Android5.X (六) ： RecycleView
RecycleView：它是谷歌替代ListView的控件，它拥有ListView的item的回收复用功能，但是RecycleView可以把ViewHolder的实现封装起来，我们只要实现自己的ViewHolder就可以了。
跟RecycleView息息相关的几个类有：
ViewHodler:需要继承RecyleView的ViewHolder
Adapter:适配器：需要继承RecycleView的Adapter
LayoutManager：用来设置用户的展示方式
ItemDecoration：用来设置分隔线的样式
ItemAnimator:关注Item的删除增加动画效果
所以它可以实现ListView，GridView，横向ListView,横向GridView，瀑布流，Item的删除添加动画的设置
//第一步：编写Adapter和ViewHolder
public class SimpleAdapter extends RecyclerView.Adapter<MyViewHodler> {
private LayoutInflater mInflater;
private List datas;
private Context context;
public SimpleAdapter(Context context,List datas) {
this.context = context;
this.datas = datas;
mInflater = LayoutInflater.from(context);
}
/**
* 创建ViewHolder
* @param parent
* @param viewType
* @return
*/
@Override
public MyViewHodler onCreateViewHolder(ViewGroup parent, int viewType) {
View v = mInflater.inflate(R.layout.item_text,parent,false);
MyViewHodler viewHodler = new MyViewHodler(v);
return viewHodler;
}
/**
* 绑定ViewHolder
* @param holder
* @param position
*/
@Override
public void onBindViewHolder(MyViewHodler holder, int position) {
holder.tv.setText(datas.get(position));
}
@Override
public int getItemCount() {
return datas.size();
}
}
class MyViewHodler extends RecyclerView.ViewHolder {
TextView tv;
public MyViewHodler(View itemView) {
super(itemView);
tv = (TextView) itemView.findViewById(R.id.tv_item);
}
} 第二步：跟ListView一样设置adapter
rv = (RecyclerView) findViewById(R.id.recylerView);
rv.setAdapter(new SimpleAdapter(this, datas));第三部：自定义它的分割线，因为谷歌并没有提供分割线，所以需要继承ItemDecoration
如果是ListView可以使用这个类：
package com.recyleview;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
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);
}
}
}
GridView可以使用这个类：
package com.recyleview;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.RecyclerView.LayoutManager;
import android.support.v7.widget.RecyclerView.State;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.View;
public class DividerGridItemDecoration extends RecyclerView.ItemDecoration
{
private static final int[] ATTRS = new int[] { android.R.attr.listDivider };
private Drawable mDivider;
public DividerGridItemDecoration(Context context)
{
final TypedArray a = context.obtainStyledAttributes(ATTRS);
mDivider = a.getDrawable(0);
a.recycle();
}
@Override
public void onDraw(Canvas c, RecyclerView parent, State state)
{
drawHorizontal(c, parent);
drawVertical(c, parent);
}
private int getSpanCount(RecyclerView parent)
{
// 列数
int spanCount = -1;
LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager)
{
spanCount = ((GridLayoutManager) layoutManager).getSpanCount();
} else if (layoutManager instanceof StaggeredGridLayoutManager)
{
spanCount = ((StaggeredGridLayoutManager) layoutManager)
.getSpanCount();
}
return spanCount;
}
public void drawHorizontal(Canvas c, RecyclerView parent)
{
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.getLeft() - params.leftMargin;
final int right = child.getRight() + params.rightMargin
+ mDivider.getIntrinsicWidth();
final int top = child.getBottom() + params.bottomMargin;
final int bottom = top + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
public void drawVertical(Canvas c, RecyclerView parent)
{
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.getTop() - params.topMargin;
final int bottom = child.getBottom() + params.bottomMargin;
final int left = child.getRight() + params.rightMargin;
final int right = left + mDivider.getIntrinsicWidth();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
