1 private TextView tv;

 2 private Button bt1;

 3 private Button bt2;

 4 private EditText et;

 5

 6 protected void onCreate(Bundle savedInstanceState) {

 7         super.onCreate(savedInstanceState);

 8         setContentView(R.layout.xml文件);

 9         et = (EditText) findViewById(R.id.sdET);

10         tv = (TextView) findViewById(R.id.sdTV);

11         bt1 = (Button) findViewById(R.id.sdBT01);

12         bt2 = (Button) findViewById(R.id.sdBT02);

13         bt1.setOnClickListener(this);

14         bt2.setOnClickListener(this);

15     }

16

17 public void onClick(View v) {

18         if (!Environment.getExternalStorageState().equals(

19                 Environment.MEDIA_MOUNTED)) {// 判断SD卡是否存在

20             Toast.makeText(Sd0.this, "SD卡不存在", 3000).show();

21             return;

22         }

23         switch (v.getId()) {

24         case R.id.sdBT01:

25             // 创建文件夹对象

26             File dir = new File(Environment.getExternalStorageDirectory(),"test");

27             if (!dir.exists()) { // 如果目录不存在，就创建

28                 dir.mkdir();

29             }

30             File file = new File(dir, "test.txt"); // 创建文件

31             PrintWriter pw;

32             try {

33                 pw = new PrintWriter(file);

34                 pw.println(et.getText().toString());

35                 pw.close();

36                 Toast.makeText(Sd0.this, "保存成功", 3000).show();

37             } catch (FileNotFoundException e) {

38                 e.printStackTrace();

39             }

40             break;

41         case R.id.sdBT02:

42             File f = new File(Environment.getExternalStorageDirectory()+

43                     "/test/test.txt");// 创建文件夹对象

44             BufferedReader br;

45             try {

46                 br = new BufferedReader(new InputStreamReader(new FileInputStream(f)));

47                 String str = null;

48                 while ((str = br.readLine()) != null) {

49                     tv.append(str);

50                 }

51             } catch (FileNotFoundException e) {

52                 e.printStackTrace();

53             } catch (IOException e) {

54                 e.printStackTrace();

55             }

56             break;

57         }

58 }