Taking the state of one activity to another

Question

I have two activity screens: Create and View. Create is where the user creates their shopping list. View is where they view their list (and can still add items).

UPDATE: Some may say why not just use the one activity instead of having both activities the same basically but this is how I've planned it out. I want it so when you add spinners by pressing the FAB on the create screen, you can select values from those. Then when you go back to the main menu, then to the view screen, those spinners and the selected values from the create screen appear here too. Additionally I want it so when you close the app and reopen it, all the spinners and values that you selected still appear. If there are any questions please comment.

I do appreciate the posts below with the examples however I'm just confused as to if it fits my situation or not!

Below is my create.java code. (view.java has exactly the same code just with .view in places instead of .create, and some extra code.)

create.java

public class create extends AppCompatActivity {


    private LinearLayout mLinearLayout;
    private ArrayList<SearchableSpinner> mSpinners;
    private List<AppCompatButton> mButtons = new ArrayList<>();
    private List<CheckBox> mCheckboxes = new ArrayList<>();
    private List<TextView> mTextviews = new ArrayList<>();
    private List<EditText> mEdittexts = new ArrayList<>();
    private List<View> mViews = new ArrayList<>();
    private Map<String, String> numberItemValues = new HashMap<>();
    List<String> itemList = new ArrayList<>();
    //Button buttontest;
    // TextView textview;
    // CheckBox checkbox;




    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_create);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        GlobalClass globalClass = (GlobalClass) this.getApplicationContext();


        ArrayList<String> items = new ArrayList<>();
        items.add(String.valueOf(mSpinners)); // add you selected item
        globalClass.setItems(items);


        mSpinners = new ArrayList<>();

        mLinearLayout = findViewById(R.id.my_linearLayout);


        //code for the add button to add more items
        FloatingActionButton floatingActionButton =
                (FloatingActionButton) findViewById(R.id.fab);

        floatingActionButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(getBaseContext(), "Item added!", Toast.LENGTH_SHORT).show();


                // Handle ze click.
                final Spinner spinner = makeSpinner();
                mLinearLayout.addView(spinner);


                LinearLayout.LayoutParams layoutParams = (LinearLayout.LayoutParams) spinner.getLayoutParams();
                layoutParams.setMargins(5, 100, 10, 0); //top 70

                Resources resources = getResources();
                DisplayMetrics metrics = resources.getDisplayMetrics();

                layoutParams.height = (int) (70 * ((float) metrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT)); //80
                layoutParams.width = (int) (240 * ((float) metrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT)); //240
                spinner.setLayoutParams(layoutParams);

                final View newView = makeView();
                //Add a new view
                mLinearLayout.addView(newView);
                mViews.add(newView);


                final EditText newEdittext = makeEdittext();
                mLinearLayout.addView(newEdittext);
                mEdittexts.add(newEdittext);


                final int listSize = mViews.size();


                //code for deleting the said item.
                newView.setOnClickListener(new View.OnClickListener() {
                    //start
                    @Override
                    public void onClick(View view) {

                        //when the 'new button' is pressed, alert shows if you are sure you want to delete the item or not.

                        final View.OnClickListener context = this;


                        AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(create.this);


                        // set title
                        alertDialogBuilder.setTitle("Delete Item");

                        // set dialog message
                        alertDialogBuilder
                                .setMessage("Are you sure you want to delete this item?")
                                .setCancelable(false)
                                .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                                    public void onClick(DialogInterface dialog, int id) {
                                        // if this button is clicked, close
                                        // current activity


                                        if (listSize > 0) {

                                            mCheckboxes.get(listSize - 1).setVisibility(View.GONE);
                                            mSpinners.get(listSize - 1).setVisibility(View.GONE);
                                            mViews.get(listSize - 1).setVisibility(View.GONE);
                                            mTextviews.get(listSize - 1).setVisibility(View.GONE);
                                            mEdittexts.get(listSize - 1).setVisibility(View.GONE);
                                            Toast.makeText(getBaseContext(), "Item removed.", Toast.LENGTH_SHORT).show();

