本文介紹了ImageView 實現Android colorPikcer 選擇器的示例代碼，分享給大家，具體如下：
Android colorPikcer 選擇器
環形的ColorPicker，主要思路是:
獲取Bitmap
在 ColorPickerView 構造函數中初始化 Bitmap。因為getBackground有多種drawable，然后獲取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); }重寫onTouch
根據Touch 事件的左邊獲取 Bitmap 對應點的顏色。
需要注意的是如果 View 的寬和高參數是 wrap_content, MotionEvent 的點擊的點一定在Bitmap 的坐標內。但是如果不是wrap_content， 需要對坐標轉換，利用矩陣Matrix 對點擊點轉換。
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; }完整的代碼：
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); }}以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持VEVB武林網。
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