List drag sorting implementation code based on JQuery

Requirements

Drag sorting, as you can imagine from the name, is to press and hold a row of data and drag it to the desired sorting position, and save the new sorting queue.

Thoughts

First create an anchor point for the list row, bind the mousedown and mouseup events, when the mouse moves to the position you want to insert, move the object row to the target row, and then sort all the rows it passes.

The idea is very simple, but there are still several issues to pay attention to

1. The position to which you move can be regarded as the position to be inserted into the target row.
2. When moving out of the top and bottom, it is judged as the first and last.
3. Processing of moving up and moving down

Solution

About the event

The mouse press and release events in Javascript are onmousedown and onmouseup. In JQuery, they are mousedown and mouseup. Therefore, mousedown and mouseup are used here

First of all, you need to know how many lines there are in the interface and how high each line is, because you need to judge the movement distance of the mouse

Copy codeThe code is as follows:

var tbodyHeight=setting.frame.outerHeight(); //setting.frame, parent object
var lineNum=$("." setting.dgLine) .length; //setting.dgLine, classname of each line
var lineHeight=Math.ceil(tbodyHeight/lineNum);

All you need to do is get lineNum (the number of lines). In addition to calculating the line height, another purpose is to use index() to move the line to the target position through the sequence index value

When the mousedown event is triggered, it is necessary to start calculating the distance of the mouse movement, which is used to determine where the line should be moved

Copy code The code is as follows:

dgid=$(this).attr(setting.id ); //The ID of the mobile row, setting.id, is the name used to mark the ID in each row 
thisIndex=$("#" setting.linePre dgid).index(); //The index of the row, setting .linePre, each line ID is off
thisLineTop=$("#" setting.linePre dgid).offset().top; //The top value of this line
topDistance=thisIndex*lineHeight; //This line The distance from the top of the first line
downDistance=(lineNum-thisIndex-1)*lineHeight; //The distance between this line and the bottom of the last line

dgid is mainly used to distinguish the identifier of each line. The general list is output by the program loop. Without such an ID, it is impossible to tell which line is which. Therefore, in HTML, You need to define a person to store the ID. The program uses attr to get this value, ensuring that each row has its own unique value.

thisLineTop is mainly used to calculate the height based on the mouse movement position, and then determine which line it has moved to based on the line height and index value. Another function is to determine whether the moving anchor point is pressed. If there is a value, it means yes, and the subsequent mouseup is established. If there is no value, it means the anchor point is not pressed, and mouseup does not perform any operation. Why do this? Because no matter where you click the mouse on the page, the mouseup event will be triggered. If there is no judgment, it will continue to execute, which will cause some problems.

topDistance and downDistance are used to determine whether the mouse has moved out of the list. If it has been removed, that is, the distance the mouse moves is greater than topDistance or downDistance, it can be judged that it needs to be moved to the first or last row.

The mousedown event mainly does these few things. Of course, for the sake of effect, you can also add some things

Copy code The code is as follows:

$("#" setting.linePre dgid).css ('background',setting.lineHighlight); //Highlight mobile lines
var left=e.pageX 20;
var top=e.pageY;
dg_tips(left,top); //Create A prompt layer
$('body').css('cursor','move'); //Change the mouse gestures of the page
$("body").disableSelection(); //Disable pressing Select the page element when the mouse is moved behind the mouse 
setting.frame.mousemove(function(e){ //Let the prompt layer follow the mouse movement
$("#dgf").css({"left":e. pageX setting.tipsOffsetLeft 'px',"top":e.pageY 'px'});
});

The purpose of these is just to make the operation more effective. For example, highlighting a row is to let the user know which row they are operating on. The prompt layer works the same way.

Regarding disabling selection, .disableSelection(); this is a method included in jQuery_UI. If you are using jQuery_UI, you can use it directly. If not, you can do this

Copy code The code is as follows:

$('body').each(function() {                                                                               select':'none',
 '-webkit-user-select':'none',
 'user-select':'none'
 }).each(function() {
 this.onselectstart = function() { return false; };
 });
});

Cancel prohibited selection

Copy code The code is as follows:

$('body').each(function() { ',

 'user-select':''
 });
});

Considering versatility, .disableSelection();
 will not be used in the following code.

Okay, here is the mouseup event. The mouseup event here is bound to the body, because if the mouseup is only bound to the anchor point, when the mouse moves out of the anchor point and then releases the mouse, you will find that the mouseup event will not be executed because it will think It is a mouseup of other objects. Therefore, the safest way is to use $('body').mouseup. Basically there will be no problems.