                                        }


                                    }
                                })
                                .setNegativeButton("No", new DialogInterface.OnClickListener() {
                                    public void onClick(DialogInterface dialog, int id) {
                                        // if this button is clicked, just close
                                        // the dialog box and do nothing
                                        dialog.cancel();
                                    }
                                });

                        // create alert dialog
                        AlertDialog alertDialog = alertDialogBuilder.create();

                        // show it
                        alertDialog.show();


                    }
                });


                //Add a new checkbox
                final CheckBox newCheckbox = makeCheckbox();
                mLinearLayout.addView(newCheckbox);

                //TODO add checkbox to your list
                mCheckboxes.add(newCheckbox);


                final TextView newTextview = makeTextview();
                mLinearLayout.addView(newTextview);
                mTextviews.add(newTextview);

                //TODO Add the spinner on item selected listener to get selected items
                spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                    @Override
                    public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
                        String currentItem = itemList.get(position);
                        String aisleNumber = numberItemValues.get(currentItem);
                        //TODO you can use the above aisle number to add to your text view
                        //mTextviews.get(mTextviews.size() -1).setText(aisleNumber);
                        newTextview.setText(aisleNumber);
                    }

                    @Override
                    public void onNothingSelected(AdapterView<?> parentView) {
                        //  code here
                    }

                });


            }
        });

    }










   /* //creates the 3 buttons on the side.
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.create_menu, menu);
        return true;
    }
*/





    //use a relative layout and specify which ones are to layout_toRightOf and layout_below

    //DUPLICATING ITEMS WHEN FAB IS PRESSED//
    private CheckBox makeCheckbox() {
        //Create new Checkbox
        CheckBox checkbox = new CheckBox(this);

        // Setup layout
        LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
                LinearLayout.LayoutParams.MATCH_PARENT,
                LinearLayout.LayoutParams.WRAP_CONTENT);


        //setup relative layout for the positioning of the objects

       /* RelativeLayout.LayoutParams relativeParams = new RelativeLayout.LayoutParams(
                relativeParams.addRule(RelativeLayout.RIGHT_OF, textview); //can't  resolve symbol textview
                )

        checkbox.setLayoutParams(relativeParams);*/
        checkbox.setLayoutParams(layoutParams);
        return checkbox;
    }


    private TextView makeTextview() {
        //create new textview
        TextView textview = new TextView(this);

        //setup layout

        LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
                LinearLayout.LayoutParams.MATCH_PARENT,
                LinearLayout.LayoutParams.WRAP_CONTENT);
        textview.setLayoutParams(layoutParams);
        textview.setText("ihi");


        return textview;
    }


    private EditText makeEdittext() {
        //create new edittext
        EditText edittext = new EditText(this);

        //setup layout
        final LinearLayout.LayoutParams lparams = new LinearLayout.LayoutParams(50, 50); // Width , height
        edittext.setLayoutParams(lparams);
        edittext.setInputType(InputType.TYPE_CLASS_NUMBER | InputType.TYPE_NUMBER_FLAG_DECIMAL | InputType.TYPE_NUMBER_FLAG_SIGNED);

        return edittext;

    }




    private View makeView() {
        //create new View

        View view = new View(this);
        view.setBackgroundColor(Color.parseColor("#ffffff"));
        LinearLayout.LayoutParams layoutParams =  new LinearLayout.LayoutParams( LinearLayout.LayoutParams.MATCH_PARENT, 100);
        new LinearLayout.LayoutParams( LinearLayout.LayoutParams.WRAP_CONTENT, 50);
        //LinearLayout.LayoutParams.MATCH_PARENT,
        // LinearLayout.LayoutParams.WRAP_CONTENT);
        view.setClickable(true);




        view.setLayoutParams(layoutParams);


        //setup layout

        return view;


    }






    private Spinner makeSpinner() {
        //opens csv
        InputStream inputStream = getResources().openRawResource(R.raw.shopitems);
        CSVFile csvFile = new CSVFile(inputStream);
        //TODO I made this variable global, declared it at the very top of this file
        itemList = csvFile.read();

