: Activity,
+        title: String,
+        message: String,
+        positiveButtonText: String? = null,
+        negativeButtonText: String? = null,
+        onPositiveBtnClick: Runnable? = null,
+        onNegativeBtnClick: Runnable? = null,
+        customView: View? = null,
+        cancelable: Boolean = true
+    ) {
+
+        /* If the custom view already has a parent, there is already a dialog showing with the view
+         * This happens for on resume - return to avoid creating a second dialog - the first one
+         * will still show
+         */
+        if (customView?.parent != null) {
+            return
+        }
+
+        showSafely(activity, AlertDialog.Builder(activity).apply {
+            setTitle(title)
+            setMessage(message)
+            setView(customView)
+            setCancelable(cancelable)
+            positiveButtonText?.let {
+                setPositiveButton(it) { _, _ -> onPositiveBtnClick?.run() }
+            }
+            negativeButtonText?.let {
+                setNegativeButton(it) { _, _ -> onNegativeBtnClick?.run() }
+            }
+        }.create())
+    }
+}