一、添加依赖
app.gradle里添加依赖：
compile 'com.android.support:recyclerview-v7:26.+'如果使用的是androidx：
implementation 'androidx.recyclerview:recyclerview:1.1.0'二、基本使用方法
1、activity的xml布局
就是写一个RecyclerView的控件：
<?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="match_parent">
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:scrollbars="horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>2、列表的item布局
随意写了一下，此处纯展示功能，所以就写了个TextView：
<?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:background="#d4d2d2"
android:layout_height="wrap_content">
<TextView
android:id="@+id/tv_item"
android:layout_width="match_parent"
android:background="#FFFFFF"
android:layout_height="200dp"
android:layout_margin="10dp"
android:gravity="center"
android:textSize="22sp"
android:text="item"/>
</LinearLayout>3、Adapter
public class InfoRecyclerViewAdapter extends RecyclerView.Adapter<InfoRecyclerViewAdapter.ViewHolder> {
private ArrayList<String> mData;
private Context mContext;//记录一个Context，如果以后需要弹出个提示框这种的，也好用
/**
* 事件回调监听
*/
private InfoRecyclerViewAdapter.OnItemClickListener onItemClickListener;
public InfoRecyclerViewAdapter(Context context,ArrayList<String> data) {
this.mContext = context;
this.mData = data;
}
public InfoRecyclerViewAdapter(Context context) {
this.mContext = context;
}
/**
* 新增数据：得到此次选择的数据后，更新数据
*/
public void initData(ArrayList<String> data,int pageIndex) {
if (mData == null) {
mData = new ArrayList<>();
}
if(pageIndex == 0){//现在增加的是第一页数据，则清除之前的数据
mData.clear();
}
if (data != null) {
int start = mData.size();
mData.addAll(data);
int count = mData.size() - start;
notifyItemRangeChanged(start, count);
}
}
/**
* 提供给外部获取数据源的方法
*/
public List<String> getDatas() {
List<String> list = new ArrayList<>(mData);
return list;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view;
// 实例化展示的view
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_list_vertical, parent, false);
// 实例化viewholder
ViewHolder viewHolder = new ViewHolder(view);
return viewHolder;
}
@Override
public void onBindViewHolder(final ViewHolder holder, int position) {
// 绑定数据
holder.tvItem.setText(mData.get(position));
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(final View v) {
if(onItemClickListener != null) {
int pos = holder.getLayoutPosition();
onItemClickListener.onItemClick(holder.itemView, pos);
}
}
});
holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
if(onItemClickListener != null) {
int pos = holder.getLayoutPosition();
onItemClickListener.onItemLongClick(holder.itemView, pos);
}
//表示此事件已经消费，不会触发单击事件
return true;
}
});
}
@Override
public int getItemViewType(int position) {
if(position == getItemCount() - 1){
return 1;
}else {
return 0;
}
}
@Override
public int getItemCount() {
return mData == null ? 0 : mData.size();
}
/**
* 往列表第一行新增一个item
*/
public void addNewItem() {
if(mData == null) {
mData = new ArrayList<>();
}
mData.add(0, "new Item");
notifyItemInserted(0);
}
/**
* 删除item
*/
public void deleteItem(int position) {
if(mData == null || mData.isEmpty()) {
return;
}
if(position >= 0 && position < mData.size()){
mData.remove(position);
notifyItemRemoved(position);
}
}
/**
* 设置回调监听
* @param listener
*/
public void setOnItemClickListener(InfoRecyclerViewAdapter.OnItemClickListener listener) {
this.onItemClickListener = listener;
}
public interface OnItemClickListener {
void onItemClick(View view, int position);
void onItemLongClick(View view, int position);
}
static class ViewHolder extends RecyclerView.ViewHolder {
@BindView(R.id.tv_item)
TextView tvItem;
ViewHolder(View view) {
super( view);
ButterKnife.bind(this, view);
}
}
}activity往列表中新增数据：
