Firebase数据返回null

Question

方法

public void loadUserInformation() {
    final String mNumber = getActivity().getIntent().getStringExtra("Phone_Number");
    DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
    DatabaseReference usesrRef = rootRef.child("Users").child(uid);
    ValueEventListener eventListener = new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            EditText Name = (EditText) rootView.findViewById(R.id.Name);
            ImageView profilePic = (ImageView) rootView.findViewById(R.id.profilePic);
            for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) {
                String image = postSnapshot.child("Image").getValue().toString();

                Picasso.get().load(image).into(profilePic);
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
            Toast.makeText(getActivity(), "Error Loading UserDetails", Toast.LENGTH_LONG).show();
        }
    };
    usesrRef.addListenerForSingleValueEvent(eventListener);
}

String image = postsnapshot.child line ...

上的空指针异常

数据库结构：

Answer 1

改变这个：

class CameraViewController: UIViewController {
    var outputURL: URL!
    func startRecording() {

        if movieOutput.isRecording == false {

            let connection = movieOutput.connection(with: AVMediaType.video)
            if (connection?.isVideoOrientationSupported)! {
                connection?.videoOrientation = currentVideoOrientation()
            }

            if (connection?.isVideoStabilizationSupported)! {
                connection?.preferredVideoStabilizationMode = AVCaptureVideoStabilizationMode.auto
            }

            let device = activeInput.device
            if (device.isSmoothAutoFocusSupported) {
                do {
                    try device.lockForConfiguration()
                    device.isSmoothAutoFocusEnabled = false
                    device.unlockForConfiguration()
                } catch {
                    print("Error setting configuration: \(error)")
                }

            }

            //EDIT2: And I forgot this
            outputURL = tempURL()
            movieOutput.startRecording(to: outputURL, recordingDelegate: self)

        }
        else {
            stopRecording()
        }

    }
}

进入这个：

<?php

function sheets($spreadsheetID) {
    $sheets = array();    
    // Load Google API library and set up client
    // You need to know $spreadsheetID (can be seen in the URL)
    $sheetService = new Google_Service_Sheets($client);   
    $spreadSheet = $sheetService->spreadsheets->get($spreadsheetID);
    $sheets = $spreadSheet->getSheets();
    foreach($sheets as $sheet) {
        $sheets[] = $sheet->properties->sheetId;
    }   
    return $sheets;
}
?>

您的数据快照位于public void onDataChange(DataSnapshot dataSnapshot) { EditText Name = (EditText) rootView.findViewById(R.id.Name); ImageView profilePic = (ImageView)rootView.findViewById(R.id.profilePic); for(DataSnapshot postSnapshot: dataSnapshot.getChildren()){ String image = postSnapshot.child("Image").getValue().toString(); Picasso.get().load(image).into(profilePic); } } ，因此您无需循环，因为public void onDataChange(DataSnapshot dataSnapshot) { EditText Name = (EditText) rootView.findViewById(R.id.Name); ImageView profilePic = (ImageView)rootView.findViewById(R.id.profilePic); String image = dataSnapshot.child("Image").getValue().toString(); Picasso.get().load(image).into(profilePic); } 是该快照的直接子项。