安卓图像视图底部阴影

Question

如何在安卓中制作这样的回收视图项目(影子(？

https://dribbble.com/shots/4020189-Scroll-and-sidebar-interaction

Answer 1

要添加阴影，您可以使用如下代码：

Paint forShadow = new Paint(); 
// radius=10, y-offset=2, color=black 
forShadow.setShadowLayer(10.0f, 0.0f, 2.0f, 0xFF000000); 
// in onDraw(Canvas) method 
canvas.drawBitmap(bitmap, 0.0f, 0.0f, forShadow);

同样对于蜂窝及以上，您需要调用setLayerType(LAYER_TYPE_SOFTWARE, forShadow)，否则您将看不到您的影子！

不幸的是，SetShadowLayer不适用于硬件加速，因此大大降低了性能。

简而言之，完整代码可能如下所示：

public class ShadowImage extends Drawable {
Bitmap bm;
@Override
public void draw(Canvas canvas) {
Paint forShadow = new Paint();
//trying for rectangle
Rect rect = new Rect(0,0,bm.getWidth(), bm.getHeight());
forShadow.setAntiAlias(true);
forShadow.setShadowLayer(5.5f, 4.0f, 4.0f, Color.BLACK);
canvas.drawRect(rect, forShadow);
canvas.drawBitmap(bm, 0.0f, 0.0f, null);
}
public ShadowImage(Bitmap bitmap) {
super();
this.bm = bitmap;
} ... }