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);
  }
}

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