带下拉刷新，上拉加载以及带自定义头布局的GridView

一、引言

相信很多人都会遇到GridView，一般都会带有下拉刷新和上拉加载，于是我们可以使用第三方框架去实现，实现方式有很多，这里我就不一一列举了，这里我经常使用的是这个https://github.com/chrisbanes/Android-PullToRefresh，使用步骤自己百度，网上很多。如何在这基础上添加自定义头布局（例如轮播图）怎么做呢，此第三方的GridView并没有addHeadView()的方法，网上的方法很多，有的要么不带下拉上拉，有的要么实现起来麻烦（事件分发问题，复用问题，性能问题），还有的我没试过，这里我借鉴了网上的一个方法，小小地改了一下。

二、使用步骤

1、添加依赖：https://github.com/chrisbanes/Android-PullToRefresh下载library,添加依赖

2、创建两个类如下：这两个类来自网上，自己稍微修改了一下

HeadGridView:

import android.annotation.SuppressLint;
import android.content.Context;
import android.database.DataSetObservable;
import android.database.DataSetObserver;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.FrameLayout;
import android.widget.GridView;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.WrapperListAdapter;

import java.util.ArrayList;
/**
* A {@link GridView} that supports adding header rows in a
* very similar way to {@link ListView}.
* See {@link HeaderGridView#addHeaderView(View, Object, boolean)}
*/
@SuppressLint("NewApi")
public class HeaderGridView extends  GridView  {
private static final String TAG = "HeaderGridView";
/**
* A class that represents a fixed view in a list, for example a header at the top
* or a footer at the bottom.
*/
private static class FixedViewInfo {
/** The view to add to the grid */
public View view;
public ViewGroup viewContainer;
/** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */
public Object data;
/** <code>true</code> if the fixed view should be selectable in the grid */
public boolean isSelectable;
}
private ArrayList<FixedViewInfo> mHeaderViewInfos = new ArrayList<FixedViewInfo>();
private void initHeaderGridView() {
super.setClipChildren(false);
}
public HeaderGridView(Context context) {
super(context);
initHeaderGridView();
}
public HeaderGridView(Context context, AttributeSet attrs) {
super(context, attrs);
initHeaderGridView();
}
public HeaderGridView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
initHeaderGridView();
}
@Override
protected void
18160
onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
ListAdapter adapter = getAdapter();
if (adapter != null && adapter instanceof HeaderViewGridAdapter) {
((HeaderViewGridAdapter) adapter).setNumColumns(getNumColumns());
}
}
@Override
public void setClipChildren(boolean clipChildren) {
// Ignore, since the header rows depend on not being clipped
}
/**
* Add a fixed view to appear at the top of the grid. If addHeaderView is
* called more than once, the views will appear in the order they were
* added. Views added using this call can take focus if they want.
* <p>
* NOTE: Call this before calling setAdapter. This is so HeaderGridView can wrap
* the supplied cursor with one that will also account for header views.
*
* @param v The view to add.
* @param data Data to associate with this view
* @param isSelectable whether the item is selectable
*/
public void addHeaderView(View v, Object data, boolean isSelectable) {
ListAdapter adapter = getAdapter();
if (adapter != null && ! (adapter instanceof HeaderViewGridAdapter)) {
throw new IllegalStateException(
"Cannot add header view to grid -- setAdapter has already been called.");
}
FixedViewInfo info = new FixedViewInfo();
FrameLayout fl = new FullWidthFixedViewLayout(getContext());
fl.addView(v);
info.view = v;
info.viewContainer = fl;
info.data = data;
info.isSelectable = isSelectable;
mHeaderViewInfos.add(info);
// in the case of re-adding a header view, or adding one later on,
// we need to notify the observer
if (adapter != null) {
((HeaderViewGridAdapter) adapter).notifyDataSetChanged();
}
}
/**
* Add a fixed view to appear at the top of the grid. If addHeaderView is
* called more than once, the views will appear in the order they were
* added. Views added using this call can take focus if they want.
* <p>
* NOTE: Call this before calling setAdapter. This is so HeaderGridView can wrap
* the supplied cursor with one that will also account for header views.
*
* @param v The view to add.
*/
public void addHeaderView(View v) {
addHeaderView(v, null, true);
}
public int getHeaderViewCount() {
