android 桌面文件平夹

引用：http://blog.csdn.net/hmg25/article/details/6574575

哈哈，好久没有写博客拉，blog里边好凄凉阿~~人也变懒了……

    android原生自带的桌面文件夹样式及其简单，没有iphone那种可以显示文件夹内文件图标缩略图的功能，今天我们来简单的实现一个。

效果如下：

从launcher源码中很容易变可以看出需要修改的文件，主要修改FolderIcon.java这个文件。修改后的代码如下：

public class FolderIcon extends BubbleTextView implements DropTarget {
    private UserFolderInfo mInfo;
    private Launcher mLauncher;
    private Drawable mCloseIcon;
    private Drawable mOpenIcon;
    // add by hmg for FolderIcon {
    private IconCache mIconCache;
    private static final int ICON_COUNT = 4;  //可显示的缩略图数
    private static final int NUM_COL = 2;    // 每行显示的个数
    private static final int PADDING = 1;    //内边距
    private static final int MARGIN = 7;     //外边距
    // add by hmg for FolderIcon }
    public FolderIcon(Context context, AttributeSet attrs) {
        super(context, attrs);
        mIconCache = ((LauncherApplication) mContext.getApplicationContext())
                .getIconCache();
    }
    public FolderIcon(Context context) {
        super(context);
        mIconCache = ((LauncherApplication) mContext.getApplicationContext())
                .getIconCache();
    }
    static FolderIcon fromXml(int resId, Launcher launcher, ViewGroup group,
            UserFolderInfo folderInfo) {
        FolderIcon icon = (FolderIcon) LayoutInflater.from(launcher).inflate(
                resId, group, false);
        // final Resources resources = launcher.getResources();
        // Drawable d = resources.getDrawable(R.drawable.ic_launcher_folder);
        // icon.mCloseIcon = d;
        // icon.mOpenIcon =
        // resources.getDrawable(R.drawable.ic_launcher_folder_open);
        // icon.setCompoundDrawablesWithIntrinsicBounds(null, d, null, null);
        icon.setText(folderInfo.title);
        icon.setTag(folderInfo);
        icon.setOnClickListener(launcher);
        icon.mInfo = folderInfo;
        icon.mLauncher = launcher;

        icon.updateFolderIcon();   //更新图标
        folderInfo.setFolderIcon(icon); //设置FolderIcon
        return icon;
    }
    // add by hmg25 for  FolderIcon {
    /**
     * Author : hmg25 Version: 1.0 Description : 更新FolderIcon显示的文件缩略图
     */
    public void updateFolderIcon() {
        float x, y;
        final Resources resources = mLauncher.getResources();
        Bitmap closebmp = BitmapFactory.decodeResource(resources,
                R.drawable.icon_folder);   //获取FolderIcon关闭时的背景图
        Bitmap openbmp = BitmapFactory.decodeResource(resources,
                R.drawable.icon_folder_open); //获取FolderIcon打开时的背景图

