Question

I’m just starting out in java & android.

Below is my code, to add all the buttons in an activity then hide them.
Question: is their anyway to automatically add all the buttons in the activity without having to list each of them, I have looked at listA.addall but didn’t understand how to add the activity as the collection.

The rational for this is I may wish to change the number of buttons and still have the code work.

public void setup2(){
    List<Button> listA = new ArrayList<Button>();

    listA.add((Button)findViewById(R.id.button1));
    listA.add((Button)findViewById(R.id.button2));
    listA.add((Button)findViewById(R.id.button3));
    listA.add((Button)findViewById(R.id.button4));
    listA.add((Button)findViewById(R.id.button5));

    for (Button item : listA)
        item.setVisibility(View.INVISIBLE);
}

Answer 1

Assuming that your buttons are in a view group e,g, LinearLayout:

for (int i = 0; i < layout.getChildCount(); i++) {
        View v = layout.getChildAt(i);
        if (v.getClass() == Button.class) {
            listA.add(v);
        }
} 

layout is a reference to the layout containing the buttons.

This simply iterates over each child view in the layout, compares it’s class type with Button and adds it to your collection if it is.