SetColorFilter çalışmıyor Xamarin.Android

Question

var upArrow = Resources.GetDrawable(Resource.Drawable.abc_ic_ab_back_material); 
upArrow.SetColorFilter(Resources.GetColor(Android.Resource.Color.White), PorterDuff.Mode.SrcIn); 
SupportActionBar.SetHomeAsUpIndicator(upArrow); 

Yukarıdaki kod, ok rengini değiştirmez. upArrow ColorFilter değeri boş. Bunun nedeni ne olmalı? Çekilebilir rengi nasıl değiştireceğimi sormuyorum. Sorum şu, yukarıdaki kodun renk filtresini ayarlamada başarısız olmasının nedeni nedir? Ana Verimlilik kodu aşağıdadır.

public class MvxFormsApplicationActivity : FormsAppCompatActivity 
{ 
    protected override void OnCreate(Bundle bundle) 
    { 
     TabLayoutResource = Resource.Layout.Tabbar; 
     ToolbarResource = Resource.Layout.Toolbar; 
     base.OnCreate(bundle); 

     Xamarin.Forms.Forms.Init(this, bundle); ; 
     //Plugins.NewictLib.Forms.Android.Renderers.GifImageViewRenderer.Init(); 
     DLToolkit.Forms.Controls.FlowListView.Init(); 
     UserDialogs.Init ((Activity) Xamarin.Forms.Forms.Context); 

     OxyPlot.Xamarin.Forms.Platform.Android.PlotViewRenderer.Init(); 

     //   var mvxFormsApp = new MvxFormsApp(); 
     //   LoadApplication (mvxFormsApp); 
     var myApp = new MyFormsApp(); 
     LoadApplication (myApp); 
     AppCompatDelegate.CompatVectorFromResourcesEnabled = true; 
     //the following needs to set so that the back button color can be changed 
     var upArrow = Resources.GetDrawable(Resource.Drawable.abc_ic_ab_back_material); 
     upArrow.SetColorFilter(Resources.GetColor(Android.Resource.Color.White), PorterDuff.Mode.SrcIn); 
     SupportActionBar.SetHomeAsUpIndicator(upArrow); 

       if (IsPlayServicesAvailable()) 
     { 
      var intent = new Intent(this, typeof(RegistrationIntentService)); 
      StartService(intent); 
     } 
     //var presenter = Mvx.Resolve<IMvxViewPresenter>() as MvxFormsDroidMasterDetailPagePresenter; 
     var presenter = Mvx.Resolve <IMvxViewPresenter>() as MVxFormsDroidCustomPagePresenter;//MvxFormsDroidPagePresenter; 
     if (presenter == null) { 
      throw new ArgumentNullException (nameof(presenter), "MvxFormsApplicationActivity: Please check your Activity class and ensure the presenter has value"); 
     } 
     //presenter.MvxFormsApp = mvxFormsApp; 
     presenter.MvxFormsApp = oznesFormsApp; 
     Mvx.Resolve<IMvxAppStart>().Start(); 
    } 
    } 

Answer 1

İşte Android 7.1 ve Android 6.0 emülatörü üzerinde çalışıyor SetColorFilter gösteren minimal örnek.

MainActivity.cs

[Activity(Label = "App39", MainLauncher = true, Icon = "@drawable/icon")] 
public class MainActivity : AppCompatActivity 
{ 
    protected override void OnCreate(Bundle bundle) 
    { 
     base.OnCreate(bundle); 

     // Set our view from the "main" layout resource 
     SetContentView (Resource.Layout.Main); 

     var upArrow = AppCompatResources.GetDrawable(this, Resource.Drawable.abc_ic_ab_back_material); 
     upArrow.SetColorFilter(new Color(ContextCompat.GetColor(this, Android.Resource.Color.HoloBlueBright)), PorterDuff.Mode.SrcIn); 
     SupportActionBar.SetDisplayHomeAsUpEnabled(true); 
     SupportActionBar.SetHomeAsUpIndicator(upArrow); 

     Button b = FindViewById<Button>(Resource.Id.button); 
     b.Click += B_Click; 
    } 

    private void B_Click(object sender, System.EventArgs e) 
    { 
     Intent i = new Intent(this, typeof(MainActivity)); 
     StartActivity(i); 
    } 
} 

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="App39.App39" android:versionCode="1" android:versionName="1.0"> 
    <uses-sdk android:minSdkVersion="16" /> 
    <application android:label="App39" android:theme="@style/Theme.AppCompat.Light"></application> 
</manifest> 

kodumu ve kod arasındaki fark nedir?

Gerçekte, Destek kitaplığı eşdeğerini kullanmanız gereken iki kullanım dışı yöntem kullanıyorsunuz. ContextCompat.GetColor gibi. İkinci olarak, Resources.GetDrawable yerine AppCompatResources veya ResourcesCompatGetDrawable yöntemini kullanmalısınız.

https://developer.android.com/reference/android/support/v7/content/res/AppCompatResources.html#getDrawable(android.content.Context, int)

https://developer.android.com/reference/android/support/v4/content/res/ResourcesCompat.html#getDrawable(android.content.res.Resources, int, android.content.res.Resources.Theme)

ait