API 19上的背景不透明

Question

I'm not able to set the background transparent on API 19, instead I get a white background. The background is only transparent on API 21 and above.

I have an activity that calls a custom dialog fragment. The parent layout of dialog fragment has background="@android:color/transparent" .

What am I doing wrong? Am I missing something. Any tips of hint would be really helpful.

Solutions that I have tried:

Changing primary color to transparent on MyActivityTheme

Parent layout background="@null"

Dialog with transparent background in Android

How to make any view background transparent?

https://mindofaandroiddev.wordpress.com/2013/12/28/making-the-status-bar-and-navigation-bar-transparent-with-a-listview-on-android-4-4-kitkat/

MyDialogFragment

public class MyDialogFragment : DialogFragment
    {    
        public override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);
            SetStyle(DialogFragmentStyle.NoTitle, Resource.Style.MyDialogTheme);
        }

        public override Dialog OnCreateDialog(Bundle savedInstanceState)
        {
            var builder = new AlertDialog.Builder(Activity);

            var inflater = Activity.LayoutInflater;

            var dialogView = inflater.Inflate(Resource.Layout.MyDialogLayout, null);

            if (dialogView != null)
            {    
                builder.SetView(dialogView);
            }

            var dialog = builder.Create();
            dialog.Window.RequestFeature(WindowFeatures.NoTitle);
            dialog.Window.SetBackgroundDrawable(new ColorDrawable(Android.Graphics.Color.Transparent));

            return dialog;
        }
    }

MyDialogLayout

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:background="@android:color/transparent"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <!-- Child layouts -->      
</LinearLayout>

Styles.xml

<style name="MyActivityTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <item name="colorPrimary">@color/Red</item>
        <item name="colorAccent">@color/White</item>
        <item name="colorControlNormal">@color/White</item>
        <item name="colorControlActivated">@color/White</item>
        <item name="android:textColorHint">@color/White</item>
        <item name="android:background">@android:color/transparent</item>
        <item name="android:windowTranslucentStatus">true</item>
        <item name="android:windowTranslucentNavigation">true</item>
</style>

<style name="MyDialogTheme" parent="android:Theme.Holo.Light.Dialog.NoActionBar">
        <item name="colorPrimary">@android:color/transparent</item>
        <item name="colorAccent">@color/Red</item>
        <item name="colorControlNormal">@color/Red</item>
        <item name="colorControlActivated">@color/Red</item>
        <item name="colorControlHighlight">@color/Red</item>
        <item name="android:windowNoTitle">true</item>
        <item name="android:textColorPrimary">@color/Red</item>
</style>

Answer 1

I think you need to add this code in your OnResume() method :

 public override void OnResume()
        {
                base.OnResume();
                // Auto size the dialog based on it's contents
                Dialog.Window.SetLayout(LinearLayout.LayoutParams.MatchParent, LinearLayout.LayoutParams.WrapContent);
                Dialog.Window.SetGravity(GravityFlags.Bottom);
                // Make sure there is no background behind our view
                Dialog.Window.SetBackgroundDrawable(new ColorDrawable(Color.Transparent));
                // Disable standard dialog styling/frame/theme: our custom view should create full UI
                SetStyle(Android.Support.V4.App.DialogFragment.StyleNoFrame, Android.Resource.Style.Theme);
        }

Hope it helps ;)