I have a table of list items (questions) and I want to be able to re-arrange them. See screenshot.
Currently, on the button down press, I can get the current binding context and I am getting that sequence property (001). What I want to be able to do is also be able to get the path of the next list items binding context (002 in this case).
Current code...
// Move Question Down
onQuestionMoveDown: function (oEvent) {
// Get binding context
var source = oEvent.getSource().getBindingContext("view");
var path = source.getPath();
var object = source.getModel().getProperty(path);
var currentQuestionSequence = object.Sequence;
MessageToast.show("Current # " + currentQuestionSequence);
}
Then once I have that I can sort my updates logic.
A possible solution could be that you have an order value on your model and you update that order when the user clicks on the button.
If the list is sorted by that value you will achieve what you're looking for.
The items should be bound to the table via list binding, and so the data set would be an Array, the path for each line will be like ".../itemSet/0, .../itemSet/1, ...". So possible solution could be:
function getNextItem(oItem){
var oContext = oItem.getBindingContext("view"), // assumpe the model name is view
sPath = oContext.getPath(),
sSetPath = sPath.substr(0, sPath.lastIndexOf("/")),
iMaxLen = oContext.getProperty(sSetPath).length,
iCurIndex = parseInt(sPath.substr(sPath.lastIndexOf("/")+1));
// If it's already reach to be bottom, return undefined
return iCurIndex < iMaxLen -1 ? oContext.getProperty(sSetPath + "/" + ++iCurIndex) : undefined;
}
Regards,
Marvin
Let's suppose: a page with some dynamically generated checkboxes outside of a form element.
After the user has checked some of the checkboxes, I would love to append all those checkboxes (either checked or unchecked) into the form element so that when the user click the "submit" button, the form takes into account the checkboxes, their ids, names, data-names and their status (checked or unchecked). Is that possible ?
I have tried a codpen here: https://codepen.io/anthonysalamin/pen/ZxvZpP?editors=1010 but was unsuccessful sofar.
The jQuery code:
//insert all checkbox input elements into the form id="reservation"
$("#reservation").submit(function(evt) {
// should append all checkboxes to the form
$("<input type='checkbox' />").append("#reservation");
});
Screenshot of my codpen here
.append() expects textual HTML as input. You have passed the id selector of #reservation instead. To effectively add the checkboxes to the form in the submit event you could do this:
// wait for DOM to be ready
$( document ).ready(function() {
//define the variable for all checkboxes on the page
var allCheckboxes = $("input:checkbox[class=outsider]");
//calls the append function on form submission
$("#form-element").submit(function(event) {
//insert all checkbox type elements into the form with id="form-element"
var checkHTML = "";
for(var checkboxIndex = 0; checkboxIndex < allCheckboxes.length; checkboxIndex++) {
checkHTML += allCheckboxes[checkboxIndex].outerHTML;
}
$("#form-element").append(checkHTML);
});
});
However, it is highly probable that your intention differs from the behavior. Problems with the code:
your checkboxes have ids and if we clone them, then you will have duplicate ids. Since an HTML cannot be valid if there are duplicate ids, cloning the checkboxes with ids will result in invalid HTML
checked state is not copied, so you will need to mine that value out and put it to the newly created checkboxes
Code dealing with all these problems:
// wait for DOM to be ready
$( document ).ready(function() {
//define the variable for all checkboxes on the page
var allCheckboxes = $("input:checkbox[class=outsider]");
//calls the append function on form submission
$("#form-element").submit(function(event) {
//insert all checkbox type elements into the form with id="form-element"
var checkHTML = "";
var checked = [];
for(var checkboxIndex = 0; checkboxIndex < allCheckboxes.length; checkboxIndex++) {
checked.push($(allCheckboxes[checkboxIndex]).prop('checked'));
allCheckboxes[checkboxIndex].remove();
checkHTML += allCheckboxes[checkboxIndex].outerHTML;
}
$("#form-element").append(checkHTML);
allCheckboxes = $('input:checkbox[class=outsider]');
console.log(checked);
for (var checkboxIndex = 0; checkboxIndex < allCheckboxes.length; checkboxIndex++) {
$(allCheckboxes[checkboxIndex]).prop('checked', checked[checkboxIndex]);
}
event.preventDefault();
});
});
So you can solve your problem by cloning the checkboxes if you handle all the problems. Alternatively, you could use a hidden input where you could put key-value pairs, where the keys will be checkbox ids and values will be their corresponding checked states and put those values into the hidden input at the submit handler. If you do not specifically intend to visually put the checkboxes into the form and you are satisfied with correct handling of data, then putting the JSON value of key-value pairs into the value of a hidden input is superior in comparison of copying checkboxes into the form, but these are only nuances.
