浮动操作按钮的阴影

Drop shadow for Floating Action Button

我正在创建自己的浮动操作按钮。为此,我使用了 RippleDrawable(由我创建)和 ShadowDrawable(也是由我创建)。我面临的问题是我的 ShadowDrawbale 没有为相应的按钮投射完美的阴影。我的ShadowDrawable的代码如下:

public class ShadowDrawable extends Drawable {

private Context context;
private float floatMaximumRadius = 0;
private int intCenterX = 0, intCenterY = 0, intShadowAlpha,intShadowColor;
private Paint paintShadow;

public ShadowDrawable(Context context) {
    this.context = context;
    paintShadow = new Paint(Paint.ANTI_ALIAS_FLAG);
    paintShadow.setStyle(Paint.Style.FILL);
}

@Override
public void draw(Canvas canvas) {
    paintShadow.setShadowLayer(dpToPx(4f), dpToPx(1f), dpToPx(3f), intShadowColor);
    paintShadow.setAlpha(intShadowAlpha);
    paintShadow.setColor(intShadowColor);
    canvas.drawCircle(intCenterX, intCenterY, floatMaximumRadius, paintShadow);
}

@Override
public int getOpacity() {
    return 0;
}

@Override
protected void onBoundsChange(Rect rectBounds) {
    super.onBoundsChange(rectBounds);
    intCenterX = rectBounds.centerX();
    intCenterY = rectBounds.centerY();
    floatMaximumRadius = (Math.min(rectBounds.width(), rectBounds.height()) / 2) - 4;
}

@Override
public void setAlpha(int alpha) {
    setShadowAlpha(alpha);
}

@Override
public void setColorFilter(ColorFilter cf) {

}

public void setShadowAlpha(int intShadowAlpha) {
    this.intShadowAlpha = intShadowAlpha;
    invalidateSelf();
}

public void setShadowColor(int intShadowColor) {
    this.intShadowColor = intShadowColor;
    invalidateSelf();
}

private int dpToPx(float dp) {
    final float scale = context.getResources().getDisplayMetrics().density;
    return Math.round(dp * scale);
}

}

告诉我如何使阴影像支持库中提供的浮动操作按钮一样清晰和适当。

您可以在 here GitHub 处查看这个 fab 库。该库允许您在 fab 上设置波纹效果颜色。

<com.melnykov.fab.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|right"
        android:layout_margin="16dp"
        android:src="@drawable/ic_action_content_new"
        fab:fab_colorNormal="@color/primary"
        fab:fab_colorPressed="@color/primary_pressed"
        fab:fab_colorRipple="@color/ripple" />