====== Layout Children ======
DroidScript's [[built_in:layouts|Layout]] comes complete with methods ChildToFront and GetChildOrder but some people seem to think it is missing a couple of methods, so I offer these functions in the hope that they may be useful.
===== ChildToBack =====
<code javascript childToBack.js>
function childToBack(layt, obj){
  if( layt.GetChildOrder( obj ) > 0 ){
    layt.RemoveChild(obj);
    layt.AddChild(obj,0);
  }
}
</code>
===== setChildOrder =====
<code javascript setChildOrder.js>
function setChildOrder(layt, obj, order){
  var tst = layt.GetChildOrder( obj );
  if ((tst >= 0) && (tst != order)){
    layt.RemoveChild(obj);
    layt.AddChild(obj,order);
  }
}
</code>
===== getChildren =====
<code javascript getChildren.js>
function getChildren(layt){ 
  //takes a layout as an argument
  var children = []; 
  var obj, order;
  //loop through all controls
  for (var id in _map) { 
    obj = _map[id]
    //check if control is on our layout
    order = layt.GetChildOrder( obj );
    if( order > -1 ) { 
      //got one!
      //zorder propery wll persist until getChildren called again
      //or manually overwritten by coder
      obj.zorder = order;
      children.push( obj ); 
    } 
  } 
  children.sort(function (a, b) { return a.zorder - b.zorder});
  return children; 
} 
</code>
===== clearLayout =====
<code JavaScript clearlayout.js>
function clearLayout(layt)
{
  //takes a layout as an argument 
  var allobjs = app.GetObjects();
  var obj, order; 
  //loop through all controls 
  for (var id in allobjs) 
  { 
      obj = allobjs[id] 
      //check if control is on our layout 
      order = layt.GetChildOrder( obj ); 
      if( order > -1 ) 
      { 
          //got one! 
          layt.DestroyChild( obj ); 
      } 
   }
} 
</code>
===== Sample app =====
This sample shows how to use the childToBack function
<code javascript toback.js>
//Called when application is started.
function OnStart()
{
    app.SetOrientation("Portrait");
    //Create a layout with objects vertically centered.
    lay = app.CreateLayout( "Linear", "VCenter,FillXY" );    
    
    //Create an absolute layout so we can position objects.
    layAbs = app.CreateLayout( "Absolute" );    
    lay.AddChild( layAbs );

    //Create first image.
    img1 = app.CreateImage( null, 0.5, 0.3 );
    img1.SetColor("#66000088");
    img1.SetOnTouchDown(img_OnTouch);
    layAbs.AddChild( img1 );
    
    //Create second image.
    img2 = app.CreateImage( null, 0.5, 0.3 );
    img2.SetColor("#66880000");
    img2.SetPosition( 0.1,0.1 );
    img2.SetOnTouchDown(img_OnTouch);
    layAbs.AddChild( img2  );
 
    //Create third image in middle
    img3 = app.CreateImage( null, 0.5, 0.3 );
    img3.SetColor("#66008800");
    img3.SetPosition( 0.2,0.2 );
    img3.SetOnTouchDown(img_OnTouch);
    layAbs.AddChild( img3,1 );
    
    //Add layout to app.    
    app.AddLayout( lay );
}

//Called when user touches image
function img_OnTouch(){
  childToBack(layAbs, this)
}

function childToBack(layt, obj){
  if( layt.GetChildOrder( obj ) > 0 ){
    layt.RemoveChild(obj);
    layt.AddChild(obj,0);
  }
}

</code>