Write To and Read From SD Card

Now we move to the source code (Java code) of this project. The following is the source code: Now I will explain the preceding code in a number of sections for a better understanding: Code Section 1 Then we get the full path of the external storage device (SD Card) using the getExternalStorageDirectory() method. Now we will make a new directory (folder) in the SD Card using the mkdirs() method and assign a name. Here we will create a folder with the name “My_File”.

Conclusion

I can summarize all the operations in the following. We are writing our data in a PrintWriter class object using the println method. The PrintWriter class inserts all the data into a FileOutputStream class object and the FileOutputStream's object converts the data into byte code form and inserts the data into our textfile. After the file is successfully written, check the storage of our device. We will find that “MyTextFile.txt” has been created in the sdcard. Now we will check the data of this text file. We can see that this text file contains the same data that we wrote in the preceding. Now I will explain how to read this data and show in a TextView. Code Section 3 In the preceding code we used the getExternalStorageDirectory method. This method returns information about the primary external storage directory. Here the primary external storage device is the sdcard. In the next line we create an object of the File class. We pass two parameters in the File class constructor. The first is the absolute path of the external storage device and the second is the path of our text file in the sdcard. We also created an object of the FileInputStream class. The FileInputStream class is used to read a byte of data from a file. We pass the path of the file as a parameter in the FileInputStream class constructor. We create an object of the BufferedReader class. The BufferedReader class wraps an existing Reader and buffers the input. In other words, the BufferedReader class retrieves data from a reader (here the reader is FileInputStream) and stores it in a buffer. Now we can easily read data from the buffer using the readline method. In the preceding code, we read data line by line from the buffer and appended (inserted) this data into the TextView. So when we click on the “Read Data” button, the output will be the following: Thanks for reading my article. In the next article, I will explain a new topic on Android.