Android文件操作

将数据写入Internal Storage：

 1 String fileName = "myfile.txt";
 2 String str="保存数据到内部存储";
 3 try {
 4                     FileOutputStream fos = openFileOutput(fileName, Context.MODE_PRIVATE);
 5                     fos.write(str.getBytes());
 6                     fos.flush();
 7                     fos.close();
 8 
 9                 } catch (FileNotFoundException e) {
10                     e.printStackTrace();
11                 } catch (IOException e) {
12                     e.printStackTrace();
13                 }

从Internal Storage读取数据：

 1 try {
 2                     FileInputStream fis = openFileInput("myfile.txt");
 3                     byte[] data = new byte[fis.available()];
 4                     fis.read(data);
 5                     fis.close();
 6 
 7                     textView.setText(new String(data));
 8 
 9 
10                 } catch (FileNotFoundException e) {
11                     e.printStackTrace();
12                 } catch (IOException e) {
13                     e.printStackTrace();
14                 }

将数据写入External Storage：

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

 1  if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
 2 
 3 
 4 
 5                     File file = new File(Environment.getExternalStorageDirectory(), "myfile.txt");
 6 
 7                     if(!file.exists())
 8                     {
 9                         try {
10                             file.createNewFile();
11                         } catch (IOException e) {
12                             e.printStackTrace();
13                         }
14                     }
15                     try {
16                         FileOutputStream fos = new FileOutputStream(file);
17                         fos.write(editText.getText().toString().getBytes());
18                         fos.close();
19 
20                     } catch (FileNotFoundException e) {
21                         e.printStackTrace();
22                     } catch (IOException e) {
23                         e.printStackTrace();
24                     }
25                 }

从External Storage读取数据：

 1 if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
 2 
 3 
 4 
 5                     File file = new File(Environment.getExternalStorageDirectory(), "myfile.txt");
 6 
 7                     try {
 8                         FileInputStream fis = new FileInputStream(file);
 9                         byte[] data = new byte[fis.available()];
10 
11                         fis.read(data);
12                         fis.close();
13 
14                         textView.setText(new String(data));
15 
16                     } catch (FileNotFoundException e) {
17                         e.printStackTrace();
18                     } catch (IOException e) {
19                         e.printStackTrace();
20                     }
21 
22                 }

在Cache目录创建文件：

 1 try {
 2                     File file = File.createTempFile("mycache", "txt", getCacheDir());
 3 
 4                     FileOutputStream fos = new FileOutputStream(file);
 5                     fos.write(editText.getText().toString().getBytes());
 6                     fos.close();
 7 
 8 
 9                   
10 
11                 } catch (IOException e) {
12                     e.printStackTrace();
13                 }

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解决方案
原文地址：https://www.cnblogs.com/l2rf/p/4351083.html