        int iconWidth = closebmp.getWidth();  //icon的宽度
        int iconHeight = closebmp.getHeight();
        Bitmap folderclose = Bitmap.createBitmap(iconWidth, iconHeight,
                Bitmap.Config.ARGB_8888);
        Bitmap folderopen = Bitmap.createBitmap(iconWidth, iconHeight,
                Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(folderclose);
        canvas.drawBitmap(closebmp, 0, 0, null);  //绘制背景
        Matrix matrix = new Matrix(); // 创建操作图片用的Matrix对象
        float scaleWidth = (iconWidth - MARGIN * 2) / NUM_COL - 2 * PADDING;  //计算缩略图的宽(高与宽相同)
        float scale = (scaleWidth / iconWidth); // 计算缩放比例
        matrix.postScale(scale, scale);    // 设置缩放比例
        for (int i = 0; i < ICON_COUNT; i++) {
            if (i < mInfo.contents.size()) {
                x = MARGIN + PADDING * (2 * (i % NUM_COL) + 1) + scaleWidth
                        * (i % NUM_COL);
                y = MARGIN + PADDING * (2 * (i / NUM_COL) + 1) + scaleWidth
                        * (i / NUM_COL);
                ShortcutInfo scInfo = (ShortcutInfo) mInfo.contents.get(i);
                Bitmap iconbmp = scInfo.getIcon(mIconCache);      //获取缩略图标
                Bitmap scalebmp = Bitmap.createBitmap(iconbmp, 0, 0, iconWidth,
                        iconHeight, matrix, true);
                canvas.drawBitmap(scalebmp, x, y, null);
            }
        }
        mCloseIcon = new FastBitmapDrawable(folderclose);  //将bitmap转换为Drawable
        setCompoundDrawablesWithIntrinsicBounds(null, mCloseIcon, null, null);
        canvas = new Canvas(folderopen);
        canvas.drawBitmap(folderclose, 0, 0, null);
        canvas.drawBitmap(openbmp, 0, 0, null);
        mOpenIcon = new FastBitmapDrawable(folderopen);  //绘制open图片
    }
    // add by hmg25 for  FolderIcon }
    public boolean acceptDrop(DragSource source, int x, int y, int xOffset,
            int yOffset, DragView dragView, Object dragInfo) {
        final ItemInfo item = (ItemInfo) dragInfo;
        final int itemType = item.itemType;
        return (itemType == LauncherSettings.Favorites.ITEM_TYPE_APPLICATION || itemType == LauncherSettings.Favorites.ITEM_TYPE_SHORTCUT)
                && item.container != mInfo.id;
    }
    public Rect estimateDropLocation(DragSource source, int x, int y,
            int xOffset, int yOffset, DragView dragView, Object dragInfo,
            Rect recycle) {
        return null;
    }
    public void onDrop(DragSource source, int x, int y, int xOffset,
            int yOffset, DragView dragView, Object dragInfo) {
        ShortcutInfo item;
        if (dragInfo instanceof ApplicationInfo) {
            // Came from all apps -- make a copy
            item = ((ApplicationInfo) dragInfo).makeShortcut();
        } else {
            item = (ShortcutInfo) dragInfo;
        }
        mInfo.add(item);
        LauncherModel.addOrMoveItemInDatabase(mLauncher, item, mInfo.id, 0, 0,
                0);
        updateFolderIcon();  //拖拽放入时更新
    }
    public void onDragEnter(DragSource source, int x, int y, int xOffset,
            int yOffset, DragView dragView, Object dragInfo) {
        setCompoundDrawablesWithIntrinsicBounds(null, mOpenIcon, null, null);
    }
    public void onDragOver(DragSource source, int x, int y, int xOffset,
            int yOffset, DragView dragView, Object dragInfo) {
    }
    public void onDragExit(DragSource source, int x, int y, int xOffset,
            int yOffset, DragView dragView, Object dragInfo) {
        setCompoundDrawablesWithIntrinsicBounds(null, mCloseIcon, null, null);
    }
}

将文件拖拽进入文件夹时响应FolderIcon中的onDrop,所以添加updateFolderIcon();

以上代码可以实现将图标拖拽进文件夹时实时更新缩略图显示，还没有对拖拽出文件夹时更新显示，所以还需要修改其他地方。跟踪代码可以看出拖拽离开文件夹时响应UserFolder中方法onDropCompleted，需要修改UserFolder.java：

public void onDropCompleted(View target, boolean success) {
       if (success) {
           ShortcutsAdapter adapter = (ShortcutsAdapter)mContent.getAdapter();
           adapter.remove(mDragItem);
          ((UserFolderInfo)mInfo).mFolderIcon.updateFolderIcon();  //add by hmg25 拖拽离开时更新
       }
   }
ublic void onDrop(DragSource source, int x, int y, int xOffset, int yOffset,
           DragView dragView, Object dragInfo) {
       ShortcutInfo item;
       if (dragInfo instanceof ApplicationInfo) {
           // Came from all apps -- make a copy
           item = ((ApplicationInfo)dragInfo).makeShortcut();
       } else {
           item = (ShortcutInfo)dragInfo;
       }
       ((ShortcutsAdapter)mContent.getAdapter()).add(item);
       LauncherModel.addOrMoveItemInDatabase(mLauncher, item, mInfo.id, 0, 0, 0);
       ((UserFolderInfo)mInfo).mFolderIcon.updateFolderIcon(); //add by hmg25  将文件直接拖拽到打开的文件夹更新

从以上代码可以看出为了传递FolderIcon对象，所以我们还需要为UserFolderInfo添加一个mFolderIcon成员，修改UserFolderInfo.java:

protected FolderIcon mFolderIcon = null; //add by hmg25 for Folder

 //add by hmg25 for Folder {
    void setFolderIcon(FolderIcon icon)
    {
    mFolderIcon=icon;
    }
 //add by hmg25 for Folder }

以上代码是在android2.2, 480*320下测试的，其他分辨率的可以修改

   private static final int ICON_COUNT = 4;  //可显示的缩略图数

    private static final int NUM_COL = 2;    // 每行显示的个数

    private static final int PADDING = 1;    //内边距

    private static final int MARGIN = 7;     //外边距

的值。