ExpanableRecyclerView
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github:https://github.com/hgDendi/ExpandableRecyclerView
自定義支持二級(jí)菜單的RecyclerViewAdapter蝇裤。
將展開閉合操作封裝在了BaseExpandableRecyclerViewAdapter中，使整個(gè)使用方式充滿彈性观蓄。
下方有具體使用方法，一般需要override 6個(gè)方法：
- getGroupCount
- getGroupItem
- onCreateGroupViewHolder
- onCreateChildViewHolder
- onBindGroupViewHolder
- onBindChildViewHolder
因?yàn)閛nCreateViewHolder和onBindViewHolder本來(lái)即是RecyclerViewAdapter需要強(qiáng)制Override的方法怠李，這里按父子關(guān)系拆分成了兩個(gè)方法针姿。而getGroupCount和getGroupItem在大概率情況下都是基于List的簡(jiǎn)單一行代碼即可實(shí)現(xiàn)乒省，故而使用起來(lái)十分簡(jiǎn)便。
Gradle
dependencies{
compile 'com.hgDendi:expandable-recyclerview-adapter:1.0.1'
}
優(yōu)點(diǎn)
- 使用便捷钝满、簡(jiǎn)潔明了
- 最大程度保留RecyclerView的原生機(jī)制兜粘，滑動(dòng)到具體條目才進(jìn)行渲染，不會(huì)滑到另一個(gè)Group渲染另一個(gè)Group下所有子Item
- itemView的部分刷新弯蚜，可以自定義展開孔轴、閉合時(shí)的刷新機(jī)制，避免GroupItem在展開閉合時(shí)刷新整個(gè)GroupItem（比如只是簡(jiǎn)單的箭頭指向改變）
- 采用泛型熟吏，用戶自定義傳入?yún)?shù)距糖，擴(kuò)展性更高
使用方法
定義父子數(shù)據(jù)結(jié)構(gòu)
其中GroupBean需要繼承自BaseGroupBean并override三個(gè)方法玄窝。
- getChildCount
- 獲取子節(jié)點(diǎn)個(gè)數(shù)
- isExpandable
- 是否為可展開的節(jié)點(diǎn)
- 默認(rèn)實(shí)現(xiàn)可以是判斷子節(jié)點(diǎn)是否為0，但是也可以做其他處理
- getChildAt
- 根據(jù)index獲取對(duì)應(yīng)的子節(jié)點(diǎn)數(shù)據(jù)結(jié)構(gòu)
class SampleGroupBean implements BaseExpandableRecyclerViewAdapter.BaseGroupBean<SampleChildBean> {
@Override
public int getChildCount() {
return mList.size();
}
// whether this group is expandable
@Override
public boolean isExpandable() {
return getChildCount() > 0;
}
@Override
public SampleChildBean getChildAt(int index) {
return mList.size() <= index ? null : mList.get(index);
}
}
public class SampleChildBean {
}
定義對(duì)應(yīng)的ViewHolder
其中Group對(duì)應(yīng)的ViewHolder要繼承BaseGroupViewHolder并改寫onExpandStatusChanged.
該方法是實(shí)現(xiàn)item局部刷新的方法悍引，在展開恩脂、閉合時(shí)會(huì)回調(diào)，比如對(duì)于大多數(shù)情況趣斤，開關(guān)閉合狀態(tài)只需要修改左邊箭頭指向俩块，就無(wú)需刷新itemView的其他部分。
實(shí)現(xiàn)原理是使用RecyclerView的payload機(jī)制實(shí)現(xiàn)局部監(jiān)聽刷新浓领。
static class GroupVH extends BaseExpandableRecyclerViewAdapter.BaseGroupViewHolder {
GroupVH(View itemView) {
super(itemView);
}
// this method is used for partial update.Which means when expand status changed,only a part of this view need to invalidate
@Override
protected void onExpandStatusChanged(RecyclerView.Adapter relatedAdapter, boolean isExpanding) {
// 1.只更新左側(cè)展開玉凯、閉合箭頭
foldIv.setImageResource(isExpanding ? R.drawable.ic_arrow_expanding : R.drawable.ic_arrow_folding);
// 2.默認(rèn)刷新整個(gè)Item
relatedAdapter.notifyItemChanged(getAdapterPosition());
}
}
static class ChildVH extends RecyclerView.ViewHolder {
ChildVH(View itemView) {
super(itemView);
}
}
使用自定義Adapter繼承基類
// !!注意這里繼承時(shí)候使用的泛型，分別為上面提到的Bean和ViewHolder
public class SampleAdapter extends BaseExpandableRecyclerViewAdapter
<SampleGroupBean, SampleChildBean, SampleAdapter.GroupVH, SampleAdapter.ChildVH>
@Override
public int getGroupCount() {
// 父節(jié)點(diǎn)個(gè)數(shù)
}
@Override
public GroupBean getGroupItem(int groupIndex) {
// 獲取父節(jié)點(diǎn)
}
@Override
public GroupVH onCreateGroupViewHolder(ViewGroup parent, int groupViewType) {
}
@Override
public ChildVH onCreateChildViewHolder(ViewGroup parent, int childViewType) {
}
@Override
public void onBindGroupViewHolder(GroupVH holder, SampleGroupBean sampleGroupBean, boolean isExpand) {
}
@Override
public void onBindChildViewHolder(ChildVH holder, SampleGroupBean sampleGroupBean, SampleChildBean sampleChildBean) {
}
}
其他用法
