How to lay out Views in RelativeLayout programmatically?

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I'm trying to achieve the following programmatically (rather than declaratively via XML):

<RelativeLayout...>
   <TextView ...
      android:id="@+id/label1" />
   <TextView ...
      android:id="@+id/label2"
      android:layout_below: "@id/label1" />
</RelativeLayout>

In other words, how do I make the second TextView appear below the first one, but I want to do it in code:

RelativeLayout layout = new RelativeLayout(this);
TextView label1 = new TextView(this);
TextView label2 = new TextView(this);
...
layout.addView(label1);
layout.addView(label2);
setContentView(layout);

Update:

Thanks, TreeUK. I understand the general direction, but it still doesn't work - "B" overlaps "A". What am I doing wrong?

RelativeLayout layout = new RelativeLayout(this);
TextView tv1 = new TextView(this);
tv1.setText("A");

TextView tv2 = new TextView(this);
tv2.setText("B");
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(
        RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.FILL_PARENT);
lp.addRule(RelativeLayout.RIGHT_OF, tv1.getId());

layout.addView(tv1);        
layout.addView(tv2, lp);
9 Answers

From what I've been able to piece together, you have to add the view using LayoutParams.

LinearLayout linearLayout = new LinearLayout(this);

RelativeLayout.LayoutParams relativeParams = new RelativeLayout.LayoutParams(
        LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
relativeParams.addRule(RelativeLayout.ALIGN_PARENT_TOP);

parentView.addView(linearLayout, relativeParams);

All credit to sechastain, to relatively position your items programmatically you have to assign ids to them.

TextView tv1 = new TextView(this);
tv1.setId(1);
TextView tv2 = new TextView(this);
tv2.setId(2);

Then addRule(RelativeLayout.RIGHT_OF, tv1.getId());

Cut the long story short: With relative layout you position elements inside the layout.

  1. create a new RelativeLayout.LayoutParams

    RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(...)
    

    (whatever... fill parent or wrap content, absolute numbers if you must, or reference to an XML resource)

  2. Add rules: Rules refer to the parent or to other "brothers" in the hierarchy.

    lp.addRule(RelativeLayout.BELOW, someOtherView.getId())
    lp.addRule(RelativeLayout.ALIGN_PARENT_LEFT)
    
  3. Just apply the layout params: The most 'healthy' way to do that is:

    parentLayout.addView(myView, lp)
    

Watch out: Don't change layout from the layout callbacks. It is tempting to do so because this is when views get their actual sizes. However, in that case, unexpected results are expected.

This approach with ViewGroup.MarginLayoutParams worked for me:

RelativeLayout myLayout = (RelativeLayout) findViewById(R.id.my_layout);

TextView someTextView = ...

int leftMargin = Util.getXPos();
int topMargin = Util.getYPos();

RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(
    new ViewGroup.MarginLayoutParams(
        RelativeLayout.LayoutParams.WRAP_CONTENT,
        RelativeLayout.LayoutParams.WRAP_CONTENT));

lp.setMargins(leftMargin, topMargin, 0, 0);

myLayout.addView(someTextView, lp);
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