我正在尝试使用DocumentFile列出我的Android 5.1手机上的外部存储设备中的文件
String rootPathURI = "file:/media/storage/sdcard1/data/example.externalstorage/files/";
File f = new File(URI(rootPathURI));
DocumentFile documentFile = DocumentFile.fromFile(f);
此代码工作正常,但我想这样做;
String rootPathURI = "file:/media/storage/sdcard1/data/example.externalstorage/files/";
DocumentFile documentFile = DocumentFile.fromTreeUri(getApplicationContext(), Uri.parse(rootPathURI));
但我得到这样的例外:
W/System.err( 5157): java.lang.IllegalArgumentException: Invalid URI:"file:/media/storage/sdcard1/data/example.externalstorage/files/"
答案 0 :(得分:1)
fromTreeUri()
用于Uri
请求返回的ACTION_OPEN_DOCUMENT_TREE
,如the documentation中所述。 可能适用于StorageVolume
Uri`。
答案 1 :(得分:0)
如果您不想使用ACTION_OPEN_DOCUMENT_TREE或ACTION_OPEN_DOCUMENT来获取Uri,则可以使用以下有效的方法将FILE转换为Uri(SAF):从API19(Android4.4-Kitkat)到API28(Android8-Oreo)。如果您要访问应用程序外部的外部可移动存储,则返回的Uri与返回对话框及其对API 28安全限制(SAF权限)的有效性相同。
/**
* Ing.N.Nyerges 2019 V2.0
*
* Storage Access Framework(SAF) Uri's creator from File (java.IO),
* for removable external storages
*
* @param context Application Context
* @param file File path + file name
* @return Uri[]:
* uri[0] = SAF TREE Uri
* uri[1] = SAF DOCUMENT Uri
*/
@RequiresApi(api = Build.VERSION_CODES.KITKAT)
public static Uri[] getSafUris (Context context, File file) {
Uri[] uri = new Uri[2];
String scheme = "content";
String authority = "com.android.externalstorage.documents";
// Separate each element of the File path
// File format: "/storage/XXXX-XXXX/sub-folder1/sub-folder2..../filename"
// (XXXX-XXXX is external removable number
String[] ele = file.getPath().split(File.separator);
// ele[0] = not used (empty)
// ele[1] = not used (storage name)
// ele[2] = storage number
// ele[3 to (n-1)] = folders
// ele[n] = file name
// Construct folders strings using SAF format
StringBuilder folders = new StringBuilder();
if (ele.length > 4) {
folders.append(ele[3]);
for (int i = 4; i < ele.length - 1; ++i) folders.append("%2F").append(ele[i]);
}
String common = ele[2] + "%3A" + folders.toString();
// Construct TREE Uri
Uri.Builder builder = new Uri.Builder();
builder.scheme(scheme);
builder.authority(authority);
builder.encodedPath("/tree/" + common);
uri[0] = builder.build();
// Construct DOCUMENT Uri
builder = new Uri.Builder();
builder.scheme(scheme);
builder.authority(authority);
if (ele.length > 4) common = common + "%2F";
builder.encodedPath("/document/" + common + file.getName());
uri[1] = builder.build();
return uri;
}
您必须使用SAF权限来授予对外部可移动存储的访问权限,如下所示:
context.grantUriPermission(context.getPackageName(), uri, Intent
.FLAG_GRANT_READ_URI_PERMISSION | Intent
.FLAG_GRANT_WRITE_URI_PERMISSION);
context.getContentResolver().takePersistableUriPermission(uri, Intent
.FLAG_GRANT_READ_URI_PERMISSION | Intent
.FLAG_GRANT_WRITE_URI_PERMISSION);