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Android 仿PhotoShop调色板应用(四) 不同区域颜色选择的颜色生成响应
上一篇讲过了主体界面的绘制，这里讲解调色板应用中的另外一个核心: 颜色选择及生成.
ColorPcikerView中不同部分的选择和ColorPickerPanelView中颜色显示是怎样响应的呢？这里当然少不了回调函数:
ColorPickerView:
public interface OnColorChangedListener {public void onColorChanged(int color);}然后看一下轨迹球的事件处理：
@Overridepublic boolean onTrackballEvent(MotionEvent event) {float x = event.getX();float y = event.getY();boolean update = false;//是否需要更新颜色if(event.getAction() == MotionEvent.ACTION_MOVE){switch(mLastTouchedPanel){case PANEL_SAT_VAL://饱和度&亮度选择区域float sat, val;sat = mSat + x/50f;val = mVal - y/50f;if(sat < 0f){sat = 0f;}else if(sat > 1f){sat = 1f;}if(val < 0f){val = 0f;}else if(val > 1f){val = 1f;}mSat = sat;mVal = val;update = true;break;case PANEL_HUE://色相选择区域float hue = mHue - y * 10f;if(hue < 0f){hue = 0f;}else if(hue > 360f){hue = 360f;}mHue = hue;update = true;break;case PANEL_ALPHA://透明度选择区域if(!mShowAlphaPanel || mAlphaRect == null){update = false;}else{int alpha = (int) (mAlpha - x*10);if(alpha < 0){alpha = 0;}else if(alpha > 0xff){alpha = 0xff;}mAlpha = alpha;update = true;}break;}}if(update){//如果需要更新，调用对用的回调函数并重新绘制if(mListener != null){//参数需要由HSV格式的float数组转换为ARGB格式的 int 参数mListener.onColorChanged(Color.HSVToColor(mAlpha, new float[]{mHue, mSat, mVal}));}invalidate();return true;}return super.onTrackballEvent(event);}
ColorPickerView中关于触摸事件的处理:
@Overridepublic boolean onTouchEvent(MotionEvent event) {boolean update = false;switch(event.getAction()){case MotionEvent.ACTION_DOWN:mStartTouchPoint = new Point((int)event.getX(), (int)event.getY());update = moveTrackersIfNeeded(event);break;case MotionEvent.ACTION_MOVE:update = moveTrackersIfNeeded(event);break;case MotionEvent.ACTION_UP:mStartTouchPoint = null;update = moveTrackersIfNeeded(event);break;}if(update){if(mListener != null){mListener.onColorChanged(Color.HSVToColor(mAlpha, new float[]{mHue, mSat, mVal}));}invalidate();return true;}return super.onTouchEvent(event);}//判断是否触发事件，更新区域颜色private boolean moveTrackersIfNeeded(MotionEvent event){if(mStartTouchPoint == null) return false;boolean update = false;//获取触摸点X,Y坐标值int startX = mStartTouchPoint.x;int startY = mStartTouchPoint.y;//判断 X,Y坐标是否在对应的区域内，并做相应的处理 if(mHueRect.contains(startX, startY)){mLastTouchedPanel = PANEL_HUE;mHue = pointToHue(event.getY());update = true;}else if(mSatValRect.contains(startX, startY)){mLastTouchedPanel = PANEL_SAT_VAL;float[] result = pointToSatVal(event.getX(), event.getY());mSat = result[0];mVal = result[1];update = true;}else if(mAlphaRect != null && mAlphaRect.contains(startX, startY)){mLastTouchedPanel = PANEL_ALPHA;mAlpha = pointToAlpha((int)event.getX());update = true;}return update;}使用时，让ColorPickerDialog实现ColorPickerView.OnColorChangedListener接口:
并完成对应方法：
@Overridepublic void onColorChanged(int color) {mNewColor.setColor(color);// mNewColor即为右下角实时显示颜色的ColorPickerPanelViewif (mHexValueEnabled)updateHexValue(color);/*if (mListener != null) {mListener.onColorChanged(color);}*/} private void updateHexValue(int color) {if (getAlphaSliderVisible()) {mHexVal.setText(ColorPickerPreference.convertToARGB(color).toUpperCase(Locale.getDefault()));} else {mHexVal.setText(ColorPickerPreference.convertToRGB(color).toUpperCase(Locale.getDefault()));}mHexVal.setTextColor(mHexDefaultTextColor);} /** 转化为ARGB格式字符串* For custom purposes. Not used by ColorPickerPreferrence* @param color* @author Unknown*/public static String convertToARGB(int color) {String alpha = Integer.toHexString(Color.alpha(color));String red = Integer.toHexString(Color.red(color));String green = Integer.toHexString(Color.green(color));String blue = Integer.toHexString(Color.blue(color));if (alpha.length() == 1) {alpha = "0" + alpha;}if (red.length() == 1) {red = "0" + red;}if (green.length() == 1) {green = "0" + green;}if (blue.length() == 1) {blue = "0" + blue;}return "#" + alpha + red + green + blue;}最后看一下ColorPickerPanelView点击后的颜色设置事件处理:
@Overridepublic void onClick(View v) {if (v.getId() == R.id.new_color_panel) {if (mListener != null) {mListener.onColorChanged(mNewColor.getColor());}}dismiss();}注意一下，这里的OnColorChangedListener是在ColorPickerDialog中定义的:
private OnColorChangedListener mListener;public interface OnColorChangedListener {public void onColorChanged(int color);}最终的颜色是怎么显示到ColorPickerPreference上呢，其实实现的方法是一样的:
implements ColorPickerDialog.OnColorChangedListener在ColorPickerPreference中实现对应的回调方法:
@Overridepublic void onColorChanged(int color) {if (isPersistent()) {persistInt(color);}mValue = color;setPreviewColor();try {getOnPreferenceChangeListener().onPreferenceChange(this, color);} catch (NullPointerException e) {}}调用setPreviewColor()改变ColorPickerPreference中颜色区域的显示:
private void setPreviewColor() {if (mView == null) return;ImageView iView = new ImageView(getContext());LinearLayout widgetFrameView = ((LinearLayout)mView.findViewById(android.R.id.widget_frame));if (widgetFrameView == null) return;widgetFrameView.setVisibility(View.VISIBLE);widgetFrameView.setPadding(widgetFrameView.getPaddingLeft(),widgetFrameView.getPaddingTop(),(int)(mDensity * 8),widgetFrameView.getPaddingBottom());// remove already create preview imageint count = widgetFrameView.getChildCount();if (count > 0) {widgetFrameView.removeViews(0, count);}widgetFrameView.addView(iView);widgetFrameView.setMinimumWidth(0);iView.setBackgroundDrawable(new AlphaPatternDrawable((int)(5 * mDensity)));iView.setImageBitmap(getPreviewBitmap());}最后调用getOnPreferenceChangeListener().onPreferenceChange(this, color);改变颜色设置值
然后在下次打开ColorPickerDialog时，传入上面onColorChanged()回调实现中已经改变的mValue参数
mDialog = new ColorPickerDialog(getContext(), mValue);至此，PS调色板应用中颜色交互的事件讲解完毕.
相信当分析完PhotoShop调色板应用后，大家会对颜色渲染方面会有一个认识上的提高.
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