ArrayList<String> mDataList= new ArrayList<>();//activity里的数据源，获取到数据后就传到adapter里更新列表获取到数据后就传到adapter里更新列表：
infoRecyclerViewAdapter.initData(mDataList);
// 由于Adapter内部是直接在首个Item位置做增加操作，增加完毕后列表移动到首个Item位置
infoLayoutManager.scrollToPosition(0);删除某个位置的item：
infoRecyclerViewAdapter.deleteItem(2);//比如我要删除位置为第三的item
// 删除完毕后列表移动到Item位置
infoLayoutManager.scrollToPosition(2);4、activity
//activity里的数据源，获取到数据后就传到adapter里更新列表
ArrayList<String> mDataList= new ArrayList<>();网格列表(像GridView)：
//竖直滑动，每行只显示四个
GridLayoutManager infoLayoutManager = new GridLayoutManager( this,4);//如果在初始化adapter的时候就已经获取到了数据源可以在初始化adapter的时候就传入数据源
InfoRecyclerViewAdapter infoRecyclerViewAdapter = new InfoRecyclerViewAdapter(this,mDataList);
//如果像是异步网络请求数据后再刷新列表的话:
InfoRecyclerViewAdapter infoRecyclerViewAdapter = new InfoRecyclerViewAdapter(this);
//获取到数据后就传到adapter里更新列表
infoRecyclerViewAdapter.initData(mDataList,0);// 设置布局管理器
infoRecyclerView.setLayoutManager(infoLayoutManager);
// 设置adapter
infoRecyclerView.setAdapter(infoRecyclerViewAdapter);
//设置间隔样式
infoRecyclerView.addItemDecoration(new DividerGridItemDecoration(this));垂直列表(像ListView)：数据更新方式同上
infoLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
// 设置布局管理器
infoRecyclerView.setLayoutManager(infoLayoutManager);
// 设置adapter
infoRecyclerViewAdapter = new InfoRecyclerViewAdapter(mDataList);
//item的点击事件
infoRecyclerViewAdapter.setOnItemClickListener(new InfoRecyclerViewAdapter.OnItemClickListener() {
@Override
public void onItemClick(View view, int position) {
Toast.makeText(ActVerticalRecycler.this,"click " + position + " item", Toast.LENGTH_SHORT).show();
}
@Override
public void onItemLongClick(View view, int position) {
Toast.makeText(ActVerticalRecycler.this,"long click " + position + " item", Toast.LENGTH_SHORT).show();
}
});
infoRecyclerView.setAdapter(infoRecyclerViewAdapter);
//设置间隔样式
// infoRecyclerView.addItemDecoration(new MyDividerItemDecoration(this, LinearLayoutManager.VERTICAL));
infoRecyclerView.addItemDecoration(new DividerGridItemDecoration(this));
// 设置Item添加和移除的动画
infoRecyclerView.setItemAnimator(new DefaultItemAnimator());水平列表:
// 设置布局管理器
infoLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false);
infoRecyclerView.setLayoutManager(infoLayoutManager);
// 设置adapter
infoRecyclerViewAdapter = new InfoRecyclerViewAdapter( mDataList );
infoRecyclerView.setAdapter(infoRecyclerViewAdapter);
//设置间隔样式
// infoRecyclerView.addItemDecoration(new MyDividerItemDecoration(this, LinearLayoutManager.HORIZONTAL));
infoRecyclerView.addItemDecoration(new DividerGridItemDecoration(this));设置列表item之间的间隔
//设置列表item之间的间隔
recycleView.addItemDecoration(new RecyclerView.ItemDecoration() {
@Override
public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
outRect.left = 2;
outRect.right = 2;
outRect.top = 2;
outRect.bottom = 2;
// super.getItemOffsets(outRect, view, parent, state);
}
});三、 长按拖动
/**
* 长按拖拽
*/
public class ItemDragHelperCallBack extends ItemTouchHelper.Callback {
private OnItemDragListener onItemDragListener;
public ItemDragHelperCallBack(OnItemDragListener onItemDragListener) {
this.onItemDragListener = onItemDragListener;
}
/**
* 返回可以滑动的方向
*
* @param recyclerView
* @param viewHolder
* @return
*/
@Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
int dragFlags;
if (manager instanceof GridLayoutManager || manager instanceof StaggeredGridLayoutManager) {
//网格布局管理器允许上下左右拖动
dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
} else {
//其他布局管理器允许上下拖动
dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
}
return makeMovementFlags(dragFlags, 0);
}
/**
* 拖拽到新位置时候的回调方法
*
* @param recyclerView
