一、RecycleView概述
RecycleView是support-v7包中的新组件，是一个强大的滑动组件。RecyclerView的官方定义如下：A flexible view for providing a limited window into a large data set。从定义可以看出，flexible（可扩展性）是RecyclerView的特点。
相比于ListView和GridView，RecycleView具有很多优点，如：数据绑定，Item的创建和View的回收复用机制等。并且RecycleView更加高级灵活，当我们数据因为用户事件或者网络事件发生改变的时候也能很好的进行显示。RecycleView最主要的特点就是可扩展、复用。
二、RecycleView的优点：
1.RecycleView封装了ViewHolder的回收复用，标准化了ViewHolder，编写Adapter面向的是ViewHolder，而不是View，高度解耦，复用的逻辑被封装，给编写代码带来更大的方便。
2.RecycleView提供了一种插拔式的体验，高度解耦，非常灵活，为了控制item的显示，RecycleView针对一个Item的显示专门抽取了相应的类，使其扩展性非常强。
3.可以控制Item增减动画，可以通过ItemAnimation来进行控制。当然，RecycleView有其自己默认的实现方式。
4.使用LayoutManager来确定每一个item的排列方式。
5.在使用RecycleView之前，需要继承RecycleView.Adapter适配，将数据与每个item进行绑定。
6.利用LayoutManager确定每一个item如何摆放、何时展示与隐藏。或者回收复用View的时候，LayoutManager会向适配器请求新的数据来替换以前的数据，该机制避免了创建过多的View和频繁调用Id方法。
三、RecycleView与ListView的区别：
1. ViewHolder的编写规范化，ListView是需要自己定义的，而RecyclerView是规范好的；
2. RecyclerView复用item全部搞定，不需要想ListView那样setTag()与getTag()；
3. RecyclerView多了一些LayoutManager工作，但实现了布局效果多样化；
4. 使用起来比ListView复杂。
四、RecycleView基本用法：
1.在项目gradle下添加依赖。
implementation 'com.android.support:recyclerview-v7:28.0.0'2.布局。
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<android.support.v7.widget.RecyclerView
android:id="@+id/id_recyclerview"
android:divider="#ffff0000"
android:dividerHeight="10dp"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>3.创建适配器。
标准实现步骤如下：
① 创建Adapter：创建一个继承RecyclerView.Adapter<VH>的Adapter类（VH是ViewHolder的类名）
② 创建ViewHolder：在Adapter中创建一个继承RecyclerView.ViewHolder的静态内部类，记为VH。ViewHolder的实现和ListView的ViewHolder实现几乎一样。
③ 在Adapter中实现3个方法：
- onCreateViewHolder()
这个方法主要生成为每个Item inflater出一个View，但是该方法返回的是一个ViewHolder。该方法把View直接封装在ViewHolder中，然后我们面向的是ViewHolder这个实例，当然这个ViewHolder需要我们自己去编写。
需要注意的是在onCreateViewHolder()中，映射Layout必须为
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyverview_item, parent, false);而不能是：
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyverview_item, null);- onBindViewHolder()
这个方法主要用于适配渲染数据到View中。方法提供给你了一viewHolder而不是原来的convertView。 - getItemCount()
这个方法就类似于BaseAdapter的getCount方法了，即总共有多少个条目。
可以看出，RecyclerView将ListView中getView()的功能拆分成了onCreateViewHolder()和onBindViewHolder()。
基本的Adapter实现如下：
package com.hbq.hickey.adapter;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.hbq.hickey.R;
import java.util.List;
/**
*
*/
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.VH> {
private List<String> mDatas;
public MyAdapter(List<String> data) {
this.mDatas = data;
}
//② 创建ViewHolder
public static class VH extends RecyclerView.ViewHolder{
public final TextView title;
public VH(View v) {
super(v);
title = (TextView) v.findViewById(R.id.title);
}
}
@NonNull
@Override
public VH onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.recyverview_item, viewGroup, false);
return new VH(v);
}
@Override
public void onBindViewHolder(@NonNull VH holder, int position) {
holder.title.setText(mDatas.get(position));
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//item 点击事件
}
});
}
@Override
public int getItemCount() {
return null == mDatas ? 0 : mDatas.size();
}
}4.设置RecyclerView
创建完Adapter，接着对RecyclerView进行设置，一般来说，需要为RecyclerView进行四大设置。
- Layout Manager(必选)，Item的布局。
- Adapter(必选)，为Item提供数据。
- Item Decoration(可选，默认为空)，Item之间的Divider。
- Item Animator(可选，默认为DefaultItemAnimator)，添加、删除Item动画。
①设置Layout Manager，布局主要有三种实现方式，本文采用流式布局进行解析。
recyclerView.setLayoutManager(new LinearLayoutManager(this));//线性布局
// recyclerView.setLayoutManager(new GridLayoutManager(this, 4));//网格布局
// recyclerView.setLayoutManager(new StaggeredGridLayoutManager
// (4, StaggeredGridLayoutManager.VERTICAL));//流式布局② 设置Adapter
MyAdapter adapter = new MyAdapter(mDatas);
recyclerView.setAdapter(adapter);③ 设置Item Decoration
mRecyclerView.addItemDecoration(
new HorizontalDividerItemDecoration.Builder(this)
.margin(10)
.setStartPosition(2)
.build()
);④设置Item Animator
mRecyclerView.setItemAnimator(new DefaultItemAnimator())。
按照这些操作步骤设置完成后，recyclerview布局的效果就出来了。
MainActivity的代码如下：
