如何在android中使用ShapeDrawable以编程方式创建一个圆形的角落边框？

问题描述

我需要通过扩展ShapeDrawable以编程方式创建带圆角的边框。我需要一个带圆角的黑色边框，外面的像素是白色，内部像素是透明的。我目前的代码有很多问题，其中的问题是它不会创建一个与边框厚度相同的光滑角落，并且边框的外部像素是透明的而不是白色。

I need to create a border with rounded corners programatically by extending ShapeDrawable. I need to have a black border with rounded corners with the pixels on the outside being white and the inner pixels being transparent. The code I have at the moment has multiple problems, of which are that it does not create a smooth corner that is the same thickness as the border and that the outer pixels of the border are transparent and not white.

这是我目前正在拍摄的角落的照片

Here is a picture of the corners I am currently getting

以下是我在构造函数中为'fill'传递Color.TRANSPARENT的代码：

Here is the code where I am passing Color.TRANSPARENT for 'fill' in the constructor:

public class CustomShape extends ShapeDrawable {
 private final Paint fillpaint, strokepaint;
public CustomShape(int fill, int strokeWidth,int radius) {

    super(new RoundRectShape(new float[] { radius, radius, radius, radius, radius, radius, radius, radius }, null, null));
    fillpaint = new Paint(this.getPaint());
    fillpaint.setColor(fill);
    strokepaint = new Paint(fillpaint);
    strokepaint.setStyle(Paint.Style.STROKE);
    strokepaint.setStrokeWidth(strokeWidth);
    strokepaint.setColor(Color.BLACK);
}



@Override
protected void onDraw(Shape shape, Canvas canvas, Paint paint) {
    shape.draw(canvas, fillpaint);
    shape.draw(canvas, strokepaint);
}

}

推荐答案

如果你需要均匀圆角（并且从你的例子中看起来像你那么做）你可以简单地使用纯色的GradentDrawable

If you need evenly rounded corners (and from your example it seems you do) you can simply use GradentDrawable with a solid color

GradientDrawable gd = new GradientDrawable();
gd.setColor(Color.RED);
gd.setCornerRadius(10);
gd.setStroke(2, Color.WHITE);

view.setBackground(gd);

可以找到GradientDrawable文档。

GradientDrawable documentation can be found here.

编辑：分别为每个角落

您可以使用 setCornerRadii（float [] radiusii）方法分别指定每个角的半径。 对于每个角，数组包含2个值，[X_radius，Y_radius]。角是按左上，右上，右下，左下排序的。仅当形状为RECTANGLE类型时才会使用此属性。

You can specify radius of each corner separately using setCornerRadii (float[] radii) method. "For each corner, the array contains 2 values, [X_radius, Y_radius]. The corners are ordered top-left, top-right, bottom-right, bottom-left. This property is honored only when the shape is of type RECTANGLE.

建议在更改此属性之前调用 mutate（）。

It is recommended to invoke mutate() before changing this property.

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