所以基本上我用mkdir创建一个文件夹，然后将一个简单的文本文件写入该文件夹。作为最后一步，我使用MediaScannerConnection.ScanFile使它们对文件资源管理器可见。
文件夹和文本文件都在我的android手机上的文件浏览器中可见。当使用MTP通过USB将手机连接到我的Windows 10计算机时，我看到所有其他文件夹，但我新创建的文件夹显示为单个文件，没有扩展名，4KB大小。
重新启动智能手机和计算机无法解决问题但是当我在我的android文件浏览器中重命名该文件夹然后重新启动手机时，它会在Windows资源管理器中显示为普通文件夹。
应用程序在单击按钮后显示一个对话框，其中包含要覆盖的文件列表，edittext以输入新文件名，否定按钮和正按钮。
这里的代码：
/*
Save Config in a File stored in interal storage --> which is emulated as external storage 0
Shows a Dialog window with the option to select a file which is already there or type in a name for a new file or choose from a list of files
--> save the new file or cancel the dialog
*/
public void savebutton(View view) {
try {
// Instantiate an AlertDialog with application context this
AlertDialog.Builder builder = new AlertDialog.Builder(this);
//External Storage storage/emulated/0/Config --> storage/emulated/0 is internal storage emulated as sd-card
dir = new File(Environment.getExternalStorageDirectory() + folder);
if (!dir.exists()) {
if (!dir.mkdir()) { //create directory if not existing yet
Log.d(MainActivity.LOG_TAG, "savebutton: directory was not created");
}
}
//set title of dialog
builder.setTitle("Save Configuration in Text File");
//Add edittext to dialog
final EditText input = new EditText(ConfigActivity.this);
LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT,
LinearLayout.LayoutParams.MATCH_PARENT);
input.setLayoutParams(lp);
input.setImeOptions(EditorInfo.IME_ACTION_DONE); // instead of a RETURN button you get a DONE button
input.setSingleLine(true); // single line cause more lines would change the layout
java.util.Calendar c = java.util.Calendar.getInstance();
int day = c.get(java.util.Calendar.DAY_OF_MONTH);
int month = c.get(java.util.Calendar.MONTH) + 1;
int year = c.get(java.util.Calendar.YEAR);
String date = Integer.toString(day) + "." + Integer.toString(month) + "." + Integer.toString(year);
String savename = name + "-" + date;
input.setText(savename);
//Append term + "=" + value --> like LevelOn=50
for (int itemcounter = 0; itemcounter < value.length; itemcounter++)
datastring += (term[itemcounter] + "=" + getvalue(itemcounter) + "\n");
//File List of already stored files for dialog
mFilelist = dir.list();
builder.setItems(mFilelist, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
mChosenFile = mFilelist[which]; // the item/file which was selected in the file list
try {
//Create text file in directory /Pump Config Files
File file = new File(dir.getAbsolutePath(), mChosenFile);
//create bufferedwrite with filewriter
BufferedWriter bw = new BufferedWriter(new FileWriter(file));
//write to file --> an existing file will be overwritten
bw.write(datastring);
//Flush bufferedwriter
bw.close();
//LOG
System.out.println("Wrote to file");
//Show a message
Toast.makeText(getApplicationContext(), "Saved data", Toast.LENGTH_SHORT).show();
// initiate media scan -->cause sometimes created files are nt shown on computer when connected to phone via USB
// restarting the smartphone or rename folder can help too
// make the scanner aware of the location and the files you want to see
MediaScannerConnection.scanFile(
getApplicationContext(),
new String[]{dir.getAbsolutePath()},
null,
new MediaScannerConnection.OnScanCompletedListener() {
@Override
public void onScanCompleted(String path, Uri uri) {
Log.v("LOG", "file " + path + " was scanned successfully: " + uri);
}
});
} catch (Exception e) {
System.out.print(e.toString());
}
//dismissing the dialog
dialog.cancel();
dialog.dismiss();
}
});
// Get the AlertDialog from builder create()
AlertDialog dialog = builder.create();
//Set dialog view/layout
dialog.setView(input);
//Add positive button to dialog
//When pressing the positive button a file with the specified name and configurtion is stored on internal storage
dialog.setButton(DialogInterface.BUTTON_POSITIVE, "Save", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
try {
filename = input.getText().toString();
//Create text file in directory /Pump Config Files
File file = new File(dir.getAbsolutePath(), filename + ".txt");
//create bufferedwrite with filewriter
BufferedWriter bw = new BufferedWriter(new FileWriter(file));
//write to file --> an existing file will be overwritten
bw.write(datastring);
//Flush bufferedwriter
bw.close();
//LOG
System.out.println("Wrote to file");
//Show a message
Toast.makeText(getApplicationContext(), "Saved data", Toast.LENGTH_SHORT).show();
} catch (Exception e) {
System.out.print(e.toString());
}
// initiate media scan -->cause sometimes created files are nt shown on computer when connected to phone via USB
// restarting the smartphone or rename folder can help too
// make the scanner aware of the location and the files you want to see
MediaScannerConnection.scanFile(
getApplicationContext(),
new String[]{dir.getAbsolutePath()},
null,
new MediaScannerConnection.OnScanCompletedListener() {
@Override
public void onScanCompleted(String path, Uri uri) {
Log.v("LOG", "file " + path + " was scanned successfully: " + uri);
}
});
dialog.cancel();
dialog.dismiss();
}
});
//Add negative button
dialog.setButton(DialogInterface.BUTTON_NEGATIVE, "Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
//show the save dialog
dialog.show();
} catch (Exception e) {
System.out.print(e.toString());
}
}
在Android API 23和API 21上测试过。 在21日工作正常但在23日没有。
答案 0 :(得分：1)
谢谢greenapps，
new String [] {dir.getAbsolutePath（）} ,.您应该让扫描文件：new String [] {file.getAbsolutePath（）}，
工作正常。
我总是错过这样的小细节。