话不多说,先上图片
![](https://img.laitimes.com/img/_0nNw4CM6IyYiwiM6ICdiwiIyVGduV2QvwVe0lmdhJ3ZvwFM38CXlZHbvN3cpR2Lc1TPB10QGtWUCpEMJ9CXsxWam9CXwADNvwVZ6l2c052bm9CXUJDT1wkNhVzLcRnbvZ2LcZXUYpVd1kmYr50MZV3YyI2cKJDT29GRjBjUIF2LcRHelR3LcJzLctmch1mclRXY39DO1gzN1gjMyETOycDM2EDMy8CX0Vmbu4GZzNmLn9Gbi1yZtl2Lc9CX6MHc0RHaiojIsJye.jpg)
图1 图2
图3
ScrollerView嵌套RecyclerView
图1:相关推荐下面recyclerView高度设置为wrap_content时,无法显示。
图2:recyclerView中最底下的item显示不全,想必大家也发现了是dividerItemDecoration分割线的原因,其实说是分割线的原因只是表面的,本质上还是MyLinearLayoutManager里面的 onMeasure()的问题。
图1:recyclerView高度设置为wrap_content时,无法显示。
原因:使用的是系统的LinLayoutManager。
我们要自己实现LinearLayoutManager,为什么呢,我们实现这个是干嘛呢?
其实我们实现的MyLinearLayoutManager就是测量计算recyclerView中数据的宽高,也就是重写我们下面的onMeasure
给我们的recyclerView设置自定义的LMyLinearLayoutManager就可以解决图一的问题了。,其实这个效果就是图三的效果
public class MyLinearLayoutManager extends LinearLayoutManager {
private static final String TAG = MyLinearLayoutManager.class.getSimpleName();
public MyLinearLayoutManager(Context context) {
super(context);
}
public MyLinearLayoutManager(Context context, int orientation, boolean reverseLayout) {
super(context, orientation, reverseLayout);
}
private int[] mMeasuredDimension = new int[2];
@Override
public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
int widthSpec, int heightSpec) {
final int widthMode = View.MeasureSpec.getMode(widthSpec);
final int heightMode = View.MeasureSpec.getMode(heightSpec);
final int widthSize = View.MeasureSpec.getSize(widthSpec);
final int heightSize = View.MeasureSpec.getSize(heightSpec);
int width = 0;
int height = 0;
for (int i = 0; i < getItemCount(); i++) {
measureScrapChild(recycler, i,
View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
mMeasuredDimension);
if (getOrientation() == HORIZONTAL) {
width = width + mMeasuredDimension[0];
if (i == 0) {
height = mMeasuredDimension[1];
}
} else {
height = height + mMeasuredDimension[1];
if (i == 0) {
width = mMeasuredDimension[0];
}
}
}
switch (widthMode) {
case View.MeasureSpec.EXACTLY:
width = widthSize;
case View.MeasureSpec.AT_MOST:
case View.MeasureSpec.UNSPECIFIED:
}
switch (heightMode) {
case View.MeasureSpec.EXACTLY:
height = heightSize;
case View.MeasureSpec.AT_MOST:
case View.MeasureSpec.UNSPECIFIED:
}
setMeasuredDimension(width, height);
}
private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
int heightSpec, int[] measuredDimension) {
try {
View view = recycler.getViewForPosition(0);
if (view != null) {
RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
getPaddingLeft() + getPaddingRight(), p.width);
int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
getPaddingTop() + getPaddingBottom(), p.height);
view.measure(childWidthSpec, childHeightSpec);
measuredDimension[0] = view.getMeasuredWidth() + p.leftMargin + p.rightMargin;
measuredDimension[1] = view.getMeasuredHeight() + p.bottomMargin + p.topMargin;
recycler.recycleView(view);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
}
}
}
图2:recyclerView中最底下的item显示不全,想必大家也发现了是dividerItemDecoration分割线的原因,其实说是分割线的原因只是表面的,本质上还是MyLinearLayoutManager里面的 onMeasure()的问题。
有些人就说了这个不是很明显就看出来了吗,这个是我为了让大家看清效果临时改的分割线,之前使用的分割线是和底色一样的颜色,貌似有点逗比,结果就只能看见底下item显示不全的现象,最后我才发现是分割线的原因,所以我们要把分割线给他去掉,当然有些人就说了我就是想加分割线呢,其实就是在MyLinearLayoutManager里面的 onMeasure方法里面把分割线的布局宽高给他算进去就可以,
//添加分割线就会出现recyclerView显示不全的问题
/* hor_dividerItemDecoration = new DividerItemDecoration(BookDetailActivity.this, DividerItemDecoration.VERTICAL_LIST);
refer_recyclerView.addItemDecoration(hor_dividerItemDecoration);*/
因为在之前的onMesure里面没有计算分割线的高度,那么在界面中分割线会占空间,就会把item挤下去,就会导致item显示不全,所以解决方法就是在onMeasure里面给计算上分割线的高度即可,就是图三的效果啦