向上偏移解决
android:focusableInTouchMode="true" android:focusable="true"
android:fillViewport="true"
卡顿解决方法
recyclerViewwg.setHasFixedSize(true);
recyclerViewwg.setNestedScrollingEnabled(false);删除条目：
lists.remove(i); notifyItemRemoved(i); notifyDataSetChanged();
mRecyclerview.invalidate();====mRecyAdapter.notifyDataSetChanged();概述
RecyclerView出现已经有一段时间了，相信大家肯定不陌生了，大家可以通过导入support-v7对其进行使用。
据官方的介绍，该控件用于在有限的窗口中展示大量数据集，其实这样功能的控件我们并不陌生，例如：ListView、GridView。
那么有了ListView、GridView为什么还需要RecyclerView这样的控件呢？整体上看RecyclerView架构，提供了一种插拔式的体验，高度的解耦，异常的灵活，通过设置它提供的不同LayoutManager，ItemDecoration , ItemAnimator实现令人瞠目的效果。
- 你想要控制其显示的方式，请通过布局管理器LayoutManager
- 你想要控制Item间的间隔（可绘制），请通过ItemDecoration
- 你想要控制Item增删的动画，请通过ItemAnimator
- 你想要控制点击、长按事件，请自己写（擦，这点尼玛。）
一.RecyclerView介绍
RecyclerView 是Android 5.0版本中新出现的东西，用来替代ListView和GridView的。
二.RecyclerView架构
RecyclerView使用布局管理器LayoutManager和适配器Adapter的适配器模式去实现架构，不关心数据的来源。耦合性非常的底，用户可以根据自己的用户界面去实现相应的效果
三.RecyclerView的优点
-
1.RecyclerView内部已经强制使用VIewHolder，优化了对Item中View的复用。
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2.提供了一个较为灵活的布局管理类，LayoutManager，用来控制RecyclerView是线性展示还是垂直展示，以及可以设置成瀑布流。并且提供了ItemDecoration这个类，来灵活的让用户来设置分割线。
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3.用ItemAnimator可以对item进行布局的删减动画效果。
设置布局管理器：
1、竖向listview
rv.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));2、横向listview
rv.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false));3、竖向gridView
rv.setLayoutManager(new GridLayoutManager(this, 5));4、横向gridview
rv.setLayoutParams(new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT));
rv.setLayoutManager(new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.HORIZONTAL));5、瀑布流
rv.setLayoutParams(new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.MATCH_PARENT));
rv.setLayoutManager(new StaggeredGridLayoutManager(5, StaggeredGridLayoutManager.VERTICAL));瀑布流实现效果
实现方法
item类型设置
for (int a=0;a<8;a++){TuijianMainEntity tuijianEntity =new TuijianMainEntity();tuijianEntity.setUname("网吧"+a);if (a>0){if (iflong){tuijianEntity.setIflong(iflong);intlonglg++;if (intlonglg==2){iflong=!iflong;intlonglg=0;}}else {tuijianEntity.setIflong(iflong);intlonglg++;if (intlonglg==2){iflong=!iflong;intlonglg=0;}}}barEntityList.add(tuijianEntity);
}设置左右间隙
if (position%2==0){holder.itemView.setPadding(12,28,12,0);}else {holder.itemView.setPadding(12,28,12,0);
}设置图片高度
if (entityList.get(position).isIflong()){int h = (int)Math.floor(heightlg*4/7)-130;int igh = h-210;
// setViewLayoutParams(holder.myli,h);setigLayoutParams(holder.myig,igh);}else {int h = (int)Math.floor(heightlg*3/7)-80;int igh = h-160;
// setViewLayoutParams(holder.myli,h);setigLayoutParams(holder.myig,igh);}item_layout 自适应高度wrap_content
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:background="@color/bg_list"android:layout_height="wrap_content"><LinearLayoutandroid:id="@+id/myli"android:layout_width="match_parent"android:layout_height="wrap_content"android:orientation="vertical"android:background="@drawable/kongwhitebg">
需在adapter随机设置高度
rvAdapter.setType(3);private int type = 0;public RvAdapter(Context context, List<Integer> datas) {this.context = context;this.datas = datas;for (int i : datas) {int height = (int) (Math.random() * 100 + 300);heights.add(height);}
}public void setType(int type) {this.type = type;
}@Override
public void onBindViewHolder(MyViewHolder holder, final int position) {RecyclerView.LayoutParams layoutParams;if (type == 0) {layoutParams = new RecyclerView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);} else if (type == 1) {layoutParams = new RecyclerView.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);} else {layoutParams = new RecyclerView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, heights.get(position));layoutParams.setMargins(2, 2, 2, 2);}设置Item增加、移除动画:
rv.setItemAnimator(new DefaultItemAnimator());
实现添加分割线:
1、添加默认分割线
//分割线
private RecyclerView.ItemDecoration itemDecoration; itemDecoration = new DividerItemDecoration(this, DividerItemDecoration.VERTICAL);
//默认分割线mHistoryRecycle.addItemDecoration(itemDecoration);
2、添加自定义分割线
mHistoryRecycle.addItemDecoration(new RecyclerViewDivider(this, LinearLayoutManager.HORIZONTAL,15, R.color.video_btn_danmaku_control_color, 2, 0));
自定义类RecyclerViewDivider
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.annotation.ColorRes;
import android.support.annotation.NonNull;
import android.support.v4.content.ContextCompat;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;import com.baidu.api.Util;
