RecycleView

一、什么是RecycleView
RecyclerView是谷歌V7包下新增的控件,用来替代ListView的使用,在RecyclerView标准化了ViewHolder类似于ListView中convertView用来做视图复用。
二、为什么用RecycleView
RecyclerView的优点就是,
他可以通过设置LayoutManager来快速实现listview、gridview、瀑布流的效果，而且还可以设置横向和纵向显示，
添加动画效果也非常简单(自带了ItemAnimation，可以设置加载和移除时的动画，方便做出各种动态浏览的效果),
控制Item的间隔
可以通过ItemDecoration
但点击事件要自己写。
官方推荐使用。
三、怎么使用RecycleView
首先要用这个控件，你需要在gradle文件中添加包的引用



然后是在XML文件用使用它



然后在Activity中使用

public class MainActivity extends Activity {
private List<String> strList = new ArrayList<String>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

for (int i = 'A'; i < 'z'; i++)
{
strList.add("" + (char) i);
}
RecyclerView recycler_view = (RecyclerView) findViewById(R.id.recycler_view);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
recycler_view.setLayoutManager(layoutManager);
recycler_view.setAdapter(new RecyclerAdapter(getApplication(), strList));

其中

new LinearLayoutManager(this));//这里用线性显示 类似于listview

new GridLayoutManager(this, 2));//这里用线性宫格显示 类似于grid view

new StaggeredGridLayoutManager(2, OrientationHelper.VERTICAL));//这里用线性宫格显示 类似于瀑布流

东

RecyclerAdapter

class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.RecycleViewHolder> {
private List<String> strList = new ArrayList<String>();
private Context context;
public RecyclerAdapter(Context context,List<String> strList){
this.context = context;
this.strList = strList;
}
@Override
public RecycleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(context).inflate(R.layout.recycler_item,parent,false);
RecycleViewHolder recycleViewHolder = new RecycleViewHolder(view);
return recycleViewHolder;
}

@Override
public void onBindViewHolder(RecycleViewHolder holder, int position) {
holder.textView.setText(strList.get(position));
}
@Override
public int getItemCount() {
return strList.size();
}
class RecycleViewHolder extends RecyclerView.ViewHolder {
private TextView textView;
public RecycleViewHolder(View itemView) {
super(itemView);
textView = (TextView) itemView.findViewById(R.id.text_view);
}
}
}

运行结果





添加分割线

recycler_view.addItemDecoration(new DividerItemDecoration(getApplicationContext(),DividerItemDecoration.VERTICAL_LIST));

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);
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);
}
}
}

添加点击事件

Adapter中interface ItemClickListener{
void click(View view,int position);
}

private ItemClickListener listener;

public void setItemClickListener(ItemClickListener listener){
this.listener = listener;
}

class RecycleViewHolder extends RecyclerView.ViewHolder {
private TextView textView;
public RecycleViewHolder(View itemView) {
super(itemView);
textView = (TextView) itemView.findViewById(R.id.text_view);
itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(listener!=null){
listener.click(v,getLayoutPosition());
}
}
});
}
}

Activity中

adapter.setItemClickListener(new RecyclerAdapter.ItemClickListener() {
@Override
public void click(View view, int position) {
Toast.makeText(MainActivity.this,position+"",Toast.LENGTH_SHORT).show();
}
});