        //Create new spinner
        // SearchableSpinner spinner = (SearchableSpinner) new Spinner(this, Spinner.MODE_DROPDOWN);
        SearchableSpinner spinner = new SearchableSpinner(this);


        // Setup layout
        LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
                LinearLayout.LayoutParams.MATCH_PARENT,
                LinearLayout.LayoutParams.WRAP_CONTENT);
        spinner.setLayoutParams(layoutParams);
        MyListAdapter adapter = new MyListAdapter(this, R.layout.listrow, R.id.txtid, itemList);


        spinner.setAdapter(adapter);



        //Add it to your list of spinners so you can retrieve their data when you click the getSpinner button
        mSpinners.add(spinner);
        return spinner;
    }



    private class CSVFile {
        InputStream inputStream;

        public CSVFile(InputStream inputStream) {
            this.inputStream = inputStream;
        }

        public List<String> read() {

            List<String> resultList = new ArrayList<String>();
            BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
            try {
                String line;
                while ((line = reader.readLine()) != null) {
                    String[] row = line.split(",");
                    //TODO I edited this part so that you'd add the values in our new hash map variable
                    numberItemValues.put(row[1], row[0]);
                    resultList.add(row[1]);
                }
            } catch (IOException e) {
                Log.e("Main", e.getMessage());
            } finally {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    Log.e("Main", e.getMessage());
                }
            }
            return resultList;
        }
    }}

create xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/colorBackground"
    android:minHeight="170dp"
    tools:context=".create"
    tools:layout_editor_absoluteY="81dp">


    <ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/scrollView2"
        android:layout_width="match_parent"
        android:layout_height="438dp"
        android:fillViewport="true"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="parent"
        tools:layout_editor_absoluteY="0dp">


        <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
            xmlns:app="http://schemas.android.com/apk/res-auto"
            xmlns:tools="http://schemas.android.com/tools"
            android:id="@+id/my_linearLayout"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">


        </LinearLayout>


    </ScrollView>

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="60dp"
        android:layout_height="70dp"
        android:layout_gravity="bottom|end"
        android:layout_marginBottom="16dp"
        android:layout_marginEnd="16dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="16dp"
        android:layout_marginStart="8dp"
        android:src="@android:drawable/ic_input_add"
        app:backgroundTint="@color/colorCreate"
        app:elevation="6dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="1.0"
        app:layout_constraintStart_toStartOf="parent"
        app:pressedTranslationZ="12dp"
        android:tint="@color/colorBackground"/>


    <View
        android:id="@+id/subheading"
        android:layout_width="match_parent"
        android:layout_height="83dp"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="1dp"
        android:layout_marginLeft="1dp"
        android:layout_marginRight="1dp"
        android:layout_marginStart="1dp"
        android:layout_marginTop="2dp"
        android:background="@color/colorBackground"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.0"
        />

    <TextView
        android:id="@+id/example"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="492dp"
        android:layout_marginLeft="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:text="TextView"
        android:hint="test"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <View
        android:id="@+id/view"
        android:layout_width="320dp"
        android:layout_height="1dp"
        android:layout_marginEnd="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="76dp"
        android:background="@color/colorText"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <View
        android:id="@+id/view2"
        android:layout_width="320dp"
        android:layout_height="1dp"
        android:layout_marginEnd="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="28dp"
        android:background="@color/colorText"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginStart="8dp"

        android:layout_marginTop="12dp"
        android:fontFamily="@font/droid_sans"
        android:text="@string/done_label"
        android:textColor="@color/colorText"
        android:textSize="20sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/textView4"
        app:layout_constraintTop_toBottomOf="@+id/view2" />

