Cannot update the data saved to Firebase

[Malavika Shanker]

Hi!
I am trying to let the user edit the old data that was saved to firebase.

public class MainActivity4 extends AppCompatActivity {
    private ImageView iv;
    private EditText title;
    private EditText type;
    private EditText prep;
    private EditText serves;
    private EditText time;
    private EditText meal;
    private EditText difficulty;
    String key, oldImageUrl;
    Uri uri;
    DatabaseReference databaseReference;
    StorageReference storageReference;
    String ImageUrl;
    String recipeName;
    String Meal;
    String Difficulty;
    String Time;
    String Ingredients;
    String Serves;
    String Recipe;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main4);
        iv = (ImageView) findViewById(R.id.addimage);
        title = findViewById(R.id.Title);
        type = findViewById(R.id.Type);
        prep = findViewById(R.id.Prep);
        serves = findViewById(R.id.Serves);
        time = findViewById(R.id.Time);
        meal = findViewById(R.id.Meal);
        difficulty = findViewById(R.id.Level);

        Bundle bundle = getIntent().getExtras();                                                                  // This part is for getting old data to show to the user while updating
        if (bundle != null) {
            Glide.with(MainActivity4.this).load(bundle.getString("oldImageUrl")).into(iv);
            title.setText(bundle.getString("titleKey"));
            meal.setText(bundle.getString("mealKey"));
            difficulty.setText(bundle.getString("levelKey"));
            time.setText(bundle.getString("timeKey"));
            prep.setText(bundle.getString("prepKey"));
            type.setText(bundle.getString("recipeKey"));
            serves.setText(bundle.getString("servesKey"));
            key = bundle.getString("key");
            oldImageUrl = bundle.getString("oldImageUrl");
        }
        databaseReference = FirebaseDatabase.getInstance().getReference("Recipe").child(key);

    }

    public void btnaddImage(View view) {
        Intent imagePicker = new Intent(Intent.ACTION_PICK);
        imagePicker.setType("image/*");
        startActivityForResult(imagePicker, 1);


    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == RESULT_OK) {
            uri = data.getData();
            iv.setImageURI(uri);
        } else {
            Toast.makeText(this, "You have not selected an image", Toast.LENGTH_SHORT).show();
        }

    }

    public void btnUpdateRecipe(View view) {
        recipeName = title.getText().toString().trim();
        Meal = meal.getText().toString().trim();
        Difficulty = difficulty.getText().toString().trim();
        Time = time.getText().toString().trim();
         Ingredients= prep.getText().toString().trim();
         Serves= serves.getText().toString().trim();
         Recipe= type.getText().toString().trim();
        storageReference = FirebaseStorage.getInstance().getReference().child("Recipe Image").child(uri.getLastPathSegment());
        ProgressDialog pd = new ProgressDialog(this);
        pd.setMessage("Recipe Updating...");
        pd.show();

        storageReference.putFile(uri).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
            @RequiresApi(api = Build.VERSION_CODES.N)
            @Override
            public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
                Task<Uri> uriTask = taskSnapshot.getStorage().getDownloadUrl();
                while (!uriTask.isComplete()) ;
                Uri urlImage = uriTask.getResult();
                ImageUrl = urlImage.toString();
                uploadRecipe();
                pd.dismiss();

            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                pd.dismiss();
            }
        });


    }
    @RequiresApi(api = Build.VERSION_CODES.N)
    public void uploadRecipe() {

        recipe RecipeData = new recipe(recipeName,Serves,Difficulty,Meal,Ingredients,Recipe,Time,ImageUrl);
        databaseReference.setValue(RecipeData).addOnCompleteListener(new OnCompleteListener<Void>() {
            @Override
            public void onComplete(@NonNull Task<Void> task) {
                StorageReference storageReference2 = FirebaseStorage.getInstance().getReferenceFromUrl(oldImageUrl);
                storageReference2.delete();
                Toast.makeText(MainActivity4.this,"Recipe Updated",Toast.LENGTH_SHORT).show();
            }
        });

Below is my logcat :

java.lang.IllegalStateException: Could not execute method for android:onClick
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:414)
        at android.view.View.performClick(View.java:6619)
        at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:992)
        at android.view.View.performClickInternal(View.java:6596)
        at android.view.View.access$3100(View.java:785)
        at android.view.View$PerformClick.run(View.java:25932)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:201)
        at android.app.ActivityThread.main(ActivityThread.java:6861)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:873)
     Caused by: java.lang.reflect.InvocationTargetException
        at java.lang.reflect.Method.invoke(Native Method)
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:409)
        at android.view.View.performClick(View.java:6619) 
        at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:992) 
        at android.view.View.performClickInternal(View.java:6596) 
        at android.view.View.access$3100(View.java:785) 
        at android.view.View$PerformClick.run(View.java:25932) 
        at android.os.Handler.handleCallback(Handler.java:873) 
        at android.os.Handler.dispatchMessage(Handler.java:99) 
        at android.os.Looper.loop(Looper.java:201) 
        at android.app.ActivityThread.main(ActivityThread.java:6861) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:873) 
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.net.Uri.getLastPathSegment()' on a null object reference
        at com.example.myrecipiebook.MainActivity4.btnUpdateRecipe(MainActivity4.java:113)
        at java.lang.reflect.Method.invoke(Native Method) 
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:409) 
        at android.view.View.performClick(View.java:6619) 
        at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:992) 
        at android.view.View.performClickInternal(View.java:6596) 
        at android.view.View.access$3100(View.java:785) 
        at android.view.View$PerformClick.run(View.java:25932) 
        at android.os.Handler.handleCallback(Handler.java:873) 
        at android.os.Handler.dispatchMessage(Handler.java:99) 
        at android.os.Looper.loop(Looper.java:201) 
        at android.app.ActivityThread.main(ActivityThread.java:6861) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:873) 

[Norm Radder]

    Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.net.Uri.getLastPathSegment()' on a null object reference
       at com.example.myrecipiebook.MainActivity4.btnUpdateRecipe(MainActivity4.java:113)

what value is in the variable uri when the statement on line 80 is executed?

        storageReference = FirebaseStorage.getInstance().getReference().child("Recipe Image").child(uri.getLastPathSegment());

[Malavika Shanker]

The uri of the image which the app gets from the gallery

[Malavika Shanker]

lines 60- 67 -- Uri

[Norm Radder]

What value is actually in the variable: uri when the statement is executed?  Is it null?  Add a print statement to see.