return mHeaderViewInfos.size();
}
/**
* Removes a previously-added header view.
*
* @param v The view to remove
* @return true if the view was removed, false if the view was not a header
*         view
*/
public boolean removeHeaderView(View v) {
if (mHeaderViewInfos.size() > 0) {
boolean result = false;
ListAdapter adapter = getAdapter();
if (adapter != null && ((HeaderViewGridAdapter) adapter).removeHeader(v)) {
result = true;
}
removeFixedViewInfo(v, mHeaderViewInfos);
return result;
}
return false;
}
private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) {
int len = where.size();
for (int i = 0; i < len; ++i) {
FixedViewInfo info = where.get(i);
if (info.view == v) {
where.remove(i);
break;
}
}
}
@Override
public void setAdapter(ListAdapter adapter) {
if (mHeaderViewInfos.size() > 0) {
HeaderViewGridAdapter hadapter = new HeaderViewGridAdapter(mHeaderViewInfos, adapter);
int numColumns = getNumColumns();
if (numColumns > 1) {
hadapter.setNumColumns(numColumns);
}
super.setAdapter(hadapter);
} else {
super.setAdapter(adapter);
}
}
private class FullWidthFixedViewLayout extends FrameLayout {
public FullWidthFixedViewLayout(Context context) {
super(context);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int targetWidth = HeaderGridView.this.getMeasuredWidth()
- HeaderGridView.this.getPaddingLeft()
- HeaderGridView.this.getPaddingRight();
widthMeasureSpec = MeasureSpec.makeMeasureSpec(targetWidth,
MeasureSpec.getMode(widthMeasureSpec));
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
}
/**
* ListAdapter used when a HeaderGridView has header views. This ListAdapter
* wraps another one and also keeps track of the header views and their
* associated data objects.
*<p>This is intended as a base class; you will probably not need to
* use this class directly in your own code.
*/
private static class HeaderViewGridAdapter implements WrapperListAdapter, Filterable {
// This is used to notify the container of updates relating to number of columns
// or headers changing, which changes the number of placeholders needed
private final DataSetObservable mDataSetObservable = new DataSetObservable();
private final ListAdapter mAdapter;
private int mNumColumns = 1;
// This ArrayList is assumed to NOT be null.
ArrayList<FixedViewInfo> mHeaderViewInfos;
boolean mAreAllFixedViewsSelectable;
private final boolean mIsFilterable;
public HeaderViewGridAdapter(ArrayList<FixedViewInfo> headerViewInfos, ListAdapter adapter) {
mAdapter = adapter;
mIsFilterable = adapter instanceof Filterable;
if (headerViewInfos == null) {
throw new IllegalArgumentException("headerViewInfos cannot be null");
}
mHeaderViewInfos = headerViewInfos;
mAreAllFixedViewsSelectable = areAllListInfosSelectable(mHeaderViewInfos);
}
public int getHeadersCount() {
return mHeaderViewInfos.size();
}
@Override
public boolean isEmpty() {
return (mAdapter == null || mAdapter.isEmpty()) && getHeadersCount() == 0;
}
public void setNumColumns(int numColumns) {
if (numColumns < 1) {
throw new IllegalArgumentException("Number of columns must be 1 or more");
}
if (mNumColumns != numColumns) {
mNumColumns = numColumns;
notifyDataSetChanged();
}
}
private boolean areAllListInfosSelectable(ArrayList<FixedViewInfo> infos) {
if (infos != null) {
for (FixedViewInfo info : infos) {
if (!info.isSelectable) {
return false;
}
}
}
return true;
}
public boolean removeHeader(View v) {
for (int i = 0; i < mHeaderViewInfos.size(); i++) {
FixedViewInfo info = mHeaderViewInfos.get(i);
if (info.view == v) {
mHeaderViewInfos.remove(i);
mAreAllFixedViewsSelectable = areAllListInfosSelectable(mHeaderViewInfos);
mDataSetObservable.notifyChanged();
return true;
}
}
return false;
}
@Override
public int getCount() {
if (mAdapter != null) {
return getHeadersCount() * mNumColumns + mAdapter.getCount();
} else {
return getHeadersCount() * mNumColumns;
}
}
@Override
public boolean areAllItemsEnabled() {
if (mAdapter != null) {
return mAreAllFixedViewsSelectable && mAdapter.areAllItemsEnabled();
} else {
return true;
}
}
@Override
public boolean isEnabled(int position) {
