C# OnDraw:画布未绘制位图
我正在使用Xamarin.Android创建一个自定义视图,我想在画布上画一个圆圈,然后在上面画一个位图。圆圈绘制正确,但位图绘制不正确 位图对应于png图像资源。 这是我的C# OnDraw:画布未绘制位图,c#,android,xamarin,android-canvas,android-custom-view,C#,Android,Xamarin,Android Canvas,Android Custom View,我正在使用Xamarin.Android创建一个自定义视图,我想在画布上画一个圆圈,然后在上面画一个位图。圆圈绘制正确,但位图绘制不正确 位图对应于png图像资源。 这是我的OnDraw protected async override void OnDraw(Canvas canvas) { base.OnDraw(canvas); Paint buttonBackgroundPaint = new Paint(PaintFlags.AntiAl
OnDraw
protected async override void OnDraw(Canvas canvas)
{
base.OnDraw(canvas);
Paint buttonBackgroundPaint = new Paint(PaintFlags.AntiAlias);
Color? c = null;
bool colorOk = Resources.TryGetColor(_backgroundColor, out c);
buttonBackgroundPaint.Color = (Color)(colorOk ? c : _context?.Resources.GetColor(AndroidRes.Resource.Color.Black));
canvas.DrawCircle(Width / 2, Height / 2, _radius, buttonBackgroundPaint);
Paint bitmapPaint = new Paint(PaintFlags.AntiAlias);
Bitmap bitmapContent = await BitmapFactory.DecodeResourceAsync(_context?.Resources, _drawableContent);
canvas.DrawBitmap(bitmapContent, 0, 0, bitmapPaint);
}
编辑:Resources.TryGetColor是我创建的一个扩展方法。我注意到旋转屏幕时会显示位图的一部分。 问题在于位图边界,因此我按如下方式解决:
protected async override void OnDraw(Canvas canvas)
{
base.OnDraw(canvas);
Paint buttonBackgroundPaint = new Paint(PaintFlags.AntiAlias);
Color? c = null;
bool colorOk = Resources.TryGetColor(_backgroundColor, out c);
buttonBackgroundPaint.Color = (Color)(colorOk ? c : _context?.Resources.GetColor(AndroidRes.Resource.Color.Black));
canvas.DrawCircle(Width / 2, Height / 2, _radius, buttonBackgroundPaint);
Drawable dr = _context.Resources.GetDrawable(Resource.Drawable.image);
dr.SetBounds(0, 0, right, bottom); // appropiate values for my case
dr.Draw(canvas);
}