import com.juejinchain.android.R;/*** 作者：created by meixi* 邮箱：15913707499@163.com* 日期：2019/6/14 08*/
public class RecyclerViewDivider extends RecyclerView.ItemDecoration {private Paint mPaint;private Drawable mDivider;private int mDividerSize = 2;//分割线高度，默认为1pxprivate int mOffsetStart = 0;private int mOffsetEnd = 0;private int mOrientation;//列表的方向：LinearLayoutManager.VERTICAL或LinearLayoutManager.HORIZONTALprivate static final int[] ATTRS = new int[]{android.R.attr.listDivider};/*** 默认分割线：高度为2px，颜色为灰色** @param context* @param orientation 列表方向*/private RecyclerViewDivider(Context context, int orientation) {if (orientation != LinearLayoutManager.VERTICAL && orientation != LinearLayoutManager.HORIZONTAL) {throw new IllegalArgumentException("请输入正确的参数！");}mOrientation = orientation;final TypedArray a = context.obtainStyledAttributes(ATTRS);mDivider = a.getDrawable(0);a.recycle();}/*** 自定义分割线** @param context* @param orientation 列表方向* @param drawableId 分割线图片*/public RecyclerViewDivider(Context context, int orientation, int drawableId) {this(context, orientation);mDivider = ContextCompat.getDrawable(context, drawableId);mDividerSize = mDivider.getIntrinsicHeight();}/*** 自定义分割线** @param context* @param orientation 列表方向* @param dividerSize 分割线高度* @param dividerColor 分割线颜色*/public RecyclerViewDivider(Context context, int orientation, int dividerSize, @ColorRes int dividerColor) {this(context, orientation);mDividerSize = dividerSize;mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);mPaint.setColor(context.getResources().getColor(dividerColor));mPaint.setStyle(Paint.Style.FILL);}/*** 自定义分割线** @param context context* @param orientation 列表方向* @param dividerHeight 分割线高度* @param dividerColor 分割线颜色* @param offsetStart 起始偏移量* @param offsetEnd 结束偏移量*/public RecyclerViewDivider(Context context, int orientation, int dividerHeight, @ColorRes int dividerColor, int offsetStart, int offsetEnd) {this(context, orientation);mDividerSize = dividerHeight;mOffsetStart = dip2px(context, offsetStart);mOffsetEnd = dip2px(context, offsetEnd);mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);if (dividerColor == 0) {dividerColor = R.color.red_500;}mPaint.setColor(context.getResources().getColor(dividerColor));mPaint.setStyle(Paint.Style.FILL);}public static int dip2px(Context context, float dipValue) {final float scale = context.getResources().getDisplayMetrics().density;return (int) (dipValue * scale + 0.5f);}//重写此方法，防止设置的波纹背景把分隔线覆盖掉。@Overridepublic void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {RecyclerView.ViewHolder childViewHolder = parent.getChildViewHolder(view);if (childViewHolder.getItemViewType() != 0) {outRect.set(0, 0, 0, 0);return;}if (mOrientation == LinearLayoutManager.HORIZONTAL) {outRect.set(0, 0, 0, mDividerSize);} else {outRect.set(0, 0, mDividerSize, 0);}}//绘制分割线@Overridepublic void onDraw(@NonNull Canvas c, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {if (mOrientation == LinearLayoutManager.VERTICAL) {drawVertical(c, parent);} else {drawHorizontal(c, parent);}}//绘制横向 item 分割线private void drawHorizontal(Canvas canvas, RecyclerView parent) {final int left = parent.getPaddingLeft() + mOffsetStart;final int right = parent.getMeasuredWidth() - (parent.getPaddingRight() + mOffsetEnd);final int childSize = parent.getChildCount();for (int i = 0; i < childSize ; i++) {final View child = parent.getChildAt(i);RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();final int top = child.getBottom() + layoutParams.bottomMargin;final int bottom = top + mDividerSize;if (mDivider != null) {mDivider.setBounds(left, top, right, bottom);mDivider.draw(canvas);}if (mPaint != null) {canvas.drawRect(left, top, right, bottom, mPaint);}}}//绘制纵向 item 分割线private void drawVertical(Canvas canvas, RecyclerView parent) {final int top = parent.getPaddingTop() + mDividerSize;final int bottom = parent.getMeasuredHeight() - parent.getPaddingBottom() + mDividerSize;final int childSize = parent.getChildCount();for (int i = 0; i < childSize; i++) {final View child = parent.getChildAt(i);RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();final int left = child.getRight() + layoutParams.rightMargin;final int right = left + mDividerSize;if (mDivider != null) {mDivider.setBounds(left, top, right, bottom);mDivider.draw(canvas);}if (mPaint != null) {canvas.drawRect(left, top, right, bottom, mPaint);}}}
}