package com.hbq.hickey;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import com.hbq.hickey.adapter.MyAdapter;
import com.hbq.hickey.view.HorizontalDividerItemDecoration;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
private RecyclerView mRecyclerView;
private ArrayList<String> mDatas;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mRecyclerView = findViewById(R.id.id_recyclerview);
mRecyclerView.setLayoutManager(new LinearLayoutManager(this));//线性布局
// recyclerView.setLayoutManager(new GridLayoutManager(this, 4));//网格布局
// recyclerView.setLayoutManager(new StaggeredGridLayoutManager
// (4, StaggeredGridLayoutManager.VERTICAL));//流式布局
initDatas();
MyAdapter adapter = new MyAdapter(mDatas);
mRecyclerView.setAdapter(adapter);
mRecyclerView.addItemDecoration(
new HorizontalDividerItemDecoration.Builder(this)
.margin(10)
.setStartPosition(0)
.build()
);
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
}
private void initDatas() {
mDatas = new ArrayList<String>();
for (int i = 1; i <= 30; i++) {
mDatas.add("Test " + i);
}
}
}分割线的代码：
package com.hbq.hickey.view;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.annotation.DimenRes;
import android.support.v4.view.ViewCompat;
import android.support.v7.widget.RecyclerView;
import android.view.View;
/**
* Created by me_touch on 2018/12/12.
*/
public class HorizontalDividerItemDecoration extends FlexibleDividerDecoration {
private MarginProvider mMarginProvider;
protected HorizontalDividerItemDecoration(Builder builder) {
super(builder);
mMarginProvider = builder.mMarginProvider;
}
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
RecyclerView.Adapter adapter = parent.getAdapter();
if (adapter == null) {
return;
}
int itemCount = adapter.getItemCount();
int lastDividerOffset = getLastDividerOffset(parent);
int validChildCount = parent.getChildCount();
int lastChildPosition = -1;
for (int i = 0; i < validChildCount; i++) {
View child = parent.getChildAt(i);
int childPosition = parent.getChildAdapterPosition(child);
if (childPosition < lastChildPosition) {
// Avoid remaining divider when animation starts
continue;
}
lastChildPosition = childPosition;
if (childPosition < startPosition)
continue;
if (removeSet.contains(childPosition))
continue;
if (!mShowLastDivider && childPosition >= itemCount - lastDividerOffset) {
// Don't draw divider for last line if mShowLastDivider = false
continue;
}
if (wasDividerAlreadyDrawn(childPosition, parent)) {
// No need to draw divider again as it was drawn already by previous column
continue;
}
int groupIndex = getGroupIndex(childPosition, parent);
if (mVisibilityProvider.shouldHideDivider(groupIndex, parent)) {
continue;
}
Rect bounds = getDividerBound(groupIndex, parent, child);
switch (mDividerType) {
case DRAWABLE:
Drawable drawable = mDrawableProvider.drawableProvider(groupIndex, parent);
drawable.setBounds(bounds);
drawable.draw(c);
break;
case PAINT:
mPaint = mPaintProvider.dividerPaint(groupIndex, parent);
c.drawLine(bounds.left, bounds.top, bounds.right, bounds.bottom, mPaint);
break;
case COLOR:
mPaint.setColor(mColorProvider.dividerColor(groupIndex, parent));
mPaint.setStrokeWidth(mSizeProvider.dividerSize(groupIndex, parent));
c.drawLine(bounds.left, bounds.top, bounds.right, bounds.bottom, mPaint);
break;
}
}
}
@Override
protected Rect getDividerBound(int position, RecyclerView parent, View child) {
Rect bounds = new Rect(0, 0, 0, 0);
int transitionX = (int) ViewCompat.getTranslationX(child);
int transitionY = (int) ViewCompat.getTranslationY(child);
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
bounds.left = parent.getPaddingLeft() +
mMarginProvider.dividerLeftMargin(position, parent) + transitionX;
bounds.right = parent.getWidth() - parent.getPaddingRight() -
mMarginProvider.dividerRightMargin(position, parent) + transitionX;
int dividerSize = getDividerSize(position, parent);
boolean isReverseLayout = isReverseLayout(parent);
if (mDividerType == DividerType.DRAWABLE) {
// set top and bottom position of divider
if (isReverseLayout) {
