ImageView 实现Android colorPikcer 选择器的示例代码

本文介绍了ImageView 实现Android colorPikcer 选择器的示例代码，分享给大家，具体如下：

Android colorPikcer 选择器

环形的ColorPicker，主要思路是:

1. Color 选在放在ImageView 的background上面，根据点击的位置判断选择的颜色。

2. 重写onTouch，在onTouch 里面判断点击点的颜色。

3. 根据当前选择的颜色设置图片的src.

获取Bitmap

在 ColorPickerView 构造函数中初始化 Bitmap。因为getBackground有多种drawable，然后获取Bitmap 的方式也不用，

void init(Context context, @Nullable AttributeSet attrs, int defStyleAttr){
   Drawable drawable = getBackground();
   if(drawable instanceof BitmapDrawable){
     mBitmap = ((BitmapDrawable) drawable).getBitmap();
   } else if(drawable instanceof VectorDrawable){
     mBitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
     Canvas vectorCanvas = new Canvas(mBitmap);
     drawable.setBounds(0, 0, vectorCanvas.getWidth(), vectorCanvas.getHeight());
     drawable.draw(vectorCanvas);
   }

重写onTouch

根据Touch 事件的左边获取 Bitmap 对应点的颜色。

需要注意的是如果 View 的宽和高参数是 wrap_content, MotionEvent 的点击的点一定在Bitmap 的坐标内。但是如果不是wrap_content， 需要对坐标转换，利用矩阵Matrix 对点击点转换。

public boolean onTouch(View v, MotionEvent event) {

if (event.getAction() == MotionEvent.ACTION_DOWN && mBitmap != null) {

float scaleX = mBitmap.getWidth()*1.0f/v.getWidth();
     float scaleY = mBitmap.getHeight()*1.0f/v.getHeight();

float[] touchPoint = new float[] { event.getX(), event.getY() };
     Matrix matrix = new Matrix();
     matrix.setScale(scaleX, scaleY);
     matrix.mapPoints(touchPoint);

mSelectColor = mBitmap.getPixel((int) touchPoint[0], (int) touchPoint[1]);
   }

return false;
 }

完整的代码：

public class ColorPickerView extends android.support.v7.widget.AppCompatImageView implements View.OnTouchListener{

private Bitmap mBitmap;
 private int mSelectColor = -1;
 private int mIndex = -1;
 private int[] mDrawableSelects;
 private int[] mColorArray;

private OnColorSelectedListener mOnColorSelectedListener;

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

public ColorPickerView(Context context, @Nullable AttributeSet attrs) {
   this(context, attrs, 0);
 }

public ColorPickerView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
   super(context, attrs, defStyleAttr);
   init(context, attrs, defStyleAttr);
 }

void init(Context context, @Nullable AttributeSet attrs, int defStyleAttr){
   Drawable drawable = getBackground();
   if(drawable instanceof BitmapDrawable){
     mBitmap = ((BitmapDrawable) drawable).getBitmap();
   } else if(drawable instanceof VectorDrawable){
     mBitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
     Canvas vectorCanvas = new Canvas(mBitmap);
     drawable.setBounds(0, 0, vectorCanvas.getWidth(), vectorCanvas.getHeight());
     drawable.draw(vectorCanvas);
   }

TypedArray resTypeArray = context.obtainStyledAttributes(attrs, R.styleable.ColorPickerView);
   int colorPickerArrayId = resTypeArray.getResourceId(R.styleable.ColorPickerView_cp_selected_drawable_array, 0);
   resTypeArray.recycle();

if (colorPickerArrayId != 0) {
     TypedArray typeArray = getResources().obtainTypedArray(colorPickerArrayId);
     mDrawableSelects = new int[typeArray.length()];
     for (int i = 0; i < typeArray.length(); i++) {
       mDrawableSelects[i] = typeArray.getResourceId(i, 0);
     }
     typeArray.recycle();
   }

setOnTouchListener(this);
 }

@Override
 public boolean onTouch(View v, MotionEvent event) {

if (event.getAction() == MotionEvent.ACTION_DOWN && mBitmap != null) {
     if(event.getX() > v.getWidth() || event.getX() < 0){
       return false;
     }

if(event.getY() > v.getHeight() || event.getY() < 0){
       return false;
     }

float scaleX = mBitmap.getWidth()*1.0f/v.getWidth();
     float scaleY = mBitmap.getHeight()*1.0f/v.getHeight();

float[] touchPoint = new float[] { event.getX(), event.getY() };
     Matrix matrix = new Matrix();
     matrix.setScale(scaleX, scaleY);
     matrix.mapPoints(touchPoint);

mSelectColor = mBitmap.getPixel((int) touchPoint[0], (int) touchPoint[1]);
     mIndex = getColorIndex(mSelectColor);

if(mDrawableSelects.length > 0 && mIndex >=0 && mIndex < mDrawableSelects.length) {
       ((ImageView) v).setImageResource(mDrawableSelects[mIndex]);
     }

if(mOnColorSelectedListener != null){
       mOnColorSelectedListener.onColorSelected(mIndex, mSelectColor);
     }
   }

return false;
 }

private int getColorIndex(int color){

for (int i = 0 ; i < mColorArray.length; i++){
     if(color == mColorArray[i]){
       return i;
     }
   }

return -1;
 }

public void setSelectColorArray(int[] array) {
   mColorArray = array;
 }

public void setSelectDrawableIdArray(int[] idArray){
   mDrawableSelects = idArray;
 }

public int getIndex(){
   return mIndex;
 }

public int getSelectColor(){
   return mSelectColor;
 }

public void setOnColorSelectedListener(OnColorSelectedListener listener){
   mOnColorSelectedListener = listener;
 }

public interface OnColorSelectedListener{
   void onColorSelected(int index , int color);
 }
}

来源：http://www.jianshu.com/p/b6f558509daa?utm_source=tuicool&utm_medium=referral