Android OTG U盘文件读写
作者:互联网
最近要求对安卓平板开发时导出Excel表格到插在平板的U盘上,初步尝试发现,对U盘的文件读写只能操作Android/包名/的目录,不能直接写在根目录,不方便客户使用,于是研究了libaums的库可用是可用,但是调用其device.init() 方法后,就不能在文件管理里面看到U盘了,所以客户使用起来还是不方便,于是想到了Linux文件操作命令。
思路是先生成文件在内置存储卡中,然后使用Linux命令将文件cp或者mv到U盘根目录
复制命令
cp -r srcPath targetPath
剪切命令
mv srcPath targetPath
首先获取U盘的路径,代码如下,有返回值说明有U盘挂载,返回值为空说明U盘未挂载
public static String getUDiskRealPath() {
String filePath = "/proc/mounts";
File file = new File(filePath);
List<String> lineList = new ArrayList<>();
InputStream inputStream =null;
try {
inputStream = new FileInputStream(file);
if (inputStream != null) {
InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "GBK");
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
String line = "";
while ((line = bufferedReader.readLine()) != null) {
if (line.contains("vfat")) {
lineList.add(line);
}
}
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (inputStream != null) {
try {
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
if (lineList.isEmpty()){
Log.i(HEAD, "getUDiskPath no usb disk ");
return "";
}
String editPath = lineList.get(lineList.size() - 1);
Log.i(HEAD,"edit path = " + editPath);
int start = editPath.indexOf("/mnt");
int end = editPath.indexOf(" vfat");
String path = editPath.substring(start, end);
return path;
}
生成你要复制或剪切到U盘的文件并获取其路径srcPath
拼接命令传入下面的执行命令方法中,其中isRooted需传入true
/**
* Execute the command.
*
* @param commands The commands.
* @param isRooted True to use root, false otherwise.
* @param isNeedResultMsg True to return the message of result, false otherwise.
* @return the single {@link CommandResult} instance
*/
public static CommandResult execCmd(final String[] commands,
final boolean isRooted,
final boolean isNeedResultMsg) {
int result = -1;
if (commands == null || commands.length == 0) {
return new CommandResult(result, null, null);
}
Process process = null;
BufferedReader successResult = null;
BufferedReader errorResult = null;
StringBuilder successMsg = null;
StringBuilder errorMsg = null;
DataOutputStream os = null;
try {
process = Runtime.getRuntime().exec(isRooted ? "su" : "sh");
os = new DataOutputStream(process.getOutputStream());
for (String command : commands) {
if (command == null) continue;
os.write(command.getBytes());
os.writeBytes(LINE_SEP);
os.flush();
}
os.writeBytes("exit" + LINE_SEP);
os.flush();
result = process.waitFor();
if (isNeedResultMsg) {
successMsg = new StringBuilder();
errorMsg = new StringBuilder();
successResult = new BufferedReader(new InputStreamReader(process.getInputStream(),
"UTF-8"));
errorResult = new BufferedReader(new InputStreamReader(process.getErrorStream(),
"UTF-8"));
String line;
if ((line = successResult.readLine()) != null) {
successMsg.append(line);
while ((line = successResult.readLine()) != null) {
successMsg.append(LINE_SEP).append(line);
}
}
if ((line = errorResult.readLine()) != null) {
errorMsg.append(line);
while ((line = errorResult.readLine()) != null) {
errorMsg.append(LINE_SEP).append(line);
}
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (os != null) {
os.close();
}
} catch (IOException e) {
e.printStackTrace();
}
try {
if (successResult != null) {
successResult.close();
}
} catch (IOException e) {
e.printStackTrace();
}
try {
if (errorResult != null) {
errorResult.close();
}
} catch (IOException e) {
e.printStackTrace();
}
if (process != null) {
process.destroy();
}
}
return new CommandResult(
result,
successMsg == null ? null : successMsg.toString(),
errorMsg == null ? null : errorMsg.toString()
);
}
例如
/**源文件*/
String srcPath = "/storage/emulated/0/test.txt";
/**目标位置,如U盘跟路径*/
String targetPath = getUDiskRealPath();
/**拼接复制命令*/
String cmd = "cp -r " + srcPath + " " + targetPath;
/**执行复制命令*/
execCmd(new String[]{cmd},true,true);
即可完成文件写在U盘根目录(或者其他目录)的操作。
写文件会了,读文件也就是反过来进行了,先复制或剪切文件到内置存储卡,在进行基本的文件操作即可。
标签:U盘,OTG,new,Android,null,os,line,String 来源: https://blog.csdn.net/Panda_Kill/article/details/106923326