bounds.bottom = child.getTop() - params.topMargin + transitionY;
bounds.top = bounds.bottom - dividerSize;
} else {
bounds.top = child.getBottom() + params.bottomMargin + transitionY;
bounds.bottom = bounds.top + dividerSize;
}
} else {
// set center point of divider
int halfSize = dividerSize / 2;
if (isReverseLayout) {
bounds.top = child.getTop() - params.topMargin - halfSize + transitionY;
} else {
bounds.top = child.getBottom() + params.bottomMargin + halfSize + transitionY;
}
bounds.bottom = bounds.top;
}
if (mPositionInsideItem) {
if (isReverseLayout) {
bounds.top += dividerSize;
bounds.bottom += dividerSize;
} else {
bounds.top -= dividerSize;
bounds.bottom -= dividerSize;
}
}
return bounds;
}
@Override
protected void setItemOffsets(Rect outRect, int position, RecyclerView parent) {
if (mPositionInsideItem) {
outRect.set(0, 0, 0, 0);
return;
}
if (isReverseLayout(parent)) {
outRect.set(0, getDividerSize(position, parent), 0, 0);
} else {
outRect.set(0, 0, 0, getDividerSize(position, parent));
}
}
private int getDividerSize(int position, RecyclerView parent) {
if (mPaintProvider != null) {
return (int) mPaintProvider.dividerPaint(position, parent).getStrokeWidth();
} else if (mSizeProvider != null) {
return mSizeProvider.dividerSize(position, parent);
} else if (mDrawableProvider != null) {
Drawable drawable = mDrawableProvider.drawableProvider(position, parent);
return drawable.getIntrinsicHeight();
}
throw new RuntimeException("failed to get size");
}
/**
* Interface for controlling divider margin
*/
public interface MarginProvider {
/**
* Returns left margin of divider.
*
* @param position Divider position (or group index for GridLayoutManager)
* @param parent RecyclerView
* @return left margin
*/
int dividerLeftMargin(int position, RecyclerView parent);
/**
* Returns right margin of divider.
*
* @param position Divider position (or group index for GridLayoutManager)
* @param parent RecyclerView
* @return right margin
*/
int dividerRightMargin(int position, RecyclerView parent);
}
public static class Builder extends FlexibleDividerDecoration.Builder<Builder> {
private MarginProvider mMarginProvider = new MarginProvider() {
@Override
public int dividerLeftMargin(int position, RecyclerView parent) {
return 0;
}
@Override
public int dividerRightMargin(int position, RecyclerView parent) {
return 0;
}
};
public Builder(Context context) {
super(context);
}
/**
* @param leftMarginDp 左侧的外边距 单位: dp
* @param rightMarginDp 右侧的外边距 单位: dp
* @return
*/
public Builder margin(final int leftMarginDp, final int rightMarginDp) {
final int leftMargin = 10;
final int rightMargin = 10;
return marginProvider(new MarginProvider() {
@Override
public int dividerLeftMargin(int position, RecyclerView parent) {
return leftMargin;
}
@Override
public int dividerRightMargin(int position, RecyclerView parent) {
return rightMargin;
}
});
}
/**
* @param horizontalMarginDp 左右边距 单位: dp
* @return
*/
public Builder margin(int horizontalMarginDp) {
return margin(horizontalMarginDp, horizontalMarginDp);
}
public Builder marginResId(@DimenRes int leftMarginId, @DimenRes int rightMarginId) {
return margin(mResources.getDimensionPixelSize(leftMarginId),
mResources.getDimensionPixelSize(rightMarginId));
}
public Builder marginResId(@DimenRes int horizontalMarginId) {
return marginResId(horizontalMarginId, horizontalMarginId);
}
public Builder marginProvider(MarginProvider provider) {
mMarginProvider = provider;
return this;
}
public HorizontalDividerItemDecoration build() {
checkBuilderParams();
return new HorizontalDividerItemDecoration(this);
}
}
}package com.hbq.hickey.view;
import android.content.Context;
import android.content.res.Resources;
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.DimenRes;
import android.support.annotation.DrawableRes;
import android.support.v4.content.ContextCompat;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import java.util.Arrays;
import java.util.TreeSet;
/**
* Created by me_touch on 2018/12/12.