* @param viewHolder
* @param target
* @return
*/
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
//不同Type之间不允许移动
if (viewHolder.getItemViewType() != target.getItemViewType()) {
return false;
}
if (onItemDragListener != null) {
onItemDragListener.onItemMove(viewHolder.getAdapterPosition(), target.getAdapterPosition());
}
return true;
}
/**
* 当用户左右滑动的时候执行的方法
*
* @param viewHolder
* @param direction
*/
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
}
/**
* 重写拖拽不可用
* @return
*/
@Override
public boolean isLongPressDragEnabled() {
return false;
}
public void setOnItemDragListeber(OnItemDragListener onItemDragListener) {
this.onItemDragListener = onItemDragListener;
}
public interface OnItemDragListener {
void onItemMove(int startPos,int endPos);
}
}activity中使用：
mItemTouchHelper = new ItemTouchHelper(new ItemDragHelperCallBack(new ItemDragHelperCallBack.OnItemDragListener() {
@Override
public void onItemMove(int startPos, int endPos) {
//交换变换位置的集合数据并刷新
Collections.swap(mAdapter.getDatas(), startPos, endPos);
mAdapter.notifyItemMoved(startPos, endPos);
}
}));
//关联RecyclerView
mItemTouchHelper.attachToRecyclerView(recyclerView);四、滑动冲突
1、ScrollView嵌套RecycleView
xml布局：
<ScrollView
android:layout_below="@+id/title_bar"
android:scrollbars="none"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:paddingTop="10dp"
android:paddingBottom="10dp"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_marginTop="20dp"
android:scrollbars="none"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
</ScrollView>代码设置：
GridLayoutManager gridLayoutManager = new GridLayoutManager(mContext,4){
@Override
public boolean canScrollVertically() {
//解决ScrollView里存在多个RecyclerView时滑动卡顿的问题
return false;
}
};
recyclerView.setLayoutManager(gridLayoutManager);
//解决数据加载不完的问题
recyclerView.setNestedScrollingEnabled(false);
recyclerView.setHasFixedSize(true);
//解决数据加载完成后, 没有停留在顶部的问题
recyclerView.setFocusable(false);五、recyclerview的item位序
1、Recyclerview.getLayoutPosition()问题
使用Recyclerview 时，如果要添加item的点击监听等功能，可以在Recyclerview.Adapter的onBindViewHolder中设置：
@Override
public void onBindViewHolder(final MyViewHolder holder, int position) {
holder.tv.setHeight(150*(1+position%4));
holder.tv.setWidth(150*(1+position%4));
holder.tv.setText(data.get(position));
if(mOnItemClickListener!=null){
holder.tv.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int pos=holder.getLayoutPosition();
mOnItemClickListener.onItemClick(v,pos);
}
});
holder.tv.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
int pos=holder.getLayoutPosition();
mOnItemClickListener.onItemLongClick(v,pos);
return false;
}
});
}
}注意这里使用了ViewHolder的getLayoutPosition方法，此方法返回的pos值与onBindViewHolder方法传入的position值有可能不同。
根据SDK中的解释，在Recyclerview 进行添加、移除item等操作时，position位置可能会变化，而所有的adapter的刷新并不总是及时的，只有这个方法返回的才是当前item经过一些变换后所处的真正位置。
getLayoutPosition：返回布局中最新的计算位置，和用户所见到的位置一致，当做用户输入（例如点击事件）的时候考虑使用
getAdapterPosition：返回数据在Adapter中的位置（也许位置的变化还未来得及刷新到布局中），当使用Adapter的时候（例如调用Adapter的notify相关方法时）考虑使用
六、分割线
1、ItemDecoration样式drawable
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" >
<gradient
android:centerColor="#ff00ff00"
android:endColor="#ff0000ff"
android:startColor="#ffff0000"
android:type="linear" />
<size android:height="4dp"/>
</shape><style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
<!-- Customize your theme here. -->
<item name="colorPrimary">@color/colorPrimary</item>
<item name="colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="colorAccent">@color/colorAccent</item>
<item name= "android:listDivider">@drawable/bg_divider </item >
</style>2、ItemDecoration
