Button setOnClickListener on for loop

Question

I have 10 buttons and i want to set OnClickListener for all that buttons. Also with clicking on any button app will go another activity. I only post the buttons' definitions on the activity class. My code;

Button button1 = (Button) findViewById(R.id.button1);
Button button2 = (Button) findViewById(R.id.button2);
Button button3 = (Button) findViewById(R.id.button3);
Button button4 = (Button) findViewById(R.id.button4);
Button button5 = (Button) findViewById(R.id.button5);
Button button6 = (Button) findViewById(R.id.button6);
Button button7 = (Button) findViewById(R.id.button7);
Button button8 = (Button) findViewById(R.id.button8);
Button button9 = (Button) findViewById(R.id.button9);
Button button10 = (Button) findViewById(R.id.button10);
Button buttons[] = {button1, button2, button3, button4, button5, button6, button7, button8, button9, button10};
final String urlOfButtons[] = {"","","","","","","","","","",""};
final String titles[] = {"","","","","","","","","","",""};

JsonNode itemNode = jsonNode.path("Docs");
for(int i=0 ; i<itemNode.size() ; i++){
    titles[i] = itemNode.get(i).path("Text").asText();
            title = titles[i];
    buttons[i].setText(title);
    urlOfButtons[i] = itemNode.get(i).path("Link").asText();
            url = urlOfButtons[i];
    buttons[i].setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            Intent intent = new Intent(HouseDetail.this, HouseDetailPdf.class);
            intent.putExtra("title", title);
            intent.putExtra("url", url);
            startActivity(intent);
        }
    });
}

This only takes the last values of title and url normally. String url, title is defined on top of class. Every button i click the same value goes to other activity. I want 10 different values to add extra. So i want to add instead of title and url; titles[i] and url[i] as extra. I hope i'm clear.

Are you adding these buttons programmatically or in your xml layout? — Renan Bandeira
– Renan Bandeira, Commented Dec 9, 2013 at 11:03

Abhishek V · Accepted Answer · 2013-12-09 11:28:35Z

3

You can set title and url as tag to each button

buttons[i].setTag(1, title);
buttons[i].setTag(2, url);

and rerieve the tag inside onClick

@Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            Intent intent = new Intent(HouseDetail.this, HouseDetailPdf.class);
            intent.putExtra("title", v.getTag(1));
            intent.putExtra("url", v.getTag(2));
            startActivity(intent);
        }

Or else you can do something like this.Store the index as the tag so that you can get the index when the button is clicked.

buttons[i].setTag(i);

Get the index which is stored as tag.

@Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
             int position = Integer.parseInt(v.getTag().toString());
            Intent intent = new Intent(HouseDetail.this, HouseDetailPdf.class);
            intent.putExtra("title", titles[position]);
            intent.putExtra("url", urlOfButtons[position]);
            startActivity(intent);
        }

edited Dec 9, 2013 at 11:28

answered Dec 9, 2013 at 11:14

Abhishek V

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3 Comments

Batuhan Coşkun Over a year ago

I used the top one. Very useful idea i will never forget that way :)

Abhishek V Over a year ago

I belive second solution is better than the first as it saves little memory:)

Batuhan Coşkun Over a year ago

I will try that also :)

Hariharan · Accepted Answer · 2013-12-09 11:30:05Z

3

Try this..

You have passed the title and url values to the next Activity. But, at the end of for loop the title and url will only have the last value of the for loop. So, irrespective of the button click only the last stored values in title and url will only go to the next activity.

You can make use of the setTag(int key, Object tag) and set the url and title values for the button as tags inside for loop and you can retrieve them inside button click using getTag(int key) method..

JsonNode itemNode = jsonNode.path("Docs");
for(int i=0 ; i<itemNode.size() ; i++){
    titles[i] = itemNode.get(i).path("Text").asText();
            title = titles[i];
    buttons[i].setText(title);

    urlOfButtons[i] = itemNode.get(i).path("Link").asText();
            url = urlOfButtons[i];

    buttons[i].setTag(1,title);
    buttons[i].setTag(2,url);

    buttons[i].setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            Intent intent = new Intent(HouseDetail.this, HouseDetailPdf.class);
            intent.putExtra("title", v.getTag(1));
            intent.putExtra("url", v.getTag(2));
            startActivity(intent);
        }
    });
}

setTag(int key, Object tag);

getTag(int key);

edited Dec 9, 2013 at 11:30

answered Dec 9, 2013 at 11:03

Hariharan

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5 Comments

Batuhan Coşkun Over a year ago

I tried that but i values can not be token on onclicklistener.

