Google出品 可以添加headViewd的GridView

Posted 2022-12-13 源于未知

使用代码:

        HeaderGridView gvContent = (HeaderGridView) view.findViewById(R.id.gvContent);
        //添加headView
        View view = LayoutInflater.from(context).inflate(R.layout.headview_work, null);
        gvContent.addHeaderView(view);
        //设置适配器
        WorkAdapter workAdapter = new WorkAdapter(context);
        gvContent.setAdapter(workAdapter);
        //点击事件
        gvContent.setOnItemClickListener(new AdapterView.OnItemClickListener() 
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) 
                Log.i("点击了",position - gvContent.getNumColumns());
            
        );

注意事项:

1.需在setAdapter之前添加headView

2.headView占的长度不是1，而是GridView的NumColumns

position - gvContent.getNumColumns()

Google自定义的GridView

/*
 * Copyright (C) 2013 The android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.android.photos.views;
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.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)
 */
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 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();
        
    

Google原文:  https://android.googlesource.com/platform/packages/apps/Gallery2/+/idea133/src/com/android/photos/views/HeaderGridView.java