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));
}
}

}

}