Return editText value into listView

Question

In Activity A , it has a multiline listView . The value return from Activity B should populate the Activity A listView .

Activity A

 MyCustomBaseAdapter objMyCustomBaseAdapter;
 ArrayList<SearchResults> results=new ArrayList<SearchResults>();

  public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.work_details);

        listview = (ListView) findViewById(R.id.listView);
        name = getIntent().getExtras().getString("Name"); // receive name from Information
        weather = getIntent().getExtras().getString("Weather"); //receive weather
        date = getIntent().getExtras().getString("date2"); //receive date
        status = getIntent().getExtras().getString("Status"); // receive status
        objMyCustomBaseAdapter=new MyCustomBaseAdapter(getApplicationContext(),results);

    }

 @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.addDetails:
                View menuItemView = findViewById(R.id.addDetails);
                PopupMenu po = new PopupMenu(this, menuItemView); //for drop-down menu
                po.getMenuInflater().inflate(R.menu.popup_details, po.getMenu());
                po.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
                public boolean onMenuItemClick(MenuItem item) {
                if ("Add Work Details".equals(item.getTitle())) {
                Intent intent = new Intent(getApplication(), B.class);  // go to B class  
                startActivityForResult(intent, PROJECT_REQUEST_CODE);
                 }
                        return true;
                    }
                });
                po.show(); //showing popup menu
        }
        return super.onOptionsItemSelected(item);

    }

 @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) { // receive from Activity B
        if (requestCode == PROJECT_REQUEST_CODE) {
            ReceiveProject = data.getStringExtra("Project");
            ReceiveDescription = data.getStringExtra("Description");
            ReceiveProgress = data.getIntExtra("progress", 0);
            ReceiveTimeIn = data.getStringExtra("TimeIn");
            ReceiveTimeOut = data.getStringExtra("TimeOut");
            MyCustomBaseAdapter objMyCustomBaseAdapter= (MyCustomBaseAdapter)listview.getAdapter();
            objMyCustomBaseAdapter.addNewItem(ReceiveProject, ReceiveDescription, ReceiveProgress, ReceiveTimeIn, ReceiveTimeOut);

        }
    }

Activity B

  save.setOnClickListener(new View.OnClickListener()
        {  // return values to Activity A
            @Override
            public void onClick(View v)
            {
                Intent returnIntent=new Intent();
                Project=project.getSelectedItem().toString();
                Description=description.getText().toString();
                progress=seekBar.getProgress();
                returnIntent.putExtra("Project",Project);
                returnIntent.putExtra("Description", Description);
                returnIntent.putExtra("progress", progress);
                Toast.makeText(getApplicationContext(), progress+"", Toast.LENGTH_LONG).show();
                returnIntent.putExtra("TimeIn", TimeIn);
                returnIntent.putExtra("TimeOut",TimeOut);
                setResult(Activity.RESULT_OK,returnIntent);
                finish();

            }
        });

MyCustomBaseAdapter.java

    public class MyCustomBaseAdapter extends BaseAdapter{   // for ListView in Activity A

     private static ArrayList<SearchResults> searchArrayList;
     private LayoutInflater mInflater;

public MyCustomBaseAdapter(Context context, ArrayList<SearchResults> results) {
                searchArrayList = results;
                mInflater = LayoutInflater.from(context);
            }

            public int getCount() {
                return searchArrayList.size();
            }

           public void addNewItem(String P,String D,int Per,String I,String O)
           {
               SearchResults obj=new SearchResults();
               obj.setProject(P);
               obj.setDescription(D);
               obj.setProgress(Per);
               obj.setTimeIn(I);
               obj.setTimeOut(O);
               searchArrayList.add(obj);
               this. notifyDataSetChanged();
           }

custom_row_view.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <TextView android:id="@+id/ListProject"
        android:textSize="15sp"
        android:textStyle="bold"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
    <TextView android:id="@+id/ListDescription"
        android:layout_width="wrap_content"
        android:textSize="15sp"
        android:layout_height="wrap_content"/>
    <TextView android:id="@+id/ListProgress"
        android:layout_width="wrap_content"
        android:textSize="15sp"
        android:layout_height="wrap_content"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="15sp"
        android:id="@+id/ListTimeIn"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="15sp"
        android:id="@+id/ListTimeOut"/>

</LinearLayout>

When I click the save button in Activity B to return value to A, app crashed .

  Process: com.example.project.myapplication, PID: 23777
    java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=1, result=-1, data=Intent { (has extras) }} to activity {com.example.project.myapplication/com.example.project.myapplication.GUI.A}: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.example.project.myapplication.Adapter.MyCustomBaseAdapter.addNewItem(java.lang.String, java.lang.String, int, java.lang.String, java.lang.String)' on a null object reference
            at android.app.ActivityThread.deliverResults(ActivityThread.java:3699)
            at android.app.ActivityThread.handleSendResult(ActivityThread.java:3742)
            at android.app.ActivityThread.-wrap16(ActivityThread.java)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1393)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:148)
            at android.app.ActivityThread.main(ActivityThread.java:5417)
            at java.lang.reflect.Method.invoke(Native Method)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.example.project.myapplication.Adapter.MyCustomBaseAdapter.addNewItem(java.lang.String, java.lang.String, int, java.lang.String, java.lang.String)' on a null object reference
            at com.example.project.myapplication.GUI.A.onActivityResult(A.java:95)

Error where the code refer to

 objMyCustomBaseAdapter.addNewItem(ReceiveProject, ReceiveDescription, ReceiveProgress, ReceiveTimeIn, ReceiveTimeOut);

Answer 1

try to set adapter to the listview before you start activity B,, the listView have no adapter so it will return null in getAdapter

edit

Add set adapter after this code to use the adapter when you call listview.getAdapter() ,, without this the adapter will be null

listview = (ListView) findViewById(R.id.listView);
        name = getIntent().getExtras().getString("Name"); // receive name from Information
        weather = getIntent().getExtras().getString("Weather"); //receive weather
        date = getIntent().getExtras().getString("date2"); //receive date
        status = getIntent().getExtras().getString("Status"); // receive status
        objMyCustomBaseAdapter=new MyCustomBaseAdapter(getApplicationContext(),results);
listview.setAdapter(objMyCustomBaseAdapter);