我找到了一个开源文件管理器。查看了代码,最终找到了解决方案。
仅适用于 Android N(7.0.0)(api 24)及以上版本。
首先获取SD卡的根路径并显示用户权限对话框。
public void takeCardUriPermission(String sdCardRootPath) {
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.N) {
File sdCard = new File(sdCardRootPath);
StorageManager storageManager = (StorageManager) getSystemService(Context.STORAGE_SERVICE);
StorageVolume storageVolume = storageManager.getStorageVolume(sdCard);
Intent intent = storageVolume.createAccessIntent(null);
try {
startActivityForResult(intent, 4010);
} catch (ActivityNotFoundException e) {
}
}
}
当用户接受请求时,onActivityResult()会被触发,我们可以从意图数据中保存 uri.
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == 4010) {
Uri uri = data.getData();
grantUriPermission(getPackageName(), uri, Intent.FLAG_GRANT_WRITE_URI_PERMISSION |
Intent.FLAG_GRANT_READ_URI_PERMISSION);
final int takeFlags = data.getFlags() & (Intent.FLAG_GRANT_WRITE_URI_PERMISSION |
Intent.FLAG_GRANT_READ_URI_PERMISSION);
getContentResolver().takePersistableUriPermission(uri, takeFlags);
}
}
现在我们可以获取SD卡根目录的URI,并将其与存储访问框架一起使用。
public Uri getUri() {
List<UriPermission> persistedUriPermissions = getContentResolver().getPersistedUriPermissions();
if (persistedUriPermissions.size() > 0) {
UriPermission uriPermission = persistedUriPermissions.get(0);
return uriPermission.getUri();
}
return null;
}