android - Canvas を Drawable に変換する

Question

int x = 10; 
int y = 10; 
int r = 4; 
Paint mPaint = new Paint(); 
mPaint.setColor(0xFF0000); 
Canvas mCanvas = new Canvas(); 
mCanvas.drawCircle(x,y,r,mPaint); 

Drawableに変換する方法はありますmCanvasか? 私の目標は、特定の形状と色のドローアブルを生成することです。

ありがとう

Answer 1

For simple shapes like your circle, I'd think a Shape Drawable would be easier. For more complicated things, just create a Bitmap for your Canvas to use, then create the Canvas and draw into it, then create a Drawable from your Bitmap. Something like:

int x = 10;
int y = 10;
int r = 4;

Paint mPaint = new Paint();
mPaint.setColor(0xFF0000);

Bitmap bitmap = Bitmap.createBitmap(/* read the docs*/);
Canvas mCanvas = new Canvas(bitmap);
mCanvas.drawCircle(x,y,r,mPaint);

BitmapDrawable drawable = new BitmapDrawable(getResources(), bitmap);

To be perhaps somewhat pedantic (and hopefully increase your understanding), a Canvas just hosts the "draw" calls and draws into a Bitmap that you specify. This means:

1. Your example code doesn't do much, since you didn't construct your Canvas with a Bitmap or call setBitmap() on it.
2. You're not converting your Canvas to a Drawable, you're constructing a Drawable from the Bitmap your Canvas calls draw into.

Answer 2

別の投稿から取得した、これを行うための疑似コードを次に示します。

キャンバス上の画像を JPEG ファイルに変換

ByteArrayOutputStream baos = new ByteArrayOutputStream()
Bitmap  bitmap = Bitmap.createBitmap( view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
view.draw(canvas); 
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos); 

// This converts the bitmap to a drawable
BitmapDrawable mDrawable = new BitmapDrawable(getResources(),bitmap);

または、そのスレッドの別の回答で概説されているように getDrawingCache() を使用できます。