Android 自定义RecyclerView.ItemDecoration（GridLayoutManager布局下）

来源：互联网发布：甲醇产业链网络协会编辑：程序博客网时间：2024/05/21 09:58

为GridLayoutManager的RecyclerView自定义ItemDecoration分隔符。

效果如下：

这里写图片描述

Item布局xml：

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"              android:layout_width="match_parent"              android:layout_height="wrap_content"              android:gravity="center_horizontal"              android:orientation="vertical"              android:paddingBottom="12dp"              android:paddingTop="11dp">    <TextView        android:id="@+id/metalNameTextView"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="现货黄金"        android:textColor="#333333"        android:textSize="16sp"/>    <TextView        android:id="@+id/metalSellTextView"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_marginBottom="2dp"        android:layout_marginTop="2dp"        android:text="1250.68"        android:textColor="#36BE32"        android:textSize="18sp"/>    <LinearLayout        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:orientation="horizontal">        <TextView            android:id="@+id/metalBuyTextView"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_marginRight="4dp"            android:text="-4.18"            android:textColor="#36BE32"            android:textSize="12sp"/>        <TextView            android:id="@+id/metalPercentTextView"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="-0.23%"            android:textColor="#36BE32"            android:textSize="12sp"/>    </LinearLayout></LinearLayout>

divider_decoration：

<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android">    <gradient        android:centerColor="#ff00ff00"        android:endColor="#ff0000ff"        android:startColor="#ffff0000"        android:type="linear"/>    <size android:height="4dp" android:width="4dp"/></shape>

自定义DividerItemDecoration：

public class DividerItemDecoration extends RecyclerView.ItemDecoration{    private Context mContext;    private Drawable mDivider;    public DividerItemDecoration(Context context)    {        this.mContext = context;        mDivider = context.getResources().getDrawable(R.drawable.divider_decoration);    }    @Override    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state)    {        drawHorizontal(c, parent);        drawVertical(c, parent);    }    //列数    private int getSpanCount(RecyclerView parent)    {        int spanCount = -1;        LayoutManager layoutManager = parent.getLayoutManager();        if (layoutManager instanceof GridLayoutManager)        {            spanCount = ((GridLayoutManager) layoutManager).getSpanCount();        }        return spanCount;    }    //画横线    public void drawHorizontal(Canvas c, RecyclerView parent)    {        int childCount = parent.getChildCount();        for (int i = 0; i < childCount; i++)        {            final View child = parent.getChildAt(i);            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child                    .getLayoutParams();            if (isFirstColum(parent, i, getSpanCount(parent), childCount))//如果是第一列            {                final int left = child.getLeft() + dip2px(15);                final int right = child.getRight() + params.rightMargin                        + mDivider.getIntrinsicWidth();                final int top = child.getBottom() + params.bottomMargin;                final int bottom = top + mDivider.getIntrinsicHeight();                mDivider.setBounds(left, top, right, bottom);                mDivider.draw(c);            } else if (isLastColum(parent, i, getSpanCount(parent), childCount))//如果是最后一列            {                final int left = child.getLeft();                final int right = child.getRight() - dip2px(15);                final int top = child.getBottom() + params.bottomMargin;                final int bottom = top + mDivider.getIntrinsicHeight();                mDivider.setBounds(left, top, right, bottom);                mDivider.draw(c);            } else            {                final int left = child.getLeft();                final int right = child.getRight() + mDivider.getIntrinsicWidth();                final int top = child.getBottom() + params.bottomMargin;                final int bottom = top + mDivider.getIntrinsicHeight();                mDivider.setBounds(left, top, right, bottom);                mDivider.draw(c);            }        }    }    //画竖线    public void drawVertical(Canvas c, RecyclerView parent)    {        final int childCount = parent.getChildCount();        for (int i = 0; i < childCount; i++)        {            final View child = parent.getChildAt(i);            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child                    .getLayoutParams();            if (i < getSpanCount(parent))//如果是第一行            {                final int top = child.getTop() + child.getPaddingTop();                final int bottom = child.getBottom();                final int left = child.getRight() + params.rightMargin;                final int right = left + mDivider.getIntrinsicWidth();                mDivider.setBounds(left, top, right, bottom);                mDivider.draw(c);            } else if (isLastRaw(parent, i, getSpanCount(parent), childCount))//如果是最后一行            {                final int top = child.getTop();                final int bottom = child.getBottom() - child.getPaddingBottom();                final int left = child.getRight() + params.rightMargin;                final int right = left + mDivider.getIntrinsicWidth();                mDivider.setBounds(left, top, right, bottom);                mDivider.draw(c);            } else            {                final int top = child.getTop();                final int bottom = child.getBottom();                final int left = child.getRight() + params.rightMargin;                final int right = left + mDivider.getIntrinsicWidth();                mDivider.setBounds(left, top, right, bottom);                mDivider.draw(c);            }        }    }    //判断是第一列    private boolean isFirstColum(RecyclerView parent, int pos, int spanCount,                                 int childCount)    {        LayoutManager layoutManager = parent.getLayoutManager();        if (layoutManager instanceof GridLayoutManager)        {            if ((pos + 1) % spanCount == 1)            {                return true;            }        }        return false;    }    //判断是最后一列    private boolean isLastColum(RecyclerView parent, int pos, int spanCount,                                int childCount)    {        LayoutManager layoutManager = parent.getLayoutManager();        if (layoutManager instanceof GridLayoutManager)        {            if ((pos + 1) % spanCount == 0)            {                return true;            }        }        return false;    }    //判断是最后一行    private boolean isLastRaw(RecyclerView parent, int pos, int spanCount,                              int childCount)    {        LayoutManager layoutManager = parent.getLayoutManager();        if (layoutManager instanceof GridLayoutManager)        {//            childCount = childCount - childCount % spanCount;//            if (pos >= childCount)//                return true;            int ranger = childCount % spanCount;            if (ranger == 0)            {                ranger = spanCount;            }            childCount = childCount - ranger;            if (pos >= childCount)            {                return true;            }        }        return false;    }    //设置每个item的偏移量，从而展示分割线    @Override    public void getItemOffsets(Rect outRect, int itemPosition,                               RecyclerView parent)    {        int spanCount = getSpanCount(parent);        int childCount = parent.getAdapter().getItemCount();        int marginRight = mDivider.getIntrinsicWidth();        int marginBottom = mDivider.getIntrinsicHeight();        if (isLastRaw(parent, itemPosition, spanCount, childCount))// 如果是最后一行，则不需要绘制底部        {            marginBottom = 0;        }        if (isLastColum(parent, itemPosition, spanCount, childCount))// 如果是最后一列，则不需要绘制右边        {            marginRight = 0;        }        outRect.set(0, 0, marginRight, marginBottom);    }    /**     * 根据手机的分辨率从 dp 的单位 转成为 px(像素)     */    public int dip2px(float dpValue)    {        final float scale = mContext.getResources().getDisplayMetrics().density;        return (int) (dpValue * scale + 0.5f);    }}

最后在RecyclerView中添加自定义分隔符即可：

recyclerView.addItemDecoration(new DividerItemDecoration(this));

参考文章： Android RecyclerView 使用完全解析体验艺术般的控件

阅读全文

0 0