android 单双层桌面切换

单双层桌面切换由于必须持久化数据 所以必须多创建单层桌面所须要的数据库表;

1. 一表为存储桌面图标，表结构跟原生 桌面表一样 直接copy一份就可以了
2. 一表为存储桌面页，表结构跟原生一样

创建上面两张表时注意下 数据库版本升级带来的影响

由于表结构跟原生一样 所以加载逻辑不需要改动 直接按原生加载 所需要改动的是加载的是哪个表

建立一个判断是否为单双层桌面的方法，此方法单双层桌面的 标志

	/**add by lmjssjj begin*/
	public static boolean isDisableAllApps(){
		return false;
	}
	/**add by lmjssjj end*/

修改加载的数据表

 public static final class WorkspaceScreens implements ChangeLogColumns {

        public static final String TABLE_NAME = "workspaceScreens";
        /**add by lmjssjj begin*/
        public static final String TABLE_DISABLEALLAPPS_NAME = "workspaceScreens_disable_allapps";
        /**add by lmjssjj end*/

        /**
         * The content:// style URL for this table
         */
        static final Uri CONTENT_URI = Uri.parse("content://" +
                ProviderConfig.AUTHORITY + "/" + /**modify by lmjssjj*/(LauncherAppState.isDisableAllApps()?TABLE_DISABLEALLAPPS_NAME:TABLE_NAME));

        /**
         * The rank of this screen -- ie. how it is ordered relative to the other screens.
         * <P>Type: INTEGER</P>
         */
        public static final String SCREEN_RANK = "screenRank";
    }

public static final class Favorites implements BaseLauncherColumns {

        public static final String TABLE_NAME = "favorites";
        /**add by lmjssjj begin*/
        public static final String TABLE_DISABLEALLAPPS_NAME = "favorites_disable_allapps";
        /**add by lmjssjj end*/
        /**
         * The content:// style URL for this table
         */
        public static final Uri CONTENT_URI = Uri.parse("content://" +
                ProviderConfig.AUTHORITY + "/" +/**modify by lmjssjj*/ (LauncherAppState.isDisableAllApps()?TABLE_DISABLEALLAPPS_NAME:TABLE_NAME));

        /**
         * The content:// style URL for a given row, identified by its id.
         *
         * @param id The row id.
         *
         * @return The unique content URL for the specified row.
         */
        public static Uri getContentUri(long id) {
            return Uri.parse("content://" + ProviderConfig.AUTHORITY +
                    "/" + (LauncherAppState.isDisableAllApps()?TABLE_DISABLEALLAPPS_NAME:TABLE_NAME) + "/" + id);
        }

添加数据库表
为了数据库版本升级 单独建立

//add by lmjssjj
        private void addFavoritesDisableAllappsTable(SQLiteDatabase db){
        	 UserManagerCompat userManager = UserManagerCompat.getInstance(mContext);
             long userSerialNumber =
                     userManager.getSerialNumberForUser(UserHandleCompat.myUserHandle());
            db.execSQL("CREATE TABLE favorites_disable_allapps (" + "_id INTEGER PRIMARY KEY," + "title TEXT,"
            		+ "intent TEXT," + "container INTEGER," + "screen INTEGER," + "cellX INTEGER,"
            		+ "cellY INTEGER," + "spanX INTEGER," + "spanY INTEGER," + "itemType INTEGER,"
            		+ "appWidgetId INTEGER NOT NULL DEFAULT -1," + "isShortcut INTEGER,"
            		+ "iconType INTEGER," + "iconPackage TEXT," + "iconResource TEXT,"
            		+ "icon BLOB," + "uri TEXT," + "displayMode INTEGER,"
            		+ "appWidgetProvider TEXT," + "modified INTEGER NOT NULL DEFAULT 0,"
            		+ "restored INTEGER NOT NULL DEFAULT 0," + "profileId INTEGER DEFAULT "
            		+ userSerialNumber + "," + "rank INTEGER NOT NULL DEFAULT 0,"
            		+ "options INTEGER NOT NULL DEFAULT 0" + ");");
        }//end by lmjssjj

        private void addWorkspacesTable(SQLiteDatabase db) {
            db.execSQL("CREATE TABLE " + TABLE_WORKSPACE_SCREENS + " ("
                    + LauncherSettings.WorkspaceScreens._ID + " INTEGER PRIMARY KEY,"
                    + LauncherSettings.WorkspaceScreens.SCREEN_RANK + " INTEGER,"
                    + LauncherSettings.ChangeLogColumns.MODIFIED + " INTEGER NOT NULL DEFAULT 0"
                    + ");");
        }

