Adding array of textviews dynamically to linear layout

Question

I tried to add an array of textviews which i defined as a public variable, but when i run the application, it force closes as soon as it gets into for loop. This is the code:

LinearLayout myLayout = (LinearLayout) findViewById(R.id.my_layout);
            LayoutParams lp = new LayoutParams( LayoutParams.WRAP_CONTENT,    LayoutParams.WRAP_CONTENT);
            pairs=new TextView[num_match+1];
            for(int l=1;l<=num_match;l++)
            {
                pairs[l].setTextSize(15);
                pairs[l].setLayoutParams(lp);
                pairs[l].setId(l);
                pairs[l].setText(m1[l]+" - "+m2[l]);
                myLayout.addView(pairs[l]);
            }

Provide some detail like LogCat error ..

Yaqub Ahmad
– Yaqub Ahmad

2012-09-20 16:21:05 +00:00
Commented Sep 20, 2012 at 16:21 — Yaqub Ahmad
– Yaqub Ahmad, Commented Sep 20, 2012 at 16:21

Sam · Accepted Answer · 2012-09-20 17:22:34Z

7

You need to create new TextViews to put into the TextView array and you are skipping the first index (pairs[0]) which will lead to trouble later:

pairs=new TextView[num_match];
for(int l=0; l<num_match; l++)
{
    pairs[l] = new TextView(this);
    pairs[l].setTextSize(15);
    pairs[l].setLayoutParams(lp);
    pairs[l].setId(l);
    pairs[l].setText(m1[l + 1]+" - "+m2[l + 1]);
    myLayout.addView(pairs[l]);
}

From your comments, I included this simple working example to help you:

public class Example extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        LinearLayout myLayout = (LinearLayout) findViewById(R.id.my_layout);
        LayoutParams lp = new LayoutParams( LayoutParams.WRAP_CONTENT,    LayoutParams.WRAP_CONTENT);
        TextView[] pairs=new TextView[4];
        for(int l=0; l<4; l++)
        {
            pairs[l] = new TextView(this);
            pairs[l].setTextSize(15);
            pairs[l].setLayoutParams(lp);
            pairs[l].setId(l);
            pairs[l].setText((l + 1) + ": something");
            myLayout.addView(pairs[l]);
        }

    }
}

With the layout main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/my_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" />

edited Sep 20, 2012 at 17:22

answered Sep 20, 2012 at 16:26

Sam

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5 Comments

Vladimir Over a year ago

when i put pairs[l] = new TextView(this); eclipse underlines new TextView(this) and the error says: The constructor TextView(new View.OnClickListener(){}) is undefined

Sam Over a year ago

Ok, add your class name before this, for example MyActivity.this.

Vladimir Over a year ago

thanks, it doesn't show error now. but i then want to see that textviews in my activity, but when i set setContentView(R.Layout.activity_main) nothing happens.

Vladimir Over a year ago

i assigned id to my linear layout and called it myLayout, maybe i should call the method with that? sry for bothering so much

Sam Over a year ago

I added an example, I hope that will help you.

LeeNeverGup · Accepted Answer · 2012-09-20 16:24:24Z

3

I think you need to initailize pairs[l] before using it, like this:

    for(int l=1;l<=num_match;l++)
    {
        pairs[l] = new TextView();
        //...
    }

Otherwise it will have NullPointerException, and collapse as described.

answered Sep 20, 2012 at 16:24

LeeNeverGup

1,1148 silver badges24 bronze badges

2 Comments

Sam Over a year ago

Why was this downvoted? (It's not perfect, but it's basic observation is correct.)

Vladimir Over a year ago

when i put pairs[l] = new TextView(this); eclipse underlines new TextView(this) and the error says: The constructor TextView(new View.OnClickListener(){}) is undefined

Community · Accepted Answer · 2017-05-23 12:27:17Z

0

Why have an array of TextViews? Can you replace it with ListView?

I think that would be a better way. Try this.

edited May 23, 2017 at 12:27

CommunityBot

11 silver badge

answered Sep 20, 2012 at 16:25

Shrikant Ballal

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