Get number from EditText to TextView and add

Question

I want when i write 5 in the EditText then i click the button i want the TextView to change to 5, then if i write 6 and click again on the button i want the TextView to change to 11...

<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="how much do you want to add ?"
    android:id="@+id/editText" />

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="0"
    android:textSize="50sp"
    android:layout_centerHorizontal="true"
    android:layout_alignParentTop="true"
    android:layout_alignParentStart="true"
    android:layout_marginTop="86dp"
    android:id="@+id/TextView" />

<Button
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/add"
    android:onClick="add"
    android:layout_below="@id/editText"
    android:hint="add"/>

Answer 1

You can check the following code snippet. Make sure to add conditions/check that input is always in numeric:

yourbtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            if(yourtxtview.getText().toString().trim().length()>0 ){
                if(youredtText.getText().toString().trim().length()>0){
                    yourtxtview.setText(String.valueOf(Integer.valueOf(yourtxtview.getText().toString())
                            +Integer.valueOf(youredtText.getText().toString())));
                }else{
                    yourtxtview.setText(String.valueOf(Integer.valueOf(yourtxtview.getText().toString())+
                            0));

                }
            }else if(youredtText.getText().toString().trim().length()>0){
                yourtxtview.setText(String.valueOf(Integer.valueOf(youredtText.getText().toString())+
                        0));
            }
        }
    });

Answer 2

    TextView textView;
    EditText editText;

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

        textView = findViewById(R.id.textView);
        editText = findViewById(R.id.editText);

        textView.setText("0");



    }

    public void add(View v) {

        int x = Integer.parseInt(textView.getText().toString());
        textView.setText(String.valueOf(x + Integer.parseInt(editText.getText().toString())));
    }