DiliderGridView

package com.lidd.view;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.View;
import android.widget.GridView;

public class DividerGridView extends GridView {

    private int columnNum;
    private int childNum;

    private Drawable leftDividerDrawable;
    private Drawable bottomDividerDrawable;

    public DividerGridView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public DividerGridView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public DividerGridView(Context context) {
        super(context);
    }



    public void setLeftDividerDrawable(Drawable leftDividerDrawable) {
        this.leftDividerDrawable = leftDividerDrawable;
    }



    public void setBottomDividerDrawable(Drawable bottomDividerDrawable) {
        this.bottomDividerDrawable = bottomDividerDrawable;
    }

    private void drawLeft(Canvas canvas,View itemView){

        int top = itemView.getTop();
        int bottom = itemView.getBottom();
        int right = itemView.getRight();
        int left = right - leftDividerDrawable.getIntrinsicWidth();

        leftDividerDrawable.setBounds(left, top, right, bottom);
        leftDividerDrawable.draw(canvas);

    }

    private void drawBottom(Canvas canvas,View itemView){

        int left = itemView.getLeft();
        int  right = itemView.getRight();
        int bottom = itemView.getBottom();
        int top = bottom - bottomDividerDrawable.getIntrinsicHeight();
        bottomDividerDrawable.setBounds(left, top, right, bottom);
        bottomDividerDrawable.draw(canvas);

    }

    private boolean isLastRight(int pos,int spanClounm){

        return (pos+1) % spanClounm == 0;

    }

    private int getColunmNum(int num,int spanClounm){


        return num / spanClounm + (((num % spanClounm) > 0)? 1:0);

    }

    private boolean isLastBottom(int pos,int allNums,int spanClounm){

        return getColunmNum(pos+1,spanClounm) == getColunmNum(allNums,spanClounm);

    }

    @Override
    protected void dispatchDraw(Canvas canvas) {
        super.dispatchDraw(canvas);

        View child0 = getChildAt(0);
        columnNum = getWidth() / child0.getWidth();
        childNum = getChildCount();

        // 底部是否需要 分割线
        //      for (int i = 0; i < childNum; i++) {
        //          
        //          if(isLastRight(i,columnNum)){
        //              
        //              if(!isLastBottom(i,childNum,columnNum)){
        //                  
        //                  drawBottom(canvas,getChildAt(i));
        //                  
        //              }
        //              
        //          }else if(isLastBottom(i,childNum,columnNum)){
        //              
        //              drawLeft(canvas,getChildAt(i));
        //              
        //          }else{
        //              
        //              drawLeft(canvas,getChildAt(i));
        //              drawBottom(canvas,getChildAt(i));
        //          }
        //      }

        for (int i = 0; i < childNum; i++) {

            if(isLastRight(i,columnNum)){


                drawBottom(canvas,getChildAt(i));


            }else{

                drawLeft(canvas,getChildAt(i));
                drawBottom(canvas,getChildAt(i));
            }
        }

    }


}