android 调色盘颜色选取

先来张效果图

android 调色盘颜色选取_第1张图片

主要是继承View的类,通过Paint的画笔类,对小圆点即选择的位置做区域限制,获取到当前选择区域的像素转换成rgb。

核心类ColorPickerView

public class ColorPickerView extends View   {

   private Context mContext;
   private Paint mRightPaint;            //画笔
   private int mHeight;                  //view高
   private int mWidth;                   //view宽
   private Bitmap mLeftBitmap;
   private Bitmap bitmapTemp;

   private Paint mBitmapPaint;//画笔
   private PointF mLeftSelectPoint;//坐标
   private OnColorBackListener onColorBackListener;
   private int mLeftBitmapRadius;
   public String colorStr="";
   private int initX = 0;
   private int initY = 0;
   private int r;//半径

   public ColorPickerView(Context context) {
      this(context, null);
   }

   public ColorPickerView(Context context, AttributeSet attrs) {
      super(context, attrs);
      mContext = context;
      init();
   }

   public void setOnColorBackListener(OnColorBackListener listener) {
      onColorBackListener = listener;
   }

   //初始化资源与画笔
   private void init() {
      bitmapTemp = BitmapFactory.decodeResource(getResources(), R.drawable.color_wheel);
      mRightPaint = new Paint();
      mRightPaint.setStyle(Paint.Style.FILL);
      mRightPaint.setStrokeWidth(1);
      mBitmapPaint = new Paint();

      mLeftBitmap = BitmapFactory.decodeResource(mContext.getResources(), R.drawable.color_wheel_dot);
      mLeftBitmapRadius = mLeftBitmap.getWidth() / 2;
      //获取圆心
      initX = bitmapTemp.getWidth() / 2;
      initY = bitmapTemp.getHeight() / 2;
      r = bitmapTemp.getHeight() / 2;
      mLeftSelectPoint = new PointF(0, 0);
   }

   //important patient please!!!
   @Override
   protected void onDraw(Canvas canvas) {
      canvas.drawBitmap(bitmapTemp , null , new Rect(0, 0, mWidth , mHeight ), mBitmapPaint);
      if(mLeftSelectPoint.x != 0 || mLeftSelectPoint.y != 0){
         canvas.drawBitmap(mLeftBitmap, mLeftSelectPoint.x - mLeftBitmapRadius,
               mLeftSelectPoint.y - mLeftBitmapRadius, 

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