public class DividerGridItemDecoration extends RecyclerView.ItemDecoration {
private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
private Drawable mDivider;
public DividerGridItemDecoration(Context context) {
final TypedArray a = context.obtainStyledAttributes(ATTRS);
mDivider = a.getDrawable(0);
a.recycle();
}
@Override
public void onDraw(Canvas c, RecyclerView parent, State state) {
drawHorizontal(c, parent);
drawVertical(c, parent);
}
/**
* 绘制水平分割线
*/
public void drawHorizontal(Canvas c, RecyclerView parent) {
int childCount = parent.getChildCount();//item总个数
for (int i = 0; i < childCount; i++) {
final View child = parent.getChildAt(i);
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
final int left = child.getLeft() - params.leftMargin;
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);
}
}
/**
* 绘制垂直分割线
*/
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();
final int top = child.getTop() - params.topMargin;
final int bottom = child.getBottom() + params.bottomMargin;
final int left = child.getRight() + params.rightMargin;
final int right = left + mDivider.getIntrinsicWidth();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
/**
* 列数
*/
private int getSpanCount(RecyclerView parent) {
int spanCount = -1;
LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager) {
spanCount = ((GridLayoutManager) layoutManager).getSpanCount();
} else if (layoutManager instanceof StaggeredGridLayoutManager) {
spanCount = ((StaggeredGridLayoutManager) layoutManager).getSpanCount();
}
return spanCount;
}
/**
* 是否是最后一列
*/
private boolean isLastColum(RecyclerView parent, int pos, int spanCount,
int childCount) {
LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager) {
if ((pos + 1) % spanCount == 0) // 如果是最后一列，则不需要绘制右边
{
return true;
}
} else if (layoutManager instanceof StaggeredGridLayoutManager) {
int orientation = ((StaggeredGridLayoutManager) layoutManager)
.getOrientation();
if (orientation == StaggeredGridLayoutManager.VERTICAL) {
if ((pos + 1) % spanCount == 0) // 如果是最后一列，则不需要绘制右边
{
return true;
}
} else {
childCount = childCount - childCount % spanCount;
if (pos >= childCount) // 如果是最后一列，则不需要绘制右边
return true;
}
}
return false;
}
/**
* 是否是最后一行
* @param parent
* @param pos 当前item的位序
* @param spanCount 列数
* @param childCount item总个数
* @return
*/
private boolean isLastRaw(RecyclerView parent, int pos, int spanCount,
int childCount) {
LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager) {
childCount = childCount - childCount % spanCount;
// 如果是最后一行，则不需要绘制底部
if (pos >= childCount){
return true;
}
} else if (layoutManager instanceof StaggeredGridLayoutManager) {
int orientation = ((StaggeredGridLayoutManager) layoutManager)
.getOrientation();
// StaggeredGridLayoutManager 且纵向滚动
if (orientation == StaggeredGridLayoutManager.VERTICAL) {
childCount = childCount - childCount % spanCount;
// 如果是最后一行，则不需要绘制底部
if (pos >= childCount){
return true;
}
} else {
// StaggeredGridLayoutManager 且横向滚动
// 如果是最后一行，则不需要绘制底部
if ((pos + 1) % spanCount == 0) {
return true;
}
}
}
return false;
}
@Override
public void getItemOffsets(Rect outRect, int itemPosition,
RecyclerView parent) {
int spanCount = getSpanCount(parent);//列数
int childCount = parent.getAdapter().getItemCount();//item总个数
if (isLastRaw(parent, itemPosition, spanCount, childCount))// 如果是最后一行，则不需要绘制底部
{
outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
} else if (isLastColum(parent, itemPosition, spanCount, childCount))// 如果是最后一列，则不需要绘制右边
{
outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
} else {
outRect.set(0, 0, mDivider.getIntrinsicWidth(),
mDivider.getIntrinsicHeight());
}
}
}