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RecyclerView 初体验
目录：
1.基本使用
2.ItemDecoration Item分割线
3.LayoutManager
4.ItemAnimator Item动画
5.Click and LongClick Item点击事件
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1.基本使用
RecyclerView的使用中最重要的是Adapter，Adapter中最重要的是ViewHolder。先看最简单的RecyclerView的Adapter实现：
class HomeAdapter extends RecyclerView.Adapter<HomeAdapter.MyViewHolder>
{
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
{
MyViewHolder holder = new MyViewHolder(LayoutInflater.from(
HomeActivity.this).inflate(R.layout.item_home, parent,
false));
return holder;
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position)
{
holder.tv.setText(mDatas.get(position));
}
@Override
public int getItemCount()
{
return mDatas.size();
}
class MyViewHolder extends ViewHolder
{
TextView tv;
public MyViewHolder(View view)
{
super(view);
tv = (TextView) view.findViewById(R.id.id_num);
}
}
}
RecyclerView的基本使用 代码：
mRecyclerView = findView(R.id.id_recyclerview); //设置布局管理器 mRecyclerView.setLayoutManager(layout); //设置adapter mRecyclerView.setAdapter(adapter) //设置Item增加、移除动画 mRecyclerView.setItemAnimator(new DefaultItemAnimator()); //添加分割线 mRecyclerView.addItemDecoration(new DividerItemDecoration( getActivity(), DividerItemDecoration.HORIZONTAL_LIST));
主要通过上面代码，即可实现和ListView类似的效果
2.ItemDecoration Item分割线
我们可以通过该方法添加分割线：
mRecyclerView.addItemDecoration()
2.1 ListView型分割线 实现类
package com.devilwwj.myapplication_recyclerview; /* * Copyright (C) 2014 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * limitations under the License. */ 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.support.v7.widget.RecyclerView.State; import android.util.Log; import android.view.View; /** * This class is from the v7 samples of the Android SDK. It‘s not by me! * <p/> * See the license above for details. */ 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); } } }
2.2 GridView型分割线 实现类
package com.devilwwj.myapplication_recyclerview; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Rect; import android.graphics.drawable.Drawable; import android.support.v4.content.ContextCompat; 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; private Paint mPaint; private int mDividerHeight = 1; public DividerGridItemDecoration(Context context) { final TypedArray a = context.obtainStyledAttributes(ATTRS); mDivider = a.getDrawable(0); a.recycle(); } /** * 自定义分割线 * * @param context * @param drawableId 分割线图片 */ public DividerGridItemDecoration(Context context, int drawableId) { mDivider = ContextCompat.getDrawable(context, drawableId); mDividerHeight = mDivider.getIntrinsicHeight(); } /** * 自定义分割线 * * @param context * @param dividerHeight 分割线高度 * @param dividerColor 分割线颜色 */ public DividerGridItemDecoration(Context context, int dividerHeight, int dividerColor) { mDividerHeight = dividerHeight; mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); mPaint.setColor(dividerColor); mPaint.setStyle(Paint.Style.FILL); } @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; } // 绘制水平线 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 + mDividerHeight; final int top = child.getBottom() + params.bottomMargin; final int bottom = top + mDividerHeight; if (mDivider != null) { mDivider.setBounds(left, top, right, bottom); mDivider.draw(c); } if (mPaint != null) { c.drawRect(left, top, right, bottom, mPaint); } } } // 绘制垂直线 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 + mDividerHeight; if (mDivider != null) { mDivider.setBounds(left, top, right, bottom); mDivider.draw(c); } if (mPaint != null) { c.drawRect(left, top, right, bottom, mPaint); } } } // 判断是否是最后一列 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; } // 判断是否是最后一行 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, mDividerHeight, 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, mDividerHeight); } else { outRect.set(0, 0, mDividerHeight, mDividerHeight); } } }
3.LayoutManager
3.1 LinearLayoutManager 线性布局管理器
3.2 GridLayoutManager 网格布局管理器
3.3 StaggeredGridLayoutManager 网格布局管理器
4.ItemAnimator Item动画
// 设置item动画 mRecyclerView.setItemAnimator(new DefaultItemAnimator());
注意，这里更新数据集不是用adapter.notifyDataSetChanged()而是 notifyItemInserted(position)与notifyItemRemoved(position)
否则没有动画效果。
为上述adapter中添加了两个方法：
public void addData(int position) { mDatas.add(position, "Insert One"); notifyItemInserted(position); } public void removeData(int position) { mDatas.remove(position); notifyItemRemoved(position); }
5.Click and LongClick Item点击事件
adapter中自己去提供回调
class HomeAdapter extends RecyclerView.Adapter<HomeAdapter.MyViewHolder> { //... public interface OnItemClickLitener { void onItemClick(View view, int position); void onItemLongClick(View view , int position); } private OnItemClickLitener mOnItemClickLitener; public void setOnItemClickLitener(OnItemClickLitener mOnItemClickLitener) { this.mOnItemClickLitener = mOnItemClickLitener; } @Override public void onBindViewHolder(final MyViewHolder holder, final int position) { holder.tv.setText(mDatas.get(position)); // 如果设置了回调，则设置点击事件 if (mOnItemClickLitener != null) { holder.itemView.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { int pos = holder.getLayoutPosition(); mOnItemClickLitener.onItemClick(holder.itemView, pos); } }); holder.itemView.setOnLongClickListener(new OnLongClickListener() { @Override public boolean onLongClick(View v) { int pos = holder.getLayoutPosition(); mOnItemClickLitener.onItemLongClick(holder.itemView, pos); return false; } }); } } //... }
Activity中去设置监听：
mAdapter.setOnItemClickLitener(new OnItemClickLitener() { @Override public void onItemClick(View view, int position) { Toast.makeText(HomeActivity.this, position + " click", Toast.LENGTH_SHORT).show(); } @Override public void onItemLongClick(View view, int position) { Toast.makeText(HomeActivity.this, position + " long click", Toast.LENGTH_SHORT).show(); mAdapter.removeData(position); } });
源码：http://pan.baidu.com/s/1slRiugX （提取码：yrfu）
参考：http://blog.csdn.net/lmj623565791/article/details/45059587
RecyclerView 初体验
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