BaseRecyclerViewAdapterHelper 网格边距

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="38px"
        >
        <TextView
            android:id="@+id/text1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="标签"
            android:paddingLeft="24px"
            android:paddingTop="12px"

            android:textStyle="bold"
            />
        <TextView
            android:id="@+id/text2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="全选"
            android:paddingRight="24px"
            android:paddingTop="12px"

            android:layout_alignParentRight="true"
            />
    </RelativeLayout>

</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    >
    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        >
        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:id="@+id/rl"


            >
            <ImageView
                android:id="@+id/img"
                android:layout_width="match_parent"
                android:layout_height="match_parent"

                android:layout_centerInParent="true"
                android:background="#c00"
                />
            <ImageView
                android:id="@+id/icon_img"
                android:layout_width="20px"
                android:layout_height="20px"
                android:scaleType="centerCrop"
                android:layout_alignParentRight="true"
                android:layout_margin="4px"

                />
        </RelativeLayout>
    </RelativeLayout>



</LinearLayout>

package me.jessyan.mvparms.demo.mvp.ui.activity;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.support.annotation.ColorInt;
import android.support.v7.widget.RecyclerView;
import android.util.TypedValue;
import android.view.View;

/**
 * 给 RecyclerView item 设置边距，
 * 构造函数需要传入 context，要设置的边距宽度（单位：dp），边距颜色
 * 使用示例：
 *
 mRecyclerView.setLayoutManager(new GridLayoutManager(_mActivity, 2));
 int color = getResources().getColor(R.color.gray);
 mRecyclerView.addItemDecoration(new GridItemDecoration(_mActivity, 8, color) {
@Override
public boolean[] getItemSidesIsHaveOffsets(int itemPosition) {
//顺序:left, top, right, bottom
boolean[] booleans = {false, false, false, false};
if (itemPosition == 0) {
//因为给 RecyclerView 添加了 header，所以原本的 position 发生了变化
//position 为 0 的地方实际上是 header，真正的列表 position 从 1 开始
} else {
switch (itemPosition % 2) {
case 0:
//每一行第二个只显示左边距和下边距
booleans[0] = true;
booleans[3] = true;
break;
case 1:
//每一行第一个显示右边距和下边距
booleans[2] = true;
booleans[3] = true;
break;
}
}
return booleans;
}
});
 */

public abstract class GridItemDecoration extends RecyclerView.ItemDecoration {

    private Paint mPaint;
    private int   lineWidth;//px 分割线宽

    public GridItemDecoration(Context context, float lineWidthPX, @ColorInt int colorRGB) {
        this.lineWidth = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_PX, lineWidthPX, context.getResources().getDisplayMetrics());
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setColor(colorRGB);
        mPaint.setStyle(Paint.Style.FILL);
    }

    public GridItemDecoration(Context context, int lineWidthPX, @ColorInt int colorRGB) {
        this(context, (float) lineWidthPX, colorRGB);
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
        //left, top, right, bottom
        int childCount1 = parent.getChildCount();
        //        int childCount2 = parent.getLayoutManager().getChildCount();
        //        int childCount3 = parent.getAdapter().getItemCount();
        //        Log.e("count", "getChildCount()=" + childCount1 + "-----getLayoutManager().getChildCount()=" + childCount2 + "----getAdapter().getItemCount()=" + childCount3);
        for (int i = 0; i < childCount1; i++) {
            View child = parent.getChildAt(i);

            int itemPosition = ((RecyclerView.LayoutParams) child.getLayoutParams()).getViewLayoutPosition();

            boolean[] sideOffsetBooleans = getItemSidesIsHaveOffsets(itemPosition);
            if (sideOffsetBooleans[0]) {
                drawChildLeftVertical(child, c, parent);
            }
            if (sideOffsetBooleans[1]) {
                drawChildTopHorizontal(child, c, parent);
            }
            if (sideOffsetBooleans[2]) {
                drawChildRightVertical(child, c, parent);
            }
            if (sideOffsetBooleans[3]) {
                drawChildBottomHorizontal(child, c, parent);
            }
        }
    }

    private void drawChildBottomHorizontal(View child, Canvas c, RecyclerView parent) {
        RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                .getLayoutParams();
        int left = child.getLeft() - params.leftMargin - lineWidth;
        int right = child.getRight() + params.rightMargin + lineWidth;
        int top = child.getBottom() + params.bottomMargin;
        int bottom = top + lineWidth;

