Android Launcher3 去掉应用列表后，在系统桌面拖动应用图标卸载应用

隐藏掉应用列表后，发现在Launcher的WorkSpace中不管怎样都市无法卸载应用的，只能删除图标。研究发现在DeleteDropTarget这个类中可以控制拖拽应用图标卸载应用。

1、修改代码，使用户每次拖动图标显示卸载选项，而不是显示删除应用图标的选项

   @Override    public void onDragStart(DragSource source, Object info, int dragAction) {        boolean isVisible = true;//        修改判断条件//        boolean useUninstallLabel = LauncherAppState.isDisableAllApps() &&//                isAllAppsApplication(source, info);        boolean useUninstallLabel = LauncherAppState.isDisableAllApps();        boolean useDeleteLabel = !useUninstallLabel && source.supportsDeleteDropTarget();        // If we are dragging an application from AppsCustomize, only show the control if we can        // delete the app (it was downloaded), and rename the string to "uninstall" in such a case.        // Hide the delete target if it is a widget from AppsCustomize.        if (!willAcceptDrop(info) || isAllAppsWidget(source, info)) {            isVisible = false;        }        if (useUninstallLabel) {            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {                UserManager userManager = (UserManager)                        getContext().getSystemService(Context.USER_SERVICE);                Bundle restrictions = userManager.getUserRestrictions();                if (restrictions.getBoolean(UserManager.DISALLOW_APPS_CONTROL, false)                        || restrictions.getBoolean(UserManager.DISALLOW_UNINSTALL_APPS, false)) {                    isVisible = false;                }            }        }        if (useUninstallLabel) {            setCompoundDrawablesRelativeWithIntrinsicBounds(mUninstallDrawable, null, null, null);        } else if (useDeleteLabel) {            setCompoundDrawablesRelativeWithIntrinsicBounds(mRemoveDrawable, null, null, null);        } else {            isVisible = false;        }        mCurrentDrawable = (TransitionDrawable) getCurrentDrawable();        mActive = isVisible;        resetHoverColor();        ((ViewGroup) getParent()).setVisibility(isVisible ? View.VISIBLE : View.GONE);//                if (isVisible && getText().length() > 0) {            setText(useUninstallLabel ? R.string.delete_target_uninstall_label                    : R.string.delete_target_label);        }    }

2、修改willAcceptDrop方法，让该方法返回true

public static boolean willAcceptDrop(Object info) {    if (info instanceof ItemInfo) {        ItemInfo item = (ItemInfo) info;        if (item.itemType == LauncherSettings.Favorites.ITEM_TYPE_APPWIDGET ||                item.itemType == LauncherSettings.Favorites.ITEM_TYPE_SHORTCUT) {            return true;        }//默认为！LauncherAppState.isDisableAllApps()，把条件改成相反就可以了        if (LauncherAppState.isDisableAllApps() &&                item.itemType == LauncherSettings.Favorites.ITEM_TYPE_FOLDER) {            return true;        }         //同上        if (LauncherAppState.isDisableAllApps() &&                item.itemType == LauncherSettings.Favorites.ITEM_TYPE_APPLICATION &&                item instanceof AppInfo) {            AppInfo appInfo = (AppInfo) info;            return (appInfo.flags & AppInfo.DOWNLOADED_FLAG) != 0;        }        if (item.itemType == LauncherSettings.Favorites.ITEM_TYPE_APPLICATION &&                item instanceof ShortcutInfo) {            if (!LauncherAppState.isDisableAllApps()) {                ShortcutInfo shortcutInfo = (ShortcutInfo) info;                return (shortcutInfo.flags & AppInfo.DOWNLOADED_FLAG) != 0;            } else {                return true;            }        }    }    return false;}

