Project——文件操作-优快云博客

本文链接：https://blog.youkuaiyun.com/tianyitianyi1/article/details/7536364

1、

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="cn.itcast.file"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <uses-library android:name="android.test.runner" />
        <activity android:name=".MainActivity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

</application>
    <uses-sdk android:minSdkVersion="8" />
    
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

<instrumentation android:name="android.test.InstrumentationTestRunner"
android:targetPackage="cn.itcast.file" android:label="Tests for My App" />
</manifest>

2、file文件夹下

package cn.itcast.file;

import cn.itcast.service.FileService;
import android.test.AndroidTestCase;
import android.util.Log;

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

public void testReadFile() throws Throwable{
  FileService service = new FileService(this.getContext());
  String content = service.getContent("itcast.txt");
  Log.i(TAG, content);
}

public void testSaveAppend() throws Throwable{
  FileService service = new FileService(this.getContext());
  service.saveAppend("append.txt", ",http://www.sohu.com");
}

public void testSaveReadable() throws Throwable{
  FileService service = new FileService(this.getContext());
  service.saveReadable("readable.txt", ",http://www.csdn.com");
}

public void testSaveWriteable() throws Throwable{
  FileService service = new FileService(this.getContext());
  service.saveWriteable("writeable.txt", "http://www.babasport.com");
}

public void testSaveRW() throws Throwable{
  FileService service = new FileService(this.getContext());
  service.saveRW("rw.txt", "http://www.sina.com");
}
}

3、file文件夹下

package cn.itcast.file;

import cn.itcast.service.FileService;
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {
private static final String TAG = "MainActivity";
    private EditText filenameText;
    private EditText filecontentText;
    private FileService service;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        service = new FileService(this);

        filenameText = (EditText)this.findViewById(R.id.filename);
        filecontentText = (EditText)this.findViewById(R.id.filecontent);
        Button button = (Button)this.findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
    String filename = filenameText.getText().toString();
    String content = filecontentText.getText().toString();
    try {
     if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
      service.saveToSDCard(filename, content);
      Toast.makeText(MainActivity.this, R.string.success, 1).show();
     }else{
      Toast.makeText(MainActivity.this, R.string.sdcarderror, 1).show();
     }
    } catch (Exception e) {
     Log.e(TAG, e.toString());
     Toast.makeText(MainActivity.this, R.string.error, 1).show();
    }
   }
  });
    }
}

4、FileService文件夹下

package cn.itcast.service;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;

import android.content.Context;
import android.os.Environment;

public class FileService {
private Context context;

public FileService(Context context) {
this.context = context;
}

public void saveToSDCard(String filename, String content) throws Exception{
  File file = new File(Environment.getExternalStorageDirectory(), filename);
  FileOutputStream outStream = new FileOutputStream(file);
  outStream.write(content.getBytes());
  outStream.close();
}

public void save(String filename, String content) throws Exception{
  FileOutputStream outStream = context.openFileOutput(filename, Context.MODE_PRIVATE);
  outStream.write(content.getBytes());
  outStream.close();
}

public void saveAppend(String filename, String content) throws Exception{// ctrl+shift+y
  FileOutputStream outStream = context.openFileOutput(filename, Context.MODE_APPEND);
  outStream.write(content.getBytes());
  outStream.close();
}

public void saveReadable(String filename, String content) throws Exception{
  FileOutputStream outStream = context.openFileOutput(filename, Context.MODE_WORLD_READABLE);
  outStream.write(content.getBytes());
  outStream.close();
}

public void saveWriteable(String filename, String content) throws Exception{
  FileOutputStream outStream = context.openFileOutput(filename, Context.MODE_WORLD_WRITEABLE);
  outStream.write(content.getBytes());
  outStream.close();
}

public void saveRW(String filename, String content) throws Exception{
  FileOutputStream outStream = context.openFileOutput(filename, Context.MODE_WORLD_WRITEABLE + Context.MODE_WORLD_READABLE);
  outStream.write(content.getBytes());
  outStream.close();
}

public String getContent(String filename) throws Exception{
  FileInputStream inStream = context.openFileInput(filename);
  ByteArrayOutputStream outStream = new ByteArrayOutputStream();
  byte[] buffer = new byte[1024];
  int len = 0;
  while( (len = inStream.read(buffer)) != -1){
   outStream.write(buffer, 0, len);
  }
  byte[] data = outStream.toByteArray();
  inStream.close();
  outStream.close();
  return new String(data);
}
}

=======================================other工程（访问文件信息）=================================

1、

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="cn.itcast.other"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <uses-library android:name="android.test.runner" />
        <activity android:name=".MainActivity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

