我在资产文件夹里有几个文件。我需要把它们都复制到一个文件夹,比如/sdcard/folder。我想从一个线程中做这件事。我该怎么做?
当前回答
试试这个,它更简单,这将帮助你:
// Open your local db as the input stream
InputStream myInput = _context.getAssets().open(YOUR FILE NAME);
// Path to the just created empty db
String outFileName =SDCARD PATH + YOUR FILE NAME;
// Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
// transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
// Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
其他回答
由于一些错误,上述解决方案无法工作:
目录创建失败 Android返回的资产也包含三个文件夹:图像,声音和webkit 增加了处理大文件的方法:在项目的资产文件夹中添加扩展名.mp3到文件,在复制目标文件时将没有.mp3扩展名
下面是代码(我留下了Log语句,但你现在可以删除它们):
final static String TARGET_BASE_PATH = "/sdcard/appname/voices/";
private void copyFilesToSdCard() {
copyFileOrDir(""); // copy all files in assets folder in my project
}
private void copyFileOrDir(String path) {
AssetManager assetManager = this.getAssets();
String assets[] = null;
try {
Log.i("tag", "copyFileOrDir() "+path);
assets = assetManager.list(path);
if (assets.length == 0) {
copyFile(path);
} else {
String fullPath = TARGET_BASE_PATH + path;
Log.i("tag", "path="+fullPath);
File dir = new File(fullPath);
if (!dir.exists() && !path.startsWith("images") && !path.startsWith("sounds") && !path.startsWith("webkit"))
if (!dir.mkdirs())
Log.i("tag", "could not create dir "+fullPath);
for (int i = 0; i < assets.length; ++i) {
String p;
if (path.equals(""))
p = "";
else
p = path + "/";
if (!path.startsWith("images") && !path.startsWith("sounds") && !path.startsWith("webkit"))
copyFileOrDir( p + assets[i]);
}
}
} catch (IOException ex) {
Log.e("tag", "I/O Exception", ex);
}
}
private void copyFile(String filename) {
AssetManager assetManager = this.getAssets();
InputStream in = null;
OutputStream out = null;
String newFileName = null;
try {
Log.i("tag", "copyFile() "+filename);
in = assetManager.open(filename);
if (filename.endsWith(".jpg")) // extension was added to avoid compression on APK file
newFileName = TARGET_BASE_PATH + filename.substring(0, filename.length()-4);
else
newFileName = TARGET_BASE_PATH + filename;
out = new FileOutputStream(newFileName);
byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1) {
out.write(buffer, 0, read);
}
in.close();
in = null;
out.flush();
out.close();
out = null;
} catch (Exception e) {
Log.e("tag", "Exception in copyFile() of "+newFileName);
Log.e("tag", "Exception in copyFile() "+e.toString());
}
}
编辑:更正了一个错位的“;”,这是抛出一个系统的“无法创建目录”错误。
您还可以使用Guava的ByteStream将文件从资产文件夹复制到SD卡。这是我最终得到的解决方案,将文件递归地从资产文件夹复制到SD卡:
/**
* Copies all assets in an assets directory to the SD file system.
*/
public class CopyAssetsToSDHelper {
public static void copyAssets(String assetDir, String targetDir, Context context)
throws IOException {
AssetManager assets = context.getAssets();
String[] list = assets.list(assetDir);
for (String f : Objects.requireNonNull(list)) {
if (f.indexOf(".") > 1) { // check, if this is a file
File outFile = new File(context.getExternalFilesDir(null),
String.format("%s/%s", targetDir, f));
File parentFile = outFile.getParentFile();
if (!Objects.requireNonNull(parentFile).exists()) {
if (!parentFile.mkdirs()) {
throw new IOException(String.format("Could not create directory %s.",
parentFile));
}
}
try (InputStream fin = assets.open(String.format("%s/%s", assetDir, f));
OutputStream fout = new FileOutputStream(outFile)) {
ByteStreams.copy(fin, fout);
}
} else { // This is a directory
copyAssets(String.format("%s/%s", assetDir, f), String.format("%s/%s", targetDir, f),
context);
}
}
}
}
这就是我的个性化文本提取类,希望对大家有用。
package lorenzo.morelli.platedetector;
import android.content.Context;
import android.content.res.AssetManager;
import android.graphics.Bitmap;
import com.googlecode.tesseract.android.TessBaseAPI;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
public class TextExtractor {
private final Context context;
private final String dirName;
private final String language;
public TextExtractor(final Context context, final String dirName, final String language) {
this.context = context;
this.dirName = dirName;
this.language = language;
}
public String extractText(final Bitmap bitmap) {
final TessBaseAPI tessBaseApi = new TessBaseAPI();
final String datapath = this.context.getFilesDir()+ "/tesseract/";
checkFile(new File(datapath + this.dirName + "/"), datapath, this.dirName, this.language);
tessBaseApi.init(datapath, this.language);
tessBaseApi.setImage(bitmap);
final String extractedText = tessBaseApi.getUTF8Text();
