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  • Android学习笔记之数据的Sdcard存储方法及操作sdcard的工具类

    FileService.java也就是操作sdcard的工具类：

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    package com.example.data_storage_sdcard.file;
     
    import java.io.ByteArrayOutputStream;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.IOException;
     
    import android.os.Environment;
     
    /**
     * sdcard的存在于上下文无关
     *
     * @author piaodangdehun
     *
     */
    public class FileService {
     
        /*
         * 存放在sdcard的根目录
         */
        public boolean saveFileToSdcardRoot(String fileName, byte[] data) {
            boolean flag = false;
            /*
             * 先判断sdcard的状态，是否存在
             */
            String state = Environment.getExternalStorageState();
            FileOutputStream outputStream = null;
            File rootFile = Environment.getExternalStorageDirectory(); // 获得sdcard的根路径
            /*
             * 表示sdcard挂载在手机上，并且可以读写
             */
            if (state.equals(Environment.MEDIA_MOUNTED)) {
                File file = new File(rootFile, fileName);
                try {
                    outputStream = new FileOutputStream(file);
                    try {
                        outputStream.write(data, 0, data.length);
                        flag = true;
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } finally {
                    if (outputStream != null) {
                        try {
                            outputStream.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }
            return flag;
        }
     
        /*
         * 存放在sdcard下自定义的目录
         */
        public boolean saveFileToSdcardDir(String fileName, byte[] data) {
            boolean flag = false;
            /*
             * 先判断sdcard的状态，是否存在
             */
            String state = Environment.getExternalStorageState();
            FileOutputStream outputStream = null;
            File rootFile = Environment.getExternalStorageDirectory(); // 获得sdcard的根路径
            /*
             * 表示sdcard挂载在手机上，并且可以读写
             */
            if (state.equals(Environment.MEDIA_MOUNTED)) {
                File file = new File(rootFile.getAbsoluteFile() + /txt);
                if (!file.exists()) {
                    file.mkdirs();
                }
                try {
                    outputStream = new FileOutputStream(new File(file, fileName));
                    try {
                        outputStream.write(data, 0, data.length);
                        flag = true;
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } finally {
                    if (outputStream != null) {
                        try {
                            outputStream.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }
            return flag;
        }
     
        /*
         * 用于读取sdcard的数据
         */
        public String readContextFromSdcard(String fileName) {
     
            String state = Environment.getExternalStorageState();
            File rooFile = Environment.getExternalStorageDirectory(); // 获得sdcard的目录
     
            FileInputStream inputStream = null;// 用于度取数据的流
            ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); // 用于存放独处的数据
     
            if (state.equals(Environment.MEDIA_MOUNTED)) {
                File file = new File(rooFile.getAbsoluteFile() + /txt/);// 在sdcard目录下创建一个txt目录
                File file2 = new File(file, fileName);
                int len = 0;
                byte[] data = new byte[1024];
                if (file2.exists()) {
                    try {
                        inputStream = new FileInputStream(file2);
                        try {
                            while ((len = inputStream.read(data)) != -1) {
                                outputStream.write(data, 0, data.length);
                            }
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        return new String(outputStream.toByteArray());
                    } catch (FileNotFoundException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    } finally {
                        if (outputStream != null) {
                            try {
                                outputStream.close();
                            } catch (IOException e) {
                                e.printStackTrace();
                            }
                        }
                    }
                }
            }
            return null;
        }
     
        /**
         * 对文件进行分类的保存到固定的文件中去
         *
         * @param fileName
         * @param data
         */
        public void saveFileToSdcardBySuff(String fileName, byte[] data) {
            // File file = Environment.getExternalStoragePublicDirectory();
            // 保存文件的目录
            File file = null;
            if (Environment.getExternalStorageState().equals(
                    Environment.MEDIA_MOUNTED)) {
     
                /*
                 * 将不同的文件放入到不同的类别中
                 */
                if (fileName.endsWith(.mp3)) {
                    file = Environment
                            .getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC);
                } else if (fileName.endsWith(.jpg) || fileName.endsWith(.png)
                        || fileName.endsWith(.gif)) {
                    file = Environment
                            .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
                } else if (fileName.endsWith(.mp4) || fileName.endsWith(.avi)
                        || fileName.endsWith(.3gp)) {
                    file = Environment
                            .getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES);
                } else {
                    file = Environment
                            .getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
                }
                FileOutputStream outputStream = null;
                try {
                    outputStream = new FileOutputStream(new File(file, fileName));
                    try {
                        outputStream.write(data, 0, data.length);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } finally {
                    if (outputStream != null) {
                        try {
                            outputStream.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }
        }
     
        /*
         * 删除一个文件
         */
        public boolean deleteFileFromSdcard(String folder, String fileName) {
            boolean flag = false;
            File file = Environment.getExternalStorageDirectory();
            if (Environment.getExternalStorageState().equals(
                    Environment.MEDIA_MOUNTED)) {
                File exitFile = new File(file.getAbsoluteFile() + / + folder);
                if (exitFile.exists()) {
                    exitFile.delete();
                }
            }
            return flag;
        }
    }


    HttpUtils.java访问网络的

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    package com.example.data_storage_sdcard.http;
     
    import java.io.IOException;
     
    import org.apache.http.HttpResponse;
    import org.apache.http.client.ClientProtocolException;
    import org.apache.http.client.HttpClient;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.impl.client.DefaultHttpClient;
    import org.apache.http.util.EntityUtils;
     
    public class HttpUtils {
        /*
         *
         */
        public static byte[] getImage(String path) {
            byte[] data = null;
            HttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(path);
            try {
                HttpResponse response = httpClient.execute(httpPost);
                if (response.getStatusLine().getStatusCode() == 200) {
                    data = EntityUtils.toByteArray(response.getEntity());
                }
            } catch (ClientProtocolException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                httpClient.getConnectionManager().shutdown();
            }
     
            return data;
     
