Create and write file in Android

writeandroidfile.java

private void writeFile(){
	String root = Environment.getExternalStorageDirectory().toString();
	//String root = Environment.getRootDirectory().toString();
    	File myDir = new File(root + "/mydir");    
    	myDir.mkdirs();
    	String fname = "myfile.txt";
    	File file = new File (myDir, fname);
    	if (file.exists ()) file.delete (); 
    		try {
    			BufferedWriter buf = new BufferedWriter(new FileWriter(file, true)); 
    			buf.append("This is the first line of my file.\n");
    			buf.append("This is the last one.");
    			buf.newLine();
    			buf.flush();
    	  		buf.close();
    		} catch (Exception e) {
    	           	e.printStackTrace();
    	           	Toast.makeText(this, e.toString(),Toast.LENGTH_LONG).show();
    	    }
    }