Fileoutputstream (file storage) and FileInputStream (file reading)

public class MainActivity extends ActionBarActivity {

	
	Button bt;
	TextView tv;
	EditText et;
	
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		bt=(Button) findViewById(R.id.button1);
		tv=(TextView) findViewById(R.id.textView1);
		et=(EditText) findViewById(R.id.editText1);
		bt.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View arg0) {
				// TODO Auto-generated method stub
				save(et.getText().toString());
				tv.setText(Reader());
			}
		});
	}
	// Save the file 
	public void save(String content)
	{
		
		
		try {
			FileOutputStream fos = openFileOutput("a.txt", MODE_PRIVATE);
			fos.write(content.getBytes());// Will a string The characters contained in the string of type are converted to byte Type and store in a byte Array .
			fos.close();
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
	// Read the file 
	public String Reader()
	{
		String content=null;
		try {
			FileInputStream fis=openFileInput("a.txt");
			ByteArrayOutputStream bos=new ByteArrayOutputStream();
			byte[] b=new byte[1024];
			int len=0;
			while((len=fis.read(b))!=-1)// Read data and write to array buffer, Judge when fis Whether the reading is finished , Play the role of cache 
			{
				bos.write(b, 0, len);// Write array bytes to ByteArrayOutputStream In object 
			}
			content=bos.toString();
			
			fis.close();
			bos.close();
			
			
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return content;
	}


}