    <TextView
        android:id="@+id/textView4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="128dp"
        android:layout_marginRight="128dp"
        android:layout_marginTop="8dp"
        android:fontFamily="@font/droid_sans"
        android:text="@string/aisle_label"
        android:textColor="@color/colorText"
        android:textSize="20sp"
        app:layout_constraintBottom_toTopOf="@+id/view"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/view2"
        app:layout_constraintVertical_bias="1.0" />

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="5dp"
        android:layout_marginEnd="32dp"
        android:layout_marginRight="32dp"
        android:layout_marginTop="5dp"
        android:fontFamily="@font/droid_sans"
        android:text="@string/qty_label"
        android:textColor="@color/colorText"
        android:textSize="20sp"
        app:layout_constraintBottom_toTopOf="@+id/view"
        app:layout_constraintEnd_toStartOf="@+id/textView4"
        app:layout_constraintTop_toBottomOf="@+id/view2"
        app:layout_constraintVertical_bias="0.7" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:fontFamily="@font/droid_sans"
        android:text="@string/item_label"
        android:textColor="@color/colorText"
        android:textSize="20sp"
        app:layout_constraintBottom_toTopOf="@+id/view"
        app:layout_constraintEnd_toStartOf="@+id/textView3"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/view2"
        app:layout_constraintVertical_bias="1.0" />


</android.support.constraint.ConstraintLayout>

Answer 1

[UPDATED]

So basically, you have 2 activity classes, create and view (as you mentioned).

Declare your spinner in the form of global. All other explanation of the code is in the form of comment.

public class create extends AppCompatActivity {

private LinearLayout mLinearLayout;
private ArrayList<SearchableSpinner> mSpinners;
//TODO add the below list of buttons and checkboxes
//private List<AppCompatButton> mButtons = new ArrayList<>();
private List<CheckBox> mCheckboxes = new ArrayList<>();
private List<View> mViews = new ArrayList<>();

Button buttonGo;

//define spinner here
Spinner spinner;


//your own code
......
floatingActionButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Toast.makeText(getBaseContext(), "Item added!", Toast.LENGTH_SHORT).show();

            RelativeLayout.LayoutParams params1 = new RelativeLayout.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.WRAP_CONTENT);
            RelativeLayout.LayoutParams params2 = new RelativeLayout.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.WRAP_CONTENT);
            // Handle the click.


            //initialise your spinner here
            spinner = makeSpinner();

            //your code as usual
        }

    //put this some where in your code where you want to start another activity after your operations are done (usually in onClick of something)
    {
        Intent i= new Intent(this, YourSecondClass.class);
        //Create the bundle
        Bundle bundle = new Bundle();

        //Add your data to bundle one by one, in this case passing spinner selected value, 
        //replace val1 with your own variable name
        bundle.putString("val1", spinner.getSelectedItem().toString());

        //if you have more spinner,add in similar way
        bundle.putString("val2", spinner2.getSelectedItem().toString());

        //Add the bundle to the intent
        i.putExtras(bundle);
        startActivity(i);
    }


}
}

Here is the sample for view activity.

public class view extends AppCompatActivity {

...

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        ...
        //initialise your spinner here
        spinner = makeSpinner();

        //Get bundle from previous intent(activity)
        Bundle bundle = getIntent().getExtras();

        //Extract the data…
        String val1= bundle.getString("val1");
        String val2= bundle.getString("val2");

        //USUALLY, you will have a list of items in your spinner, do what you should do, this is just an example.
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.select_state, android.R.layout.simple_spinner_item);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

        //set the adapter
        mSpinner.setAdapter(adapter);


        if (val1 != null) {
            int spinnerPosition = adapter.getPosition(val1);
            spinner.setSelection(spinnerPosition);
        }       
        ...


    }
...

}

NOTE: This is just a guidance or 'framework' to give you some clues on where you should place your code. NOT FULL SOLUTION as your code is too long and I can't assure its correct, so I did not include them.