I'm trying to test out Firebase to allow users to post comments using push. I want to display the data I retrieve with the following;
fbl.child('sell').limit(20).on("value", function(fbdata) {
// handle data display here
}
The problem is the data is returned in order of oldest to newest - I want it in reversed order. Can Firebase do this?
Since this answer was written, Firebase has added a feature that allows ordering by any child or by value. So there are now four ways to order data: by key, by value, by priority, or by the value of any named child. See this blog post that introduces the new ordering capabilities.
The basic approaches remain the same though:
1. Add a child property with the inverted timestamp and then order on that.
2. Read the children in ascending order and then invert them on the client.
Firebase supports retrieving child nodes of a collection in two ways:
by name
by priority
What you're getting now is by name, which happens to be chronological. That's no coincidence btw: when you push an item into a collection, the name is generated to ensure the children are ordered in this way. To quote the Firebase documentation for push:
The unique name generated by push() is prefixed with a client-generated timestamp so that the resulting list will be chronologically-sorted.
The Firebase guide on ordered data has this to say on the topic:
How Data is Ordered
By default, children at a Firebase node are sorted lexicographically by name. Using push() can generate child names that naturally sort chronologically, but many applications require their data to be sorted in other ways. Firebase lets developers specify the ordering of items in a list by specifying a custom priority for each item.
The simplest way to get the behavior you want is to also specify an always-decreasing priority when you add the item:
var ref = new Firebase('https://your.firebaseio.com/sell');
var item = ref.push();
item.setWithPriority(yourObject, 0 - Date.now());
Update
You'll also have to retrieve the children differently:
fbl.child('sell').startAt().limitToLast(20).on('child_added', function(fbdata) {
console.log(fbdata.exportVal());
})
In my test using on('child_added' ensures that the last few children added are returned in reverse chronological order. Using on('value' on the other hand, returns them in the order of their name.
Be sure to read the section "Reading ordered data", which explains the usage of the child_* events to retrieve (ordered) children.
A bin to demonstrate this: http://jsbin.com/nonawe/3/watch?js,console
Since firebase 2.0.x you can use limitLast() to achieve that:
fbl.child('sell').orderByValue().limitLast(20).on("value", function(fbdataSnapshot) {
// fbdataSnapshot is returned in the ascending order
// you will still need to order these 20 items in
// in a descending order
}
Here's a link to the announcement: More querying capabilities in Firebase
To augment Frank's answer, it's also possible to grab the most recent records--even if you haven't bothered to order them using priorities--by simply using endAt().limit(x) like this demo:
var fb = new Firebase(URL);
// listen for all changes and update
fb.endAt().limit(100).on('value', update);
// print the output of our array
function update(snap) {
var list = [];
snap.forEach(function(ss) {
var data = ss.val();
data['.priority'] = ss.getPriority();
data['.name'] = ss.name();
list.unshift(data);
});
// print/process the results...
}
Note that this is quite performant even up to perhaps a thousand records (assuming the payloads are small). For more robust usages, Frank's answer is authoritative and much more scalable.
This brute force can also be optimized to work with bigger data or more records by doing things like monitoring child_added/child_removed/child_moved events in lieu of value, and using a debounce to apply DOM updates in bulk instead of individually.
DOM updates, naturally, are a stinker regardless of the approach, once you get into the hundreds of elements, so the debounce approach (or a React.js solution, which is essentially an uber debounce) is a great tool to have.
