如何在Android-Studio中使用Uri-Path修复我的"FileNotFoundException"(没有这样的文件或目录)错误？

Question

我正在编写一个应用程序来将文件(图片)保存为csv文件中的列给出的特定名称。用户必须首先使用文件浏览器选择 csv，然后将文件复制到我的目录数据目录。

一切都很好，但似乎我从File src Object得到的路径不适用于操作。 我希望这里明显出现错误(第二个代码框) 如果很明显/容易避免，请提前说明，这是我的第一个Android项目。

我已经尝试使用具有不同参数类型的不同复制函数，并且还尝试了其他格式，例如uri.toString()给出的字符串。

开瓶器

public void performFileSearch() {
// ACTION_OPEN_DOCUMENT is the intent to choose a file via the system's file
// browser.
Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
// Filter to only show results that can be "opened"
intent.addCategory(Intent.CATEGORY_OPENABLE);
// Filter to show only  .csv  using the image MIME data type.
// For all it would be "*/*".
intent.setType("text/comma-separated-values");
startActivityForResult(intent, READ_REQUEST_CODE);
}

创建路径

@Override
public void onActivityResult(int requestCode, int resultCode,
Intent resultData) {
if (requestCode == READ_REQUEST_CODE && resultCode == Activity.RESULT_OK)
{
if (resultData != null) {
Uri path = resultData.getData();
stringUri = path.getPath();
File src = new File(stringUri);
File destination = new File(getFilesDir().getPath());
try {
copyDirectoryOneLocationToAnotherLocation(src,destination);
}
catch(IOException e) {
e.printStackTrace();
System.out.print("error in upload");
}
Toast.makeText(MainActivity.this, "Path: "+stringUri , Toast.LENGTH_SHORT).show();
}

}
}

从 StackOverflow 复制操作

public static void copyDirectoryOneLocationToAnotherLocation(File sourceLocation, File targetLocation)
throws IOException {
if (sourceLocation.isDirectory()) {
if (!targetLocation.exists()) {
targetLocation.mkdir();
}
String[] children = sourceLocation.list();
for (int i = 0; i < sourceLocation.listFiles().length; i++) {
copyDirectoryOneLocationToAnotherLocation(new File(sourceLocation, children[i]),
new File(targetLocation, children[i]));
}
} else {
InputStream in = new FileInputStream(sourceLocation);
OutputStream out = new FileOutputStream(targetLocation);
// Copy the bits from instream to outstream
byte[] buf = new byte[1024];
int len;
while ((len = in.read(buf)) > 0) {
out.write(buf, 0, len);
}
in.close();
out.close();
}
}

我希望将所选文件复制到我的数据/数据/...目录，稍后在应用程序中使用。

但是：我从物品中获得的路径对我不起作用

Answer 1

Thx @Mike M. ，使用 getContentResolver() 的提示让我在尝试后大吃一惊。

最后使用另一个复制功能并重新设计了onActivityResult();

public void onActivityResult(int requestCode, int resultCode,
Intent resultData) {
if (requestCode == READ_REQUEST_CODE && resultCode == Activity.RESULT_OK)
{
if (resultData != null) {
try {
String destination = getFilesDir().getPath();
InputStream src = getContentResolver().openInputStream(resultData.getData()); // use the uri to create an inputStream
try {
convertInputStreamToFile(src, destination);
} catch (IOException e) {
e.printStackTrace();
System.out.print("error in upload");
}
} catch (FileNotFoundException ex) {
}
String destination = getFilesDir().getPath();
Toast.makeText(MainActivity.this, "Success!: CSV-File copyed to : " +destination  , Toast.LENGTH_SHORT).show();
}
}

}
public static void convertInputStreamToFile(InputStream is, String destination) throws IOException
{
OutputStream outputStream = null;
try
{
File file = new File(destination + "/Student.csv");
outputStream = new FileOutputStream(file);
int read = 0;
byte[] bytes = new byte[1024];
while ((read = is.read(bytes)) != -1) {
outputStream.write(bytes, 0, read);
}
}
finally
{
if(outputStream != null)
{
outputStream.close();
}
}
}