How do I repeat the same text after clicking a button?

Question

I'm trying to make a simple calculator in Android Studio, and I'm having trouble repeating the same number in text view.

For example, if I press 1 on the calculator, it will show the number 1 on top, but if I press it again, nothing happens.

Therefore, I can't make numbers greater than 9.

Here's my code:

public class MainActivity extends AppCompatActivity {

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

        Button btn = findViewById(R.id.button0);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                TextView tv = findViewById(R.id.textView);
                tv.setVisibility(view.VISIBLE);
                tv.setText("0");
            }
        });

        btn = findViewById(R.id.button1);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                TextView tv = findViewById(R.id.textView);
                tv.setVisibility(view.VISIBLE);
                tv.setText("1");
            }
        });
    }
}

Add your code as text instead of screenshot of code – Vikasdeep Singh Jul 10 '18 at 00:40 — Vikasdeep Singh, Jul 10 '18 at 00:40

Sagar · Accepted Answer · 2018-07-10T01:36:32.223

3

Using textViewObj.setText("1"); will always replace the existing text in the view. Based on your description of the requirement, textViewObj.append("1"); should be the one which can achieve it.

Replace textViewObj.setText("1"); with textViewObj.append("1"); appropriately, as follows

    btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            TextView tv = findViewById(R.id.textView);
            tv.setVisibility(view.VISIBLE);
            tv.append("1");
        }
    });

edited Jul 10 '18 at 01:36

answered Jul 10 '18 at 00:42

Sagar

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Thanks for replying. Do you think you could show an example because I'm still a little confused on this? – weightbonny Jul 10 '18 at 01:30
@RayaanAfzal no problem. Remember to mark answer as accepted, so that others can benefit too. – Sagar Jul 10 '18 at 01:36

score 0 · Answer 2 · answered Jul 10 '18 at 01:28

btn is the button you clicked:

btn.setOnClickListener((view)->{
String currentNumber = txtViewObj.getText().toString();
String number =  ((TextView)view).getText().toString(); //I assume that you already named each button corresponding to its number, for example button1 call it 1, button2 call it 2
txtViewObj.setText(currentNumber+number);
});

score 0 · Answer 3 · answered Jul 10 '18 at 01:32

Actually what exactly happens is that using textView.setText("1") each time will destroy the TextView's buffer containing any text and simply replace it with the new text i.e. "1" and using textView.append("1") will update the buffer of the TextView to display the concatenated text. Refer to this answer for more details.

How do I repeat the same text after clicking a button?

3 Answers3