首先我们先来了解一下RecycleView：
RecycleView相对于原来的ListView和GridView要灵活很多，可以很快的在listView和gridView以及瀑布流之间进行切换，它主要提供了3中布局方式，LinearLayoutManager（ListView）、GridLayoutManager（GridView）、StaggeredGridLayoutManager（瀑布流）。
RecyclerView比ListView,GridView之类控件都有哪些优点：
1、数据绑定2、Item View创建3、View的回收以及重用等机制。
下面我们来介绍一下RecycleView瀑布流的用法
一、我们需要一个瀑布流的工具类
DividerItemDecoration.java
/*瀑布流
* */
public class DividerItemDecoration extends RecyclerView.ItemDecoration {
private static final int[] ATTRS = new int[]{
android.R.attr.listDivider
};
public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;
public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;
private Drawable mDivider;
private int mOrientation;
public DividerItemDecoration(Context context, int orientation) {
final TypedArray a = context.obtainStyledAttributes(ATTRS);
mDivider = a.getDrawable(0);
a.recycle();
setOrientation(orientation);
}
public void setOrientation(int orientation) {
if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {
throw new IllegalArgumentException("invalid orientation");
}
mOrientation = orientation;
}
@Override
public void onDraw(Canvas c, RecyclerView parent) {
if (mOrientation == VERTICAL_LIST) {
drawVertical(c, parent);
} else {
drawHorizontal(c, parent);
}
}
public void drawVertical(Canvas c, RecyclerView parent) {
final int left = parent.getPaddingLeft();
final int right = parent.getWidth() - parent.getPaddingRight();
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.getBottom() + params.bottomMargin +
Math.round(ViewCompat.getTranslationY(child));
final int bottom = top + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
public void drawHorizontal(Canvas c, RecyclerView parent) {
final int top = parent.getPaddingTop();
final int bottom = parent.getHeight() - parent.getPaddingBottom();
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 left = child.getRight() + params.rightMargin +
Math.round(ViewCompat.getTranslationX(child));
final int right = left + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
@Override
public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
if (mOrientation == VERTICAL_LIST) {
outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
} else {
outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
}
}
}
二、我们来建一个Activity
RecyclerActivity.java
先来看一下布局
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.edu.jereh.android14.recyclerlistview.RecyclerActivity">
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/rv"
></android.support.v7.widget.RecyclerView>
</RelativeLayout>三、我们来看一下 具体代码的写法：
public class RecyclerActivity extends Activity {
@Bind(R.id.rv)
RecyclerView rv;
private List<Map> list;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_recycler);
ButterKnife.bind(this);
list =new ArrayList<>();
initDate();
MyAdapter myAdapter =new MyAdapter(list);
//瀑布流管理器
StaggeredGridLayoutManager sgm = new StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL);
rv.setLayoutManager(sgm);
rv.setAdapter(myAdapter);
//设置分割线
DividerItemDecoration itemDecoration =
new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST);
rv.addItemDecoration(itemDecoration);
}
public void initDate(){
HashMap map =new HashMap();
map.put("img",R.mipmap.a);
map.put("text","x1");
list.add(map);
map=new HashMap();
map.put("img",R.mipmap.b);
map.put("text","x2");
list.add(map);
map=new HashMap();
map.put("img",R.mipmap.as);
map.put("text","x3");
list.add(map);
map=new HashMap();
map.put("img",R.mipmap.e);
map.put("text","x2");
list.add(map);
map=new HashMap();
map.put("img",R.mipmap.e);
map.put("text","x3");
list.add(map);
map=new HashMap();
map.put("img",R.mipmap.as);
map.put("text","x2");
list.add(map);
map=new HashMap();
map.put("img",R.mipmap.lh3);
map.put("text","x3");
list.add(map);
map=new HashMap();
map.put("img",R.mipmap.b);
map.put("text","x2");
list.add(map);
map=new HashMap();
map.put("img",R.mipmap.as);
map.put("text","x3");
list.add(map);
map=new HashMap();
map.put("img",R.mipmap.lh1);
map.put("text","x2");
list.add(map);
map=new HashMap();
map.put("img",R.mipmap.lh2);
map.put("text","x3");
list.add(map);
}
public class MyAdapter extends RecyclerView.Adapter<MyViewHolder>{
private List<Map> mapList;
public MyAdapter(List<Map> mapList) {
this.mapList = mapList;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view=LayoutInflater.from(getBaseContext()).inflate(R.layout.recycle_stag,parent,false);
MyViewHolder viewHolder = new MyViewHolder(view);
return viewHolder;
}
//绑定
@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
Map map = mapList.get(position);
holder.imageView.setImageResource((Integer) map.get("img"));
holder.textView.setText(map.get("text").toString());
}
@Override
public int getItemCount() {
return mapList.size();
}
}
public class MyViewHolder extends RecyclerView.ViewHolder{
ImageView imageView;
TextView textView;
public MyViewHolder(View itemView) {
super(itemView);
imageView=(ImageView)itemView.findViewById(R.id.iv);
textView =(TextView)itemView.findViewById(R.id.tvi1);
}
}
}
下面是效果图
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