Answer 2

buttonGo.setOnClickListener(new View.OnClickListener() {
             public void onClick(View v) {
if(spinner!=null){

Intent i= new Intent(create.this, viewscreen.class);
//Create the bundle
Bundle bundle = new Bundle();

//Add your data to bundle
bundle.putString("dropdown", dropdown_value);

//Add the bundle to the intent
i.putExtras(bundle);
startActivity(i);
             }
         });

Answer 3

public class create extends AppCompatActivity {

private LinearLayout mLinearLayout;
private ArrayList<SearchableSpinner> mSpinners;
//TODO add the below list of buttons and checkboxes
// private List<AppCompatButton> mButtons = new ArrayList<>();
private List<CheckBox> mCheckboxes = new ArrayList<>();
private List<View> mViews = new ArrayList<>();
Button buttonGo;
Spinner spinner;
......
floatingActionButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Toast.makeText(getBaseContext(), "Item added!", Toast.LENGTH_SHORT).show();

            RelativeLayout.LayoutParams params1 = new RelativeLayout.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.WRAP_CONTENT);
            RelativeLayout.LayoutParams params2 = new RelativeLayout.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.WRAP_CONTENT);
            // Handle the click.


            // Handle ze click.
            //final Spinner spinner = makeSpinner();
            //mLinearLayout.addView(spinner);

            spinner = makeSpinner();
}

Answer 4

I don't know why you are stuck in this problem still. When you know to pass values in Activities. If I think about your problem, I get various solutions in my mind.

Solution 1: Use @Angus solution, I checked your code when you followed his answer.

Basically you have to pass an value to next activity, like position/ spinner selected value.

bundle.putString("selectedPos", spinner.getSelectedItemPosition());

or

bundle.putString("selectedItem", ((String) spinner.getSelectedItem()));

Solution 2: You have SharedPreference to store these values in first activity, then get saved values in second activity.

Solution 3: I don't suggest to use Application class to store variables, but yes!, that's a solution. Like this answer. I don't use Application class to store values, because we need to clear the fields after use manually, to recover RAM uses.

Solution 4: As you said both of your Activities are almost same, then why don't you just use one Activity and manage Views accordingly.

Edit

If I am getting right, then you can pass the generated Spinners items list and selected items to next Activity. You can pass Parcelable List for ease.

First Activity passes the Spinner model list.

ArrayList<ModelSpinner> list = new ArrayList<>();
list.add(new ModelSpinner(itemsList, (String) spinner.getSelectedItem()));
startActivity(new Intent(this, MainActivity.class).putParcelableArrayListExtra("key", list));

Second activity gets the list and make according views

ArrayList<ModelSpinner> list = getIntent().getParcelableArrayListExtra("key");
for (ModelSpinner spinner : list) {
//            render spinners
    Spinner spinner = makeSpinner(spinner.getItems(),spinner.getSelectedValue());
    // todo create method makeSpinner(List<String> list, String selectedItem), add this spinner to your activity.
}

ModelSpinner.class

public class ModelSpinner implements Parcelable {
    private ArrayList<String> items;
    private String selectedValue;

    // getter setter

    public ModelSpinner(ArrayList<String> items, String selectedValue){
       this.items = items;
       this.selectedValue = selectedValue;
    }


    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeStringList(this.items);
        dest.writeString(this.selectedValue);
    }

    public ModelSpinner() {
    }

    protected ModelSpinner(Parcel in) {
        this.items = in.createStringArrayList();
        this.selectedValue = in.readString();
    }

    public static final Parcelable.Creator<ModelSpinner> CREATOR = new Parcelable.Creator<ModelSpinner>() {
        @Override
        public ModelSpinner createFromParcel(Parcel source) {
            return new ModelSpinner(source);
        }

        @Override
        public ModelSpinner[] newArray(int size) {
            return new ModelSpinner[size];
        }
    };
}

Answer 5

The best solution for this scenario will be using ViewModel and LiveData from architectural components library which will simply provide you consistency in data in both the Activities. A single ViewModel for both Activities and shared LiveDatas for both Activities which will be helpful when you update any LiveData from any Activity it will get reflected in all the Activities which is observing the defined LiveData in the ViewModel.

