android5.0中RecycleView的用法
jopen
9年前
最近学习了android5.0中新增的一个组件RecycleView，是用来代替当前的listview开发的，是因为在RecycleView中已经有了viewholder缓存，并且不同的item之间可以设置不同的布局。能非常有效地维护了意见数量有限，滚动大的数据集。使用 RecyclerView当你拥有的数据的集合，它的元素在运行时改变基于用户行为和网络事件的小部件
首先看看RecyclerView的一个小例子：
需要引入：android-support-v7-appcompat.jar
android-v7-RecyclerView.jar来支持低版本的android系统
新建一个my_layout.xml布局文件：里边放置一个RecyclerView
<android.support.v7.widget.RecyclerView android:id="@+id/rvlist" android:layout_width="match_parent" android:layout_height="match_parent" android:scrollbars="vertical" />
在之前的listview开发中，我们需要自定义viewholder来缓存listView中的数据，而在RecyclerView中，已经封装好了viewholder在adapter中，接下来自定义我们的adapter
public class MyAdapter2 extends RecyclerView.Adapter<MyAdapter2.ViewHolder> { // 数据集 private String[] mDataset; public MyAdapter2(String[] dataset) { super(); mDataset = dataset; } @Override public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) { // 创建一个View，简单起见直接使用系统提供的布局，就是一个TextView View view = View.inflate(viewGroup.getContext(),R.layout.viewholder_item, null); // 创建一个ViewHolder ViewHolder holder = new ViewHolder(view); return holder; } @Override public void onBindViewHolder(ViewHolder viewHolder, int i) { // 绑定数据到ViewHolder上 viewHolder.mTextView.setText(mDataset[i]); } @Override public int getItemCount() { return mDataset.length; } public static class ViewHolder extends RecyclerView.ViewHolder { public TextView mTextView; public ViewHolder(View itemView) { super(itemView); // mTextView = (TextView) itemView; mTextView = (TextView) itemView.findViewById(R.id.view_text_id); } } }在activity这样调用，并设置adapter
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.rvlist); // 创建一个线性布局管理器 LinearLayoutManager layoutManager = new LinearLayoutManager(this); layoutManager.setOrientation(LinearLayoutManager.VERTICAL); // 设置布局管理器 recyclerView.setLayoutManager(layoutManager); // 创建数据集 String[] dataset = new String[100]; for (int i = 0; i < dataset.length; i++){ dataset[i] = "item" + i; } // 创建Adapter，并指定数据集 MyAdapter2 adapter = new MyAdapter2(dataset); // 设置Adapter recyclerView.setAdapter(adapter); }运行效果：
在这个例子中只是用到了最基本的布局，下面结合android中新增的CardView和RecycleView实现一个复杂的布局：
先看效果图：
CardView继承自FrameLayout，允许你在card视图中显示信息. CardView也可以设置阴影和圆角。（其实现在很多应用都自定义了Card视图，Google这回将card视图作为基本控件，可以拿来直接使用了）
Layout中为CardView设置圆角使用card_view:cardCornerRadius属性
代码中为CardView设置圆角使用CardView.setRadius方法
为CardView设置背景颜色使用card_view:cardBackgroundColor属性
1.在item布局中引入cardview组件
<android.support.v7.widget.CardView android:id="@+id/cardview_id" android:layout_width="match_parent" android:layout_height="match_parent" app:cardCornerRadius="5dp" app:cardElevation="0dp" > <RelativeLayout android:layout_width="match_parent" android:layout_height="match_parent" android:padding="5dp" > <ImageView android:id="@+id/image_id" android:layout_width="20dp" android:layout_height="20dp" android:layout_alignParentLeft="true" /> <TextView android:id="@+id/text_id" android:layout_width="wrap_content" android:layout_height="match_parent" android:textColor="#f89ef5" android:textSize="20dp" android:layout_centerInParent="true" /> </RelativeLayout> </android.support.v7.widget.CardView>
需要注意的是要在最底层的layout中引入cardview的命名空间：
xmlns:app=http://schemas.android.com/apk/res-auto
要实现不同的item有不同的布局，需要有一个type字段来作为区分，这里，我新建一个UserInfo类，如下：
public class UserInfo { public static final int hasImage = 1; public static final int noImage = 2; private String mUserName; private int userImage; int type; public String getmUserName() { return mUserName; } public void setmUserName(String mUserName) { this.mUserName = mUserName; } public int getUserImage() { return userImage; } public void setUserImage(int userImage) { this.userImage = userImage; } public int getType() { return type; } public void setType(int type) { this.type = type; } public UserInfo(String mUserName, int type) { this.mUserName = mUserName; this.type = type; } public UserInfo(String mUserName, int userImage, int type) { this.mUserName = mUserName; this.userImage = userImage; this.type = type; } } hasImage和noImage分别表示该item需不需要加载图片，来加载不同的布局。 接下来看看Adapter的代码：