There is really no way but seems we have the recyclerview we can have this
query=mCommentsReference.orderByChild("date_added");
query.keepSynced(true);
// Initialize Views
mRecyclerView = (RecyclerView) view.findViewById(R.id.recyclerView);
mManager = new LinearLayoutManager(getContext());
// mManager.setReverseLayout(false);
mManager.setReverseLayout(true);
mManager.setStackFromEnd(true);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setLayoutManager(mManager);
I have a date variable (long) and wanted to keep the newest items on top of the list. So what I did was:
Add a new long field 'dateInverse'
Add a new method called 'getDateInverse', which just returns: Long.MAX_VALUE - date;
Create my query with: .orderByChild("dateInverse")
Presto! :p
You are searching limitTolast(Int x) .This will give you the last "x" higher elements of your database (they are in ascending order) but they are the "x" higher elements
if you got in your database {10,300,150,240,2,24,220}
this method:
myFirebaseRef.orderByChild("highScore").limitToLast(4)
will retrive you : {150,220,240,300}
In Android there is a way to actually reverse the data in an Arraylist of objects through the Adapter. In my case I could not use the LayoutManager to reverse the results in descending order since I was using a horizontal Recyclerview to display the data. Setting the following parameters to the recyclerview messed up my UI experience:
llManager.setReverseLayout(true);
llManager.setStackFromEnd(true);
The only working way I found around this was through the BindViewHolder method of the RecyclerView adapter:
#Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
final SuperPost superPost = superList.get(getItemCount() - position - 1);
}
Hope this answer will help all the devs out there who are struggling with this issue in Firebase.
Firebase: How to display a thread of items in reverse order with a limit for each request and an indicator for a "load more" button.
This will get the last 10 items of the list
FBRef.child("childName")
.limitToLast(loadMoreLimit) // loadMoreLimit = 10 for example
This will get the last 10 items. Grab the id of the last record in the list and save for the load more functionality. Next, convert the collection of objects into and an array and do a list.reverse().
LOAD MORE Functionality: The next call will do two things, it will get the next sequence of list items based on the reference id from the first request and give you an indicator if you need to display the "load more" button.
this.FBRef
.child("childName")
.endAt(null, lastThreadId) // Get this from the previous step
.limitToLast(loadMoreLimit+2)
You will need to strip the first and last item of this object collection. The first item is the reference to get this list. The last item is an indicator for the show more button.
I have a bunch of other logic that will keep everything clean. You will need to add this code only for the load more functionality.
list = snapObjectAsArray; // The list is an array from snapObject
lastItemId = key; // get the first key of the list
if (list.length < loadMoreLimit+1) {
lastItemId = false;
}
if (list.length > loadMoreLimit+1) {
list.pop();
}
if (list.length > loadMoreLimit) {
list.shift();
}
// Return the list.reverse() and lastItemId
// If lastItemId is an ID, it will be used for the next reference and a flag to show the "load more" button.
}
I'm using ReactFire for easy Firebase integration.
Basically, it helps me storing the datas into the component state, as an array. Then, all I have to use is the reverse() function (read more)
Here is how I achieve this :
import React, { Component, PropTypes } from 'react';
import ReactMixin from 'react-mixin';
import ReactFireMixin from 'reactfire';
import Firebase from '../../../utils/firebaseUtils'; // Firebase.initializeApp(config);
#ReactMixin.decorate(ReactFireMixin)
export default class Add extends Component {
constructor(args) {
super(args);
this.state = {
articles: []
};
}
componentWillMount() {
let ref = Firebase.database().ref('articles').orderByChild('insertDate').limitToLast(10);
this.bindAsArray(ref, 'articles'); // bind retrieved data to this.state.articles
}
render() {
return (
<div>
{
this.state.articles.reverse().map(function(article) {
return <div>{article.title}</div>
})
}
</div>
);
}
}
There is a better way. You should order by negative server timestamp. How to get negative server timestamp even offline? There is an hidden field which helps. Related snippet from documentation:
var offsetRef = new Firebase("https://<YOUR-FIREBASE-APP>.firebaseio.com/.info/serverTimeOffset");
offsetRef.on("value", function(snap) {
var offset = snap.val();
var estimatedServerTimeMs = new Date().getTime() + offset;
});
To add to Dave Vávra's answer, I use a negative timestamp as my sort_key like so
Setting
const timestamp = new Date().getTime();
const data = {
name: 'John Doe',
city: 'New York',
sort_key: timestamp * -1 // Gets the negative value of the timestamp
}
Getting
const ref = firebase.database().ref('business-images').child(id);
const query = ref.orderByChild('sort_key');
return $firebaseArray(query); // AngularFire function
This fetches all objects from newest to oldest. You can also $indexOn the sortKey to make it run even faster
I had this problem too, I found a very simple solution to this that doesn't involved manipulating the data in anyway. If you are rending the result to the DOM, in a list of some sort. You can use flexbox and setup a class to reverse the elements in their container.
