1、国开Android智能手机编程单元5形考任务1package com.carlos.utils;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.util.ArrayList;import android.os.Environment;public class FileUtils private String SDPATH; public FileUtils() SDPATH=Environment.getExternalStorageDirectory()+"/" /System.out.println(Environment.getExternalStorageDirectory().getAbsolutePath(); /创建文件,一定不会返回

2、空 /* * * param path 直接创建文件即可，无需考虑文件夹有没有创建,若文件已存在返回null * param fileName * return */ public File createSDFile(String path,String fileName) File file=null; createSDDir(path); try file=new File(SDPATH+path+fileName); if(file.exists() && file.isFile() return null; file.createNewFile(); /创建文件 catch(Exception e) e.printStackTrace(); return file; /创建目录,如果存在同名文件夹则返回该文件夹，否则创建文件 public File createSDDir(String dirName) File dir=new File(SDPATH+dirName); if(dir.exists() && dir.isDirectory()

3、return dir; dir.mkdirs(); /可创建多级文件夹 return dir; /这里写相对目录 public ArrayList<String> listContentsOfFile(String path) ArrayList<String> list=new ArrayList<String>(); File file=new File(SDPATH+path); File fileList=file.listFiles(); if(fileList=null) return list; for(int i=0; i<fileList.length;i+) System.out.println(fileListi.getName(); return list; /判断SD卡文件夹是否存在 public boolean isFileExist(String path,String fileName) File file=new File(SDPATH+path+fileName); return file.exists();

4、 /获得文件输入流 public InputStream getInputStreamFromFile(String path,String fileName) InputStream input=null; File file=new File(SDPATH+path+fileName); if(file.exists()=false) return null; try input=new FileInputStream(file); catch (FileNotFoundException e) / TODO Auto-generated catch bloc e.printStackTrace(); return null; return input; /* * * param in * param path 文件存储的相对路径 * param fileName * return */ public boolean saveInputStreamToFile(InputStream in, String path,String fileName ) File file=creat

5、eSDFile(path,fileName); /相对路径即可 int length=0; if(file=null) return true; /其实这里的情况是文件已存在 byte buffer=new byte1024; FileOutputStream fOut=null; try fOut=new FileOutputStream(file); while(length=in.read(buffer)!=-1) /要利用read返回的实际成功读取的字节数，将buffer写入文件，否则将会出现错误的字节 fOut.write(buffer, 0, length); catch (Exception e) / TODO Auto-generated catch block e.printStackTrace(); return false; finally try fOut.close(); catch (Exception e) / TODO Auto-generated catch block e.printStackTrace(); return false; return

6、 true; public String getSDRootPath() return Environment.getExternalStorageDirectory().getAbsolutePath()+"/" public String getSDPATH() return SDPATH; public void setSDPATH(String sDPATH) SDPATH = sDPATH; 复制代码各个函数的功能已经有说明，这个属于一个工具类，可无需改动使用。 二、数据库，用于存放所查的单词的单词、音标、释义、例句1、首先需创建一个DataBaseHelper类，继承SQLiteOpenHelper类：复制代码package com.carlos.database;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import and

7、roid.database.sqlite.SQLiteOpenHelper;public class DataBaseHelperDict extends SQLiteOpenHelper public Context mContext=null; public String tableName=null; public static int VERSION=1; public DataBaseHelperDict(Context context, String name, CursorFactory factory, int version) super(context, name, factory, version); / TODO Auto-generated constructor stub mContext=context; tableName=name; public DataBaseHelperDict(Context context, String name, CursorFactory factory) this(context,name,factory,VERSION); mContext=context; tableName=name; public DataBaseHelperDict(Context conte

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