3、当用户拖动图标完成后，会执行completeDrop方法。该方法中的isUninstallFromWorkspace是判断是否可以从

WorkSpace中卸载应用，所以也要修改这里，让该方法返回true。判断该应用是否是系统应用中，有一个bug没有

解 决。所以不引用源码的方法判断，自己写了一个方法判断应用是否是系统应用。

    private void completeDrop(DragObject d) {        ItemInfo item = (ItemInfo) d.dragInfo;        int myAppInfoFlags = 0;        boolean wasWaitingForUninstall = mWaitingForUninstall;        mWaitingForUninstall = false;        if (isAllAppsApplication(d.dragSource, item)) {            // Uninstall the application if it is being dragged from AppsCustomize            AppInfo appInfo = (AppInfo) item;            mLauncher.startApplicationUninstallActivity(appInfo.componentName, appInfo.flags,                    appInfo.user);        } else if (isUninstallFromWorkspace(d)) {            ShortcutInfo shortcut = (ShortcutInfo) item;            if (shortcut.intent != null && shortcut.intent.getComponent() != null) {                final ComponentName componentName = shortcut.intent.getComponent();                final DragSource dragSource = d.dragSource;                final UserHandleCompat user = shortcut.user;                /**                 *获取手机中所有已安装的应用，根据包名，判断当前应用是否系统应用                 */                List<PackageInfo> packages = getContext().getPackageManager().getInstalledPackages(0);                for (int i = 0; i < packages.size(); i++) {                    PackageInfo packageInfo = packages.get(i);                    if (packageInfo.packageName.equals(componentName.getPackageName())) {                        if ((packageInfo.applicationInfo.flags &                                ApplicationInfo.FLAG_SYSTEM)==0) {                            Log.e(TAG, "This is user app ");                            myAppInfoFlags = 1;                        }                    }                }                mWaitingForUninstall = mLauncher.startApplicationUninstallActivity(                        componentName, myAppInfoFlags, user);                //-------------------------------------------//                mWaitingForUninstall = mLauncher.startApplicationUninstallActivity(//                        componentName, shortcut.flags, user);                if (mWaitingForUninstall) {                    final Runnable checkIfUninstallWasSuccess = new Runnable() {                        @Override                        public void run() {                            mWaitingForUninstall = false;                            String packageName = componentName.getPackageName();                            boolean uninstallSuccessful = !AllAppsList.packageHasActivities(                                    getContext(), packageName, user);                            if (dragSource instanceof Folder) {                                ((Folder) dragSource).                                        onUninstallActivityReturned(uninstallSuccessful);                            } else if (dragSource instanceof Workspace) {                                ((Workspace) dragSource).                                        onUninstallActivityReturned(uninstallSuccessful);                            }                        }                    };                    mLauncher.addOnResumeCallback(checkIfUninstallWasSuccess);                }            }        } else if (isWorkspaceOrFolderApplication(d)) {            LauncherModel.deleteItemFromDatabase(mLauncher, item);        } else if (isWorkspaceFolder(d)) {            // Remove the folder from the workspace and delete the contents from launcher model            FolderInfo folderInfo = (FolderInfo) item;            mLauncher.removeFolder(folderInfo);            LauncherModel.deleteFolderContentsFromDatabase(mLauncher, folderInfo);        } else if (isWorkspaceOrFolderWidget(d)) {            // Remove the widget from the workspace            mLauncher.removeAppWidget((LauncherAppWidgetInfo) item);            LauncherModel.deleteItemFromDatabase(mLauncher, item);            final LauncherAppWidgetInfo launcherAppWidgetInfo = (LauncherAppWidgetInfo) item;            final LauncherAppWidgetHost appWidgetHost = mLauncher.getAppWidgetHost();            if ((appWidgetHost != null) && launcherAppWidgetInfo.isWidgetIdValid()) {                // Deleting an app widget ID is a void call but writes to disk before returning                // to the caller...                new AsyncTask<Void, Void, Void>() {                    public Void doInBackground(Void... args) {                        appWidgetHost.deleteAppWidgetId(launcherAppWidgetInfo.appWidgetId);                        return null;                    }                }.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, (Void) null);            }        }        if (wasWaitingForUninstall && !mWaitingForUninstall) {            if (d.dragSource instanceof Folder) {                ((Folder) d.dragSource).onUninstallActivityReturned(false);            } else if (d.dragSource instanceof Workspace) {                ((Workspace) d.dragSource).onUninstallActivityReturned(false);            }        }    }

4、修改isUninstallFromWorkspace方法，注释掉的代码是源码的返回方法，我只是把！给去掉了。然后就可以在

workspace中卸载应用了。

    private boolean isUninstallFromWorkspace(DragObject d) {        if (LauncherAppState.isDisableAllApps() && isWorkspaceOrFolderApplication(d)) {            ShortcutInfo shortcut = (ShortcutInfo) d.dragInfo;            // Only allow manifest shortcuts to initiate an un-install.//            return !InstallShortcutReceiver.isValidShortcutLaunchIntent(shortcut.intent);            return InstallShortcutReceiver.isValidShortcutLaunchIntent(shortcut.intent);        }        return false;    }