我正在使用Drive API在Google Drive的隐藏应用程序文件夹中创建文件。我想获取该文件的资源ID，但它一直返回null。以下是代码。一旦创建文件，它应该在回调中获取文件资源ID，但它返回null。它可以获取正常的Drive，但这完全没有帮助，因为获取Drive ID需要资源ID。有没有办法获取资源ID？我已经检查了多个不同的链接，但都没有帮助。
//<editor-fold desc="Variables">
// Define Variable Int MY_PERMISSIONS_WRITE_EXTERNAL_STORAGE//
public static int MY_PERMISSIONS_WRITE_EXTERNAL_STORAGE = 0;
// Define Variable int RESOLVE_CONNECTION_REQUEST_CODE//
public static final int RESOLVE_CONNECTION_REQUEST_CODE = 3;
// Define Variable GoogleApiClient googleApiClient//
public GoogleApiClient googleApiClient;
// Define Variable String title//
String title = "Notes.db";
// Define Variable String mime//
String mime = "application/x-sqlite3";
// Define Variable String currentDBPath//
String dBPath = "/School Binder/Note Backups/Notes.db";
// Define Variable File data//
File data = Environment.getExternalStorageDirectory();
// Define Variable File dbFile//
File dbFile = new File(data, dBPath);
// Create Metadata For Database Files//
MetadataChangeSet meta = new MetadataChangeSet.Builder().setTitle(title).setMimeType(mime).build();
String EXISTING_FILE_ID = "CAESABjaBSCMicnCsFQoAA";
//</editor-fold>
// Method That Runs When Activity Starts//
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Initiate allowWriteExternalStorage Method//
allowWriteExternalStorage();
// Initiate connectToGoogleDrive Method//
connectToGoogleDrive();
}
// Method That Runs When App Is Resumed//
protected void onResume() {
super.onResume();
// Checks If Api Client Is Null//
if (googleApiClient == null) {
// Create Api Client//
googleApiClient = new GoogleApiClient.Builder(this)
.addApi(Drive.API)
.addScope(Drive.SCOPE_FILE)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.build();
}
// Attempt To Connect To Google drive//
googleApiClient.connect();
}
// Method That Runs When App is paused//
@Override
protected void onPause() {
// Checks If Api Was Used//
if (googleApiClient != null) {
// Disconnect From Google Drive//
googleApiClient.disconnect();
}
super.onPause();
}
// Method That Runs When App Is Successfully Connected To Users Google Drive//
@Override
public void onConnected(@Nullable Bundle bundle) {
// Add New File To Drive//
Drive.DriveApi.newDriveContents(googleApiClient).setResultCallback(contentsCallback);
}
// Method That Runs When Connection Is Suspended//
@Override
public void onConnectionSuspended(int i) {
}
// Method That Runs When App Failed To Connect To Google Drive//
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
// Checks If Connection Failure Can Be Resolved//
if (connectionResult.hasResolution()) {
// If Above Statement Is True, Try To Fix Connection//
try {
// Resolve The Connection//
connectionResult.startResolutionForResult(this, RESOLVE_CONNECTION_REQUEST_CODE);
} catch (IntentSender.SendIntentException ignored) {
}
} else {
// Show Connection Error//
GoogleApiAvailability.getInstance().getErrorDialog(this, connectionResult.getErrorCode(), 0).show();
}
}
// Method That Gives App Permission To Access System Storage//
public void allowWriteExternalStorage() {
// Allow Or Un - Allow Write To Storage//
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.WRITE_EXTERNAL_STORAGE)
!= PackageManager.PERMISSION_GRANTED) {
// Request To Write To External Storage//
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
MY_PERMISSIONS_WRITE_EXTERNAL_STORAGE);
}
}
// Method That Connects To Google Drive//
public void connectToGoogleDrive() {
// Create Api Client//
googleApiClient = new GoogleApiClient.Builder(this)
.addApi(Drive.API)
.addScope(Drive.SCOPE_FILE)
.addScope(Drive.SCOPE_APPFOLDER)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.build();
// Attempt To Connect To Google drive//
googleApiClient.connect();
}
//<editor-fold desc="Contents Callback">
// What Happens When App Is Trying To Make A New File Or Folder//
final private ResultCallback<DriveApi.DriveContentsResult> contentsCallback = new ResultCallback<DriveApi.DriveContentsResult>() {
@Override
public void onResult(@NonNull DriveApi.DriveContentsResult result) {
// Runs When File Failed To Create//
if (!result.getStatus().isSuccess()) {
// Log That File Failed To Create//
Log.d("log", "Error while trying to create new file contents");
return;
}
// Checks If Creating File Was Successful//
DriveContents cont = result.getStatus().isSuccess() ? result.getDriveContents() : null;
// Write File//
if (cont != null) try {
OutputStream oos = cont.getOutputStream();
if (oos != null) try {
InputStream is = new FileInputStream(dbFile);
byte[] buf = new byte[5000];
int c;
while ((c = is.read(buf, 0, buf.length)) > 0) {
oos.write(buf, 0, c);
oos.flush();
}
} finally {
oos.close();
}
} catch (Exception e) {
e.printStackTrace();
}
// Put File In User Hidden App Folder//
Drive.DriveApi.getAppFolder(googleApiClient).createFile(googleApiClient, meta, cont).setResultCallback(fileCallback);
}
};
//</editor-fold>
//<editor-fold desc="File Callback">
// What Happens If File IS mAde Correctly Or In-Correctly//
final private ResultCallback<DriveFolder.DriveFileResult> fileCallback = new ResultCallback<DriveFolder.DriveFileResult>() {
@Override
public void onResult(@NonNull DriveFolder.DriveFileResult result) {
// Checks If It Failed//
if (!result.getStatus().isSuccess()) {
Log.d("log", "Error while trying to create the file");
return;
}
Drive.DriveApi.requestSync(googleApiClient);
Log.d("log", "Created a file in App Folder: " + result.getDriveFile().getDriveId());
String File_ID = String.valueOf(result.getDriveFile().getDriveId().getResourceId());
Drive.DriveApi.fetchDriveId(googleApiClient, File_ID).setResultCallback(idCallback);
}
};
//</editor-fold>
//<editor-fold desc="Id Callback">
final private ResultCallback<DriveApi.DriveIdResult> idCallback = new ResultCallback<DriveApi.DriveIdResult>() {
@Override
public void onResult(DriveApi.DriveIdResult result) {
if (!result.getStatus().isSuccess()) {
Log.d("Message", "Cannot find DriveId. Are you authorized to view this file?");
return;
}
DriveId driveId = result.getDriveId();
DriveFile file = driveId.asDriveFile();
file.getMetadata(googleApiClient)
.setResultCallback(metadataCallback);
}
};
//</editor-fold>
//<editor-fold desc="metadata Callback">
final private ResultCallback<DriveResource.MetadataResult> metadataCallback = new
ResultCallback<DriveResource.MetadataResult>() {
@Override
public void onResult(DriveResource.MetadataResult result) {
if (!result.getStatus().isSuccess()) {
Log.d("Message", "Problem while trying to fetch metadata");
return;
}
Metadata metadata = result.getMetadata();
Log.d("Message", "Metadata successfully fetched. Title: " + metadata.getTitle());
}
};
//</editor-fold>
}