Lecture 18: Android Internal Storage with Example скачать в хорошем качестве

Lecture 18: Android Internal Storage with Example

Android Internal Storage with Example: In android, we have different storage options such as shared preferences, internal storage, external storage, SQLite storage, etc. to store and retrieve the application data based on our requirements. Internal Storage option is to store and retrieve the data from the device’s internal memory. In android, Internal Storage is useful to store the data files locally on the device’s internal memory using a FileOutputStream object. After storing the data files in device internal storage, we can read the data file from the device using a FileInputStream object. The data files saved in the internal are managed by an android framework and it can be accessed anywhere within the app to read or write data into the file, but it’s not possible to access the file from any other app so it’s secured. When the user uninstalls the app, automatically these data files will be removed from the device internal storage. Write a File to Internal Storage: By using the android FileOutputStream object openFileOutput method, we can easily create and write data to a file in a device’s internal storage. Following is the code snippet to create and write a private file to the device's internal memory. String FILENAME = "users"; String name = "amol"; FileOutputStream fstream = openFileOutput(FILENAME, Context.MODE_PRIVATE); fstream.write(name.getBytes()); fstream.close(); openFileOutput method with file name and MODE_PRIVATE mode to make the file private to our application. We used write() method to write the data in file and used close() method to close the stream. In android, we have different modes such as MODE_APPEND, MODE_WORLD_READBLE, MODE_WORLD_WRITEABLE etc. to use it in our application based on your requirements. write(byte[] b, int off, int len): It writes len bytes from the specified byte array starting at offset off to the file output stream. By using the android FileInputStream object openFileInput method, we can easily read the file from the device’s internal storage. Following is the code snippet to read data from a file: String FILENAME = "users"; FileInputStream fstream = openFileInput(FILENAME); StringBuffer sbuffer = new StringBuffer(); int i; while ((i = fstream.read())!= -1){ sbuffer.append((char)i); } fstream.close(); We used read() method to read one character at a time from the file. Prof. A. M. Jagtap MTech CSE