java - 无法获取Firebase DataSnap快照值字符串

public class SettingsActivity extends AppCompatActivity { private CircleImageView settingsDisplayProfileImage; private TextView settingsDisplayname; private TextView settingsDisplayStatus; private TextView settingsDisplayaddress; private TextView settingsDisplayphone; private TextView settingsDisplayservice; private Button settingsChangeProfileImageButton; private Button settingsUpdateProfileButton; private final static int Gallery_Pick = 1; private StorageReference storeProfileImagestorageRef; private DatabaseReference getUserDataReference; private FirebaseAuth mAuth; Bitmap thumb_bitmap = null; private StorageReference thumbImageRef; private ProgressDialog loadingBar; private String downloadImageUrl; private String online_user_id; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_settings); mAuth = FirebaseAuth.getInstance(); online_user_id = mAuth.getCurrentUser().getUid(); getUserDataReference = FirebaseDatabase.getInstance().getReference().child("Users").child(online_user_id); getUserDataReference.keepSynced(true); storeProfileImagestorageRef = FirebaseStorage.getInstance().getReference().child("Profile_Images"); thumbImageRef = FirebaseStorage.getInstance().getReference().child("Thumb_Images"); settingsDisplayProfileImage = (CircleImageView) findViewById(R.id.settings_profile_image); settingsDisplayname = (TextView) findViewById(R.id.settings_username); settingsDisplayaddress = (TextView) findViewById(R.id.settings_user_address); settingsDisplayphone = (TextView)findViewById(R.id.settings_user_phone); settingsDisplayservice = (TextView) findViewById(R.id.settings_user_service); settingsDisplayStatus = (TextView) findViewById(R.id.settings_user_status); settingsChangeProfileImageButton = (Button) findViewById(R.id.settings_change_profile_image_button); settingsUpdateProfileButton = (Button) findViewById(R.id.settings_update_profile); loadingBar= new ProgressDialog(this); getUserDataReference.addValueEventListener(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { if (dataSnapshot.exists()) { //error occurs here first line below String name = dataSnapshot.child("user_name").getValue().toString(); String status = dataSnapshot.child("user_status").getValue().toString(); final String image = dataSnapshot.child("user_image").getValue().toString(); String address = dataSnapshot.child("user_address").getValue().toString(); String phone = dataSnapshot.child("user_phone").getValue().toString(); String service = dataSnapshot.child("user_service").getValue().toString(); String thumb_image = dataSnapshot.child("user_thumb_image").getValue().toString(); settingsDisplayname.setText(name); settingsDisplayservice.setText(service); settingsDisplayStatus.setText(status); settingsDisplayaddress.setText(address); settingsDisplayphone.setText(phone); if (!image.equals("default_profile")) { //

