Android开发文件I/O操作示例

Android开发文件I/O操作示例,打开文件写入内容,然后从文件中读出显示在View上.

01 package com.isandroid.android.simple.fileio;
02 import java.io.File;
03 import java.io.FileInputStream;
04 import java.io.FileOutputStream;
05 import java.io.IOException;
06 import org.apache.http.util.EncodingUtils;
07 import android.app.Activity;
08 import android.os.Bundle;
09 import android.util.Log;
10 import android.widget.TextView;
11 public class FileIO extends Activity {
12
13     final String FILE_PATH =
14         "/data/data/com.isandroid.android.simple.fileio/";
15     final String FILE_NAME = "test.txt";
16     final String TAG = "I/O";
17     final String TEXT_ENCODING = "UTF-8";
18
19     File file;
20     FileOutputStream out;
21     FileInputStream in;
22     TextView tv;
23     String display;
24     /** Called when the activity is first created. */
25     @Override
26     public void onCreate(Bundle savedInstanceState) {
27         super.onCreate(savedInstanceState);
28         try {
29             //创建文件
30             file = new File(FILE_PATH , FILE_NAME);
31             file.createNewFile();
32
33             //打开文件file的OutputStream
34             out = new FileOutputStream(file);
35             String infoToWrite = "面朝大海,春暖花开.";
36             //将字符串转换成byte数组写入文件
37             out.write(infoToWrite.getBytes());
38             //关闭文件file的OutputStream
39             out.close();
40
41             //打开文件file的InputStream
42             in = new FileInputStream(file);
43             //将文件内容全部读入到byte数组
44             int length = (int)file.length();
45             byte[] temp = new byte[length];
46             in.read(temp, 0, length);
47             //将byte数组用UTF-8编码并存入display字符串中
48             display =  EncodingUtils.getString(temp,TEXT_ENCODING);
49             //关闭文件file的InputStream
50             in.close();
51         } catch (IOException e) {
52             //将出错信息打印到Logcat
53             Log.e(TAG, e.toString());
54             this.finish();
55         }
56
57         //将读出的字符串用TextView显示到主界面
58         tv = new TextView(this);
59         tv.setText(display);
60         setContentView(tv);
61     }
62 }