想象一下,你想检查“/folder/subfolder/subsubfolder/test/test.txt”文件是否存在,你会做如下:
DocumentFile sdCard = ...; // i have already retrieved the sd card root with the users help via SAF
String path = "<SD CARD>/folder/subfolder/subsubfolder/test/test.txt";
List<String> pathParts = Arrays.asList(path.split("/"));
DocumentFile doc = sdCard;
// go through all folders, starting at sd card, to check, if the desired file exists
for (int i = 1; i < pathParts.size(); i++)
{
DocumentFile nextDoc = doc.findFile(pathParts.get(i));
if (nextDoc != null)
doc = nextDoc;
else
{
doc = null;
break;
}
}
if (doc == null)
{
// file does not exist
}
else
{
// file does exist
}
这很慢,有没有更快的方法至少检查 SD 卡上是否存在文件?我不想创建每个 DocumentFile
只是为了检查路径是否存在...
最佳答案
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
Uri uri = data.getData();
DocumentFile pickedDir = DocumentFile.fromTreeUri(MainActivity.this, uri);
String id = DocumentsContract.getTreeDocumentId(uri);
/* id is : "primary:namefolder" if user select a "namefolder" from internal storage.
or CABB-5641 if user select external storage,
*/
id = id + "/folder/subfolder/subsubfolder/test/test.txt"; // your path, you must to ensure is consistent with that chosen by the user,
Uri childrenUri = DocumentsContract.buildDocumentUriUsingTree(uri,id);
DocumentFile chhildfile = DocumentFile.fromSingleUri(MainActivity.this,childrenUri);
if(chhildfile != null && chhildfile.exists()){
Log.d("laporan file", "file ini ada");
}
}
我不是专家,我不知道这是否适用于大多数 android,但我已经在 Android 模拟器和 Asus Zenfone 5 中尝试过,希望这会有所帮助
关于android - SAF DocumentFile - 检查路径是否存在而不在每个文件夹级别创建每个 DocumentFile,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/37966386/