File Handling

File Handlingin AndroidHow to read & write file in Android

Basic Steps Create new project. Create interface(main_activity)

File Name File Text Write file (Button) Read file (Button) Edit text where read data is placed

Basic Steps (cont.) Create a FileOperations class

FileWriter BufferedWriter FileReader BufferedReader

Create MainActivity.java file Add permission to manifest

Step 1: done Project and Interface is created

Step 2: Create FileOperations

java Class

=> Create String path.

=> Create FileReader/FileWriter with path.

Create BufferedReader/ BufferedWriter.

Read file / write file.

Step 3: Create MainActivity java file

Use Object of FileOperations class

for reading and writing purposes

from in.

Step 4: Add permission to

manifest

Run AVD and install you .apk file

Difference between FileOutputSream & FileWriterFile fout = new File(file_location_string);

FileOutputStream fos = new FileOutputStream(fout);

BufferedWriter out = new BufferedWriter(new OutputStreamWriter(fos));

out.write("something");

FileWriter fstream = new FileWriter(file_location_string);

BufferedWriter out = new BufferedWriter(fstream);

out.write("something");

Difference between FileOutputSream & FileWriter FileOutputStream is meant for writing

streams of raw bytes such as image data. For writing streams of characters, consider using FileWriter.

There is actually no difference per se, FileWriter is just a convenience class. It extends OutputStreamWriter and creates the needed FileOutputStream itself.

Uses of FileOutputSream & FileWriter If you are dealing with binary data (e.g.

an image) use Streams. If you are using non-ASCII Unicode

characters, e.g. Chinese, use Readers/Writers.

If you are using ordinary ASCII text (the traditional 0-127 characters) you can (usually) use either.

Simple Example of FileOutputStream

String FILENAME = "hello_file";String string = "hello world!";

FileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);

fos.write(string.getBytes());fos.close();

Other useful methodes getFilesDir() Gets the absolute path to the

filesystem directory where your internal files are saved.

getDir() Creates (or opens an existing) directory within your internal storage space.

deleteFile() Deletes a file saved on the internal storage.

fileList() Returns an array of files currently saved by your application

How to append data to existing file Just one change. FileOutputStream fOut =

openFileOutput("savedData.txt", MODE_APPEND | MODE_WORLD_READABLE );

Delete a file You should always delete files that you no

longer need. The most straightforward way to delete a file is to have the opened file reference call delete() on itself.

myFile.delete(); If the file is saved on internal storage, you

can also ask the Context to locate and delete a file by calling deleteFile():

myContext.deleteFile(fileName);