初次接触recyclerview记录（1）

来源：互联网发布：韩国bj 知乎编辑：程序博客网时间：2024/06/01 15:56

1. 我们创建项目，添加依赖支持recycerview的包：

compile 'com.android.support:recyclerview-v7:24.2.0'1

//在xml布局文件里添加控件

<android.support.v7.widget.RecyclerView    android:id="@+id/recyclerview"    android:layout_width="match_parent"    android:layout_height="match_parent"></android.support.v7.widget.RecyclerView>
//接下来就是一些很简单的事情了  我们在activity里初始化

mRecyclerView= (RecyclerView) findViewById(R.id.recyclerview);mRecyclerView.setLayoutManager(new LinearLayoutManager(this));//这里是线性布局，下面还有Grid布局
//既然recyclerview是listview  gridview的升级版，

那么也同样需要数据适配器，下面是适配器

class Recycle extends RecyclerView.Adapter<Recycle.Viewholder>{//这里的泛型  就是它自己的 ViewHolder    @Override    public Viewholder onCreateViewHolder(ViewGroup parent, int viewType) {        Viewholder holder=new Viewholder(LayoutInflater.from                (Recycleview_Activity.this).inflate(R.layout.item_recyclerview,parent,false));//将item布局填充        return holder;    }    @Override    public void onBindViewHolder(Viewholder holder, int position) {        holder.mTextview.setText(mData.get(position));    }    @Override    public int getItemCount() {        return mData.size();    }    class Viewholder extends RecyclerView.ViewHolder {         TextView mTextview;        public Viewholder(View itemView) {            super(itemView);            mTextview= (TextView) itemView.findViewById(R.id.recyclerview_text);        }    }}
接着绑定适配器
mAdapter=new Recycle();//实例化适配器mRecyclerView.setAdapter(mAdapter);//绑定适配器
下面要添加分割线，系统没有提供分割线的方法，我们在  xml文件中  设置divider是无效的
我们通过此方法添加分割线：
mRecyclerView.addItemDecoration(new DividerItemDecoration(this,        DividerItemDecoration.VERTICAL_LIST) );//直接写这句话会发现没有  DividerItemRecoration，无法实例化
原因就是因为系统并没有为我们提供分割线的方法  ，但是我们可以自己去实现
新建一个类文件 继承ItemDecorationpublic 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);            android.support.v7.widget.RecyclerView v = new android.support.v7.widget.RecyclerView(parent.getContext());            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child                    .getLayoutParams();            final int top = child.getBottom() + params.bottomMargin;            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;            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);        }    }}

这样就会出现系统默认的分割线
当然我们也可以更改分隔条的样式
在主题的style中添加listDivider item
<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/recyclerview_divider</item></style>
添加drawable  shape样式
<shape xmlns:android="http://schemas.android.com/apk/res/android">    <gradient        android:centerColor="#000000"        android:endColor="#ff000069"        android:startColor="#ffff0fff"        android:type="linear" />    <size android:height="5dp"/></shape>

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