tessBaseApi.end();
return extractedText;
}
private void checkFile(final File dir, final String datapath, final String dirName, final String language) {
//directory does not exist, but we can successfully create it
if (!dir.exists()&& dir.mkdirs()) {
copyFiles(datapath, dirName, language);
} //The directory exists, but there is no data file in it
if(dir.exists()) {
final String datafilepath = datapath + "/" + dirName + "/" + language + ".traineddata";
final File datafile = new File(datafilepath);
if (!datafile.exists()) {
copyFiles(datapath, dirName, language);
}
}
}
private void copyFiles(final String datapath, final String dirName, final String language) {
try {
//location we want the file to be at
final String filepath = datapath + "/" + dirName + "/" + language + ".traineddata";
//get access to AssetManager
final AssetManager assetManager = this.context.getAssets();
//open byte streams for reading/writing
final InputStream instream = assetManager.open(dirName + "/" + language + ".traineddata");
final OutputStream outstream = new FileOutputStream(filepath);
//copy the file to the location specified by filepath
byte[] buffer = new byte[1024];
int read;
while ((read = instream.read(buffer)) != -1) {
outstream.write(buffer, 0, read);
}
outstream.flush();
outstream.close();
instream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
要使用它,你需要训练过的数据文件。你可以从这个链接下载trainddata文件。
一旦你下载了你想要的traineddata文件,你需要在你的Android项目中创建一个名为assets的Android资源目录。在新创建的资产文件夹中,你需要创建一个名为“tessdata”的常规目录,在那里你可以放置你的训练数据文件。 最后你必须初始化MainActivity中的“TextExtractor”类。
final TextExtractor textExtractor = new TextExtractor(this, "tessdata", "eng");
第一个参数是上下文,第二个参数是刚刚创建的目录名,最后一个参数是刚刚下载的训练数据的语言。
要提取文本,你必须调用"extractText"方法:
final String text = textExtractor.extractText(imageWithText);
注意,extractText需要一个位图图像才能工作!! 你可以用这一行从你的可绘制文件中创建一个BitMap图像:
final BitMap image = BitmapFactory.decodeResource(getResources(), R.drawable.test_image);
如果你需要更多的支持,我建议你遵循这个有用的指南:https://github.com/SamVanRoy/Android_OCR_App
复制所有文件和目录从资产到您的文件夹!
为了更好地复制,使用apache Commons IO
public void doCopyAssets() throws IOException {
File externalFilesDir = context.getExternalFilesDir(null);
doCopy("", externalFilesDir.getPath());
}
//这是复制的主要方法
private void doCopy(String dirName, String outPath) throws IOException {
String[] srcFiles = assets.list(dirName);//for directory
for (String srcFileName : srcFiles) {
String outFileName = outPath + File.separator + srcFileName;
String inFileName = dirName + File.separator + srcFileName;
if (dirName.equals("")) {// for first time
inFileName = srcFileName;
}
try {
InputStream inputStream = assets.open(inFileName);
copyAndClose(inputStream, new FileOutputStream(outFileName));
} catch (IOException e) {//if directory fails exception
new File(outFileName).mkdir();
doCopy(inFileName, outFileName);
}
}
}
public static void closeQuietly(AutoCloseable autoCloseable) {
try {
if(autoCloseable != null) {
autoCloseable.close();
}
} catch(IOException ioe) {
//skip
}
}
public static void copyAndClose(InputStream input, OutputStream output) throws IOException {
copy(input, output);
closeQuietly(input);
closeQuietly(output);
}
public static void copy(InputStream input, OutputStream output) throws IOException {
byte[] buffer = new byte[1024];
int n = 0;
while(-1 != (n = input.read(buffer))) {
output.write(buffer, 0, n);
}
}
基于您的解决方案,我自己做了一些事情来允许子文件夹。有些人可能会觉得这很有用:
...
copyFileOrDir("myrootdir");
...
private void copyFileOrDir(String path) {
AssetManager assetManager = this.getAssets();
String assets[] = null;
try {
assets = assetManager.list(path);
if (assets.length == 0) {
copyFile(path);
} else {
String fullPath = "/data/data/" + this.getPackageName() + "/" + path;
File dir = new File(fullPath);
if (!dir.exists())
dir.mkdir();
for (int i = 0; i < assets.length; ++i) {
copyFileOrDir(path + "/" + assets[i]);
}
}
} catch (IOException ex) {
Log.e("tag", "I/O Exception", ex);
}
}
private void copyFile(String filename) {
AssetManager assetManager = this.getAssets();
InputStream in = null;
OutputStream out = null;
try {
in = assetManager.open(filename);
String newFileName = "/data/data/" + this.getPackageName() + "/" + filename;
out = new FileOutputStream(newFileName);
byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1) {
out.write(buffer, 0, read);
}
in.close();
in = null;
out.flush();
out.close();
out = null;
} catch (Exception e) {
Log.e("tag", e.getMessage());
}
}
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