Android output error. TextView won't display output

Question

package com.culligandev.www;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class threeRows extends Activity {

    TextView display;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.output);
        display = (TextView) findViewById(R.id.tvDisplay);

        int a = 3;

        for(int i = 0; i < a; i++) {
            for(int j = 0; j <= i; j++) {
                display.setText("*");
            }
            display.setText("");
        }
    }
}

This activity is called by the press of a button and then should output a triangle made of asterisks like this:

*
**
***

It doesn't output anything and just shows a blank screen. Can you help, please?

it won't make a triangle, because every time you call setText it sets a new text, so the last sequence to be entered to the textview will be "", which means after you run this code, your TextView will contain "" in it — user849998
– user849998, Commented Dec 5, 2011 at 0:14

Nixit Patel · Accepted Answer · 2011-12-05 00:35:20Z

1

setText is not working as printf or println

if you want to display a pattern then you can do it using StringBuilder or StringBuffer and then use that string buffer/builder object in setText to display the pattern

answered Dec 5, 2011 at 0:35

Nixit Patel

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2 Comments

user1080667 Over a year ago

what would a stringBuilder look like?

Nixit Patel Over a year ago

java2s.com/Tutorial/CSharp/0100__String/0400__StringBuilder.htm hear is the example of string builder that you might need to check

Sam · Accepted Answer · 2012-07-16 21:44:02Z

1

You have problem in your "for". The last thing your app will do is display.setText(""), which means your text will be empty. You should put something like

display.setText(display.getText() + "\n");

And for the other one:

display.setText(display.getText() + "*");

edited Jul 16, 2012 at 21:44

Sam

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answered Dec 5, 2011 at 0:13

Belurd

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Comments

Dan · Accepted Answer · 2011-12-05 01:07:04Z

0

TextView.append might be what you're after, or use a StringBuilder as has been suggested

answered Dec 5, 2011 at 1:07

Dan

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Comments

Hiral Vadodaria · Accepted Answer · 2011-12-07 10:37:43Z

0

try this:

for(int i = 0; i < a; i++) {
      for(int j = 0; j <= i; j++) 
      {
                display.setText(display.getText().toString().trim()+"*");
      }
      display.setText(display.getText().toString().trim()+"\n");
}

answered Dec 7, 2011 at 10:37

Hiral Vadodaria

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