launcher修改--获取widget信息（图片，文字等）（源码追踪）

      在launcher中，长按屏幕，图挂了，我们在代码里面找一下：

首先，找到onLongClick(View v)方法，然后在这个方法中，有如下代码：

if (mWorkspace.allowLongPress()) {            if (cellInfo.cell == null) {                if (cellInfo.valid) {                    // User long pressed on empty space                    mWorkspace.setAllowLongPress(false);                    showAddDialog(cellInfo);                }            } else {                if (!(cellInfo.cell instanceof Folder)) {                    // User long pressed on an item                    mWorkspace.startDrag(cellInfo);                }            }        }

然后，继续追踪showAddDialog（）方法：

private void showAddDialog(CellLayout.CellInfo cellInfo) {        mAddItemCellInfo = cellInfo;        mWaitingForResult = true;        showDialog(DIALOG_CREATE_SHORTCUT);    }

继续找showDialog,没什么发现，showDialog()方法是该类父类Activity()方法，携带参数DIALOG_CREATE_SHORTCUT，但是它最后是调用的Launcher.java的onCreateDialog(int id)这个方法：

@Override    protected Dialog onCreateDialog(int id) {        switch (id) {            case DIALOG_CREATE_SHORTCUT:                return new CreateShortcut().createDialog();

在这里，使用了CreateShortcut.createDialog()方法，在源代码的2708行：

private class CreateShortcut implements DialogInterface.OnClickListener,
            DialogInterface.OnCancelListener, DialogInterface.OnDismissListener,            DialogInterface.OnShowListener {        private AddAdapter mAdapter;        Dialog createDialog() {            mWaitingForResult = true;            mAdapter = new AddAdapter(Launcher.this);            final AlertDialog.Builder builder = new AlertDialog.Builder(Launcher.this);            builder.setTitle(getString(R.string.menu_item_add_item));            builder.setAdapter(mAdapter, this);            builder.setInverseBackgroundForced(true);            AlertDialog dialog = builder.create();            dialog.setOnCancelListener(this);            dialog.setOnDismissListener(this);            dialog.setOnShowListener(this);            return dialog;        }        public void onCancel(DialogInterface dialog) {            mWaitingForResult = false;            cleanup();        }        public void onDismiss(DialogInterface dialog) {            mWorkspace.unlock();        }        private void cleanup() {            mWorkspace.unlock();            dismissDialog(DIALOG_CREATE_SHORTCUT);        }        /**         * Handle the action clicked in the "Add to home" dialog.         */        public void onClick(DialogInterface dialog, int which) {            Resources res = getResources();            cleanup();            switch (which) {                case AddAdapter.ITEM_SHORTCUT: {                    // Insert extra item to handle picking application                    pickShortcut(REQUEST_PICK_SHORTCUT, R.string.title_select_shortcut);                    break;                }                case AddAdapter.ITEM_APPWIDGET: {                    int appWidgetId = Launcher.this.mAppWidgetHost.allocateAppWidgetId();                    Intent pickIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_PICK);                    pickIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);                    // add the search widget                    ArrayList<AppWidgetProviderInfo> customInfo =                            new ArrayList<AppWidgetProviderInfo>();                    AppWidgetProviderInfo info = new AppWidgetProviderInfo();                    info.provider = new ComponentName(getPackageName(), "XXX.YYY");                    info.label = getString(R.string.group_search);                    info.icon = R.drawable.ic_search_widget;                    customInfo.add(info);                    pickIntent.putParcelableArrayListExtra(                            AppWidgetManager.EXTRA_CUSTOM_INFO, customInfo);                    ArrayList<Bundle> customExtras = new ArrayList<Bundle>();                    Bundle b = new Bundle();                    b.putString(EXTRA_CUSTOM_WIDGET, SEARCH_WIDGET);                    customExtras.add(b);                    pickIntent.putParcelableArrayListExtra(                            AppWidgetManager.EXTRA_CUSTOM_EXTRAS, customExtras);                    // start the pick activity                    startActivityForResult(pickIntent, REQUEST_PICK_APPWIDGET);                    break;                }                case AddAdapter.ITEM_LIVE_FOLDER: {                    // Insert extra item to handle inserting folder                    Bundle bundle = new Bundle();                    ArrayList<String> shortcutNames = new ArrayList<String>();                    shortcutNames.add(res.getString(R.string.group_folder));                    bundle.putStringArrayList(Intent.EXTRA_SHORTCUT_NAME, shortcutNames);                    ArrayList<ShortcutIconResource> shortcutIcons =                            new ArrayList<ShortcutIconResource>();                    shortcutIcons.add(ShortcutIconResource.fromContext(Launcher.this,                            R.drawable.ic_launcher_folder));                    bundle.putParcelableArrayList(Intent.EXTRA_SHORTCUT_ICON_RESOURCE, shortcutIcons);                    Intent pickIntent = new Intent(Intent.ACTION_PICK_ACTIVITY);                    pickIntent.putExtra(Intent.EXTRA_INTENT,                            new Intent(LiveFolders.ACTION_CREATE_LIVE_FOLDER));                    pickIntent.putExtra(Intent.EXTRA_TITLE,                            getText(R.string.title_select_live_folder));                    pickIntent.putExtras(bundle);                    startActivityForResult(pickIntent, REQUEST_PICK_LIVE_FOLDER);                    break;                }                case AddAdapter.ITEM_WALLPAPER: {                    startWallpaper();                    break;                }                case AddAdapter.ITEM_ANYCUT: {                Intent anycutIntent=new Intent();                anycutIntent.setClass(Launcher.this, CustomShirtcutActivity.class);                startActivityForResult(anycutIntent, REQUEST_PICK_ANYCUT);                    break;                }            }        }        public void onShow(DialogInterface dialog) {            mWorkspace.lock();        }    }

