Recycler 的用法（listView、gridView和瀑布流）

RecyclerView

1.特点

1.不关心Item是否显示

LayoutManager

2.不关心Item 之间如何分隔

控制分隔效果 - - ItemDecoration
下载地址https://gist.github.com/alexfu/0f464fc3742f134ccd1e

3.不关注Item增加与删除的动画效果

ItemAnimation 删除动画的效果

4.只关注如何回收和复用View

2.主要相关的几个类

• Adapter
• ViewHolder
• LayoutManager （显示风格，（纵横）listView、gridView、瀑布流）
• ItemDecoration （分隔效果）
• ItemAnimation （内部Item增删的动画效果）

  3.简单实用（实现listView）

  3.1布局中加入RecyclerView

<android.support.v7.widget.RecyclerView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/id_recyclerView"
    >

3.2ViewHolder 类

public class MySimpleAdapter extends RecyclerView.Adapter<MyViewHolder> {

private LayoutInflater mInflater;
private Context mContext;
private List<String> mDatas;

public MySimpleAdapter(Context context, List<String> datas) {

    this.mContext = context;
    this.mDatas = datas;
    mInflater = LayoutInflater.from(context);
}

@Override
public MyViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {

    View view = mInflater.inflate(R.layout.item_single_textview,viewGroup,false);
    MyViewHolder viewHolder = new MyViewHolder(view);

    return viewHolder;
}

@Override
public void onBindViewHolder(MyViewHolder myViewHolder, int i) {
    myViewHolder.tv.setText(mDatas.get(i));
}

@Override
public int getItemCount() {
    return mDatas.size();
    }
}

class MyViewHolder extends RecyclerView.ViewHolder {
    // 一般会有当前item 所有的控件
    TextView tv;

    public MyViewHolder(View itemView) {
        super(itemView);
        tv  = (TextView) itemView.findViewById(R.id.id_tv);
    }
}

3.3 Item 布局

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="72dp"
    android:layout_margin="3dp"
    android:background="#44ff0000"
    >
    <TextView
        android:layout_width="72dp"
        android:layout_height="match_parent"
        android:id="@+id/id_tv"
        android:gravity="center"
        />

</FrameLayout>

3.4 MainActivity

public class MainActivity extends AppCompatActivity {

private RecyclerView mRecyclerView;
private List<String> mDatas;
private MySimpleAdapter mAdapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    initDatas();
    initViews();

    mAdapter = new MySimpleAdapter(this,mDatas);
    mRecyclerView.setAdapter(mAdapter);

    //设置RecyclerView的布局管理    //展现为listView 的Style
    LinearLayoutManager manager = new LinearLayoutManager(this, LinearLayout.VERTICAL,false);
    mRecyclerView.setLayoutManager(manager);

    //设置RecyclerView之间的分割线
    mRecyclerView.addItemDecoration(new DividerItemDecoration(this,
            DividerItemDecoration.VERTICAL_LIST));
}

private void initDatas() {
    mDatas = new ArrayList<String>();
    for (int i=0;i<10;i++){
        mDatas.add("miss" + i);
  }
}

private void initViews() {
    mRecyclerView = (RecyclerView) findViewById(R.id.id_recyclerView);
    }
}

3.5　分割线（divider_02）

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

<resources>

<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
    <!-- 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/divider_02</item>

</style>

</resources>

4.GridView

//gridView 展示
public void grid(View view){
    mRecyclerView.setLayoutManager(new GridLayoutManager(this,3));
}
//gridView 横向显示
public void gridh(View view){
    mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(5,
            StaggeredGridLayoutManager.HORIZONTAL));
}

5.瀑布流

5.1 控制高度MySimpleAdapter，MyViewHolder转换成内部类

 private List<Integer> mHeights;

public MySimpleAdapter(Context context, List<String> datas) {

    this.mContext = context;
    this.mDatas = datas;
    mInflater = LayoutInflater.from(context);

    mHeights = new ArrayList<Integer>();
    for (int i=0; i<mDatas.size();i++){
        mHeights.add((int)(100+Math.random()*300));
    }
}

5.2 瀑布流

 //gridView 瀑布流
public void gridh(View view){
    mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(3,
            StaggeredGridLayoutManager.VERTICAL));
}

增加和删除Item的方法

Adapter里面
 public void addData(int pos){
    mDatas.add(pos,"insert one");
    notifyItemInserted(pos);
}

public void deleteData(int pos){
    mDatas.remove(pos);
    notifyItemRemoved(pos);
}
方便调用
Activity中
 public void add(View view){
    mAdapter.addData(1);
}

public void delete(View view){
    mAdapter.deleteData(1);
}

7.添加监听

7.1 在Adapter类中添加

public interface OnItemClickListener{
    void onItemClick(View view,int postion);
    void onItemLongClick(View view,int postion);
}

private OnItemClickListener mOnItemClickListener;

public void setOnItemClickListener(OnItemClickListener listener){
    this.mOnItemClickListener =  listener;
}

7.2 在onBindViewHolder

 public void onBindViewHolder(final MyViewHolder myViewHolder, final int i) {
    myViewHolder.tv.setText(mDatas.get(i));

    if (mOnItemClickListener != null){

        myViewHolder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
              mOnItemClickListener.onItemClick(myViewHolder.itemView,i);
            }
        });
        //longClick
        myViewHolder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View view) {
               mOnItemClickListener.onItemLongClick(myViewHolder.itemView,i);
                return false;
            }
        });
    }
}

7.3 监听的实现

   mAdapter = new MySimpleAdapter(this,mDatas);
    mRecyclerView.setAdapter(mAdapter);

    mRecyclerView.setItemAnimator(new DefaultItemAnimator());

    mAdapter.setOnItemClickListener(new MySimpleAdapter.OnItemClickListener() {
        @Override
        public void onItemClick(View view, int postion) {
            Toast.makeText(MainActivity.this, "Click："+postion, Toast.LENGTH_SHORT).show();
        }

        @Override
        public void onItemLongClick(View view, int postion) {
            Toast.makeText(MainActivity.this, "LongClick："+postion, Toast.LENGTH_SHORT).show();
        }
    });
}

7.4 存在问题，Click postion 不对，愿意:notifyInsert..()不会刷新所有的view

在点击事件之后，加入

 public void onClick(View view) {
     int layoutPosition = myViewHolder.getLayoutPosition();
     mOnItemClickListener.onItemClick(myViewHolder.itemView,layoutPosition);
            }