Question

我正在尝试制作一个颜色选择器，允许用户通过简单的触摸输入来选择颜色。我的hueShade给色环提供了色调，而饱和度给出了色调我把鳕鱼从中心掏出来。 SweepGradient不需要半径，但Radial Gradient确实需要它。但是，我在创建时调用它时无法获得宽度和高度的实际值。相反，它会获取所述的值。是否存在可在该信息可用时设置半径的中间步骤？或者我应该尝试不同的方法吗？

private Paint mPaint;
private int[] mColors;

private int viewWidth = 120;
private int viewHeight = 120;
private int centerX = 60;
private int centerY = 60;
private int padding = 10;

public ColorWheelView(Context context) {
    super(context);
    onInitialize();
    // TODO Auto-generated constructor stub
}


private void onInitialize()
{

    mColors = new int[] {
            0xFFFF0000, 0xFFFF00FF, 0xFF0000FF, 0xFF00FFFF, 0xFF00FF00,
            0xFFFFFF00, 0xFFFF0000
        };

        Shader totalShade = new SweepGradient(0, 0, mColors, null);
        Shader hueShade = new SweepGradient(0, 0, mColors, null);
        Shader saturationShade = new RadialGradient(0, 0, (float)viewWidth-padding, 0xFFFFFFFF, 0x00FFFFFF, Shader.TileMode.CLAMP);
        //Shader valueShade;

        totalShade = new ComposeShader(hueShade, saturationShade, PorterDuff.Mode.SCREEN);

        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setShader(totalShade);
        mPaint.setStyle(Paint.Style.FILL);
}

protected void onSizeChanged(int xNew, int yNew, int xOld, int yOld) 
{
    super.onSizeChanged(xNew, yNew, xOld, yOld);
    viewWidth = xNew;
    viewHeight = yNew;
    centerX = viewWidth / 2;
    centerY = viewHeight / 2;
}

protected void onLayout(boolean changed, int left, int top, int right, int bottom)
{
    super.onLayout(changed, left, top, right, bottom);
    viewWidth = right - left;
    viewHeight = bottom - top;
    centerX = viewWidth / 2;
    centerY = viewHeight / 2;
}

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    int measuredHeight = measureHeight(heightMeasureSpec);
    int measuredWidth = measureWidth(widthMeasureSpec);
    setMeasuredDimension(measuredWidth, measuredHeight);
}

如果它有助于弄清楚我正在实现的目标，我正在努力使这个视图可用于不同尺寸的屏幕。这就是我需要设备信息的原因。

Answer 1

最好在onLayout中调用它，因为当执行任何大小或方向的更改时，通常会保证这一点。我以前没有获得所需的值，但那是因为我继承了Android.view.View类以外的基类。

自定义视图中的RadialGradient

1 个答案: