Question

我一直在寻找如何实施颜色选择器，我找到this
@Raghunandan精彩的答案很好用。

唯一的问题是：

我无法将视图集中在对话框上，它始终位于对话框的左上角。我甚至无法设置填充。任何人都知道如何解决这个问题？

如果可能，如何将对话框主题更改为Holo（黑色），我的整个应用程序都使用此主题。

[EDITED]

代码是：

public class ColorPickerDialog extends Dialog {

public interface OnColorChangedListener {
    void colorChanged(int color);
}

private OnColorChangedListener mListener;
private int mInitialColor;

private static class ColorPickerView extends View {
    private Paint mPaint;
    private Paint mCenterPaint;
    private final int[] mColors;
    private OnColorChangedListener mListener;

    ColorPickerView(Context c, OnColorChangedListener l, int color) {
        super(c);
        mListener = l;
        mColors = new int[] {
            0xFFFF0000, 0xFFFF00FF, 0xFF0000FF, 0xFF00FFFF, 0xFF00FF00,
            0xFFFFFF00, 0xFFFF0000
        };
        Shader s = new SweepGradient(0, 0, mColors, null);

        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setShader(s);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeWidth(32);

        mCenterPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mCenterPaint.setColor(color);
        mCenterPaint.setStrokeWidth(5);
    }

    private boolean mTrackingCenter;
    private boolean mHighlightCenter;

    @Override
    protected void onDraw(Canvas canvas) {
        float r = CENTER_X - mPaint.getStrokeWidth()*0.5f;

        canvas.translate(CENTER_X, CENTER_X);

        canvas.drawOval(new RectF(-r, -r, r, r), mPaint);
        canvas.drawCircle(0, 0, CENTER_RADIUS, mCenterPaint);

        if (mTrackingCenter) {
            int c = mCenterPaint.getColor();
            mCenterPaint.setStyle(Paint.Style.STROKE);

            if (mHighlightCenter) {
                mCenterPaint.setAlpha(0xFF);
            } else {
                mCenterPaint.setAlpha(0x80);
            }
            canvas.drawCircle(0, 0,
                              CENTER_RADIUS + mCenterPaint.getStrokeWidth(),
                              mCenterPaint);

            mCenterPaint.setStyle(Paint.Style.FILL);
            mCenterPaint.setColor(c);
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        setMeasuredDimension(CENTER_X*2, CENTER_Y*2);
    }

    private static final int CENTER_X = 100;
    private static final int CENTER_Y = 100;
    private static final int CENTER_RADIUS = 32;

    private int floatToByte(float x) {
        int n = java.lang.Math.round(x);
        return n;
    }
    private int pinToByte(int n) {
        if (n < 0) {
            n = 0;
        } else if (n > 255) {
            n = 255;
        }
        return n;
    }

    private int ave(int s, int d, float p) {
        return s + java.lang.Math.round(p * (d - s));
    }

    private int interpColor(int colors[], float unit) {
        if (unit <= 0) {
            return colors[0];
        }
        if (unit >= 1) {
            return colors[colors.length - 1];
        }

        float p = unit * (colors.length - 1);
        int i = (int)p;
        p -= i;

        // now p is just the fractional part [0...1) and i is the index
        int c0 = colors[i];
        int c1 = colors[i+1];
        int a = ave(Color.alpha(c0), Color.alpha(c1), p);
        int r = ave(Color.red(c0), Color.red(c1), p);
        int g = ave(Color.green(c0), Color.green(c1), p);
        int b = ave(Color.blue(c0), Color.blue(c1), p);

        return Color.argb(a, r, g, b);
    }

    private int rotateColor(int color, float rad) {
        float deg = rad * 180 / 3.1415927f;
        int r = Color.red(color);
        int g = Color.green(color);
        int b = Color.blue(color);

