Android以编程方式设置按钮布局

Question

Hi I'm trying to load a button into a view pager and i have it loading in but it's currently filling the entire screen i would like it it to wrap content to its exact size and then position it in the middle of the screen. i have tried to set layoutparams for the button but when i run the app it still fills parent. does anyone know how to programmatically set layout and position of a button?

heres what i have tried so far

@Override
        public Object instantiateItem(View collection, int position) {

            RelativeLayout.LayoutParams rel_btn = new RelativeLayout.LayoutParams(
            LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
            rel_btn.addRule(RelativeLayout.CENTER_VERTICAL);
            rel_btn.addRule(RelativeLayout.CENTER_HORIZONTAL);
            rel_btn.height = 60;
            rel_btn.width = 60;
            Button tv = new Button(cxt);
            tv.setLayoutParams(rel_btn);
            tv.setText("League " + (position+1));
            tv.setTextColor(Color.WHITE);
            tv.setTextSize(30);
            tv.setBackgroundDrawable(getResources().getDrawable(R.drawable.ls_level_eng1));

            ((ViewPager) collection).addView(tv,0);

            return tv;
        }

Answer 1

Is there any particular reason you're doing this via code? You could simply inflate a layout and use the Layout Editor to help you adjust your Button . That way you won't be guessing so much.

public Object instantiateItem(View collection, int position) {

final LayoutInflater mLayoutInflater = (LayoutInflater) collection.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);

final View view = inflater.inflate(R.layout.your_layout, null);

((ViewPager) collection).addView(view, 0);

return view;

In that case, you need to do this. I added notes within the code.

    public Object instantiateItem(View collection, int position) {

    // Create your LayoutParams
    final RelativeLayout.LayoutParams rel_btn = new RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.WRAP_CONTENT,
            RelativeLayout.LayoutParams.WRAP_CONTENT);

    // Add your rules
    rel_btn.addRule(RelativeLayout.CENTER_VERTICAL);
    rel_btn.addRule(RelativeLayout.CENTER_HORIZONTAL);

    // And anything extra
    rel_btn.height = 60;
    rel_btn.width = 60;

    // Create a new RelativeLayout for your RelativeLayout.LayoutParams
    RelativeLayout relativeLayout = new RelativeLayout(MainActivity.this);

    // Give your RelativeLayout LayoutParams
    relativeLayout.setLayoutParams(rel_btn);

    // Create your Button
    Button tv = new Button(MainActivity.this);
    tv.setText("League " + (position + 1));
    tv.setTextColor(Color.WHITE);
    tv.setTextSize(30);
    tv.setLayoutParams(rel_btn);
    // You don't need to use setBackgroundDrawable if you're only
    // grabbing a Resource
    tv.setBackgroundResource(R.drawable.ls_level_eng1);

    // Add your Button to your RelativeLayout
    relativeLayout.addView(tv);

    // Return your RelativeLayout
    ((ViewPager)collection).addView(relativeLayout, 0);
    return relativeLayout;
}