Try this,

Intent i = new Intent(mamm.this, sua.class);
startActivityForResult(i, 0);

I have some issues with Android Studio program
I am currently coding a multi-activity program.
Most activities work just fine, but some of my activities do not proceed to the next one.
Here are my codes.

public class mamm extends AppCompatActivity{

    ListView listview;
    String aGangList[] = {"a", "b"};
    String desAGangList[] = {"A", "B"};
    int imageList[] = {R.drawable.ddda, R.drawable.ddda};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_mamm);

        listview = findViewById(R.id.agang);
        MyAdapter adapter = new MyAdapter(this, aGangList, desAGangList, imageList);
        listview.setAdapter(adapter);

        listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                if (position == 0){
                    Toast.makeText(mamm.this, "a", Toast.LENGTH_SHORT).show();
                    Intent i = new Intent(view.getContext(), sua.class);
                    startActivityForResult(i, 0);
                }
                if (position == 1){
                    Toast.makeText(mamm.this, "b", Toast.LENGTH_SHORT).show();
                }
            }
        });
    }

   class MyAdapter extends ArrayAdapter<String>{

        Context context;
        String rTitle[];
        String rDes[];
        int rImage[];

        MyAdapter(Context c, String title[], String des [], int image[]){
            super(c, R.layout.row, R.id.title, title);
            this.context = c;
            this.rTitle = title;
            this.rDes = des;
            this.rImage = image;
        }

        @NonNull
        @Override
        public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
            LayoutInflater l = (LayoutInflater)getApplicationContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View r = l.inflate(R.layout.row, parent, false);
            ImageView images = r.findViewById(R.id.image);
            TextView mTitle = r.findViewById(R.id.textView1);
            TextView mSub = r.findViewById(R.id.textView2);

            images.setImageResource(rImage[position]);
            mTitle.setText(rTitle[position]);
            mSub.setText(rDes[position]);

            return r;

        }
    }
}

this is my mamm class, and I want mamm activity to go to sua class when the listview is clicked.

public class sua extends AppCompatActivity{

    ListView listview;
    String haGangList[] = {"c", "d"};
    String desHaGangList[] = {"C", "d"};
    int imageList[] = {R.drawable.ddda, R.drawable.ddda};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_sua);

        listview = findViewById(R.id.agang);
        MyAdapter adapter = new MyAdapter(this, haGangList, desHaGangList, imageList);
        listview.setAdapter(adapter);

        listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                if (position == 0){
                    Toast.makeText(sua.this, "c", Toast.LENGTH_SHORT).show();
                }
                if (position == 1){
                    Toast.makeText(sua.this, "d", Toast.LENGTH_SHORT).show();
                    Intent i = new Intent(view.getContext(), taeban.class);
                    startActivityForResult(i, 1);
                }
            }
        });
    }

    class MyAdapter extends ArrayAdapter<String>{

        Context context;
        String rTitle[];
        String rDes[];
        int rImage[];

        MyAdapter(Context c, String title[], String des [], int image[]){
            super(c, R.layout.row, R.id.title, title);
            this.context = c;
            this.rTitle = title;
            this.rDes = des;
            this.rImage = image;
        }

        @NonNull
        @Override
        public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
            LayoutInflater l = (LayoutInflater)getApplicationContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View r = l.inflate(R.layout.row, parent, false);
            ImageView images = r.findViewById(R.id.image);
            TextView mTitle = r.findViewById(R.id.textView1);
            TextView mSub = r.findViewById(R.id.textView2);

            images.setImageResource(rImage[position]);
            mTitle.setText(rTitle[position]);
            mSub.setText(rDes[position]);

            return r;

        }
    }
}

For some reason, mamm class does not move to sua class.

But when I substitute other classes instead of sua class, it works perfectly.

I don’t why it does not work.
Can you guys please help…