让GridView可以addHeaderView

[代码] 带HeaderView的GridView

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packagecom.kuaiyouxi.gamepad.sdk.kamcord.watch.widget;

 

/*

  * 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.

  */

importandroid.content.Context;

importandroid.database.DataSetObservable;

importandroid.database.DataSetObserver;

importandroid.util.AttributeSet;

importandroid.view.View;

importandroid.view.ViewGroup;

importandroid.widget.AdapterView;

importandroid.widget.Filter;

importandroid.widget.Filterable;

importandroid.widget.FrameLayout;

importandroid.widget.GridView;

importandroid.widget.ListAdapter;

importandroid.widget.WrapperListAdapter;

importjava.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)}  

 */

publicclass HeaderGridView extendsGridView {

    privatestatic 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.  

     */

    privatestatic class FixedViewInfo {

        /** The view to add to the grid */

        publicView view;

        publicViewGroup viewContainer;

        /**

         * The data backing the view. This is returned from

         * {@link ListAdapter#getItem(int)}.

         */

        publicObject data;

        /** <code>true</code> if the fixed view should be selectable in the grid */

        publicboolean isSelectable;

    }

 

    privateArrayList<FixedViewInfo> mHeaderViewInfos = newArrayList<FixedViewInfo>();

 

    privatevoid initHeaderGridView() {

        super.setClipChildren(false);

    }

 

    publicHeaderGridView(Context context) {

        super(context);

        initHeaderGridView();

    }

 

    publicHeaderGridView(Context context, AttributeSet attrs) {

        super(context, attrs);

        initHeaderGridView();

    }

 

    publicHeaderGridView(Context context, AttributeSet attrs, intdefStyle) {

        super(context, attrs, defStyle);

        initHeaderGridView();

    }

 

    @Override

    protectedvoid onMeasure(intwidthMeasureSpec, intheightMeasureSpec) {

        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        ListAdapter adapter = getAdapter();

        if(adapter != null&& adapter instanceofHeaderViewGridAdapter) {

            ((HeaderViewGridAdapter) adapter).setNumColumns(getNumColumns());

        }

    }

 

    @Override

    publicvoid setClipChildren(booleanclipChildren) {

        // 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  

     */

    publicvoid addHeaderView(View v, Object data, booleanisSelectable) {

        ListAdapter adapter = getAdapter();

        if(adapter != null&& !(adapter instanceofHeaderViewGridAdapter)) {

            thrownew IllegalStateException(

                    "Cannot add header view to grid -- setAdapter has already been called.");

        }

        FixedViewInfo info = newFixedViewInfo();

        FrameLayout fl = newFullWidthFixedViewLayout(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.  

     */

    publicvoid addHeaderView(View v) {

        addHeaderView(v,null,true);

    }

 

    publicint getHeaderViewCount() {

        returnmHeaderViewInfos.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  

     */

    publicboolean removeHeaderView(View v) {

        if(mHeaderViewInfos.size() > 0) {

            booleanresult = false;

            ListAdapter adapter = getAdapter();

            if(adapter != null

                    && ((HeaderViewGridAdapter) adapter).removeHeader(v)) {

                result = true;

            }

            removeFixedViewInfo(v, mHeaderViewInfos);

            returnresult;

        }

        returnfalse;

    }

 

    privatevoid removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) {

        intlen = where.size();

        for(inti = 0; i < len; ++i) {

            FixedViewInfo info = where.get(i);

            if(info.view == v) {

                where.remove(i);

                break;

            }

        }

    }

 

    @Override

    publicvoid setAdapter(ListAdapter adapter) {

        if(mHeaderViewInfos.size() > 0) {

            HeaderViewGridAdapter hadapter = newHeaderViewGridAdapter(

                    mHeaderViewInfos, adapter);

            intnumColumns = getNumColumns();

            if(numColumns > 1) {

                hadapter.setNumColumns(numColumns);

            }

            super.setAdapter(hadapter);

        }else{

            super.setAdapter(adapter);

        }

    }

 

    privateclass FullWidthFixedViewLayout extendsFrameLayout {

        publicFullWidthFixedViewLayout(Context context) {

            super(context);

        }

 

        @Override

        protectedvoid onMeasure(intwidthMeasureSpec, intheightMeasureSpec) {

            inttargetWidth = 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.  