Picasso.with(SettingsActivity.this).load(image).placeholder(R.drawable.default_profile).into(settingsDisplayProfileImage); Picasso.with(SettingsActivity.this).load(image).fit().centerInside().networkPolicy(NetworkPolicy.OFFLINE) .placeholder(R.drawable.default_profile).into(settingsDisplayProfileImage, new Callback() { @Override public void onSuccess() { } @Override public void onError() { Picasso.with(SettingsActivity.this).load(image).fit().centerInside().placeholder(R.drawable.default_profile).into(settingsDisplayProfileImage); } }); } } } @Override public void onCancelled(DatabaseError databaseError) { } }); settingsChangeProfileImageButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Intent galleryIntent = new Intent(); galleryIntent.setAction(Intent.ACTION_GET_CONTENT); galleryIntent.setType("image/*"); startActivityForResult(galleryIntent, Gallery_Pick); } }); settingsUpdateProfileButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { String old_status = settingsDisplayStatus.getText().toString(); String old_address = settingsDisplayaddress.getText().toString(); String old_phone = settingsDisplayphone.getText().toString(); String old_service = settingsDisplayservice.getText().toString(); Intent profileIntent = new Intent(SettingsActivity.this, ProfileActivity.class); profileIntent.putExtra("user_status", old_status); profileIntent.putExtra("user_service", old_service); profileIntent.putExtra("user_phone", old_phone); profileIntent.putExtra("user_address", old_address); startActivity(profileIntent); } }); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); if(requestCode==Gallery_Pick && resultCode==RESULT_OK &&data!=null) { Uri ImageUri = data.getData(); CropImage.activity() .setGuidelines(CropImageView.Guidelines.ON) .setAspectRatio(1, 1) .start(this); } if (requestCode == CropImage.CROP_IMAGE_ACTIVITY_REQUEST_CODE) { CropImage.ActivityResult result = CropImage.getActivityResult(data); if (resultCode == RESULT_OK) { loadingBar.setTitle("Updating Profile Image"); loadingBar.setMessage("Please wait while profile image is updated"); loadingBar.show(); Uri resultUri = result.getUri(); File thumb_filepathUri = new File(resultUri.getPath()); String user_id = mAuth.getCurrentUser().getUid(); try { thumb_bitmap = new Compressor(this) .setMaxWidth(100) .setMaxHeight(100) .setQuality(50) .compressToBitmap(thumb_filepathUri); } catch (IOException e) { e.printStackTrace(); } ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); thumb_bitmap.compress(Bitmap.CompressFormat.JPEG, 50, byteArrayOutputStream); final byte[] thumb_byte = byteArrayOutputStream.toByteArray(); StorageReference filePath = storeProfileImagestorageRef.child(user_id + ".jpg"); final StorageReference thumb_filePath = thumbImageRef.child(user_id + ".jpg"); filePath.putFile(resultUri).addOnCompleteListener(new OnCompleteListener<UploadTask.TaskSnapshot>() { @Override public void onComplete(@NonNull final Task<UploadTask.TaskSnapshot> task) { if (task.isSuccessful()) { Toast.makeText(SettingsActivity.this, "Saving profile image...", Toast.LENGTH_LONG).show(); // final String downloadUrl = task.getResult().getDownloadUrl().toString(); downloadImageUrl =thumb_filePath .getDownloadUrl().toString(); UploadTask uploadTask = thumb_filePath.putBytes(thumb_byte); uploadTask.addOnCompleteListener(new OnCompleteListener<UploadTask.TaskSnapshot>() { @Override public void onComplete(@NonNull Task<UploadTask.TaskSnapshot>thumb_task) { String thumb_downloadUrl = thumb_filePath.getDownloadUrl().toString(); // thumb_downloadImageUrl = filePath.getDownloadUrl().toString(); if (task.isSuccessful()) { Map update_user_data = new HashMap(); update_user_data.put("user_image", downloadImageUrl); update_user_data.put("user_thumb_image", thumb_downloadUrl); getUserDataReference.updateChildren(update_user_data) .addOnCompleteListener(new OnCompleteListener<Void>() { @Override public void onComplete(@NonNull Task<Void> task) { Toast.makeText(SettingsActivity.this, "Profile Image Updated Successfully", Toast.LENGTH_SHORT).show(); loadingBar.dismiss(); } }); } } }); } else { Toast.makeText(SettingsActivity.this, "Error occurred while uploading your profile picture..", Toast.LENGTH_SHORT).show(); loadingBar.dismiss(); } } }); } else if (resultCode == CropImage.CROP_IMAGE_ACTIVITY_RESULT_ERROR_CODE) { Exception error = result.getError(); } } } }

11-15 03:22:10.646 27837-27837/com.paddi.paddi.paddi E/AndroidRuntime: FATAL EXCEPTION: main Process: com.paddi.paddi.paddi, PID: 27837 java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.Object.toString()' on a null object reference at com.paddi.paddi.paddi.SettingsActivity$1.onDataChange(SettingsActivity.java:101) at com.google.firebase.database.core.ValueEventRegistration.fireEvent(com.google.firebase:firebase-database@@16.0.4:75) at com.google.firebase.database.core.view.DataEvent.fire(com.google.firebase:firebase-database@@16.0.4:63) at com.google.firebase.database.core.view.EventRaiser$1.run(com.google.firebase:firebase-database@@16.0.4:55) at android.os.Handler.handleCallback(Handler.java:815) at android.os.Handler.dispatchMessage(Handler.java:104) at android.os.Looper.loop(Looper.java:207) at android.app.ActivityThread.main(ActivityThread.java:5765) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679)