File Handling in Android How to read & write file in Android
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);