android 将一些信息保存到本地，以后更新版本或者替换之后，数据在新安装的项目中还能使用

HongxinLocalSaveUtil

public class HongxinLocalSaveUtil{

private static final String SAVE_URL = "/youban/radio/cache/hongxindata/";

private static final String FILENAME = "record.cfg";

private static HongxinLocalSaveUtilinstance = null;

private static String SDPATH;

public static HongxinLocalSaveUtilgetInstance() {

if (instance == null) {

instance = new HongxinLocalSaveUtil();

}

return instance;

}

private HongxinLocalSaveUtil() {

SDPATH = android.os.Environment.getExternalStorageDirectory()+ "";

}

/**

* 是否能创建和写入文件

*/

public boolean isCanCreateAndWriteFile() {

if (Environment.getExternalStorageState().equals(

Environment.MEDIA_MOUNTED)) {

return true;

}

return false;

}

// 创建目录

public File createDir(String fileName) throws IOException {

File dir = new File(SDPATH + fileName);

dir.mkdirs();

return dir;

}

// 创建文件

public File createFile(String fileName) throws IOException {

File file = new File(SDPATH + fileName);

file.createNewFile();

return file;

}

public void saveRecord(List<MusicData> musicDatas) {

if (Environment.getExternalStorageState().equals(

Environment.MEDIA_MOUNTED)) {

FileOutputStream outStream = null;

DataOutputStream dos = null;

try {

if (!isExist()) {

File file = new File(SDPATH + SAVE_URL + FILENAME);

if (file != null) {

file.delete();

}

}

createDir(SAVE_URL);

File file = createFile(SAVE_URL + FILENAME);

outStream = new FileOutputStream(file);

dos = newDataOutputStream(outStream);

if (musicDatas != null) {

int size = musicDatas.size();

dos.writeInt(size);

for (int i = 0 ; i < size ; i++) {

MusicData musicData = musicDatas.get(i);

if (musicData == null) {

continue;

}

dos.writeUTF(musicData.getImageUrl());

dos.writeUTF(musicData.getMp3Long());

dos.writeUTF(musicData.getMusicName());

dos.writeUTF(musicData.getPlayLink());

dos.writeInt(musicData.getID());

dos.writeUTF(musicData.getLyrics());

}

}else {

dos.writeInt(0);

}

dos.flush();

} catch (FileNotFoundException e) {

// TODO Auto-generatedcatch block

e.printStackTrace();

} catch (IOException e) {

// TODO Auto-generatedcatch block

e.printStackTrace();

} finally {

if (dos != null) {

try {

dos.close();

} catch (IOException e) {

// TODO Auto-generatedcatch block

e.printStackTrace();

}

}

if (outStream != null) {

try {

outStream.close();

} catch (Exception e) {

}

}

}

}

}

// 判断文件是否存在

public boolean isExist() {

File file = new File(SDPATH + SAVE_URL + FILENAME);

return file.exists();

}

public List<MusicData> readData() {

/* sdcard可读状态 */

if (android.os.Environment.getExternalStorageState().equals(

android.os.Environment.MEDIA_MOUNTED)) {

if (!isExist()) {

return null;

}

FileInputStream fis = null;

DataInputStream dis = null;

try {

File file = new File(SDPATH + SAVE_URL + FILENAME);

fis = new FileInputStream(file);

dis = new DataInputStream(fis);

int size = dis.readInt();

if (size == 0) {

return null;

}

List<MusicData> musicDatas = newArrayList<MusicData>();

for (int i = 0 ; i < size ; i++) {

MusicData musicData = new MusicData();

musicData.setImageUrl(dis.readUTF());

musicData.setMp3Long(dis.readUTF());

musicData.setMusicName(dis.readUTF());

musicData.setPlayLink(dis.readUTF());

musicData.setID(dis.readInt());

musicData.setLyrics(dis.readUTF());

musicDatas.add(musicData);

}

return musicDatas;

} catch (Exception e) {

} finally {

if (dis != null) {

try {

dis.close();

} catch (IOException e) {

// TODO Auto-generatedcatch block

e.printStackTrace();

}

}

if (fis != null) {

try {

fis.close();

} catch (Exception e) {

}

}

}

}

return null;

}

}

需要导入权限

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

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