Answer 6

You are calling the context as "This" but is calling it from within a method that overwrites a method in the interface, but the method is not in this class and therefore does not know what "This" is, to solve it do this, in you Create Class:

public class Create extends AppCompatActivity {
  private Context context;
  @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_view);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        context = this;
        buttonGo.setOnClickListener(new View.OnClickListener() {
                                        public void onClick(View v) {

                                            if(spinner!=null){

                                                Intent i= new Intent(context, View.class);
                                                startActivity(i);
                                            }
                                        };
  }
}

You can pass data with the intent,or can pass data using a static variable in the Create class.

Create Class:

    public class Create extends AppCompatActivity {
        public static String optionSelected;
//other code....
            spinner.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                        @Override
                        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                          Create.optionSelected = parent.getItemAtPosition(position).toString();  
                        }
                    });
//other code....

            }

In your View Class to call optionSelected:

public class View extends AppCompatActivity {

 String dropdown_value= Create.optionSelected;

  // rest of code
}

If you want to use a Category Adapter Class:

public class CategoryAdapter extends FragmentPagerAdapter {

    public CategoryAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {
        switch (position){
            case 0:
                return new CreateFragment();
            case 1:
                return new ViewFragment();
            default:
                return null;
        }
    }

    @Override
    public int getCount() {
        return 2;
    }
}

Answer 7

I think what you want to do is pass the user selected items from the create screen to the view screen.

You can use a global class to store the values of the selected items. And use it like a normal java class.

public class GlobalClass extends Application {
    ArrayList<String> items = new ArrayList<>();

    public ArrayList<String> getItems() {
        return items;
    }

    public void setItems(ArrayList<String> items) {
        this.items = items;
    }
}

Define this in the application tag of the manifest file

<application
    android:name=".GlobalClass"

and use it like this in the onCreate function of both activities

globalClass = (GlobalClass) this.getApplicationContext();

then you can use getters and setters to access your selected item list. in create activity,

ArrayList<String> items = new ArrayList<>();
items.add(item); // add you selected item
globalClass.setItems(items);

in view activity,

ArrayList<String> items = globalClass.getItems();

Answer 8

I had a similar requirement. I solved it with a different logic.

1. Create a class for reference.
2. Store data in this class, then stringify using Gson and pass it to second activity.
3. Get back from stringified json to class object using Gson.
4. OnCreate, update the UI according to the object content u received in Step 3.

This will make the flow in control and development friendly. Hope this serves your requirement well.

Storing the view and transferring is not a better idea since this can lead to development complexity later.

Incase of multiple data for n number of spinners, you can use ArrayList of product objects and create spinner view dynamically.

Answer 9

Alright so what I suggest doing is create an ArrayList of Integer to keep track of both the number of Spinners you created in the first Activity through ArrayList.size() and the position of each spinner which would be the value in the ArrayList.

So first when a button is clicked in the first Activity put this code in the onClick method:

ArrayList<Integer> spinnerList = new ArrayList<>(); 
for(int i = 0; i < mSpinners.size(); i++) { 
    spinnerList.add(mSpinners.get(i).getSelectedItemPosition()); 

} 
Bundle newBundle = new Bundle(); 
newBundle.putIntegerArrayList("arraylist", spinnerList); 
Intent newIntent = new Intent(create.this, view.class); 
newIntent.putExtra("extraBundle", newBundle);
startActivity(newIntent);

And then in the second Activity (view Activity) get the ArrayList like this:

Intent gotIntent = getIntent();
Bundle bundle = getIntent().getBundleExtra("extraBundle");
ArrayList<Integer> spinnerArrayList = bundle.getIntegerArrayList("arraylist");

After getting the ArrayList create a For loop same number of times as the size of the ArrayList which is the number of spinners you had and add the code for adding the spinner and other views:

for(int i = 0; i < spinnerArrayList.size(); i++ { 
    //code for adding all views 

    //at the end of the loop 
    int positionOfSpinner = spinnerArrayList.get(i); 
    spinner.setSelection(positionOfSpinner);

}