     */

    privatestatic class HeaderViewGridAdapter implementsWrapperListAdapter,

            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

        privatefinal DataSetObservable mDataSetObservable = newDataSetObservable();

        privatefinal ListAdapter mAdapter;

        privateint mNumColumns = 1;

        // This ArrayList is assumed to NOT be null.

        ArrayList<FixedViewInfo> mHeaderViewInfos;

        booleanmAreAllFixedViewsSelectable;

        privatefinal boolean mIsFilterable;

 

        publicHeaderViewGridAdapter(ArrayList<FixedViewInfo> headerViewInfos,

                ListAdapter adapter) {

            mAdapter = adapter;

            mIsFilterable = adapter instanceofFilterable;

            if(headerViewInfos == null) {

                thrownew IllegalArgumentException(

                        "headerViewInfos cannot be null");

            }

            mHeaderViewInfos = headerViewInfos;

            mAreAllFixedViewsSelectable = areAllListInfosSelectable(mHeaderViewInfos);

        }

 

        publicint getHeadersCount() {

            returnmHeaderViewInfos.size();

        }

 

        @Override

        publicboolean isEmpty() {

            return(mAdapter == null|| mAdapter.isEmpty())

                    && getHeadersCount() == 0;

        }

 

        publicvoid setNumColumns(intnumColumns) {

            if(numColumns < 1) {

                thrownew IllegalArgumentException(

                        "Number of columns must be 1 or more");

            }

            if(mNumColumns != numColumns) {

                mNumColumns = numColumns;

                notifyDataSetChanged();

            }

        }

 

        privateboolean areAllListInfosSelectable(ArrayList<FixedViewInfo> infos) {

            if(infos != null) {

                for(FixedViewInfo info : infos) {

                    if(!info.isSelectable) {

                        returnfalse;

                    }

                }

            }

            returntrue;

        }

 

        publicboolean removeHeader(View v) {

            for(inti = 0; i < mHeaderViewInfos.size(); i++) {

                FixedViewInfo info = mHeaderViewInfos.get(i);

                if(info.view == v) {

                    mHeaderViewInfos.remove(i);

                    mAreAllFixedViewsSelectable = areAllListInfosSelectable(mHeaderViewInfos);

                    mDataSetObservable.notifyChanged();

                    returntrue;

                }

            }

            returnfalse;

        }

 

        @Override

        publicint getCount() {

            if(mAdapter != null) {

                returngetHeadersCount() * mNumColumns + mAdapter.getCount();

            }else{

                returngetHeadersCount() * mNumColumns;

            }

        }

 

        @Override

        publicboolean areAllItemsEnabled() {

            if(mAdapter != null) {

                returnmAreAllFixedViewsSelectable

                        && mAdapter.areAllItemsEnabled();

            }else{

                returntrue;

            }

        }

 

        @Override

        publicboolean isEnabled(intposition) {

            // Header (negative positions will throw an

            // ArrayIndexOutOfBoundsException)

            intnumHeadersAndPlaceholders = getHeadersCount() * mNumColumns;

            if(position < numHeadersAndPlaceholders) {

                return(position % mNumColumns == 0)

                        && mHeaderViewInfos.get(position / mNumColumns).isSelectable;

            }

            // Adapter

            finalint adjPosition = position - numHeadersAndPlaceholders;

            intadapterCount = 0;

            if(mAdapter != null) {

                adapterCount = mAdapter.getCount();

                if(adjPosition < adapterCount) {

                    returnmAdapter.isEnabled(adjPosition);

                }

            }

            thrownew ArrayIndexOutOfBoundsException(position);

        }

 

