Xamarin Toast.MakeText change Color-CodePudding

how can I change the backgroundcolor of a Toast in a Xamarin Forms Application?

I've tried this code on Android 11:

        Context context = Android.App.Application.Context;
        string message = "Hello toast!";
        ToastLength duration = ToastLength.Short;

        Toast t = Toast.MakeText(context, message, duration);
        System.Drawing.Color c = Xamarin.Forms.Color.Green;
        ColorMatrixColorFilter CM = new ColorMatrixColorFilter(new float[]
            {
                0,0,0,0,c.R,
                0,0,0,0,c.G,
                0,0,0,0,c.B,
                0,0,0,1,0            
            });
        t.View.Background.SetColorFilter(CM);
        t.Show();

But I get the following Error: System.NullReferenceException: 'Object reference not set to an instance of an object.'

CodePudding user response：

The custom toast views are deprecated since Android 11. So the value of t.View in your code is null.

Just like the official document says:

Custom toast views are deprecated. Apps can create a standard text toast with the makeText(android.content.Context, java.lang.CharSequence, int)

You can check the following case:Toast.getView() returns null on Android 11 (API 30)