*
*
*/
public abstract class FlexibleDividerDecoration extends RecyclerView.ItemDecoration {
private static final int DEFAULT_SIZE = 2;
private static final int[] ATTRS = new int[]{
android.R.attr.listDivider
};
protected enum DividerType {
DRAWABLE, PAINT, COLOR
}
protected DividerType mDividerType = DividerType.DRAWABLE;
protected VisibilityProvider mVisibilityProvider;
protected PaintProvider mPaintProvider;
protected ColorProvider mColorProvider;
protected DrawableProvider mDrawableProvider;
protected SizeProvider mSizeProvider;
protected boolean mShowLastDivider;
protected boolean mPositionInsideItem;
protected int startPosition;
protected Paint mPaint;
protected TreeSet<Integer> removeSet = new TreeSet<>();
protected FlexibleDividerDecoration(Builder builder) {
if (builder.mPaintProvider != null) {
mDividerType = DividerType.PAINT;
mPaintProvider = builder.mPaintProvider;
} else if (builder.mColorProvider != null) {
mDividerType = DividerType.COLOR;
mColorProvider = builder.mColorProvider;
mPaint = new Paint();
setSizeProvider(builder);
} else {
mDividerType = DividerType.DRAWABLE;
if (builder.mDrawableProvider == null) {
TypedArray a = builder.mContext.obtainStyledAttributes(ATTRS);
final Drawable divider = a.getDrawable(0);
a.recycle();
mDrawableProvider = new DrawableProvider() {
@Override
public Drawable drawableProvider(int position, RecyclerView parent) {
return divider;
}
};
} else {
mDrawableProvider = builder.mDrawableProvider;
}
mSizeProvider = builder.mSizeProvider;
}
mVisibilityProvider = builder.mVisibilityProvider;
mShowLastDivider = builder.mShowLastDivider;
startPosition = builder.startPosition;
mPositionInsideItem = builder.mPositionInsideItem;
}
private void setSizeProvider(Builder builder) {
mSizeProvider = builder.mSizeProvider;
if (mSizeProvider == null) {
mSizeProvider = new SizeProvider() {
@Override
public int dividerSize(int position, RecyclerView parent) {
return DEFAULT_SIZE;
}
};
}
}
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
RecyclerView.Adapter adapter = parent.getAdapter();
if (adapter == null) {
return;
}
int itemCount = adapter.getItemCount();
int lastDividerOffset = getLastDividerOffset(parent);
int validChildCount = parent.getChildCount();
int lastChildPosition = -1;
for (int i = 0; i < validChildCount; i++) {
View child = parent.getChildAt(i);
int childPosition = parent.getChildAdapterPosition(child);
if (childPosition < lastChildPosition) {
// Avoid remaining divider when animation starts
continue;
}
lastChildPosition = childPosition;
if (!mShowLastDivider && childPosition >= itemCount - lastDividerOffset) {
// Don't draw divider for last line if mShowLastDivider = false
continue;
}
if(childPosition < startPosition)
continue;
if (removeSet.contains(childPosition))
continue;
if (wasDividerAlreadyDrawn(childPosition, parent)) {
// No need to draw divider again as it was drawn already by previous column
continue;
}
int groupIndex = getGroupIndex(childPosition, parent);
if (mVisibilityProvider.shouldHideDivider(groupIndex, parent)) {
continue;
}
Rect bounds = getDividerBound(groupIndex, parent, child);
switch (mDividerType) {
case DRAWABLE:
Drawable drawable = mDrawableProvider.drawableProvider(groupIndex, parent);
drawable.setBounds(bounds);
drawable.draw(c);
break;
case PAINT:
mPaint = mPaintProvider.dividerPaint(groupIndex, parent);
c.drawLine(bounds.left, bounds.top, bounds.right, bounds.bottom, mPaint);
break;
case COLOR:
mPaint.setColor(mColorProvider.dividerColor(groupIndex, parent));
mPaint.setStrokeWidth(mSizeProvider.dividerSize(groupIndex, parent));
c.drawLine(bounds.left, bounds.top, bounds.right, bounds.bottom, mPaint);
break;
}
}
}
@Override
public void getItemOffsets(Rect rect, View v, RecyclerView parent, RecyclerView.State state) {
int position = parent.getChildAdapterPosition(v);
int itemCount = parent.getAdapter().getItemCount();