After mouseup is triggered, you must first determine whether thisLineTop has a value to prevent meaningless event execution. Then determine whether the distance moved by the mouse is positive or negative, that is, moving up or down.

var moveDistance=e.pageY-thisLineTop;

Do different processing according to different directions

Copy code

The code is as follows:if(moveDistance<0){ if( thisIndex!=0){ moveDistance=Math.abs(moveDistance); //When it is a negative number, take the absolute value

if(moveDistance>lineHeight/2){ //Judge whether the moving distance exceeds the line height 1/2

 if(moveDistance>topDistance){ //If the moving distance is greater than the distance from the row to the top edge
 focusIndex=0;
 }else{
 focusIndex=thisIndex-Math.ceil( moveDistance/lineHeight);
 }
 $("." setting.dgLine).eq(focusIndex).before($("#" setting.linePre dgid));//Insert the line into the target position
 }
 }
}else{
 if(thisIndex!=lineNum-1){
 if(moveDistance>lineHeight/2 lineHeight){
 if(moveDistance>downDistance){
 focusIndex=lineNum-1;
 }else{
 focusIndex=thisIndex Math.ceil(moveDistance/lineHeight)-1;
 }
 $("." setting.dgLine).eq( focusIndex).after($("#" setting.linePre dgid));
 }
 }
}




The reason why it is judged whether the movement distance exceeds 1/2 of the row height is because if it only moves a small point, it can be regarded as not moving. When calculating the target index value, Math.ceil is used, and the carry is the most. When the moving distance is greater than 0, the carry is -1, because it is downward. 


Moving up and moving down use different insertion methods, before and after. You can try to think about why before and after are used. 

After moving, you still need to remove the effect used when pressing the mouse

Copy code

The code is as follows:$("#dgf").remove(); //Remove the prompt layer$("#" setting.linePre dgid).css('background','');//Convert the highlighted line to normaldgid='';// Leave the ID value of the mobile line empty

thisLineTop=0;//Change the Top value of the mobile line to 0

$('body').css('cursor','default');//Change the mouse gesture is the default 

Basically this is the situation, the main problem is in handling movement and determining where to insert. Everything else is very simple. 

The complete package program is given below, including the update data part

Copy code

The code is as follows:

/*
*
* DragList.js
* @author fuweiyi
*
*/
(function($){
$.fn.DragList=function(setting){
  var _setting = {
   frame : $(this),
   dgLine : 'DLL',
   dgButton : 'DLB',
   id : 'action-id',
   linePre : 'list_',
   lineHighlight : '#ffffcc',
   tipsOpacity : 80,
   tipsOffsetLeft : 20,
   tipsOffsetTop : 0,
   JSONUrl : '',
   JSONData : {},
   maskLoaddingIcon : '',
   maskBackgroundColor : '#999',
   maskOpacity : 30,
   maskColor : '#000',
   maskLoadIcon:'',
  };
  var setting = $.extend(_setting,setting);

  var dgid='',thisIndex,thisLineTop=0,topDistance,downDistance;
  var tbodyHeight=setting.frame.outerHeight();
  var lineNum=$("."+setting.dgLine).length;
  var lineHeight=Math.ceil(tbodyHeight/lineNum);

  $("."+setting.dgButton).mousedown(function(e){
   dgid=$(this).attr(setting.id);
   thisIndex=$("#"+setting.linePre+dgid).index();
   var left=e.pageX+20;
   var top=e.pageY;
   thisLineTop=$("#"+setting.linePre+dgid).offset().top;
   topDistance=thisIndex*lineHeight;
   downDistance=(lineNum-thisIndex-1)*lineHeight;
   $("#"+setting.linePre+dgid).css('background',setting.lineHighlight);

   dg_tips(left,top);
   $('body').css('cursor','move');
   unselect();
   setting.frame.mousemove(function(e){
    $("#dgf").css({"left":e.pageX+setting.tipsOffsetLeft+'px',"top":e.pageY+'px'});
   });
  });

  $('body').mouseup(function(e){
   if(thisLineTop>0){
    var moveDistance=e.pageY-thisLineTop;
    if(moveDistance<0){
if(thisIndex!=0){
moveDistance=Math.abs(moveDistance);
if(moveDistance>lineHeight/2){
       if(moveDistance>topDistance){
        focusIndex=0;
       }else{
        focusIndex=thisIndex-Math.ceil(moveDistance/lineHeight);
       }
       $("."+setting.dgLine).eq(focusIndex).before($("#"+setting.linePre+dgid));
       dg_update(thisIndex,focusIndex);
      }
     }
    }else{
     if(thisIndex!=lineNum-1){
      if(moveDistance>lineHeight/2+lineHeight){
       if(moveDistance>downDistance){
        focusIndex=lineNum-1;
       }else{
        focusIndex=thisIndex+Math.ceil(moveDistance/lineHeight)-1;
       }
       $("."+setting.dgLine).eq(focusIndex).after($("#"+setting.linePre+dgid));
       dg_update(thisIndex,focusIndex);
      }
     }
    }
    $("#dgf").remove();
    $("#"+setting.linePre+dgid).css('background','');
    dgid='';
    thisLineTop=0;
    $('body').css('cursor','default');
    onselect();
   }
  });

  function dg_update(thisIndex,focusIndex){
   dg_mask();
   var start=thisIndex var end=thisIndex var ids='',vals='';
for(var i=start;i<=end;i++){
ids+=i==start?$("."+setting.dgLine).eq(i).attr(setting.id):','+$("."+setting.dgLine).eq(i).attr(setting.id);
vals+=i==start?i:','+i;
}
$.getJSON(setting.JSONUrl,{'do':'changeorders','ids':ids,'vals':vals},function(d){
$("#dg_mask").remove();
});
}

function dg_mask(){
var W=setting.frame.outerWidth();
var H=setting.frame.outerHeight();
var top=setting.frame.offset().top;
var left=setting.frame.offset().left;
var mask="