An alert dialog fragment that supports new material background.

MaterialDialogFragment.kt

/**
 * Designed and developed by Seanghay Yath (@seanghay)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.seanghay.materialdialog

import android.annotation.SuppressLint
import android.app.Activity
import android.app.Dialog
import android.os.Bundle
import androidx.annotation.NonNull
import androidx.appcompat.app.AlertDialog
import androidx.appcompat.app.AppCompatDialogFragment
import androidx.fragment.app.DialogFragment
import com.google.android.material.dialog.MaterialAlertDialogBuilder

/**
 * An alert dialog fragment that supports new material background.
 * It uses {@link MaterialAlertDialogBuilder}.
 */
open class MaterialDialogFragment: AppCompatDialogFragment() {

    /**
     * Create a MaterialAlertDialog
     * @return AlertDialog
     */
    override fun onCreateDialog(savedInstanceState: Bundle?): AlertDialog {
        val builder = MaterialAlertDialogBuilder(context, theme)
        return builder.create()
    }

    override fun onActivityCreated(savedInstanceState: Bundle?) {
        // We don't have to do anything if it doesn't show
        if (!showsDialog) {
            return
        }

        // Disable showsDialog so that the code of super class is not executed
        showsDialog = false

        // We have to call super
        super.onActivityCreated(savedInstanceState)

        val v = view
        if (v != null) {
            if (v.parent != null) {
                throw IllegalStateException("DialogFragment can not be attached to a container view")
            }

            if (dialog is AlertDialog) {
                // If it's an alert dialog set view instead of contentView
                (dialog as AlertDialog).setView(v)
            } else {
                // Fallback to the old one
                dialog?.setContentView(v)
            }
        }

        val activity = activity
        if (activity != null) {
            dialog?.setOwnerActivity(activity)
        }

        dialog?.setCancelable(isCancelable)
        dialog?.setOnCancelListener(this)
        dialog?.setOnDismissListener(this)

        if (savedInstanceState != null) {
            // Restore states of the dialog
            val dialogState = savedInstanceState.getBundle("android:savedDialogState")
            if (dialogState != null) {
                dialog?.onRestoreInstanceState(dialogState)
            }
        }

        showsDialog = true
    }

}