增加父子的種類
通過(guò)改寫getChildType和getGroupType方法進(jìn)行控制type联贩，該type會(huì)在onCreateGroupViewHolder和onCreateChildViewHolder時(shí)回傳漫仆。
protected int getGroupType(GroupBean groupBean) {
return 0;
}
abstract public GroupViewHolder onCreateGroupViewHolder(ViewGroup parent, int groupViewType);
protected int getChildType(GroupBean groupBean, ChildBean childBean) {
return 0;
}
abstract public ChildViewHolder onCreateChildViewHolder(ViewGroup parent, int childViewType);
增加列表為空時(shí)候的EmptyView
adapter.setEmptyViewProducer(new ViewProducer() {
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent) {
View emptyView = LayoutInflater.from(parent.getContext()).inflate(R.layout.empty, parent, false);
return new DefaultEmptyViewHolder(emptyView);
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder) {
}
});
增加HeaderView
adapter.setEmptyViewProducer(new ViewProducer() {
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent) {
View emptyView = LayoutInflater.from(parent.getContext()).inflate(R.layout.header, parent, false);
return new DefaultEmptyViewHolder(emptyView);
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder) {
}
},false);
監(jiān)聽事件
可以通過(guò)setListener的方式設(shè)置監(jiān)聽事件。
public interface ExpandableRecyclerViewOnClickListener<GroupBean extends BaseGroupBean, ChildBean> {
/**
* 長(zhǎng)按時(shí)的操作
*
* @param groupItem
* @return
*/
boolean onGroupLongClicked(GroupBean groupItem);
/**
* 在可展開group被點(diǎn)擊的時(shí)候觸發(fā)的回調(diào)泪幌，返回布爾值表示是否攔截該操作
*
* @param groupItem
* @param isExpand
* @return true 使點(diǎn)擊無(wú)效盲厌。false 正常執(zhí)行展開、閉合操作祸泪。
*/
boolean onInterceptGroupExpandEvent(GroupBean groupItem, boolean isExpand);
/**
* 點(diǎn)擊GroupView時(shí)的操作(該Group的isExpandable返回false才會(huì)觸發(fā)這個(gè)回調(diào))
*
* @param groupItem
*/
void onGroupClicked(GroupBean groupItem);
/**
* 點(diǎn)擊子View時(shí)的操作
*
* @param groupItem
* @param childItem
*/
void onChildClicked(GroupBean groupItem, ChildBean childItem);
}
實(shí)現(xiàn)原理
父子結(jié)構(gòu)劃分
- 通過(guò)getItemType判斷所處類型吗浩，在基類中就先劃分為四種類型的View。
private static final int TYPE_EMPTY = ViewProducer.VIEW_TYPE_EMPTY;
private static final int TYPE_HEADER = ViewProducer.VIEW_TYPE_HEADER;
private static final int TYPE_GROUP = ViewProducer.VIEW_TYPE_EMPTY >> 2;
private static final int TYPE_CHILD = ViewProducer.VIEW_TYPE_EMPTY >> 3;
private static final int TYPE_MASK = TYPE_GROUP | TYPE_CHILD | TYPE_EMPTY | TYPE_HEADER;
// 通過(guò)getItemView判斷類型没隘，這里默認(rèn)是使用上面定義的MASK懂扼，可以重載使Group和Child中再劃分子類，但是不允許和TYPE_MASK沖突右蒲，否則會(huì)報(bào)Exception
@Override
public final int getItemViewType(int position) {
if (mIsEmpty) {
return position == 0 && mShowHeaderViewWhenEmpty ? TYPE_HEADER : TYPE_EMPTY;
}
if (position == 0 && mHeaderViewProducer != null) {
return TYPE_HEADER;
}
int[] coord = translateToDoubleIndex(position);
GroupBean groupBean = getGroupItem(coord[0]);
if (coord[1] < 0) {
int groupType = getGroupType(groupBean);
if ((groupType & TYPE_MASK) == 0) {
return groupType | TYPE_GROUP;
} else {
throw new IllegalStateException(
String.format(Locale.getDefault(), "GroupType [%d] conflits with MASK [%d]", groupType, TYPE_MASK));
}
} else {
int childType = getChildType(groupBean, groupBean.getChildAt(coord[1]));
if ((childType & TYPE_MASK) == 0) {
return childType | TYPE_CHILD;
} else {
throw new IllegalStateException(
String.format(Locale.getDefault(), "ChildType [%d] conflits with MASK [%d]", childType, TYPE_MASK));
}
}
}
- 在onCreateViewHolder和onBindViewHolder中進(jìn)行類型判斷阀湿，調(diào)用不同的方法，這些方法在子類中進(jìn)行重載瑰妄。注意這里將這三個(gè)方法都置為final炕倘，防止子類重載，子類只能重載對(duì)應(yīng)不同type的具體方法翰撑。