        ColorMatrix cm = new ColorMatrix();
        ColorMatrix tmp = new ColorMatrix();

        cm.setRGB2YUV();
        tmp.setRotate(0, deg);
        cm.postConcat(tmp);
        tmp.setYUV2RGB();
        cm.postConcat(tmp);

        final float[] a = cm.getArray();

        int ir = floatToByte(a[0] * r +  a[1] * g +  a[2] * b);
        int ig = floatToByte(a[5] * r +  a[6] * g +  a[7] * b);
        int ib = floatToByte(a[10] * r + a[11] * g + a[12] * b);

        return Color.argb(Color.alpha(color), pinToByte(ir),
                          pinToByte(ig), pinToByte(ib));
    }

    private static final float PI = 3.1415926f;

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        float x = event.getX() - CENTER_X;
        float y = event.getY() - CENTER_Y;
        boolean inCenter = java.lang.Math.sqrt(x*x + y*y) <= CENTER_RADIUS;

        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                mTrackingCenter = inCenter;
                if (inCenter) {
                    mHighlightCenter = true;
                    invalidate();
                    break;
                }
            case MotionEvent.ACTION_MOVE:
                if (mTrackingCenter) {
                    if (mHighlightCenter != inCenter) {
                        mHighlightCenter = inCenter;
                        invalidate();
                    }
                } else {
                    float angle = (float)java.lang.Math.atan2(y, x);
                    // need to turn angle [-PI ... PI] into unit [0....1]
                    float unit = angle/(2*PI);
                    if (unit < 0) {
                        unit += 1;
                    }
                    mCenterPaint.setColor(interpColor(mColors, unit));
                    invalidate();
                }
                break;
            case MotionEvent.ACTION_UP:
                if (mTrackingCenter) {
                    if (inCenter) {
                        mListener.colorChanged(mCenterPaint.getColor());
                    }
                    mTrackingCenter = false;    // so we draw w/o halo
                    invalidate();
                }
                break;
        }
        return true;
    }
}

public ColorPickerDialog(Context context,
                         OnColorChangedListener listener,
                         int initialColor) {
    super(context);

    mListener = listener;
    mInitialColor = initialColor;
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    OnColorChangedListener l = new OnColorChangedListener() {
        public void colorChanged(int color) {
            mListener.colorChanged(color);
            dismiss();
        }
    };

    setContentView(new ColorPickerView(getContext(), l, mInitialColor));
    setTitle("Pick a Color");
 }
}

并exib对话框：

button.setOnClickListener(new OnClickListener(){
    public void OnClick(View v){
          //param - context / listener / inicialColor
          new ColorPickerDialog(MainActivity.this, this, Color.RED).show();
    }  
});

Answer 1

选项1：

在自定义视图中，您可以像这样覆盖onSizeChanged：

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    width = w;
    height = h;

    // Move your calculation logic here.
    super.onSizeChanged(w, h, oldw, oldh);
}

这样，当您将视图设置为对话框的内容时，您就知道它的大小。在onDraw（）方法中了解这一点，您可以使用width / 2和height / 2轻松计算视图的中心。您可以修改绘制调用以在中心绘制：

 int centerX = widht / 2;
 int centerY = height / 2;
 int offset = *Your required view size here* / 2;
 canvas.drawOval(new RectF(centerX - offset, 0, centerX + offset, height), mPaint);
 canvas.drawCircle(centerX, centerY, CENTER_RADIUS, mCenterPaint);

这样，视图将水平居中绘制并填充所有高度。如果需要，也可以使用与rect的左右坐标相同的方式垂直居中。另外，避免在onDraw（）方法中分配对象是一个好习惯，因为根据视图，它可能被调用很多次（在动画期间等）。一旦知道了视图的大小，就可以在onSizeChanged（）中计算你的RectF。

选项2：

在将对象添加到对话框时，只需设置正确的布局参数，就可以避免修改自定义视图。如果我没记错的话，Dialog使用ViewGroup.LayoutParams。他们没有重力场。因此，在您创建的对话框中，您可以将视图包裹在LinearLayout或任何其他支持重力的视图中，并将中心引力设置为您的视图：

LinearLayout layout = new LinearLayout(getContext());

YourView view = new ColorPickerView(getContext(), l, mInitialColor);
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(*Width of you view or wrap_content*,*height of your view or wrap_content*);
params.gravity = Gravity.CENTER_HORIZONTAL;
view.setLayoutParams(params);

layout.addView(view)
setContentView(layout);

将重力和填充设置为视图

1 个答案: