ColorPickerDialog.java

package com.bosi.chineseclass.views.paint;

import android.os.Bundle;
import android.app.Dialog;
import android.content.Context;
import android.graphics.*;
import android.view.MotionEvent;
import android.view.View;
import android.widget.LinearLayout;

public class ColorPickerDialog extends Dialog {

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

	private OnColorChangedListener mListener;
	private int mInitialColor;
	private Context context;

	private static class ColorPickerView extends View {
		private Paint mPaint;
		private Paint mCenterPaint;
		private Paint mHSVPaint;
		private final int[] mColors;
		private int[] mHSVColors;
		private boolean mRedrawHSV;
		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(80);

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

			mHSVColors = new int[] { 0xFF000000, color, 0xFFFFFFFF };

			mHSVPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
			mHSVPaint.setStrokeWidth(10);

			mRedrawHSV = true;

		}

		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);
			int c = mCenterPaint.getColor();

			if (mRedrawHSV) {
				mHSVColors[1] = c;
				mHSVPaint.setShader(new LinearGradient(-100, 0, 100, 0,
						mHSVColors, null, Shader.TileMode.CLAMP));
			}

			canvas.drawOval(new RectF(-r, -r, r, r), mPaint);
			canvas.drawCircle(0, 0, CENTER_RADIUS, mCenterPaint);
			canvas.drawRect(new RectF(-150, 200, 150, 160), mHSVPaint);

			if (mTrackingCenter) {
				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);
			}

			mRedrawHSV = true;
		}

		@Override
		protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
			setMeasuredDimension(CENTER_X * 2, (CENTER_Y + 25) * 2);
		}

		private static final int CENTER_X = 150;
		private static final int CENTER_Y = 150;
		private static final int CENTER_RADIUS = 50;

		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 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 if ((x >= -150 & x <= 150) && (y <= 200 && y >= 160))
				// see
				// if
				// we're
				// in
				// the
				// hsv
				// slider
				{
					int a, r, g, b, c0, c1;
					float p;

					// set the center paint to this color
					if (x < 0) {
						c0 = mHSVColors[0];
						c1 = mHSVColors[1];
						p = (x + 150) / 150;
					} else {
						c0 = mHSVColors[1];
						c1 = mHSVColors[2];
						p = x / 150;
					}

					a = ave(Color.alpha(c0), Color.alpha(c1), p);
					r = ave(Color.red(c0), Color.red(c1), p);
					g = ave(Color.green(c0), Color.green(c1), p);
					b = ave(Color.blue(c0), Color.blue(c1), p);

					mCenterPaint.setColor(Color.argb(a, r, g, b));

					mRedrawHSV = false;
					invalidate();
				}//ȷ������ѡ���������
				else if ((Math.pow(x, 2) + Math.pow(y, 2)) < 150 * 150) {
					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);
		this.context = 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();
			}
		};
		LinearLayout layout = new LinearLayout(context);
		layout.addView(new ColorPickerView(getContext(), l, mInitialColor));
		layout.setPadding(30, 20, 20, 30);
		setContentView(layout);
		setCanceledOnTouchOutside(true);
		setTitle("颜色选择");
	}
}