- Android Basics
- Android - User Interface
Here are some other possible directories for installed apps: /system/app/ - Contains pre-installed system apps /data/asec/ - Stores secure apps generated from external memory storage /data/app-private - Contains third party protected apps; Apps may also generate data for use during runtime. For example, an app may create a database file that. Files by Google is an easy-to-use trustable phone cleaner app for Android users. While cleaning junk files, the app recommends users delete old memes, photos, unused apps, and a lot more. ES File Explorer (File Manager): ES File Explorer (Figure A) is an Android file manager that.
- Android Advanced Concepts
- Android Useful Examples
- Android Useful Resources
- Selected Reading
Android provides many kinds of storage for applications to store their data. These storage places are shared preferences, internal and external storage, SQLite storage, and storage via network connection.
In this chapter we are going to look at the internal storage. Internal storage is the storage of the private data on the device memory.
By default these files are private and are accessed by only your application and get deleted , when user delete your application.
Writing file
In order to use internal storage to write some data in the file, call the openFileOutput() method with the name of the file and the mode. The mode could be private , public e.t.c. Its syntax is given below −
The method openFileOutput() returns an instance of FileOutputStream. So you receive it in the object of FileInputStream. After that you can call write method to write data on the file. Its syntax is given below −
Reading file
In order to read from the file you just created , call the openFileInput() method with the name of the file. It returns an instance of FileInputStream. Its syntax is given below −
After that, you can call read method to read one character at a time from the file and then you can print it. Its syntax is given below −
Apart from the the methods of write and close, there are other methods provided by the FileOutputStream class for better writing files. Cisdem video player 4 5 00. These methods are listed below −
Sr.No | Method & description |
---|---|
1 | FileOutputStream(File file, boolean append) This method constructs a new FileOutputStream that writes to file. |
2 | getChannel() This method returns a write-only FileChannel that shares its position with this stream |
3 | getFD() This method returns the underlying file descriptor |
4 | write(byte[] buffer, int byteOffset, int byteCount) This method Writes count bytes from the byte array buffer starting at position offset to this stream |
Apart from the the methods of read and close, there are other methods provided by the FileInputStream class for better reading files. These methods are listed below −
Sr.No | Method & description |
---|---|
1 | available() This method returns an estimated number of bytes that can be read or skipped without blocking for more input |
2 | getChannel() This method returns a read-only FileChannel that shares its position with this stream Waltr 2 6 2015. |
3 | getFD() This method returns the underlying file descriptor |
4 | read(byte[] buffer, int byteOffset, int byteCount) This method reads at most length bytes from this stream and stores them in the byte array b starting at offset |
Example
Here is an example demonstrating the use of internal storage to store and read files. It creates a basic storage application that allows you to read and write from internal storage.
To experiment with this example, you can run this on an actual device or in an emulator.
Steps | Description |
---|---|
1 | You will use Android Studio IDE to create an Android application under a package com.example.sairamkrishna.myapplication. |
2 | Modify src/MainActivity.java file to add necessary code. |
3 | Modify the res/layout/activity_main to add respective XML components |
4 | Run the application and choose a running android device and install the application on it and verify the results |
Following is the content of the modified main activity file src/MainActivity.java.
Following is the modified content of the xml res/layout/activity_main.xml.
In the following code abc indicates the logo of tutorialspoint.com
Following is the content of the res/values/string.xml.
Following is the content of AndroidManifest.xml file.
Let's try to run our Storage application we just modified. I assume you had created your AVD while doing environment setup. To run the app from Android studio, open one of your project's activity files and click Run icon from the tool bar. Android studio installs the app on your AVD and starts it and if everything is fine with your set-up and application, it will display following Emulator window −
Now what you need to do is to enter any text in the field. For example , i have entered some text. Press the save button. The following notification would appear in you AVD −
Now when you press the load button, the application will read the file , and display the data. In case of our, following data would be returned −
Note you can actually view this file by switching to DDMS tab. In DDMS , select file explorer and navigate this path.
This has also been shown in the image below.
![Android app file storage location Android app file storage location](https://cdn57.androidauthority.net/wp-content/uploads/2016/09/storedata_internalstorage.png)
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The Device File Explorer allows you to view, copy, and delete files on anAndroid device. This is useful when examining files that are created by your appor if you want to transfer files to and from a device.
Note: Most device data is not visible unless you are using a rooted device or anemulator with a standard Android (AOSP) system image (not one of the Google APIsor Google Play system images). And when using a connected device, be sure youenable USB debugging.To work with a device's file system, proceed as follows:
- Click View > Tool Windows > Device File Explorer or click theDevice File Explorer button in the tool window bar to open the Device File Explorer.
- Select a device from the drop down list.
- Interact with the device content in the file explorer window. Right-click on a file or directory to create a new file or directory, save the selected file or directory to your machine, upload, delete, or synchronize. Double-click a file to open it in Android Studio.Android Studio saves files you open this way in a temporary directory outside of your project. If you make modifications to a file you opened using the Device File Explorer, and would like to save your changes back to the device, you must manually upload the modified version of the file to the device.
Figure 1. The Device File Explorer tool window
When exploring a device's files, the following directories are particularlyuseful:
Android App File Storage Location
data/data/app_name/
- Contains data files for your app stored oninternal storage
sdcard/
- Contains user files stored onexternal userstorage (pictures, etc.)
Best Storage App For Android
Note: Not all files on a hardware device arevisible in the Device File Explorer. For example, in the
data/data/
directory, entries corresponding to apps on the device that are not debuggablecannot be expanded in the Device File Explorer.