int lastDividerOffset = getLastDividerOffset(parent);
if (!mShowLastDivider && position >= itemCount - lastDividerOffset) {
// Don't set item offset for last line if mShowLastDivider = false
return;
}
if (removeSet.contains(position)) {
// 如果属于需要移除分割线的位置,就不分配偏移量
return;
}
if (position < startPosition) {
return;
}
int groupIndex = getGroupIndex(position, parent);
if (mVisibilityProvider.shouldHideDivider(groupIndex, parent)) {
return;
}
setItemOffsets(rect, groupIndex, parent);
}
/**
* Check if recyclerview is reverse layout
*
* @param parent RecyclerView
* @return true if recyclerview is reverse layout
*/
protected boolean isReverseLayout(RecyclerView parent) {
RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof LinearLayoutManager) {
return ((LinearLayoutManager) layoutManager).getReverseLayout();
} else {
return false;
}
}
public void removePositions(Integer ... position){
this.removeSet.addAll(Arrays.asList(position));
}
public void addPositions(Integer ... position){
this.removeSet.removeAll(Arrays.asList(position));
}
public void setStartPosition(int startPosition){
this.startPosition = startPosition;
}
/**
* In the case mShowLastDivider = false,
* Returns offset for how many views we don't have to draw a divider for,
* for LinearLayoutManager it is as simple as not drawing the last child divider,
* but for a GridLayoutManager it needs to take the span count for the last items into account
* until we use the span count configured for the grid.
*
* @param parent RecyclerView
* @return offset for how many views we don't have to draw a divider or 1 if its a
* LinearLayoutManager
*/
protected int getLastDividerOffset(RecyclerView parent) {
if (parent.getLayoutManager() instanceof GridLayoutManager) {
GridLayoutManager layoutManager = (GridLayoutManager) parent.getLayoutManager();
GridLayoutManager.SpanSizeLookup spanSizeLookup = layoutManager.getSpanSizeLookup();
int spanCount = layoutManager.getSpanCount();
int itemCount = parent.getAdapter().getItemCount();
for (int i = itemCount - 1; i >= 0; i--) {
if (spanSizeLookup.getSpanIndex(i, spanCount) == 0) {
return itemCount - i;
}
}
}
return 1;
}
/**
* Determines whether divider was already drawn for the row the item is in,
* effectively only makes sense for a grid
*
* @param position current view position to draw divider
* @param parent RecyclerView
* @return true if the divider can be skipped as it is in the same row as the previous one.
*/
protected boolean wasDividerAlreadyDrawn(int position, RecyclerView parent) {
if (parent.getLayoutManager() instanceof GridLayoutManager) {
GridLayoutManager layoutManager = (GridLayoutManager) parent.getLayoutManager();
GridLayoutManager.SpanSizeLookup spanSizeLookup = layoutManager.getSpanSizeLookup();
int spanCount = layoutManager.getSpanCount();
return spanSizeLookup.getSpanIndex(position, spanCount) > 0;
}
return false;
}
/**
* Returns a group index for GridLayoutManager.
* for LinearLayoutManager, always returns position.
*
* @param position current view position to draw divider
* @param parent RecyclerView
* @return group index of items
*/
protected int getGroupIndex(int position, RecyclerView parent) {
if (parent.getLayoutManager() instanceof GridLayoutManager) {
GridLayoutManager layoutManager = (GridLayoutManager) parent.getLayoutManager();
GridLayoutManager.SpanSizeLookup spanSizeLookup = layoutManager.getSpanSizeLookup();
int spanCount = layoutManager.getSpanCount();
return spanSizeLookup.getSpanGroupIndex(position, spanCount);
}
return position;
}
protected abstract Rect getDividerBound(int position, RecyclerView parent, View child);
protected abstract void setItemOffsets(Rect outRect, int position, RecyclerView parent);
/**
* Interface for controlling divider visibility
*/
public interface VisibilityProvider {
/**
* Returns true if divider should be hidden.
