I will introduce how to change stacking order of view as below picture.
Environment : Android Studio 2.2.1, API 19
In the case of Android, remove view from layout and set view to layout again.
Then index is set 0 and view move to back. Index is not set and view move to front.
I introduce how to capture screen on Android this time.
環境：Android Studio 2.2.1, API 19
You can capture screen every views on Android.
And you must use setDrawingCacheEnabled(false) after getting view's capture.
Sample code is below.
I introduce how to capture screen and make a bitmap image on iOS this time.
Environment：Xcode 8.3, Swift 3
Sample code is below.
At first, use UIGraphicsBeginImageContextWithOptions, and make context of bitmap for capturing screen.
And write screen's objects' info at context.("self.view.layer.render(in:context)")
And use UIGraphicsGetImageFromCurrentImageContext, and get UIImage from context.
At last, use UIGraphicsEndImageContext, and close context.
You can use Sqlite for saving data on Android.
Environment: Android Studio 2.2.1, API 19
Make class extended SqLiteOpenHelper and declare database layout.
You can define table layout to use "Create Table" in onCreate method.
You can change table layout to use "Alter Table" in onUpgrade method, when application version is up.
When you want to save Bitmap data, define BLOB data type.
2.How to Insert data
Use getWritableDatabase method of class which is made by SQLiteOpenHelper, and you can get writable SQLiteDatabase class.
When you execute InsertOrThrow method of SQLiteDatabase class, and new data is inserted in Sqlite.
And you'd better not use Insert method of SQLiteDatabase class, because this method don't return Exception class when error occur.
Use ContentValues to set field names and values.
If you want to save Bitmap Data, you must change Bitmap to byte data type.
3.How to update data.
Use update method of SQLiteDatabase class, you can update data in Sqlite.
You can use ContentValues to set field names and values like inserting data.
You can set your search criteria to the third argument and the fourth argument of update method.
4.How to delete data
Use delete method of SQLiteDatabase class, you can delete data in Sqlite.
Method of setting your search criteria is the same as updating data.
5.How to select data
When you select data in Sqlite, execute getReadableDatabase method of class which is made by SQLiteOpenHelper, and get SQLiteDatabase class(read only).
After, Use rawQuery method of SQLiteDatabase class, and you can select data in Sqlite.
You can do database programming by Core Data, O/R mapping tool for Sqlite, on iOS.
Environment: Xcode 8.3, Swift 3
At first, Check "Use Core Data" when project is created.
And code of Core Data Objects are created in AppDelegate.
Next, select "[project name].xcdatamodeld" and define table layout.
To save UIImage, select "Binary Data" in Type and check "Allow External Storage".
When the size of UIImage is big, URL of UIImage is saved in Core Data.
When you don't check "Allow External Storage", the time of saving core data will take and memory utilization will be increase instantly, and an application will crash.
After table layout definition, execute [Editor]-[Create NSManagedObject Subclass] on Xcode.
And class of table layout definition, NSManagedObject is created.
At last, declare "import Core Data" at the top of class using Core Data.
2.How to INSERT
At first, Make NSManagedObjectContext in AppDelegate.
Next, Make NSManagedObject from NSManagedObjectContext.
Let's see code for inserting new data by Core Data.
2.How to SELECT
Let's see code for selecting data by Core Data.
Use NSPredicate for designating searching options.
Use NSSortDescriptor and ascending option for designation sort options.
If you road UIImage, check UIImageOrientation.
If UIImageOrientation is down, you must invert UIImage.
3.How to UPDATE
Update value of data which is read.
Let's see code for updating data by Core Data.
4.How to DELETE
Delete data which is read.