// Header (negative positions will throw an ArrayIndexOutOfBoundsException)
int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
if (position < numHeadersAndPlaceholders) {
return (position % mNumColumns == 0)
&& mHeaderViewInfos.get(position / mNumColumns).isSelectable;
}
// Adapter
final int adjPosition = position - numHeadersAndPlaceholders;
int adapterCount = 0;
if (mAdapter != null) {
adapterCount = mAdapter.getCount();
if (adjPosition < adapterCount) {
return mAdapter.isEnabled(adjPosition);
}
}
throw new ArrayIndexOutOfBoundsException(position);
}
@Override
public Object getItem(int position) {
// Header (negative positions will throw an ArrayIndexOutOfBoundsException)
int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
if (position < numHeadersAndPlaceholders) {
if (position % mNumColumns == 0) {
return mHeaderViewInfos.get(position / mNumColumns).data;
}
return null;
}
// Adapter
final int adjPosition = position - numHeadersAndPlaceholders;
int adapterCount = 0;
if (mAdapter != null) {
adapterCount = mAdapter.getCount();
if (adjPosition < adapterCount) {
return mAdapter.getItem(adjPosition);
}
}
throw new ArrayIndexOutOfBoundsException(position);
}
@Override
public long getItemId(int position) {
int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
if (mAdapter != null && position >= numHeadersAndPlaceholders) {
int adjPosition = position - numHeadersAndPlaceholders;
int adapterCount = mAdapter.getCount();
if (adjPosition < adapterCount) {
return mAdapter.getItemId(adjPosition);
}
}
return -1;
}
@Override
public boolean hasStableIds() {
if (mAdapter != null) {
return mAdapter.hasStableIds();
}
return false;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// Header (negative positions will throw an ArrayIndexOutOfBoundsException)
int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns ;
if (position < numHeadersAndPlaceholders) {
View headerViewContainer = mHeaderViewInfos
.get(position / mNumColumns).viewContainer;
if (position % mNumColumns == 0) {
return headerViewContainer;
} else {
if (convertView == null) {
convertView = new View(parent.getContext());
}
// We need to do this because GridView uses the height of the last item
// in a row to determine the height for the entire row.
convertView.setVisibility(View.INVISIBLE);
convertView.setMinimumHeight(headerViewContainer.getHeight());
return convertView;
}
}
// Adapter
final int adjPosition = position - numHeadersAndPlaceholders;
int adapterCount = 0;
if (mAdapter != null) {
adapterCount = mAdapter.getCount();
if (adjPosition < adapterCount) {
return mAdapter.getView(adjPosition, convertView, parent);
}
}
throw new ArrayIndexOutOfBoundsException(position);
}
@Override
public int getItemViewType(int position) {
int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
if (position < numHeadersAndPlaceholders && (position % mNumColumns != 0)) {
// Placeholders get the last view type number
return mAdapter != null ? mAdapter.getViewTypeCount() : 1;
}
if (mAdapter != null && position >= numHeadersAndPlaceholders) {
int adjPosition = position - numHeadersAndPlaceholders;
int adapterCount = mAdapter.getCount();
if (adjPosition < adapterCount) {
return mAdapter.getItemViewType(adjPosition);
}
}
return AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER;
}
@Override
public int getViewTypeCount() {
if (mAdapter != null) {
return mAdapter.getViewTypeCount() + 1;
}
return 2;
}
@Override
public void registerDataSetObserver(DataSetObserver observer) {
mDataSetObservable.registerObserver(observer);
if (mAdapter != null) {
mAdapter.registerDataSetObserver(observer);
}
}
@Override
public void unregisterDataSetObserver(DataSetObserver observer) {
mDataSetObservable.unregisterObserver(observer);
if (mAdapter != null) {
mAdapter.unregisterDataSetObserver(observer);
}
}
@Override
public Filter getFilter() {
if (mIsFilterable) {
return ((Filterable) mAdapter).getFilter();
}
return null;
}
@Override
public ListAdapter getWrappedAdapter() {
return mAdapter;
}
public void notifyDataSetChanged() {
mDataSetObservable.notifyChanged();
}
}

