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);
  }
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。