Android文件读取简单操作

Posted 2020-07-31 学无止境

 1 public class MainActivity extends ActionBarActivity {
 2     
 3     final String FILE_NAME = "crazyit.bin";
 4     @Override
 5     protected void onCreate(Bundle savedInstanceState) {
 6         super.onCreate(savedInstanceState);
 7         setContentView(R.layout.activity_main);
 8         
 9         
10         System.out.println(new StringBuilder("a").append("b").append("c").toString());
11         
12         Button read = (Button) findViewById(R.id.read);
13         Button write = (Button) findViewById(R.id.write);
14         
15         
16         final EditText edit1 = (EditText) findViewById(R.id.edit1);
17         final EditText edit2 = (EditText) findViewById(R.id.edit2);
18         
19         write.setOnClickListener(new OnClickListener() {
20             
21             public void onClick(View v) {
22                 write(edit1.getText().toString());
23                 edit1.setText("");
24             }
25         });
26         
27         read.setOnClickListener(new OnClickListener() {
28             
29             public void onClick(View v) {
30                 edit2.setText(read());
31             }
32         });
33         
34     }
35     
36     public void write(String content){
37         try {
38             FileOutputStream fos = openFileOutput(FILE_NAME, MODE_APPEND);
39             PrintStream ps = new PrintStream(fos);
40             ps.println(content);
41             ps.close();
42             
43         } catch (FileNotFoundException e) {
44             e.printStackTrace();
45         }
46         
47     }
48     
49     public String read(){
50         try {
51             FileInputStream fis = openFileInput(FILE_NAME);
52             byte [] buff = new byte[1024];
53             int hasRead = 0;
54             StringBuilder builder = new StringBuilder("");
55             while ( (hasRead = fis.read(buff)) > 0 ) {
56                 builder.append(new String(buff, 0, hasRead));
57             }
58             fis.close();
59             return builder.toString();
60             
61         } catch (FileNotFoundException e) {
62             e.printStackTrace();
63         } catch (IOException e) {
64             e.printStackTrace();
65         }
66         
67         return null;
68         
69

xml布局文件如下：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <Button
        android:id="@+id/read"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Read" />

    <Button
        android:id="@+id/write"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Write" />

    <EditText
        android:id="@+id/edit1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10" >

        <requestFocus />
    </EditText>

    <EditText
        android:id="@+id/edit2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10" />

</LinearLayout>

 

70 }