java - 六边形 ImageView 圆角

Question

您好，我想要如上图所示的圆角。我设法制作了六角形 ImageView。但我无法绕过角落。请帮忙。如果有人想看一下，我正在复制代码。我试过给出椭圆形 ImageView 中使用的弧线，但它不起作用。我是android的新手。任何帮助将不胜感激。

public class HexagonImageView extends ImageView {

private Path hexagonPath;
private Path hexagonBorderPath;
private float radius;
private Bitmap image;
private int viewWidth;
private int viewHeight;
private Paint paint;
private BitmapShader shader;
private Paint paintBorder;
private int borderWidth = 5;

public HexagonImageView(Context context) {
    super(context);
    setup();
}

public HexagonImageView(Context context, AttributeSet attrs) {
    super(context, attrs);
    setup();
}

public HexagonImageView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    setup();
}

private void setup() {
    paint = new Paint();
    paint.setAntiAlias(true);

    paintBorder = new Paint();
    setBorderColor(Color.WHITE);
    paintBorder.setAntiAlias(true);
    this.setLayerType(LAYER_TYPE_SOFTWARE, paintBorder);
    paintBorder.setShadowLayer(4.0f, 1.0f, 1.0f, Color.BLACK);

    hexagonPath = new Path();
    hexagonBorderPath = new Path();

}

public void setRadius(float r) {
    this.radius = r;
    calculatePath();
    this.invalidate();
}

public void setBorderWidth(int borderWidth)  {
    this.borderWidth = borderWidth;
    this.invalidate();
}

public void setBorderColor(int borderColor)  {
    if (paintBorder != null)
        paintBorder.setColor(borderColor);

    this.invalidate();
}

private void calculatePath() {

    float triangleHeight = (float) (Math.sqrt(3) * radius / 2);
    float centerX = viewWidth/2;
    float centerY = viewHeight/2;

    hexagonBorderPath.moveTo(centerX, centerY + radius);
    hexagonBorderPath.lineTo(centerX - triangleHeight, centerY + radius/2);
    hexagonBorderPath.lineTo(centerX - triangleHeight, centerY - radius/2);
    hexagonBorderPath.lineTo(centerX, centerY - radius);
    hexagonBorderPath.lineTo(centerX + triangleHeight, centerY - radius/2);
    hexagonBorderPath.lineTo(centerX + triangleHeight, centerY + radius/2);
    hexagonBorderPath.moveTo(centerX, centerY + radius);

    float radiusBorder = radius - borderWidth;    
    float triangleBorderHeight = (float) (Math.sqrt(3) * radiusBorder / 2);

    hexagonPath.moveTo(centerX, centerY + radiusBorder);
    hexagonPath.lineTo(centerX - triangleBorderHeight, centerY + radiusBorder/2);
    hexagonPath.lineTo(centerX - triangleBorderHeight, centerY - radiusBorder/2);
    hexagonPath.lineTo(centerX, centerY - radiusBorder);
    hexagonPath.lineTo(centerX + triangleBorderHeight, centerY - radiusBorder/2);
    hexagonPath.lineTo(centerX + triangleBorderHeight, centerY + radiusBorder/2);
    hexagonPath.moveTo(centerX, centerY + radiusBorder);

    this.invalidate();
}

private void loadBitmap()  {
    BitmapDrawable bitmapDrawable = (BitmapDrawable) this.getDrawable();

    if (bitmapDrawable != null)
        image = bitmapDrawable.getBitmap();
}

@SuppressLint("DrawAllocation")
@Override
public void onDraw(Canvas canvas){
    super.onDraw(canvas);

    loadBitmap();

    // init shader
    if (image != null) {

        canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);

        shader = new BitmapShader(Bitmap.createScaledBitmap(image, canvas.getWidth(), canvas.getHeight(), true), Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
        paint.setShader(shader);

        canvas.drawPath(hexagonBorderPath, paintBorder);
        canvas.drawPath(hexagonPath, paint);
        canvas.clipPath(hexagonPath, Region.Op.DIFFERENCE);
    }

}

@Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec){
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);

    int width = measureWidth(widthMeasureSpec);
    int height = measureHeight(heightMeasureSpec, widthMeasureSpec);

    viewWidth = width - (borderWidth * 2);
    viewHeight = height - (borderWidth * 2);

    radius = height / 2 - borderWidth;

    calculatePath();

    setMeasuredDimension(width, height);
}

private int measureWidth(int measureSpec)   {
    int result = 0;
    int specMode = MeasureSpec.getMode(measureSpec);
    int specSize = MeasureSpec.getSize(measureSpec);

    if (specMode == MeasureSpec.EXACTLY)  {
        result = specSize;
    }
    else {
        result = viewWidth;
    }

    return result;
}

private int measureHeight(int measureSpecHeight, int measureSpecWidth)  {
    int result = 0;
    int specMode = MeasureSpec.getMode(measureSpecHeight);
    int specSize = MeasureSpec.getSize(measureSpecHeight);

    if (specMode == MeasureSpec.EXACTLY) {
        result = specSize;
    }
    else {
        result = viewHeight;
    }

    return result;
}
}

Answer 1

您需要用 hexagonPath.cubicTo 或 hexagonPath.quadTo 替换您的 hexagonPath.lineTo 命令。就个人而言，我发现后者易于使用。就像您的线条绘制一样，两者都从最后一个点开始绘制，但是，它们分别允许您指定 2 个或 1 个控制点以及目标点的坐标。控制点会导致绘图点之间的弓形效果。

如果这听起来工作量太大(实际比听起来容易)，可以引用 this answer 中的库来满足您的具体要求。 .