Android Linear Layout Weight Programmatically

Use new LinearLayout.LayoutParams(int width, int height, float weight) to set weights when setting layout params to the subviews

Here its the solution

    LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(0, 100);
    lp.weight = 1;

See Full Solution

LinearLayout ll1, ll2, ll3;
    /* Find these LinearLayout by ID 
     i.e ll1=(LinearLayout)findViewById(R.id.ll1);
     */

    LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(0, 100);
    lp.weight = 1;
    ll1.setLayoutParams(lp);
    ll2.setLayoutParams(lp);
    ll3.setLayoutParams(lp);

Do this way..

protected void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    txtNote = (LinedEditText) findViewById(R.id.txtNote);
    lnr = (LinearLayout) findViewById(R.id.lnr);
    LinearLayout l1 = new LinearLayout(this);
    LinearLayout l2 = new LinearLayout(this);
    LinearLayout l3 = new LinearLayout(this);
    l1.setBackgroundResource(android.R.color.holo_green_light);
    l2.setBackgroundResource(android.R.color.holo_orange_dark);
    l3.setBackgroundResource(android.R.color.holo_blue_bright);

    LinearLayout.LayoutParams param = new LinearLayout.LayoutParams(0,LinearLayout.LayoutParams.MATCH_PARENT, 1);
    lnr.addView(l1, param);
    lnr.addView(l2, param);
    lnr.addView(l3, param);

}