如何在SeekBar thumb中显示Android SeekBar progressChanged值?
我想用Android SeekBar的拇指显示当前进度点的值。这就是我迄今为止所尝试的:如何在SeekBar thumb中显示Android SeekBar progressChanged值?,android,bitmapdrawable,gradientdrawable,Android,Bitmapdrawable,Gradientdrawable,我想用Android SeekBar的拇指显示当前进度点的值。这就是我迄今为止所尝试的: SeekBar progBar = (SeekBar)FindViewById(Resource.Id.seekBar1); progBar.ProgressChanged += (object sender, SeekBar.ProgressChangedEventArgs e) => { if (e.FromUser)
SeekBar progBar = (SeekBar)FindViewById(Resource.Id.seekBar1);
progBar.ProgressChanged += (object sender, SeekBar.ProgressChangedEventArgs e) =>
{
if (e.FromUser)
{
Drawable d = ContextCompat.GetDrawable(this, Resource.Drawable.thumb);
Bitmap bitmap = BitmapFactory.DecodeResource(Resources, Resource.Drawable.thumb);
Bitmap bmp = bitmap.Copy(Bitmap.Config.Argb8888, true);// this line gives me a System.NullReferenceException: Object reference not set to an instance of an object. error
Canvas c = new Canvas(bmp);
Canvas c = new Canvas(bmp);
string text = Integer.ToString(progBar.Progress);
Paint p = new Paint();
p.SetTypeface(Typeface.DefaultBold);
p.TextSize = 14;
p.Color = Color.White;
int width = (int)p.MeasureText(text);
int yPos = (int)((c.Height / 2) - ((p.Descent() + p.Ascent()) / 2));
c.DrawText(text, (bmp.Width - width) / 2, yPos, p);
progBar.SetThumb(new BitmapDrawable(Resources, bmp));
}
};
当我得到可绘制的d类型时,它是一个渐变可绘制的。我研究了一下,但我找不到一种方法来将渐变绘制成位图
Drawable d = ContextCompat.GetDrawable(this, Resource.Drawable.thumb);
Canvas c = new Canvas();
Bitmap bitmap = Bitmap.CreateBitmap(d.IntrinsicWidth, d.IntrinsicHeight, Bitmap.Config.Argb8888);
c.SetBitmap(bitmap);
d.SetBounds(0, 0, d.IntrinsicWidth, d.IntrinsicHeight);
d.Draw(c);
//Bitmap bmp = bitmap.Copy(Bitmap.Config.Argb8888, true);
string text = Integer.ToString(progress) + "%";
Paint p = new Paint();
p.SetTypeface(Typeface.CreateFromAsset(Assets, "fonts/Brandon_bld.otf"));
p.TextSize = 18;
p.Color = Color.White;
int width = (int)p.MeasureText(text);
int yPos = (int)((c.Height / 2) - ((p.Descent() + p.Ascent()) / 2));
c.DrawText(text, (bitmap.Width - width) / 2, yPos, p);
progBar.SetThumb(new BitmapDrawable(Resources, bitmap));
使用画布创建位图有效
使用画布创建位图有效