Scroll from left to right in scrollview using specific buttons.

Hi..

I've a scrollView and added many images to it. It scrolls finely. Now I want to do it using buttons, so that i can scroll over individual images from let to right and vice versa. Here is my code.

controller

function lscroll (e) {
  $.pictureview.scrollTo(0,0 );
}
function rscroll (e) {
    var pictureviewwidth = Ti.Platform.displayCaps.platformWidth*90/100;
    $.pictureview.scrollTo(0, pictureviewwidth );
}
 
 
function pictureshow () {
 
    var leftPlace = 10;
    for(var i =0;i< pictures.length;i++){
        var img = pictures[0];
        length = 70
        var images = Ti.UI.createImageView({
            image: img,
            width:length,
            left:leftPlace,
            height:length,
        });
        $.pictureview.add(images);
        leftPlace += length+10;
    }
 
}

View

<View id="pictures">
    <Button id="leftscroll" onClick="lscroll"></Button>
        <ScrollView id="pictureview"></ScrollView>
        <Button id="rightscroll" onClick="rscroll"></Button>
</View>

Style

"#pictureview":{
 
        scrollType:'horizontal',
        top:'5dp', bottom: '5dp',
        height: '40dp',
        width: '89%',
        backgroundColor: '#585858',
        contentWidth:'auto',
        showHorizontalScrollIndicator:true,
        showVerticalScrollIndicator:true
}

Also I'd like to know how to align the contents(images) to center of scrollview if there is only one or two images.

Please help me.