1 public class MainActivity extends Activity {
2
3 final String FILE_NAME = "crazyit.bin";
4
5 @Override
6 protected void onCreate(Bundle savedInstanceState) {
7 super.onCreate(savedInstanceState);
8 setContentView(R.layout.activity_main);
9
10 final EditText et1 = (EditText) findViewById(R.id.edt1);
11 final EditText et2 = (EditText) findViewById(R.id.edt2);
12
13 Button btnWrite = (Button) findViewById(R.id.btnIn);
14 btnWrite.setOnClickListener(new OnClickListener() {
15
16 @Override
17 public void onClick(View v) {
18 write(et1.getText().toString());
19 et1.setText("");
20 }
21 });
22 Button btnRead = (Button) findViewById(R.id.btnOut);
23 btnRead.setOnClickListener(new OnClickListener() {
24
25 @Override
26 public void onClick(View v) {
27 et2.setText(read());
28 }
29 });
30
31 }
32
33 /**
34 * 写入到/data/data/[包名]/files 路径下
35 *
36 * @param content
37 */
38 private void write(String content) {
39 try {
40 FileOutputStream fos = openFileOutput(FILE_NAME, Context.MODE_APPEND);
41 PrintStream ps = new PrintStream(fos);
42 ps.println(content);
43 ps.close();
44
45 } catch (FileNotFoundException e) {
46 e.printStackTrace();
47 }
48 }
49
50 /**
51 * /data/data/[包名]/files 路径下读取文件
52 *
53 * @return
54 */
55 private String read() {
56 try {
57
58 FileInputStream fis = openFileInput(FILE_NAME);
59 byte[] buff = new byte[1024];
60 int hasRead = 0;
61 StringBuilder sb = new StringBuilder("");
62 while ((hasRead = fis.read(buff)) > 0) {
63 sb.append(new String(buff, 0, hasRead));
64 }
65 fis.close();
66 return sb.toString();
67
68 } catch (FileNotFoundException e) {
69 e.printStackTrace();
70 } catch (IOException e) {
71 e.printStackTrace();
72 }
73
74 return null;
75 }
76
77 }
