RecyclerView+MaterialRefreshLayout

最近有用到RecyclerView和MaterialRefreshLayout，故在此做个笔记方便下次查看，俗话说好记性不如烂笔头，何况我记性不好。

这里介绍RecyclerView和MaterialRefreshLayout的最基本用发，高手勿喷。。。

1、RecyclerView非常强大，它可以代替ListView、GridView等一系列类似的控件，所以以后基本上也就用它了

在需要使用RecyclerView的布局中添加如下代码：

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

和使用一般控件一样添加如上基本熟悉

2、在.java文件中添加如下代码：

/*Init RecyclerView*/
recyclerView = (RecyclerView) view.findViewById(R.id.home_recycle_view);
recyclerView.setLayoutManager(new LinearLayoutManager(context));
List<String> datas = new ArrayList<>();
for (int i = 0; i < 50; ++i) {
datas.add("" + i);
}
recyclerView.setAdapter(new MyAdapter(context, datas));
recyclerView.setItemAnimator(new DefaultItemAnimator());

//添加分割线
recyclerView.addItemDecoration(new DividerItemDecoration(context, DividerItemDecoration.VERTICAL_LIST));

这里也很简单，首先获取到布局中RecyclerView的id，调用setLayoutManager()为RecyclerView的每一项设置子布局，再调用setAdapter()添加适配器，这里的MyAdapter继承了RecyclerView.Adapter父类，下面贴出，setItemAnimator()设置项的删除或者添加的动画，这里使用默认，有时间再去研究它的自定义动画，最后addItemDecoration()添加分割器，通俗点击就是每一项之间分割的线的风格，系统为提供默认风格，所以需要自定义，下面贴出。

3、定义适配器，新建MyAdapter类，继承RecyclerView.Adapter父类，如下：

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHodler> {

private List<String> datas;

private Context mContext;

public MyAdapter(Context context, List<String> datas) {
this.mContext = context;
this.datas = datas;
}

@Override
public MyViewHodler onCreateViewHolder(ViewGroup parent, int viewType) {
MyViewHodler viewHolder = new MyViewHodler(LayoutInflater.from(mContext).inflate(R.layout.recycler_view_item, parent, false));
return viewHolder;
}

@Override
public void onBindViewHolder(MyViewHodler holder, int position) {
holder.text.setText(datas.get(position));

}

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

class MyViewHodler extends RecyclerView.ViewHolder {
TextView text;

public MyViewHodler(View itemView) {
super(itemView);
text = (TextView) itemView.findViewById(R.id.text);
}
}

}

这个适配器的执行逻辑我们要搞清楚，当RecyclerView添加适配器时首先会调用onCreateViewHolder()这个函数处理的是MyViewHolder类，用MyViewHolder类加载子项的布局文件并将其返回，这是个自定义的类作用是管理RecyclerView中每个子项的布局的资源，那么我们需要定义这个类，我这里子项中只放了一个TextView所以只将TextView获取到就行了，随后会调用onBindViewHolder类，这个类就将MyViewHolder类作为参数传了进来，然后我们可以对MyViewHolder当中的资源进行处理，即将想要显示的类容绑定到RecyclerView上，至于getItemCount()我们将数据的总数通过它返回即可。

4、自定义DividerItemDecoration，这是参考的网上的代码，具体执行过程等有时间了再去研究，贴出代码如下：

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) {
//        Log.v("recyclerview - itemdecoration", "onDraw()");

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);
}
}
}

5、到处RecyclerView的基本的设置就完成了，如下：



6、下面添加上拉刷新和下拉刷新，这个实现起来更简单了，通过MaterialRefreshLayout这个布局来。

这是github上的开源代码，https://github.com/android-cjj/Android-MaterialRefreshLayout

里面有详细的配置教程，我这里直接上代码：

7、首先添加依赖的库，有几种方式：

第一：在Module的build.grad里面的dependencies项中直接加入语句，compile 'com.cjj.materialrefreshlayout:library:1.3.0'，我这样添加出了错误不知道咋回事不过可以换种方法；

第二：把github上的源码下载下来，将其中的library添加到自己的module中，导入library这个module，然后右击自己的module->open module setting->Dependencies，点击+号->Module dependency，加入library即可。

8、在布局文件中添加如下代码：

    <com.cjj.MaterialRefreshLayout
android:id="@+id/material_refresh"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:overlay="true"
app:wave_show="false">
<android.support.v7.widget.RecyclerView
android:id="@+id/home_recycle_view"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</android.support.v7.widget.RecyclerView>
</com.cjj.MaterialRefreshLayout>

可以看到直接将RecyclerView包含到MaterialRefreshLayout布局中即可。

9、添加java代码，如下：

/* init MaterialRefreshLayout */
materialRefreshLayout = (MaterialRefreshLayout) view.findViewById(R.id.material_refresh);
// 允许下拉刷新
materialRefreshLayout.setLoadMore(true);
materialRefreshLayout.setMaterialRefreshListener(new MaterialRefreshListener() {
@Override
public void onRefresh(final MaterialRefreshLayout materialRefreshLayout) {
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
// 结束上拉刷新
materialRefreshLayout.finishRefresh();
}
}, 3000);
}

@Override
public void onRefreshLoadMore(final MaterialRefreshLayout materialRefreshLayout) {
super.onRefreshLoadMore(materialRefreshLayout);
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
// 结束下拉刷新
materialRefreshLayout.finishRefreshLoadMore();
}
}, 3000);
}
});

代码也很简单不多讲，效果如下：



附上源码下载地址：https://github.com/android-yanwen/RecyclerView