*
* @param position Divider position (or group index for GridLayoutManager)
* @param parent RecyclerView
* @return True if the divider at position should be hidden
*/
boolean shouldHideDivider(int position, RecyclerView parent);
}
/**
* Interface for controlling paint instance for divider drawing
*/
public interface PaintProvider {
/**
* Returns {@link Paint} for divider
*
* @param position Divider position (or group index for GridLayoutManager)
* @param parent RecyclerView
* @return Paint instance
*/
Paint dividerPaint(int position, RecyclerView parent);
}
/**
* Interface for controlling divider color
*/
public interface ColorProvider {
/**
* Returns {@link android.graphics.Color} value of divider
*
* @param position Divider position (or group index for GridLayoutManager)
* @param parent RecyclerView
* @return Color value
*/
int dividerColor(int position, RecyclerView parent);
}
/**
* Interface for controlling drawable object for divider drawing
*/
public interface DrawableProvider {
/**
* Returns drawable instance for divider
*
* @param position Divider position (or group index for GridLayoutManager)
* @param parent RecyclerView
* @return Drawable instance
*/
Drawable drawableProvider(int position, RecyclerView parent);
}
/**
* Interface for controlling divider size
*/
public interface SizeProvider {
/**
* Returns size value of divider.
* Height for horizontal divider, width for vertical divider
*
* @param position Divider position (or group index for GridLayoutManager)
* @param parent RecyclerView
* @return Size of divider
*/
int dividerSize(int position, RecyclerView parent);
}
public static class Builder<T extends Builder> {
private Context mContext;
protected Resources mResources;
private PaintProvider mPaintProvider;
private ColorProvider mColorProvider;
private DrawableProvider mDrawableProvider;
private SizeProvider mSizeProvider;
private VisibilityProvider mVisibilityProvider = new VisibilityProvider() {
@Override
public boolean shouldHideDivider(int position, RecyclerView parent) {
return false;
}
};
private boolean mShowLastDivider = false;
private boolean mPositionInsideItem = false;
private int startPosition = -1;
public Builder(Context context) {
mContext = context;
mResources = context.getResources();
}
public T paint(final Paint paint) {
return paintProvider(new PaintProvider() {
@Override
public Paint dividerPaint(int position, RecyclerView parent) {
return paint;
}
});
}
public T paintProvider(PaintProvider provider) {
mPaintProvider = provider;
return (T) this;
}
public T color(final int color) {
return colorProvider(new ColorProvider() {
@Override
public int dividerColor(int position, RecyclerView parent) {
return color;
}
});
}
public T colorResId(@ColorRes int colorId) {
return color(ContextCompat.getColor(mContext, colorId));
}
public T colorProvider(ColorProvider provider) {
mColorProvider = provider;
return (T) this;
}
public T drawable(@DrawableRes int id) {
return drawable(ContextCompat.getDrawable(mContext, id));
}
public T drawable(final Drawable drawable) {
return drawableProvider(new DrawableProvider() {
@Override
public Drawable drawableProvider(int position, RecyclerView parent) {
return drawable;
}
});
}
public T drawableProvider(DrawableProvider provider) {
mDrawableProvider = provider;
return (T) this;
}
public T size(final int size) {
return sizeProvider(new SizeProvider() {
@Override
public int dividerSize(int position, RecyclerView parent) {
return size;
}
});
}
public T sizeResId(@DimenRes int sizeId) {
return size(mResources.getDimensionPixelSize(sizeId));
}
public T sizeProvider(SizeProvider provider) {
mSizeProvider = provider;
return (T) this;
}
public T setStartPosition(int position){
this.startPosition = position;
return (T)this;
}
public T visibilityProvider(VisibilityProvider provider) {
mVisibilityProvider = provider;
return (T) this;
}
public T showLastDivider() {
mShowLastDivider = true;
return (T) this;
}
public T positionInsideItem(boolean positionInsideItem) {
mPositionInsideItem = positionInsideItem;
return (T) this;
}
protected void checkBuilderParams() {
if (mPaintProvider != null) {
if (mColorProvider != null) {
throw new IllegalArgumentException(
"Use setColor method of Paint class to specify line color. Do not provider ColorProvider if you set PaintProvider.");
}
if (mSizeProvider != null) {
throw new IllegalArgumentException(
"Use setStrokeWidth method of Paint class to specify line size. Do not provider SizeProvider if you set PaintProvider.");
}
}
}
}
}
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