Android文件操作

将数据写入Internal Storage：

 String fileName = "myfile.txt";
 String str="保存数据到内部存储";
 try {
                     FileOutputStream fos = openFileOutput(fileName, Context.MODE_PRIVATE);
                     fos.write(str.getBytes());
                     fos.flush();
                     fos.close();

                 } catch (FileNotFoundException e) {
                     e.printStackTrace();
                 } catch (IOException e) {
                     e.printStackTrace();
                 }

从Internal Storage读取数据：

 try {
                     FileInputStream fis = openFileInput("myfile.txt");
                     byte[] data = new byte[fis.available()];
                     fis.read(data);
                     fis.close();

                     textView.setText(new String(data));

                 } catch (FileNotFoundException e) {
                     e.printStackTrace();
                 } catch (IOException e) {
                     e.printStackTrace();
                 }

将数据写入External Storage：

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

  if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {

                     File file = new File(Environment.getExternalStorageDirectory(), "myfile.txt");

                     if(!file.exists())
                     {
                         try {
                             file.createNewFile();
                         } catch (IOException e) {
                             e.printStackTrace();
                         }
                     }
                     try {
                         FileOutputStream fos = new FileOutputStream(file);
                         fos.write(editText.getText().toString().getBytes());
                         fos.close();

                     } catch (FileNotFoundException e) {
                         e.printStackTrace();
                     } catch (IOException e) {
                         e.printStackTrace();
                     }
                 }

从External Storage读取数据：

 if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {

                     File file = new File(Environment.getExternalStorageDirectory(), "myfile.txt");

                     try {
                         FileInputStream fis = new FileInputStream(file);
                         byte[] data = new byte[fis.available()];

                         fis.read(data);
                         fis.close();

                         textView.setText(new String(data));

                     } catch (FileNotFoundException e) {
                         e.printStackTrace();
                     } catch (IOException e) {
                         e.printStackTrace();
                     }

                 }

在Cache目录创建文件：

 try {
                     File file = File.createTempFile("mycache", "txt", getCacheDir());

                     FileOutputStream fos = new FileOutputStream(file);
                     fos.write(editText.getText().toString().getBytes());
                     fos.close();

                 } catch (IOException e) {
                     e.printStackTrace();
                 }