 private void setFlagDisableAllAppsEmptyDbCreated() {
        	String spKey = LauncherAppState.getSharedPreferencesKey();
        	SharedPreferences sp = mContext.getSharedPreferences(spKey, Context.MODE_PRIVATE);
        	sp.edit().putBoolean(EMPTY_DISABLEALLAPPS_DATABASE_CREATED, true).commit();
        }

public void clearFlagDisableAllAppsEmptyDbCreated() {
    	String spKey = LauncherAppState.getSharedPreferencesKey();
    	getContext().getSharedPreferences(spKey, Context.MODE_PRIVATE).edit()
    	.remove(EMPTY_DISABLEALLAPPS_DATABASE_CREATED).commit();
    }

数据库表已建立完成 接下来需要修改数据库的写入 通过上面的判断方法 修改写的读的表

 private long initializeMaxItemId(SQLiteDatabase db) {
            return getMaxId(db, LauncherAppState.isDisableAllApps()?TABLE_FAVORITES_DISABLE_ALLAPPS:TABLE_FAVORITES);
        }

private long initializeMaxScreenId(SQLiteDatabase db) {
            return getMaxId(db, LauncherAppState.isDisableAllApps()?TABLE_WORKSPACE_SCREENS_DISABLE_ALLAPPS:TABLE_WORKSPACE_SCREENS);
        }

 @Override
        public long insertAndCheck(SQLiteDatabase db, ContentValues values) {
            return dbInsertAndCheck(this, db, LauncherAppState.isDisableAllApps()?TABLE_FAVORITES_DISABLE_ALLAPPS:TABLE_FAVORITES, null, values);
        }

接下来 数据加载

boolean bl = prefs.getBoolean(LauncherAppState.isDisableAllApps()?LauncherProvider.EMPTY_DISABLEALLAPPS_DATABASE_CREATED:LauncherProvider.EMPTY_DATABASE_CREATED, false);

if(LauncherAppState.isDisableAllApps())
					LauncherAppState.getLauncherProvider().clearFlagDisableAllAppsEmptyDbCreated();

加载单层数据,双层数据照原生逻辑

		private void loadAllAppsFirst() {

				final Callbacks oldCallbacks = mCallbacks.get();
				if (oldCallbacks == null) {
					return;
				}
				final List<UserHandleCompat> profiles = mUserManager.getUserProfiles();
				mBgAllAppsList.clear();
				for (UserHandleCompat user : profiles) {

					final List<LauncherActivityInfoCompat> apps = mLauncherApps.getActivityList(null, user);

					if (apps == null || apps.isEmpty()) {
						return;
					}

					for (int i = 0; i < apps.size(); i++) {
						LauncherActivityInfoCompat app = apps.get(i);

						mBgAllAppsList.add(new AppInfo(mContext, app, user, mIconCache));

					}
					mBgAllAppsList.added.clear();

			}
			verifyApplications();
			updateIconCache();
			
			loadAndBindWidgetsAndShortcuts(tryGetCallbacks(oldCallbacks), true /* refresh */);

		}

切换时重新加载我采用的是在设置页面（设置页在自己的进程） kill 自己：

ActivityManager activityManager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
			activityManager.killBackgroundProcesses(getPackageName());
finish();

合并数据

private void verifyApplications() {
		final Context context = mApp.getContext();

		// Cross reference all the applications in our apps list with items in
		// the workspace
		ArrayList<ItemInfo> tmpInfos;
		ArrayList<ItemInfo> added = new ArrayList<ItemInfo>();
		synchronized (sBgLock) {
			for (AppInfo app : mBgAllAppsList.data) {
				tmpInfos = getItemInfoForComponentName(app.componentName, app.user);
				if (tmpInfos.isEmpty()) {
					// We are missing an application icon, so add this to the
					// workspace
					added.add(app);
					// This is a rare event, so lets log it
					Log.e(TAG, "Missing Application on load: " + app);
				}
			}
		}
		if (!added.isEmpty()) {
			addAndBindAddedWorkspaceItems(context, added,true);
		}
	}

总结：
需要注意的
1、创建单层桌面所须数据库
2、数据库增删改查
3、当第一次加载单层桌面时，应用合并
4、当安装应用时
5、当卸载应用时(原生逻辑)
6、当应用更新时(原生逻辑)
7、判断应用是否是要卸载或者图标删除
8、快捷图标创建细节
9、单双切换

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