Question

So I have a LinearLayout in horizontal mode which I add buttons to at random times in code and I like them all to fill up the space equally.

This is my current code so far:

layoutParams = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                                             ViewGroup.LayoutParams.WRAP_CONTENT);
layoutParams.gravity = Gravity.FILL;

and I add it to my view here:

linearLayout.addView(button, layoutParams);

All it does is add the buttons as if it was wrap_content and not expanding their width to fill up the available space as in the buttons look left justified.

I also have tried linearLayout.setGravity(Gravity.FILL_HORIZONTAL); and

linearLayout.setWeightSum(++weightSum);
linearLayout.addView(button, layoutParams);

where layoutParams in this case is:

layoutParams = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                                             ViewGroup.LayoutParams.WRAP_CONTENT, 1);

I also tried setting the layout width to zero per answers to other questions.

Am I missing another technique?

Edit: I figured it out, I forgot to set the width of the LinearLayout to match_parent instead of wrap_content.

Answer 1

Button‘s background has “margins” so they will always have gaps even if there’s no space between buttons. You have to change background to your own image which doesn’t have these margins.

EDIT: You should use weights for buttons.

    LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
            0, LayoutParams.WRAP_CONTENT);
    params.weight = 1;
    for( int i = 0; i < 5; ++i) {
        Button button = new Button(this);
        button.setText("Button" + (i + 1));
        linearLayout.addView(button, params);
    }