安卓开发的RecyclerView部分
RecyclerView是Android开发中强大的控件，可以实现ListView、GridView以及StaggeredView（瀑布流），并支持垂直滚动和水平滚动两种方式。 本文介绍这三种View的垂直和水平滚动实现方法。
RecyclerView的实现由三个步骤组成：
- 使用布局管理器确定布局
- 设计布局条目的外观和点击事件
- 定义指定布局的Adapter显示数据
- 设置RecyclerView样式为列表布局，并设置垂直或水平布局
private void showList(boolean isVertical, boolean isReverse) {
//设置RecyclerView样式
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
// 设置水平or垂直
layoutManager.setOrientation(isVertical ? LinearLayoutManager.VERTICAL : LinearLayoutManager.HORIZONTAL);
layoutManager.setReverseLayout(isReverse);
mList.setLayoutManager(layoutManager);
// 创建适配器
mAdapter = new ListViewAdapter(mData);
//设置到RecyclerView中
mList.setAdapter(mAdapter);
// 初始化点击事件
initListener();
}- 定义Adapter，重构后的BaseAdapter，三种布局Adapter均继承之
public abstract class RecyclerViewBaseAdapter extends RecyclerView.Adapter<RecyclerViewBaseAdapter.InnerHolder> {
private final List<ItemBean> mData;
private OnItemClickListener mOnItemClickListener;
public RecyclerViewBaseAdapter(List<ItemBean> data) {
this.mData = data;
}
@Override
public InnerHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = getSubView(parent, viewType);
return new InnerHolder(view);
}
protected abstract View getSubView(ViewGroup parent, int viewType);
/**
* 这个方法用来绑定holder，设置数据
*
* @param holder
* @param position
*/
@Override
public void onBindViewHolder(@NonNull RecyclerViewBaseAdapter.InnerHolder holder, int position) {
// 在这里设置数据
holder.setData(mData.get(position), position);
}
/**
* 返回条目的数目
*
* @return
*/
@Override
public int getItemCount() {
if (mData != null) {
return mData.size();
}
return 0;
}
public void setOnItemClickListener(OnItemClickListener listener) {
//设置一个接口
this.mOnItemClickListener = listener;
}
public interface OnItemClickListener {
void onItemClick(int position);
}
public class InnerHolder extends RecyclerView.ViewHolder {
private final ImageView mIcon;
private final TextView mTitle;
private int mPosition;
public InnerHolder(@NonNull View itemView) {
super(itemView);
// 找到条目控件
mIcon = itemView.findViewById(R.id.icon);
mTitle = itemView.findViewById(R.id.title);
itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mOnItemClickListener != null) {
mOnItemClickListener.onItemClick(mPosition);
}
}
});
}
public void setData(ItemBean itemBean, int position) {
this.mPosition = position;
mIcon.setImageResource(itemBean.icon);
mTitle.setText(itemBean.title);
}
}
}public class ListViewAdapter extends RecyclerViewBaseAdapter {
public ListViewAdapter(List<ItemBean> data) {
super(data);
}
@Override
protected View getSubView(ViewGroup parent, int viewType) {
View view = View.inflate(parent.getContext(), R.layout.item_list_view, null);
return view;
}
}- 设置RecyclerView样式为网格布局，并设置垂直或水平布局
private void showGrid(boolean isVertical, boolean isReverse) {
//创建布局管理器
GridLayoutManager layoutManager = new GridLayoutManager(this, 3);
layoutManager.setOrientation(isVertical ? GridLayoutManager.VERTICAL : GridLayoutManager.HORIZONTAL);
layoutManager.setReverseLayout(isReverse);
//设置布局管理器
mList.setLayoutManager(layoutManager);
//创建适配器
mAdapter = new GridViewAdapter(mData);
//设置适配器
mList.setAdapter(mAdapter);
// 初始化点击事件
initListener();
}- GridViewAdapter
public class GridViewAdapter extends RecyclerViewBaseAdapter {
public GridViewAdapter(List<ItemBean> data) {
super(data);
}
@Override
protected View getSubView(ViewGroup parent, int viewType) {
View view = View.inflate(parent.getContext(), R.layout.item_grid_view, null);
return view;
}
}- 设置RecyclerView样式为瀑布流布局，并设置垂直或水平布局
private void showStagger(boolean isVertical, boolean isReverse) {
//布局管理器
StaggeredGridLayoutManager layoutManager = new StaggeredGridLayoutManager(2, isVertical ? StaggeredGridLayoutManager.VERTICAL : StaggeredGridLayoutManager.HORIZONTAL);
//设置布局管理器
layoutManager.setReverseLayout(isReverse);
//设置管理器到RecyclerView
mList.setLayoutManager(layoutManager);
//创建适配器
mAdapter = new StaggerAdapter(mData);
//设置适配器
mList.setAdapter(mAdapter);
// 初始化点击事件
initListener();
}- StaggerAdapter
public class StaggerAdapter extends RecyclerViewBaseAdapter {
public StaggerAdapter(List<ItemBean> data) {
super(data);
}
@Override
protected View getSubView(ViewGroup parent, int viewType) {
View view = View.inflate(parent.getContext(), R.layout.item_stagger_item, null);
return view;
}
}- 这种布局主要考虑Adapter的定义
public class MultiTypeAdapter extends RecyclerView.Adapter {
//定义三种条目类型
public static final int TYPE_FULL_IMAGE = 0;
public static final int TYPE_RIGHT_IMAGE = 1;
public static final int TYPE_THREE_IMAGES = 2;
private final List<MultiTypeBean> mData;
public MultiTypeAdapter(List<MultiTypeBean> data){
this.mData = data;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = null;
if(viewType == TYPE_FULL_IMAGE){
view = View.inflate(parent.getContext(), R.layout.item_type_full_img, null);
return new FullImageHolder(view);
}else if(viewType == TYPE_RIGHT_IMAGE) {
view = View.inflate(parent.getContext(), R.layout.item_type_right_img, null);
return new RightImageHolder(view);
}else{
view = View.inflate(parent.getContext(), R.layout.item_type_three_img, null);
return new ThreeImageHolder(view);
}
}
@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
}
@Override
public int getItemCount() {
if (mData != null) {
return mData.size();
}
return 0;
}
//复写getItemViewType，返回条目类型
@Override
public int getItemViewType(int position) {
MultiTypeBean multiTypeBean = mData.get(position);
return multiTypeBean.type;
}
private class FullImageHolder extends RecyclerView.ViewHolder{
public FullImageHolder(@NonNull View itemView) {
super(itemView);
}
}
private class RightImageHolder extends RecyclerView.ViewHolder{
public RightImageHolder(@NonNull View itemView) {
super(itemView);
}
}
private class ThreeImageHolder extends RecyclerView.ViewHolder{
public ThreeImageHolder(@NonNull View itemView) {
super(itemView);
}
}
}