        c.drawRect(left, top, right, bottom, mPaint);
    }

    private void drawChildTopHorizontal(View child, Canvas c, RecyclerView parent) {
        RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                .getLayoutParams();
        int left = child.getLeft() - params.leftMargin - lineWidth;
        int right = child.getRight() + params.rightMargin + lineWidth;
        int bottom = child.getTop() - params.topMargin;
        int top = bottom - lineWidth;

        c.drawRect(left, top, right, bottom, mPaint);
    }

    private void drawChildLeftVertical(View child, Canvas c, RecyclerView parent) {
        RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                .getLayoutParams();
        int top = child.getTop() - params.topMargin - lineWidth;
        int bottom = child.getBottom() + params.bottomMargin + lineWidth;
        int right = child.getLeft() - params.leftMargin;
        int left = right - lineWidth;

        c.drawRect(left, top, right, bottom, mPaint);
    }

    private void drawChildRightVertical(View child, Canvas c, RecyclerView parent) {
        RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                .getLayoutParams();
        int top = child.getTop() - params.topMargin - lineWidth;
        int bottom = child.getBottom() + params.bottomMargin + lineWidth;
        int left = child.getRight() + params.rightMargin;
        int right = left + lineWidth;

        c.drawRect(left, top, right, bottom, mPaint);
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        //outRect 看源码可知这里只是把Rect类型的outRect作为一个封装了left,right,top,bottom的数据结构,
        //作为传递left,right,top,bottom的偏移值来用的
        int itemPosition = ((RecyclerView.LayoutParams) view.getLayoutParams()).getViewLayoutPosition();
        boolean[] sideOffsetBooleans = getItemSidesIsHaveOffsets(itemPosition);

        //如果是设置左边或者右边的边距，就只设置成指定宽度的一半，
        // 因为这个项目中的 Grid 是一行二列，如果不除以二的话，那么中间的间距就会很宽，
        //可根据实际项目需要修改成合适的值
        int left = sideOffsetBooleans[0] ? lineWidth/2 : 0;
        int top = sideOffsetBooleans[1] ? lineWidth : 0;
        int right = sideOffsetBooleans[2] ? lineWidth/2 : 0;
        int bottom = sideOffsetBooleans[3] ? lineWidth : 0;

        outRect.set(left, top, right, bottom);
    }

    /**
     * 顺序:left, top, right, bottom
     *
     * @return boolean[4]
     */
    public abstract boolean[] getItemSidesIsHaveOffsets(int itemPosition);


}

public void getData(){
    list=new ArrayList<>();
    PhotoListFooterAdapterBean bean=null;
    for (int i = 0; i <100 ; i++) {
        bean=new PhotoListFooterAdapterBean();
        bean.setItemType(PhotoListFooterAdapterBean.ITEM_I);
        list.add(bean);
    }

    for (int i = 0; i <20 ; i++) {
        int min=0;
        int max=list.size();
        Random random = new Random();
        int num = random.nextInt(max)%(max-min+1) + min;
        bean=new PhotoListFooterAdapterBean();
        bean.setItemType(PhotoListFooterAdapterBean.ITEM_T);

        list.add(num,bean);

        Timber.e(num+"###"+max);
    }

    int tempnum=0;

    for (int i = 0; i <list.size() ; i++) {
        PhotoListFooterAdapterBean bean1 = list.get(i);
        if ( bean1.getItemType()==PhotoListFooterAdapterBean.ITEM_T){
            tempnum=0;
        }else if (bean1.getItemType()==PhotoListFooterAdapterBean.ITEM_I){
            bean1.setTypeNum(tempnum);
            tempnum++;

        }
    }


}

rl2.addItemDecoration(new GridItemDecoration(this, 10, color) {
    @Override
    public boolean[] getItemSidesIsHaveOffsets(int itemPosition) {
        boolean[] booleans = {false, false, false, false};

        PhotoListFooterAdapterBean bean = list.get(itemPosition);
        if (bean.getItemType()==PhotoListFooterAdapterBean.ITEM_I){
            int typeNum = bean.getTypeNum();
            if (typeNum%4==0){
                //  booleans[0] = true;
                booleans[1] = true;
                booleans[2] = true;


            }

            if (typeNum%4==1){
                booleans[0] = true;
                booleans[1] = true;
                booleans[2] = true;

            }
            if (typeNum%4==2){
                booleans[0] = true;
                booleans[1] = true;
                booleans[2] = true;

            }
            if (typeNum%4==3){
                booleans[0] = true;
                booleans[1] = true;
                //booleans[2] = true;



            }


        }
       
        return booleans;
    }
});

GridLayoutManager footLayoutManager = new GridLayoutManager(this, 4);

BaseRecyclerViewAdapterHelper 网格 边距

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BaseRecyclerViewAdapterHelper 网格边距