我们可以在CreateShortcut类中onclick()方法里面找到一下代码（这里是2.2的代码）：

case AddAdapter.ITEM_APPWIDGET: {                    int appWidgetId = Launcher.this.mAppWidgetHost.allocateAppWidgetId();                    Intent pickIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_PICK);                    pickIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);                    // add the search widget                    ArrayList<AppWidgetProviderInfo> customInfo =                            new ArrayList<AppWidgetProviderInfo>();                    AppWidgetProviderInfo info = new AppWidgetProviderInfo();                    info.provider = new ComponentName(getPackageName(), "XXX.YYY");                    info.label = getString(R.string.group_search);                    info.icon = R.drawable.ic_search_widget;                    customInfo.add(info);                    pickIntent.putParcelableArrayListExtra(                            AppWidgetManager.EXTRA_CUSTOM_INFO, customInfo);                    ArrayList<Bundle> customExtras = new ArrayList<Bundle>();                    Bundle b = new Bundle();                    b.putString(EXTRA_CUSTOM_WIDGET, SEARCH_WIDGET);                    customExtras.add(b);                    pickIntent.putParcelableArrayListExtra(                            AppWidgetManager.EXTRA_CUSTOM_EXTRAS, customExtras);                    // start the pick activity                    startActivityForResult(pickIntent, REQUEST_PICK_APPWIDGET);                    break;                }

这里是2.3的代码：

case AddAdapter.ITEM_APPWIDGET: {                    int appWidgetId = Launcher.this.mAppWidgetHost.allocateAppWidgetId();                    Intent pickIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_PICK);                    pickIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);                    // start the pick activity                    startActivityForResult(pickIntent, REQUEST_PICK_APPWIDGET);                    break;                }

在这里又是如何实现的呢？我么看到了startActivityForResult()方法，它实际上是运行了package/apps/Settings/src/com/android/settings/AppWidgetPickActivity.java 

我们来看下代码中是如何获取widget信息的：

void putAppWidgetItems(List<AppWidgetProviderInfo> appWidgets,            List<Bundle> customExtras, List<PickAdapter.Item> items) {        if (appWidgets == null) return;        final int size = appWidgets.size();        for (int i = 0; i < size; i++) {            AppWidgetProviderInfo info = appWidgets.get(i);                    Drawable icon = null;            CharSequence label = info.label;            if (info.icon != 0) {                icon = mPackageManager.getDrawable(info.provider.getPackageName(), info.icon, null);                if (icon == null) {                    Log.w(TAG, "Can't load icon drawable 0x" + Integer.toHexString(info.icon)                            + " for provider: " + info.provider);                }            }                      PickAdapter.Item item = new PickAdapter.Item(this, label, icon);                       item.packageName = info.provider.getPackageName();            item.className = info.provider.getClassName();                       if (customExtras != null) {                item.extras = customExtras.get(i);            }                      items.add(item);        }

和方法：

@Override    protected List<PickAdapter.Item> getItems() {        List<PickAdapter.Item> items = new ArrayList<PickAdapter.Item>();                putInstalledAppWidgets(items);        putCustomAppWidgets(items);                // Sort all items together by label        Collections.sort(items, new Comparator<PickAdapter.Item>() {                Collator mCollator = Collator.getInstance();                public int compare(PickAdapter.Item lhs, PickAdapter.Item rhs) {                    return mCollator.compare(lhs.label, rhs.label);                }            });   return items;    }

下面是我自己写的获取widget的图标：

List<AppWidgetProviderInfo> mAppinfoList = mAppWidgetManager.getInstalledProviders();            List<Drawable> mIconList=new ArrayList();            for(AppWidgetProviderInfo appWidgetInfo:mAppinfoList)            {                Drawable icon = null;                PackageManager packageManager = getPackageManager();                icon = packageManager.getDrawable(appWidgetInfo.provider.getPackageName(), appWidgetInfo.icon, null);                    mIconList.add(icon);            } 

在这段代码里，能获取widget的列表。

不知道是何种原因，使用以下代码：

List<AppWidgetProviderInfo> mAppinfoList = mAppWidgetManager.getInstalledProviders();for(AppWidgetProviderInfo appWidgetInfo:mAppinfoList)        {            mThumbs.add(appWidgetInfo.icon);        }

却不能获取widget的图标，而是别的图，望清楚原因者告知。