        @Override

        publicObject getItem(intposition) {

            // Header (negative positions will throw an

            // ArrayIndexOutOfBoundsException)

            intnumHeadersAndPlaceholders = getHeadersCount() * mNumColumns;

            if(position < numHeadersAndPlaceholders) {

                if(position % mNumColumns == 0) {

                    returnmHeaderViewInfos.get(position / mNumColumns).data;

                }

                returnnull;

            }

            // Adapter

            finalint adjPosition = position - numHeadersAndPlaceholders;

            intadapterCount = 0;

            if(mAdapter != null) {

                adapterCount = mAdapter.getCount();

                if(adjPosition < adapterCount) {

                    returnmAdapter.getItem(adjPosition);

                }

            }

            thrownew ArrayIndexOutOfBoundsException(position);

        }

 

        @Override

        publiclong getItemId(intposition) {

            intnumHeadersAndPlaceholders = getHeadersCount() * mNumColumns;

            if(mAdapter != null&& position >= numHeadersAndPlaceholders) {

                intadjPosition = position - numHeadersAndPlaceholders;

                intadapterCount = mAdapter.getCount();

                if(adjPosition < adapterCount) {

                    returnmAdapter.getItemId(adjPosition);

                }

            }

            return-1;

        }

 

        @Override

        publicboolean hasStableIds() {

            if(mAdapter != null) {

                returnmAdapter.hasStableIds();

            }

            returnfalse;

        }

 

        @Override

        publicView getView(intposition, View convertView, ViewGroup parent) {

            // Header (negative positions will throw an

            // ArrayIndexOutOfBoundsException)

            intnumHeadersAndPlaceholders = getHeadersCount() * mNumColumns;

            if(position < numHeadersAndPlaceholders) {

                View headerViewContainer = mHeaderViewInfos.get(position

                        / mNumColumns).viewContainer;

                if(position % mNumColumns == 0) {

                    returnheaderViewContainer;

                }else{

                    if(convertView == null) {

                        convertView = newView(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());

                    returnconvertView;

                }

            }

            // Adapter

            finalint adjPosition = position - numHeadersAndPlaceholders;

            intadapterCount = 0;

            if(mAdapter != null) {

                adapterCount = mAdapter.getCount();

                if(adjPosition < adapterCount) {

                    returnmAdapter.getView(adjPosition, convertView, parent);

                }

            }

            thrownew ArrayIndexOutOfBoundsException(position);

        }

 

        @Override

        publicint getItemViewType(intposition) {

            intnumHeadersAndPlaceholders = getHeadersCount() * mNumColumns;

            if(position < numHeadersAndPlaceholders

                    && (position % mNumColumns != 0)) {

                // Placeholders get the last view type number

                returnmAdapter != null? mAdapter.getViewTypeCount() : 1;

            }

            if(mAdapter != null&& position >= numHeadersAndPlaceholders) {

                intadjPosition = position - numHeadersAndPlaceholders;

                intadapterCount = mAdapter.getCount();

                if(adjPosition < adapterCount) {

                    returnmAdapter.getItemViewType(adjPosition);

                }

            }

            returnAdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER;

        }

 

        @Override

        publicint getViewTypeCount() {

            if(mAdapter != null) {

                returnmAdapter.getViewTypeCount() + 1;

            }

            return2;

        }

 

        @Override

        publicvoid registerDataSetObserver(DataSetObserver observer) {

            mDataSetObservable.registerObserver(observer);

            if(mAdapter != null) {

                mAdapter.registerDataSetObserver(observer);

            }

        }

 

        @Override

        publicvoid unregisterDataSetObserver(DataSetObserver observer) {

            mDataSetObservable.unregisterObserver(observer);

            if(mAdapter != null) {

                mAdapter.unregisterDataSetObserver(observer);

            }

        }

 

        @Override

        publicFilter getFilter() {

            if(mIsFilterable) {

                return((Filterable) mAdapter).getFilter();

            }

            returnnull;

        }

 

        @Override

        publicListAdapter getWrappedAdapter() {

            returnmAdapter;

        }

 

        publicvoid notifyDataSetChanged() {

            mDataSetObservable.notifyChanged();

        }

    }

}