Android 怎么将fragment 动态地添加到布局中的任意位置？

我们通常是用

getSupportFragmentManager().beginTransaction().replace(R.id.fragment_view, fragment).commit()

来添加fragment到指定的视图位置。所以你的需求只需你动态的改变需要替换的这个view的位置就好了，替换流程还是不变的。

动态的改变view的位置，这需要你在java代码里动态的设置view的位置。

ListView是有addHeaderView和 addFooterView两个方法的.

但是作为官方推荐的ListView的升级版RecyclerView缺无法实现这两个方法。

那么如果使用RecyclerView实现这两个方法的效果该怎么做呢？

网上查询了很久，试过各种各样的实现方式，终于让我发现一个还不错的实现方法，那么就给大家推荐一下。

项目地址（别人写的，非博主的）https://github.com/jczmdeveloper/XCRecyclerView

我看了下这个源码，很简单，即写了一个继承RecyclerView的控件，自己实现addHeaderView和addFooterView两个方法

?

code

package com.xqx.com.recyclerviewheaderdemo

import android.content.Context

import android.support.v7.widget.RecyclerView

import android.util.AttributeSet

import android.util.Log

import android.view.View

import android.view.ViewGroup

import java.util.ArrayList

import java.util.List

public class XCRecyclerView extends RecyclerView{

private ArrayList<View>mHeaderViews = new ArrayList<>()

private ArrayList<View>mFooterViews = new ArrayList<>()

private RecyclerView.Adapter mAdapter

private RecyclerView.Adapter mWrapAdapter

private static final int TYPE_HEADER = -101

private static final int TYPE_FOOTER = -102

private static final int TYPE_LIST_ITEM = - 103

public XCRecyclerView(Context context) {

this(context, null)

}

public XCRecyclerView(Context context, AttributeSet attrs) {

this(context, attrs, 0)

}

public XCRecyclerView(Context context, AttributeSet attrs, int defStyle) {

super(context, attrs, defStyle)

init(context)

}

private void init(Context context){

}

@Override

public void setAdapter(Adapter adapter) {

mAdapter = adapter

mWrapAdapter = new WrapAdapter(mHeaderViews, mFooterViews, adapter)

super.setAdapter(mWrapAdapter)

mAdapter.registerAdapterDataObserver(mDataObserver)

}

public void addHeaderView(View view){

mHeaderViews.clear()

mHeaderViews.add(view)

}

public void addFooterView(View view){

mFooterViews.clear()

mFooterViews.add(view)

}

public int getHeaderViewsCount(){

return mHeaderViews.size()

}

public int getFooterViewsCount(){

return mFooterViews.size()

}

private final RecyclerView.AdapterDataObserver mDataObserver = new RecyclerView.AdapterDataObserver() {

@Override

public void onChanged() {

mWrapAdapter.notifyDataSetChanged()

}

@Override

public void onItemRangeChanged(int positionStart, int itemCount) {

mWrapAdapter.notifyItemRangeChanged(positionStart, itemCount)

}

//@Override

//public void onItemRangeChanged(int positionStart, int itemCount, Object payload) {

//mWrapAdapter.notifyItemRangeChanged(positionStart, itemCount, payload)

//}

@Override

public void onItemRangeInserted(int positionStart, int itemCount) {

mWrapAdapter.notifyItemRangeInserted(positionStart, itemCount)

}

@Override

public void onItemRangeMoved(int fromPosition, int toPosition, int itemCount) {

mWrapAdapter.notifyItemMoved(fromPosition, toPosition)

}

@Override

public void onItemRangeRemoved(int positionStart, int itemCount) {

mWrapAdapter.notifyItemRangeRemoved(positionStart, itemCount)

}

}

private class WrapAdapter extends RecyclerView.Adapter<ViewHolder>{

private Adapter mAdapter

private List<View>mHeaderViews

private List<View>mFooterViews

public WrapAdapter(List<View>headerViews,List<View>footerViews,Adapter adapter){

this.mAdapter = adapter

this.mHeaderViews = headerViews

this.mFooterViews = footerViews

}

public int getHeaderCount(){

return this.mHeaderViews.size()

