android的文件操作

目前，机会搜有的设备都会涉及到文件的操作，例如什么电脑，手机等设备。android的文件操作和电脑是比较类似的，既可以存储在手机内置的存储器里也可以是sd卡。在这次的博客里主要介绍在手机内置存储器里的文件操作。

一.开发流程

（1）界面的设计

（2）设计android的业务层

（3）单元测试
（4）设置android的控制器层

二.开发步骤

（1）设计软件界面

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/filename"
    />
<EditText
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:id="@+id/filename"
    />
   <TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/content"

    />
<EditText
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:id="@+id/content"
    android:minLines="3"
    />
    <Button
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:text="@string/button"
     android:id="@+id/button"/>
</LinearLayout>

这里也把R文件给大家看看

/* AUTO-GENERATED FILE. DO NOT MODIFY.
*
* This class was automatically generated by the
* aapt tool from the resource data it found. It
* should not be modified by hand.
*/

package org.lxh.file;

public final class R {
    public static final class attr {
    }
    public static final class drawable {
        public static final int icon=0x7f020000;
    }
    public static final class id {
        public static final int button=0x7f050002;
        public static final int content=0x7f050001;
        public static final int filename=0x7f050000;
    }
    public static final class layout {
        public static final int main=0x7f030000;
    }
    public static final class string {
        public static final int app_name=0x7f040001;
        public static final int button=0x7f040004;
        public static final int content=0x7f040003;
        public static final int failure=0x7f040006;
        public static final int filename=0x7f040002;
        public static final int hello=0x7f040000;
        public static final int success=0x7f040005;
    }
}

(2)设计业务层

package org.lxh.service;

import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;

import java.io.FileOutputStream;

import android.content.Context;
import android.util.Log;

public class FileService {
    private Context context;

    public FileService(Context context) { //通过构造方法传入context
        this.context = context;
    }
    //保存文件
    public void saveFile(String filename,String content) throws Exception{ //异常交给调用处处理
        FileOutputStream out=context.openFileOutput(filename, Context.MODE_PRIVATE);
        out.write(content.getBytes());
        out.close();
    }
    public String readFile(String filename) throws Exception{ //异常交给调用处处理
        FileInputStream in=context.openFileInput(filename);
        byte b[]=new byte[1024];
        int len=0;
        ByteArrayOutputStream array=new ByteArrayOutputStream();

        while((len=in.read(b))!=-1){ //开始读取文件
            array.write(b,0,len);
        }
        byte data[]=array.toByteArray(); //把内存里的数据读取出来

        in.close(); //每个流都必须关闭
        array.close();
        return new String(data); //把byte数组转换为字符串并返回
    }
}

下面开始做单元测试，要添加的环境就不说了

package org.lxh.test;

import org.lxh.service.FileService;

import android.test.AndroidTestCase;
import android.util.Log;

public class Test extends AndroidTestCase {
    public static final String TAG = "Test";

    public void testSave() {
        FileService service = new FileService(this.getContext());
        try {
            service.saveFile("01.txt", &qu

补充：移动开发 , Android ,