Batuhan Coşkun Over a year ago

Change modifier of 'i' to final . Eclipse gives that suggestion.

Iain Over a year ago

I'm not sure that this is right. By the time onClick gets called, the for loop has run to completion and i will always equal itemNode.size() (that's if you can get the compiler to let it through, which I doubt - java has a syntax rule that frowns on this sort of thing)

Iain Over a year ago

Yo, Tamilan: at the moment your suggestion creates 10 OnClickListeners with identical code and it's making the garbage collector sad... (not very sad, but you know. Sadness is best avoided :) )

Batuhan Coşkun Over a year ago

Thanks for your suggestions but i have used another answer. Your solution is also works.

Iain · Accepted Answer · 2013-12-09 11:09:51Z

0

You can grab the relevant title and url in each iteration of the loop and store them in something final, then you can use them in the onClickListener.

for(int i=0 ; i<itemNode.size() ; i++){
    final String title = itemNode.get(i).path("Text").asText();
    final String url = itemNode.get(i).path("Link").asText();
    buttons[i].setOnClickListener(/* same as you had before */);
}

(warning: untested code).

Obviously if you're using the titles and urls arrays somewhere else, you should assign the values there too.

answered Dec 9, 2013 at 11:09

Iain

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3 Comments

Batuhan Coşkun Over a year ago

Also i should change modifier of 'int i' to final? Then what about i++ on for loop?

Iain Over a year ago

Nope. You only need i to be final if you refer to it from inside the body of the OnClickListener. In the code I suggested, for every iteration of the loop, we create a new variable title and a new variable url that are based on i. Then each time around we construct a new OnClickListener that depends on the title and the url. So i can change and track through the loop, and title and url are unchanging from the point of view of each OnClickListener

Iain Over a year ago

@abhishek V's answer is better than this, though - why have 10 OnClickListeners when one will do?

TharakaNirmana · Accepted Answer · 2013-12-09 11:10:51Z

Your class should implement onclickListner like this:

public class HomeScreen extends Activity implements OnClickListener

Initialize your buttons:

Button button1 = (Button) findViewById(R.id.button1);
button1.setOnClickListener(this);
Button button2 = (Button) findViewById(R.id.button2);
button2.setOnClickListener(this);
Button button3 = (Button) findViewById(R.id.button3);
button3.setOnClickListener(this);
Button button4 = (Button) findViewById(R.id.button4);
butto4.setOnClickListener(this);

Handle the click item for all buttons:

public void onClick(View v) {
        switch (v.getId()) {        
        case R.id.button1:
            Intent intent = new Intent(HouseDetail.this, HouseDetailPdf.class);
            intent.putExtra("title", title);
            intent.putExtra("url", url);
startActivity(intent);
            break;
        case R.id.button2:
                Intent intent = new Intent(HouseDetail.this, HouseDetailPdf.class);
            intent.putExtra("title", title);
            intent.putExtra("url", url);
startActivity(intent);
            break;
        case R.id.button3:
                Intent intent = new Intent(HouseDetail.this, HouseDetailPdf.class);
            intent.putExtra("title", title);
            intent.putExtra("url", url);
startActivity(intent);
            break;
        case R.id.button4:
                Intent intent = new Intent(HouseDetail.this, HouseDetailPdf.class);
            intent.putExtra("title", title);
            intent.putExtra("url", url);
startActivity(intent);
            break;
        }

Renan Bandeira · Accepted Answer · 2013-12-09 11:14:43Z

A good way to make it is avoiding this loop. Just define the url and the title in xml file.

you could put this in your button definition:

android:tag="title|url"

and then, in the onClickListener you should put:

        @Override
        public void onClick(View v) {
            if(v.getTag() != null){
                        String[] details = v.getTag().split("|");
                        Intent intent = new Intent(HouseDetail.this, HouseDetailPdf.class);
                        intent.putExtra("title", details[0]);
                        intent.putExtra("url", details[1]);
                        startActivity(intent);
            }
        }
    });

And then, the loop just could be used to setOnClickButtonListener(listener); But sure, you must define this listener as the code above.

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