Android开发文件I/O操作示例

最新推荐文章于 2022-11-29 15:52:53 发布

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最新推荐文章于 2022-11-29 15:52:53 发布

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分类专栏： Android开发文章标签： android import file string byte encoding

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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.

 
   01package com.isandroid.android.simple.fileio; 
 
   02import java.io.File; 
 
   03import java.io.FileInputStream; 
 
   04import java.io.FileOutputStream; 
 
   05import java.io.IOException; 
 
   06import org.apache.http.util.EncodingUtils; 
 
   07import android.app.Activity; 
 
   08import android.os.Bundle; 
 
   09import android.util.Log; 
 
   10import android.widget.TextView; 
 
   11public 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}