}

PullToRefreshGridView:

/**
* @author hf  2016-11-08 13:16
* @version 1.0
* @des
* @版本 $Rev: 10638 $
* @change $Author: hufan $  $Date: 2016-11-08 17:00:27 +0800 (周二, 08 十一月 2016) $
* @des ${TODO}
*/

import android.annotation.TargetApi;
import android.content.Context;
import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import android.util.AttributeSet;
import android.view.View;

import com.handmark.pulltorefresh.library.OverscrollHelper;
import com.handmark.pulltorefresh.library.PullToRefreshAdapterViewBase;
import com.handmark.pulltorefresh.library.internal.EmptyViewMethodAccessor;

public class PullToRefreshGridView extends PullToRefreshAdapterViewBase<HeaderGridView> {

public PullToRefreshGridView(Context context) {
super(context);
}

public PullToRefreshGridView(Context context, AttributeSet attrs) {
super(context, attrs);
}

public PullToRefreshGridView(Context context, Mode mode) {
super(context, mode);
}

public PullToRefreshGridView(Context context, Mode mode, AnimationStyle style) {
super(context, mode, style);
}

@Override
public final Orientation getPullToRefreshScrollDirection() {
return Orientation.VERTICAL;
}

private HeaderGridView gv;
@Override
protected final HeaderGridView createRefreshableView(final Context context, AttributeSet attrs) {

if (VERSION.SDK_INT >= VERSION_CODES.GINGERBREAD) {
gv = new InternalGridViewSDK9(context, attrs);
} else {
gv = new InternalGridView(context, attrs);
}
// Use Generated ID (from res/values/ids.xml)
gv.setId(R.id.gridview);
return gv;
}

public void initHeadView(final Context context,ViewCallback callback) {
setCallback(callback);
View view=mCallback.setHeadView();
gv.addHeaderView(view);
}

class InternalGridView extends HeaderGridView implements EmptyViewMethodAccessor {

public InternalGridView(Context context, AttributeSet attrs) {
super(context, attrs);
}

@Override
public void setEmptyView(View emptyView) {
PullToRefreshGridView.this.setEmptyView(emptyView);
}

@Override
public void setEmptyViewInternal(View emptyView) {
super.setEmptyView(emptyView);
}
}

@TargetApi(9)
final class InternalGridViewSDK9 extends InternalGridView {

public InternalGridViewSDK9(Context context, AttributeSet attrs) {
super(context, attrs);
}

@Override
protected boolean overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY, int scrollRangeX,
int scrollRangeY, int maxOverScrollX, int maxOverScrollY, boolean isTouchEvent) {

final boolean returnValue = super.overScrollBy(deltaX, deltaY, scrollX, scrollY, scrollRangeX,
scrollRangeY, maxOverScrollX, maxOverScrollY, isTouchEvent);

// Does all of the hard work...
OverscrollHelper.overScrollBy(PullToRefreshGridView.this, deltaX, scrollX, deltaY, scrollY, isTouchEvent);

return returnValue;
}
}

public interface ViewCallback {
View setHeadView();
}

public void setCallback(ViewCallback viewCallback) {
this.mCallback = viewCallback;
}

private ViewCallback mCallback;
}

三、在xml文件中引用，注意是自己改写的那个，高度要设为match_parent ，否则会不显示

<包名下PullToRefreshGridView
android:id="@+id/jifen_gridView1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#e8ebed"
android:cacheColorHint="@color/bg_light_grey"
android:horizontalSpacing="@dimen/dp15"
android:numColumns="2"
android:overScrollMode="never"
android:scrollbars="none"
android:stretchMode="columnWidth"
android:verticalSpacing="@dimen/dp8">
</包名下PullToRefreshGridView>

四、初始化时，找到并设置GridView，调用了initHeadView方法才会显示头布局，不一定要写在这里

/**
* 配置刷新参数
*/
private void DoSetRefresh() {
mGridView.setMode(PullToRefreshBase.Mode.BOTH);
mGridView.setShowIndicator(false);//隐藏方向标
mGridView.setFocusable(true);
mGridView.initHeadView(mContext, new PullToRefreshGridView.ViewCallback() {
@Override
public View setHeadView() {
View view = View.inflate(mContext, LayoutResourcesId, null);
//这里可以对你的头布局做自己的操作，比如说添加Banner
return view;
}
});

ILoadingLayout startLabels = mGridView
.getLoadingLayoutProxy(true, false);
startLabels.setPullLabel("下拉刷新...");// 刚下拉时，显示的提示
startLabels.setRefreshingLabel("刷新中...");// 刷新时
startLabels.setReleaseLabel("松开刷新数据...");// 下来达到一定距离时，显示的提示

ILoadingLayout endLabels = mGridView.getLoadingLayoutProxy(
false, true);
endLabels.setPullLabel("上拉加载...");// 刚下拉时，显示的提示
endLabels.setRefreshingLabel("加载中...");// 刷新时
endLabels.setReleaseLabel("松开加载数据...");// 下来达到一定距离时，显示的提示
}

五、发起网络请求，得到数据之后设置Adapter

六、设置监听（省略），点击监听，头布局position从1开始，头布局下面position是从2开始

七、这里有个小问题，由于头布局与GridView是一体的，如果GridView的宽度设置margin离左右有点距离，导致头布局离左右也会有点距离，怎么办呢，只能动态改变item的属性了，设置GridVIew宽度填充屏幕,界所在界面颜色背景为#e8ebed,条目根布局也是这个颜色，里面再多嵌套一层LinearLayout 

//为了让头布局宽度充满整个屏幕，而下面的其他条目左边离屏幕有一定的距离，右边的条目离右边有点距离
LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) holder.itemLayout.getLayoutParams();
if (position % 2 == 0) {
params.leftMargin = mContext.getResources().getDimensionPixelSize(R.dimen.dp8);
params.rightMargin = 0;
} else {
params.leftMargin = 0;
params.rightMargin = mContext.getResources().getDimensionPixelSize(R.dimen.dp8);
}
holder.itemLayout.setLayoutParams(params);

这里在Adapter中动态改变它的属性就可以了