public class MyAdapter extends RecyclerView.Adapter<ViewHolder>{ private List<UserInfo>mList = null; private Context context = null; public MyAdapter(List<UserInfo> mList, Context context) { super(); this.mList = mList; this.context = context; // for (int i = 0; i < mList.size(); i++) { // Log.d("liuhang","==="+mList.get(i).getmUserName()+"==="+mList.get(i).getUserImage()); // } } public void addToList(UserInfo info,int position) { mList.add(0, info); notifyItemInserted(position); notifyDataSetChanged(); } public class TextOnClick implements OnClickListener { private int position = 0; public TextOnClick(int position) { this.position = position; } @Override public void onClick(View v) { Toast.makeText(context,"text the name:"+mList.get(position).getmUserName(),1000).show(); } } public class ImageOnclick implements OnClickListener { private int position = 0; public ImageOnclick(int position) { this.position = position; } @Override public void onClick(View v) { // TODO Auto-generated method stub Toast.makeText(context,"image the imageId:"+mList.get(position).getUserImage(),1000).show(); } } public class ItemOnClick implements OnItemClickListener { @Override public void onItemClick(AdapterViewCompat<?> arg0, View arg1, int arg2, long arg3) { // TODO Auto-generated method stub Toast.makeText(context,"you choose the item",1000).show(); } } @Override public int getItemCount() { return mList.size(); } public class TextViewHolder extends RecyclerView.ViewHolder { public TextView textView = null; public TextViewHolder(View view) { super(view); this.textView = (TextView) view.findViewById(R.id.text_id); } } public class ImageTextViewHolder extends RecyclerView.ViewHolder { public ImageView imageView = null; public TextView textView = null; public ImageTextViewHolder(View view) { super(view); this.imageView = (ImageView) view.findViewById(R.id.image_id); this.textView = (TextView) view.findViewById(R.id.text_id); } } @Override public int getItemViewType(int position) { // TODO Auto-generated method stub return mList.get(position).getType(); } @Override public void onBindViewHolder(ViewHolder holder, int position) { switch (getItemViewType(position)) { case UserInfo.hasImage: ImageTextViewHolder imageTextViewHolder = (ImageTextViewHolder) holder; imageTextViewHolder.imageView.setImageResource(mList.get(position).getUserImage()); imageTextViewHolder.textView.setText(mList.get(position).getmUserName()); imageTextViewHolder.textView.setOnClickListener(new TextOnClick(position)); imageTextViewHolder.imageView.setOnClickListener(new ImageOnclick(position)); break; case UserInfo.noImage: TextViewHolder textViewHolder = (TextViewHolder) holder; textViewHolder.textView.setText(mList.get(position).getmUserName()); textViewHolder.textView.setOnClickListener(new TextOnClick(position)); } } @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int type) { ViewHolder holder = null; View view = null; switch (type) { case UserInfo.hasImage: view = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_text_image_item,null); holder = new ImageTextViewHolder(view); break; case UserInfo.noImage: view = LayoutInflater.from(parent.getContext()).inflate(R.layout.card_text_item,null); holder = new TextViewHolder(view); break; } <a target=_blank href="http://download.csdn.net/detail/mockingbirds/8312357">源码下载</a> return holder; } }在activity中这样调用：
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_id); recyclerView.setHasFixedSize(true); LinearLayoutManager linaLayout = new LinearLayoutManager(this); linaLayout.setOrientation(1); recyclerView.setLayoutManager(linaLayout); recyclerView.getRecycledViewPool().setMaxRecycledViews(0, 10); int[]userImage = {R.drawable.icon08,R.drawable.icon00,R.drawable.icon01, R.drawable.icon02,R.drawable.icon03,R.drawable.icon04, R.drawable.icon05,R.drawable.icon06,R.drawable.icon07}; List<UserInfo>userList = new ArrayList<UserInfo>(); int position = 0; for (int i = 0; i < 35; i++) { position = (int) (Math.random() * 8); UserInfo userInfo1 = new UserInfo("zhangsan"+i,2); UserInfo userInfo2 = new UserInfo("lisi"+i,userImage[position],1); userList.add(userInfo1); userList.add(userInfo2); } final MyAdapter adapter= new MyAdapter(userList, this); recyclerView.setAdapter(adapter); recyclerView.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub Toast.makeText(MyActivity.this,"you choose the item",1000).show(); } }); Button button = (Button) findViewById(R.id.add); button.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { adapter.addToList(new UserInfo("new add"+ newAdd++, 2),0); } });<a target=_blank href="http://download.csdn.net/detail/mockingbirds/8312357">源码下载</a>
来自： http://blog.csdn.net//mockingbirds/article/details/42245991