}

public int getFooterCount(){

return this.mFooterViews.size()

}

public boolean isHeader(int position){

return position >= 0 &&position <this.mHeaderViews.size()

}

public boolean isFooter(int position){

return position <getItemCount() &&position >= getItemCount() - this.mFooterViews.size()

}

@Override

public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

if(viewType == TYPE_HEADER){

return new CustomViewHolder(this.mHeaderViews.get(0))

}else if(viewType == TYPE_FOOTER){

return new CustomViewHolder(this.mFooterViews.get(0))

}else{

return this.mAdapter.onCreateViewHolder(parent,viewType)

}

}

@Override

public void onBindViewHolder(ViewHolder holder, int position) {

if(isHeader(position)) return

if(isFooter(position)) return

int rePosition = position - getHeaderCount()

int itemCount = this.mAdapter.getItemCount()

if(this.mAdapter != null){

if(rePosition <itemCount){

Log.v("czm","rePosition/itemCount="+rePosition+"/"+itemCount)

this.mAdapter.onBindViewHolder(holder,rePosition)

return

}

}

}

@Override

public long getItemId(int position) {

if (this.mAdapter != null &&position >= getHeaderCount()) {

int rePosition = position - getHeaderCount()

int itemCount = this.mAdapter.getItemCount()

if (rePosition <itemCount) {

return this.mAdapter.getItemId(rePosition)

}

}

return -1

}

@Override

public int getItemViewType(int position) {

if(isHeader(position)){

return TYPE_HEADER

}

if(isFooter(position)){

return TYPE_FOOTER

}

int rePosition = position - getHeaderCount()

int itemCount = this.mAdapter.getItemCount()

if(rePosition <itemCount){

return this.mAdapter.getItemViewType(position)

}

return TYPE_LIST_ITEM

}

@Override

public int getItemCount() {

if(this.mAdapter != null){

return getHeaderCount() + getFooterCount() + this.mAdapter.getItemCount()

}else{

return getHeaderCount() + getFooterCount()

}

}

@Override

public void registerAdapterDataObserver(AdapterDataObserver observer) {

if(this.mAdapter != null){

this.mAdapter.registerAdapterDataObserver(observer)

}

}

@Override

public void unregisterAdapterDataObserver(AdapterDataObserver observer) {

if(this.mAdapter != null){

this.mAdapter.unregisterAdapterDataObserver(observer)

}

}

private class CustomViewHolder extends ViewHolder{

public CustomViewHolder(View itemView) {

super(itemView)

}

}

}

}

XCRecyclerView

使用方法github里也写的清清楚楚的

?

code

private MyAdapter mAdapter

private XCRecyclerView mRecyclerView

private List<String>mData

private View mHeaderView

private View mFooterView

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState)

setContentView(R.layout.activity_main)

mData = new ArrayList<String>()

for(int i = 0i <10 i++){

mData.add("item_" + i)

}

mAdapter = new MyAdapter(mData)

mRecyclerView = (XCRecyclerView) findViewById(R.id.recycler_view)

mRecyclerView.setLayoutManager(new LinearLayoutManager(this))

mHeaderView = LayoutInflater.from(this).inflate(R.layout.layout_header,mRecyclerView,false)

mFooterView = LayoutInflater.from(this).inflate(R.layout.layout_footer,mRecyclerView,false)

mRecyclerView.addHeaderView(mHeaderView)

mRecyclerView.addFooterView(mFooterView)

mRecyclerView.setAdapter(mAdapter)

}

注意点：

addHeaderView之后 列表的数据坐标即相应发生变化！即addHeadView一次，列表第一个数据的下坐标+1（0-->1）

你可以用ArrayList当数据源，每次加一张图片都放到ArrayList里面去，再通过你GridView的设配器通知更新：imgAdapter.notifyDataSetChanged()

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