@Override
public final RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
switch (viewType & TYPE_MASK) {
case TYPE_EMPTY:
return mEmptyViewProducer.onCreateViewHolder(parent);
case TYPE_HEADER:
return mHeaderViewProducer.onCreateViewHolder(parent);
case TYPE_CHILD:
return onCreateChildViewHolder(parent, viewType ^ TYPE_CHILD);
case TYPE_GROUP:
return onCreateGroupViewHolder(parent, viewType ^ TYPE_GROUP);
default:
throw new IllegalStateException(
String.format(Locale.getDefault(), "Illegal view type : viewType[%d]", viewType));
}
}
@Override
public final void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
onBindViewHolder(holder, position, null);
}
@Override
public final void onBindViewHolder(RecyclerView.ViewHolder holder, int position, List<Object> payloads) {
switch (holder.getItemViewType() & TYPE_MASK) {
case TYPE_EMPTY:
mEmptyViewProducer.onBindViewHolder(holder);
break;
case TYPE_HEADER:
mHeaderViewProducer.onBindViewHolder(holder);
break;
case TYPE_CHILD:
final int[] childCoord = translateToDoubleIndex(position);
GroupBean groupBean = getGroupItem(childCoord[0]);
bindChildViewHolder((ChildViewHolder) holder, groupBean, groupBean.getChildAt(childCoord[1]), payloads);
break;
case TYPE_GROUP:
bindGroupViewHolder((GroupViewHolder) holder,
getGroupItem(translateToDoubleIndex(position)[0]), payloads);
break;
default:
throw new IllegalStateException(
String.format(Locale.getDefault(), "Illegal view type : position [%d] ,itemViewType[%d]", position, holder.getItemViewType()));
}
}
展開閉合操作
操作
當(dāng)groupBean的isExpandable返回true的時(shí)候，為itemView設(shè)置點(diǎn)擊事件啊央，進(jìn)行展開閉合眶诈。
展開閉合的具體原理是在Set中記錄展開閉合情況，當(dāng)發(fā)生展開瓜饥、閉合操作的時(shí)候進(jìn)行更新逝撬，并使用notifyItemChange接口進(jìn)行列表的局部刷新。
private Set<GroupBean> mExpandGroupSet;
protected void bindGroupViewHolder(final GroupViewHolder holder, final GroupBean groupBean, List<Object> payload) {
// ...
if (!groupBean.isExpandable()) {
// ...
} else {
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
final boolean isExpand = mExpandGroupSet.contains(groupBean);
if (mListener == null || !mListener.onInterceptGroupExpandEvent(groupBean, isExpand)) {
final int adapterPosition = holder.getAdapterPosition();
holder.onExpandStatusChanged(BaseExpandableRecyclerViewAdapter.this, !isExpand);
if (isExpand) {
mExpandGroupSet.remove(groupBean);
notifyItemRangeRemoved(adapterPosition + 1, groupBean.getChildCount());
} else {
mExpandGroupSet.add(groupBean);
notifyItemRangeInserted(adapterPosition + 1, groupBean.getChildCount());
}
}
}
});
}
// 子類實(shí)現(xiàn)
onBindGroupViewHolder(holder, groupBean, isGroupExpand(groupBean));
}
局部刷新原理
定義了Payload乓土，采用Payload機(jī)制進(jìn)行局部刷新宪潮。
在notifyItemChange時(shí)傳入payload溯警，在onBindViewHolder操作中判斷是否帶有payload，若帶有payload狡相，則執(zhí)行部分刷新的操作梯轻。
private static final Object EXPAND_PAYLOAD = new Object();
// 局部刷新時(shí)調(diào)用的接口(已封裝好，用戶無(wú)需調(diào)用)
notifyItemChanged(position, EXPAND_PAYLOAD);
// 處理payload
protected void bindGroupViewHolder(final GroupViewHolder holder, final GroupBean groupBean, List<Object> payload) {
if (payload != null && payload.size() != 0) {
if (payload.contains(EXPAND_PAYLOAD)) {
// holder方法有抽象方法尽棕，在此方法中實(shí)現(xiàn)具體的展開喳挑、閉合邏輯
holder.onExpandStatusChanged(BaseExpandableRecyclerViewAdapter.this, isGroupExpand(groupBean));
if (payload.size() == 1) {
return;
}
}
onBindGroupViewHolder(holder, groupBean, isGroupExpand(groupBean), payload);
return;
}
}
License
MIT
