Recognizing a button from a dynamic view

问题

I have written this code for a dynamic layout where I am using this loop to generate a pair of buttons (this is the part of code where I generate them)

  for(int i = 1; i <= 2 ; i++) {
        Button button1 = new Button(this);
        button1.setTag("age");
        button1.setId(i);
        layout.addView(button1);

        Button button2 = new Button(this);
        button2.setId(i);
        button2.setTag("country");
        button2.setEnabled(false);
        layout.addView(button2);

        button1.setOnClickListener(this);
        button2.setOnClickListener(this);
       }

What I wish to do is if button1 is clicked, button2 should get enabled (initially it is disabled).

This would be a very easy task to do if the buttons were created in xml as then they will have separate R.id.xxxxx names for each, but here I am unable to understand how to detect the other button in the OnClick(View v) method so that I can change if it is enabled or not, I have tried to add the tag for each button so that I have another parameter to recognize the buttons but I have no idea how to recognize the other button with the view information of the clicked button1.

回答1:

I assume that you are using the button tags in your click processing. To keep the tag data and add the needed wiring between buttons, you can create a data structure that would serve as a tag:

static class ButtonTag {
    String buttonType;
    Button partner;
    ButtonTag(String type, Button button) {
        buttonType = type;
        partner = button;
    }
}

Then you could reorganize your setup code:

for(int i = 1; i <= 2 ; i++) {
    Button button1 = new Button(this);
    button1.setId(i);
    layout.addView(button1);

    Button button2 = new Button(this);
    button2.setId(i);
    button2.setEnabled(false);
    button1.setTag(new ButtonTag("age", button2));
    button2.setTag(new ButtonTag("country", button1));
    layout.addView(button2);
}

The click processing will obviously need to be changed to cast getTag() to a ButtonTag instead of a String.

If you don't need the "age" and "country" information to distinguish button types, just set each button as the tag for the other.

EDIT:

With the latter scheme, here's how you would use this in a click listener:

public void onClick(View v) {
    Object tag = v.getTag();
    if (tag instanceof Button) {
        Button btn = (Button) tag;
        btn.setEnabled(true);
        v.setEnabled(false);
    }
}

If you needed the "age" and "country" part of the tag for other reasons, the code would be only a little different:

public void onClick(View v) {
    Object tag = v.getTag();
    if (tag instanceof ButtonTag) {
        ButtonTag bTag = (ButtonTag) tag;
        bTag.partner.setEnabled(true);
        v.setEnabled(false);
    }
}

回答2:

I got a solution to the problem after referring to this question here ( find button by ID or TAG ), it solves the problem I was facing as such !

public class DynmaicViewExperimentActivity extends Activity implements OnClickListener{

List<Button> buttons;

@Override
public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        buttons = new ArrayList<Button>();
        setDynamicContentViewOfThisPage();
    }

public void onClick(View v) {
    // TODO Auto-generated method stub
    int buttonType = 0;
    if (v.getTag()=="age")
            buttonType = 1;
    else if (v.getTag()=="country")
            buttonType = 2;
    switch (buttonType) {
        case 1:
            for(Button b: buttons) {
                if(b.getId() == v.getId() && b.getTag().equals("country")){
                    b.setEnabled(true);
                    v.setEnabled(false);
                    }
        case 2:
            for(Button b: buttons) {
                if(b.getId() == v.getId() && b.getTag().equals("age")){
                    b.setEnabled(true);
                    v.setEnabled(false);
                    }
                }
            }
        }


private void setDynamicContentViewOfThisPage() {
    // Defining the Scroll View and the LinearLayout
    ScrollView sv = new ScrollView(this);
    LinearLayout l = new LinearLayout(this);
    l.setOrientation(LinearLayout.VERTICAL);
    sv.addView(l);

                                for(int i = 1; i <= 2 ; i++) {

                                  Button button1 = new Button(this);
                                  button1.setId(i);
                                  button1.setTag("age");
                                  buttons.add(button1);
                                  l.addView(button1);

                                  Button button2 = new Button(this);
                                  button2.setId(i);
                                  button2.setTag("country");
                                  buttons.add(button2);
                                  l.addView(button2);

                                  button.setOnClickListener(this);
                                  button2.setOnClickListener(this);

    // Set the content View to this
        this.setContentView(sv);
    }
   }
 }

来源：https://stackoverflow.com/questions/10890100/recognizing-a-button-from-a-dynamic-view