Android: How to get a file's creation date?

This is my code:

File TempFiles = new File(Tempfilepath);
if (TempFiles.exists()) {
String[] child = TempFiles.list();
for (int i = 0; i < child.length; i++) {
Log.i("File: " + child[i] + " creation date ?");
// how to get file creation date..?
}
}
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The file creation date is not an available piece of data exposed by the Java File class. I recommend you rethink what you are doing and change your plan so you will not need it.

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最佳答案

The file creation date is not an available, but you can get the last-modified date:

File file = new File(filePath);
Date lastModDate = new Date(file.lastModified());


System.out.println("File last modified @ : "+ lastModDate.toString());
小开

Here's how I would do it

// Used to examplify deletion of files more than 1 month old
// Note the L that tells the compiler to interpret the number as a Long
final int MAXFILEAGE = 2678400000L; // 1 month in milliseconds


// Get file handle to the directory. In this case the application files dir
File dir = new File(getFilesDir().toString());


// Obtain list of files in the directory.
// listFiles() returns a list of File objects to each file found.
File[] files = dir.listFiles();


// Loop through all files
for (File f : files ) {


// Get the last modified date. Milliseconds since 1970
Long lastmodified = f.lastModified();


// Do stuff here to deal with the file..
// For instance delete files older than 1 month
if(lastmodified+MAXFILEAGE<System.currentTimeMillis()) {
f.delete();
}
}
小开

There is an alternate way. When you open the file for the first time save the lastModified date, before you modify the folder.

long createdDate =new File(filePath).lastModified();

And then when you close the file do

File file =new File(filePath);
file.setLastModified(createdDate);

If you have done this since the file was created, then you will have the createdDate as the lastModified date all the time.

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Starting in API level 26, you can do this:

File file = ...;
BasicFileAttributes attr = Files.readAttributes(file.toPath(), BasicFileAttributes.class);
long createdAt = attr.creationTime().toMillis();
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Having backward compatibility in mind I would rather use the following:

fun getLastModifiedTimeInMillis(file: File): Long? {
return try {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
getLastModifiedTimeFromBasicFileAttrs(file)
} else {
file.lastModified()
}
} catch (x: Exception) {
x.printStackTrace()
null
}
}


@RequiresApi(Build.VERSION_CODES.O)
private fun getLastModifiedTimeFromBasicFileAttrs(file: File): Long {
val basicFileAttributes = Files.readAttributes(
file.toPath(),
BasicFileAttributes::class.java
)
return basicFileAttributes.creationTime().toMillis()
}

alternatively, if you are dealing with jpg, jpegs you can use ExifInterface


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