        }
    }

    ImageCache.java将文件放到cache中的：

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    package com.example.data_storage_sdcard.img;
     
    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.IOException;
     
    import android.os.Environment;
     
    public class ImageCache {
     
        public static  String saveImageCache(String fileName, byte[] data) {
            File file = Environment.getExternalStorageDirectory(); // 根目录
            FileOutputStream outputStream = null;
            if (Environment.getExternalStorageState().equals(
                    Environment.MEDIA_MOUNTED)) {
                try {
                    outputStream = new FileOutputStream(new File(file, fileName));
                    outputStream.write(data, 0, data.length);
     
                    return file.getAbsolutePath() + / + fileName;
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    if (outputStream != null) {
                        try {
                            outputStream.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }
            return null;
        }
    }


    MainActivity.java

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    package com.example.data_storage_sdcard;
     
    import android.app.Activity;
    import android.app.ProgressDialog;
    import android.graphics.Bitmap;
    import android.graphics.BitmapFactory;
    import android.os.AsyncTask;
    import android.os.Bundle;
    import android.view.Menu;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    import android.widget.ImageView;
     
    import com.example.data_storage_sdcard.http.HttpUtils;
    import com.example.data_storage_sdcard.img.ImageCache;
     
    public class MainActivity extends Activity {
        private Button button;
        private ImageView imageView;
        private ProgressDialog progressDialog;
     
        private String imageName;
     
        private final String pathString = http://www.baidu.com/img/bd_logo1.png;
     
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            button = (Button) this.findViewById(R.id.button1);
            imageView = (ImageView) this.findViewById(R.id.imageView1);
     
            progressDialog = new ProgressDialog(this);
            progressDialog.setTitle(下载提示);
            progressDialog.setMessage(load...);
            button.setOnClickListener(new OnClickListener() {
     
                @Override
                public void onClick(View v) {
                    new MyTask().execute(pathString);
                }
            });
        }
     
        class MyTask extends AsyncTask<string,> {
     
            @Override
            protected void onPreExecute() {
                super.onPreExecute();
                progressDialog.show();
            }
     
            @Override
            protected byte[] doInBackground(String... params) {
                String name = params[0];
                imageName = name
                        .substring(name.lastIndexOf(/) + 1, name.length());
                return HttpUtils.getImage(params[0]);
            }
     
            @Override
            protected void onProgressUpdate(Void... values) {
                super.onProgressUpdate(values);
            }
     
            @Override
            protected void onPostExecute(byte[] result) {
                super.onPostExecute(result);
                if (result != null) {
                    Bitmap bm = BitmapFactory.decodeByteArray(result, 0,
                            result.length);
                    imageView.setImageBitmap(bm);
                    ImageCache.saveImageCache(, result);
                } else {
                    imageView.setImageResource(R.drawable.ic_launcher);
                }
                progressDialog.dismiss();
            }
        }
     
        @Override
        public boolean onCreateOptionsMenu(Menu menu) {
            // Inflate the menu; this adds items to the action bar if it is present.
            getMenuInflater().inflate(R.menu.main, menu);
            return true;
        }
     
    }
    </string,>


    测试类：

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    package com.example.data_storage_sdcard;
     
    import java.io.FileWriter;
     
    import com.example.data_storage_sdcard.file.FileService;
     
    import android.nfc.Tag;
    import android.test.AndroidTestCase;
    import android.util.Log;
     
    public class MyTest extends AndroidTestCase {
     
        public void saveFileToSdcardTest() {
            FileService fileService = new FileService();
     
            fileService.saveFileToSdcardRoot(aa.txt,
                    jkhdsfjkhdskjfhdsjf.getBytes());
        }
     
        public void saveFileToSdcardDir() {
            FileService fileService = new FileService();
     
            fileService.saveFileToSdcardRoot(aa.txt,
                    jkhdsfjkhdskjfhdsjf.getBytes());
        }
     
        public void readContextFromSdcardTest() {
            FileService fileService = new FileService();
            String msg = fileService.readContextFromSdcard(aa.txt);
            System.err.println(--> + msg);
        }
     
        public void saveFileToSdcardBySuffTest() {
            FileService fileService = new FileService();
            fileService.saveFileToSdcardBySuff(aa.avi,
                    asdfkajsgdhagsdfhdgsf.getBytes());
        }
     
        public void delFile() {
            FileService fileService = new FileService();
            boolean flag = fileService.deleteFileFromSdcard(txt, aa.txt);
        }
    }


    需要在请单位按中加入访问网络的权限、操作sdcard的权限、测试的权限

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    <!--?xml version=1.0 encoding=utf-8?-->
    <manifest android:versioncode="1" android:versionname="1.0" package="com.example.data_storage_sdcard" xmlns:android="http://schemas.android.com/apk/res/android">
     
        <uses-sdk android:minsdkversion="8" android:targetsdkversion="18">
     
        <instrumentation android:name="android.test.InstrumentationTestRunner" android:targetpackage="com.example.data_storage_sdcard">
        </instrumentation>
        <!-- 添加访问sdcard的权限 -->
        <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE">
        <!-- 添加访问网络的权限 -->
        <uses-permission android:name="android.permission.INTERNET">
     
         
            <uses-library android:name="android.test.runner">
     
             
                <intent-filter>
                     
     
                    <category android:name="android.intent.category.LAUNCHER">
                </category></action></intent-filter>
            </activity>
     
            <uses-library>
            </uses-library>
        </uses-library></application>
     
    </uses-permission></uses-permission></uses-sdk></manifest>
     

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  • 原文地址：https://www.cnblogs.com/rabbit-bunny/p/4238064.html
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