private boolean isLastColum(RecyclerView parent, int pos, int spanCount,
int childCount)
{
LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager)
{
if ((pos + 1) % spanCount == 0)// 如果是最后一列，则不需要绘制右边
{
return true;
}
} else if (layoutManager instanceof StaggeredGridLayoutManager)
{
int orientation = ((StaggeredGridLayoutManager) layoutManager)
.getOrientation();
if (orientation == StaggeredGridLayoutManager.VERTICAL)
{
if ((pos + 1) % spanCount == 0)// 如果是最后一列，则不需要绘制右边
{
return true;
}
} else
{
childCount = childCount - childCount % spanCount;
if (pos >= childCount)// 如果是最后一列，则不需要绘制右边
return true;
}
}
return false;
}
private boolean isLastRaw(RecyclerView parent, int pos, int spanCount,
int childCount)
{
LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager)
{
childCount = childCount - childCount % spanCount;
if (pos >= childCount)// 如果是最后一行，则不需要绘制底部
return true;
} else if (layoutManager instanceof StaggeredGridLayoutManager)
{
int orientation = ((StaggeredGridLayoutManager) layoutManager)
.getOrientation();
// StaggeredGridLayoutManager 且纵向滚动
if (orientation == StaggeredGridLayoutManager.VERTICAL)
{
childCount = childCount - childCount % spanCount;
// 如果是最后一行，则不需要绘制底部
if (pos >= childCount)
return true;
} else
// StaggeredGridLayoutManager 且横向滚动
{
// 如果是最后一行，则不需要绘制底部
if ((pos + 1) % spanCount == 0)
{
return true;
}
}
}
return false;
}
@Override
public void getItemOffsets(Rect outRect, int itemPosition,
RecyclerView parent)
{
int spanCount = getSpanCount(parent);
int childCount = parent.getAdapter().getItemCount();
if (isLastRaw(parent, itemPosition, spanCount, childCount))// 如果是最后一行，则不需要绘制底部
{
outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
} else if (isLastColum(parent, itemPosition, spanCount, childCount))// 如果是最后一列，则不需要绘制右边
{
outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
} else
{
outRect.set(0, 0, mDivider.getIntrinsicWidth(),
mDivider.getIntrinsicHeight());
}
}
} //设置分割线
rv.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));第四步：设置它的显示模式：
它的manager有以下几种：
//设置垂直的ListView
linearLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL,false);
rv.setLayoutManager(linearLayoutManager); //设置成GridView模式,3列
GridLayoutManager gridLayoutManager = new GridLayoutManager(this,3);
rv.setLayoutManager(gridLayoutManager);
rv.addItemDecoration(new DividerGridItemDecoration(this));
//横向GridView模式，5行
StaggeredGridLayoutManager staggeredGridLayoutManager = new StaggeredGridLayoutManager(5,StaggeredGridLayoutManager.HORIZONTAL);
rv.setLayoutManager(staggeredGridLayoutManager);
//瀑布流模式：3列
StaggeredGridLayoutManager sta = new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL);
rv.setLayoutManager(sta);设置删除添加动画：Google它提供了默认的删除添加动画
第五步：
// 设置item动画
rv.setItemAnimator(new DefaultItemAnimator());第六步：添加item的点击事件
这个只要在adapter中写一个接口就可以啦
private onItemClickListener lisener;
public interface onItemClickListener{
void onClick(View itemView, int pos);
}
public void setOnItemClickLisener(onItemClickListener lisener){
this.lisener = lisener;
}
@Override
public void onBindViewHolder(final MyViewHodler holder, int position) {
ViewGroup.LayoutParams params = holder.itemView.getLayoutParams();
params.height = heights.get(position);
holder.itemView.setLayoutParams(params);
holder.tv.setText(datas.get(position));
if(lisener != null){
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int pos = holder.getLayoutPosition();
lisener.onClick(holder.itemView,pos);
}
});
}
}
这样就算大功告成啦！
但是如果每个都这样写，那是不是很麻烦？
有空的话，我会抽取出一个基类出来，供大家使用~