</application>
<uses-sdk android:minSdkVersion="8" />
<instrumentation android:name="android.test.InstrumentationTestRunner"
android:targetPackage="cn.itcast.other" android:label="Tests for My App" />
</manifest>

2、

package cn.itcast.other;

import android.content.Context;
import android.content.SharedPreferences;
import android.test.AndroidTestCase;
import android.util.Log;

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

public void testAccessPreference() throws Throwable{
  /*String path = "/data/data/cn.itcast.set/shared_prefs/itcast.xml";
  File file = new File(path);
  FileInputStream inStream = new FileInputStream(file);
  */
  Context otherContext = this.getContext().createPackageContext("cn.itcast.set",
    Context.CONTEXT_IGNORE_SECURITY);

  SharedPreferences preferences = otherContext.getSharedPreferences("itcast", Context.MODE_WORLD_READABLE);
  Log.i(TAG, "name="+ preferences.getString("name", ""));
  Log.i(TAG, "age="+ String.valueOf(preferences.getInt("age", 20)));
}
}

3、

package cn.itcast.other;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;

import cn.itcast.utils.StreamTool;

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

public class AccessOtherFileTest extends AndroidTestCase {
private static final String TAG = "AccessOtherFileTest";
//找不到文件
//访问其他应用中使用Context.MODE_PRIVATE创建的文件
public void testAccessPrivateFile() throws Throwable{
  String path = "/data/data/cn.itcast.file/files/itcast.txt";
  File file = new File(path);
  FileInputStream inStream = new FileInputStream(file);
  byte[] data = StreamTool.readInputStream(inStream);
  String content = new String(data);
  Log.i(TAG, content);
}
//访问其他应用中使用Context.MODE_APPEND创建的文件
public void testAccessAppendFile() throws Throwable{
  String path = "/data/data/cn.itcast.file/files/append.txt";
  File file = new File(path);
  FileInputStream inStream = new FileInputStream(file);
  byte[] data = StreamTool.readInputStream(inStream);
  String content = new String(data);
  Log.i(TAG, content);
}

//访问其他应用中使用Context.MODE_WORLD_READABLE创建的文件
public void testAccessReadableFile() throws Throwable{
  String path = "/data/data/cn.itcast.file/files/readable.txt";
  File file = new File(path);
  FileInputStream inStream = new FileInputStream(file);
  byte[] data = StreamTool.readInputStream(inStream);
  String content = new String(data);
  Log.i(TAG, content);
}

//往其他应用中使用Context.MODE_WORLD_WRITEABLE创建的文件写入数据
public void testWriteWriteableFile() throws Throwable{
  String path = "/data/data/cn.itcast.file/files/writeable.txt";
  File file = new File(path);
  FileOutputStream outStream = new FileOutputStream(file);
  outStream.write("www.itcast.cn".getBytes());
  outStream.close();
}

//访问其他应用中使用Context.MODE_WORLD_WRITEABLE创建的文件
public void testAccessWriteableFile() throws Throwable{
  String path = "/data/data/cn.itcast.file/files/writeable.txt";
  File file = new File(path);
  FileInputStream inStream = new FileInputStream(file);
  byte[] data = StreamTool.readInputStream(inStream);
  String content = new String(data);
  Log.i(TAG, content);
}

//往其他应用中使用Context.MODE_WORLD_WRITEABLE + Context.MODE_WORLD_READABLE创建的文件写入数据
public void testWriteRWFile() throws Throwable{
  String path = "/data/data/cn.itcast.file/files/rw.txt";
  File file = new File(path);
  FileOutputStream outStream = new FileOutputStream(file);
  outStream.write("www.itcast.cn".getBytes());
  outStream.close();
}

//访问其他应用中使用Context.MODE_WORLD_WRITEABLE + Context.MODE_WORLD_READABLE创建的文件
public void testAccessRWFile() throws Throwable{
  String path = "/data/data/cn.itcast.file/files/rw.txt";
  File file = new File(path);
  FileInputStream inStream = new FileInputStream(file);
  byte[] data = StreamTool.readInputStream(inStream);
  String content = new String(data);
  Log.i(TAG, content);
}
}

4、

package cn.itcast.other;

import android.app.Activity;
import android.os.Bundle;

public class MainActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }
}

5、StreamTool文件夹

package cn.itcast.utils;

import java.io.ByteArrayOutputStream;
import java.io.InputStream;

public class StreamTool {

public static byte[] readInputStream(InputStream inStream) throws Exception{
  ByteArrayOutputStream outStream = new ByteArrayOutputStream();
  byte[] buffer = new byte[1024];
  int len = 0;
  while( (len = inStream.read(buffer)) != -1){
   outStream.write(buffer, 0, len);
  }
  byte[] data = outStream.toByteArray();
  inStream.close();
  outStream.close();
  return data;
}
}