.reverse {
display: flex;
flex-direction: column-reverse;
}
myarray.reverse(); or this.myitems = items.map(item => item).reverse();
I did this by prepend.
query.orderByChild('sell').limitToLast(4).on("value", function(snapshot){
snapshot.forEach(function (childSnapshot) {
// PREPEND
});
});
Someone has pointed out that there are 2 ways to do this:
Manipulate the data client-side
Make a query that will order the data
The easiest way that I have found to do this is to use option 1, but through a LinkedList. I just append each of the objects to the front of the stack. It is flexible enough to still allow the list to be used in a ListView or RecyclerView. This way even though they come in order oldest to newest, you can still view, or retrieve, newest to oldest.
You can add a column named orderColumn where you save time as
Long refrenceTime = "large future time";
Long currentTime = "currentTime";
Long order = refrenceTime - currentTime;
now save Long order in column named orderColumn and when you retrieve data
as orderBy(orderColumn) you will get what you need.
just use reverse() on the array , suppose if you are storing the values to an array items[] then do a this.items.reverse()
ref.subscribe(snapshots => {
this.loading.dismiss();
this.items = [];
snapshots.forEach(snapshot => {
this.items.push(snapshot);
});
**this.items.reverse();**
},
For me it was limitToLast that worked. I also found out that limitLast is NOT a function:)
const query = messagesRef.orderBy('createdAt', 'asc').limitToLast(25);
The above is what worked for me.
PRINT in reverse order
Let's think outside the box... If your information will be printed directly into user's screen (without any content that needs to be modified in a consecutive order, like a sum or something), simply print from bottom to top.
So, instead of inserting each new block of content to the end of the print space (A += B), add that block to the beginning (A = B+A).
If you'll include the elements as a consecutive ordered list, the DOM can put the numbers for you if you insert each element as a List Item (<li>) inside an Ordered Lists (<ol>).
This way you save space from your database, avoiding unnecesary reversed data.
I have a form in as3 flash with textfields and radio buttons with their "instance name" all set consecutively such as:
field_1
field_2
field_3
...etc
Is there an easy way in AS3 code to loop over all those fields and get their values in an array? Ideally I'd like a simply loop to get the values (so I can add in a simple popup if a value is missing) and then with the filled array simply post it using URLRequest.
Thanks!
If you want a way that's a little less work and more maintainable (if the amount of text can change in the future or you need to reuse the code on other forms or don't want to bother with instance names), then you could do something like the code below.
Keep in mind this assumes all your text fields are children of the same parent and is in the scope of that parent (so on a frame in the timeline that holds all your text fields)
function validateTextFields(){
var tmpTf:TextField;
var i:int = numChildren;
while(i--){ //iterate through all the display objects on this timeline
tmpTf = getChildAt(i) as TextField;
if(tmpTf){
//now that you have the textfield, you can check for an appropriate value, or send the value to a server, or store it in an array etc.
//check if the value is blank, if so set the background to red
if(tmpTf.text == ""){
tmpTf.background = true;
tmpTf.backgroundColor = 0xFF0000;
}else{
tmpTf.background = false;
}
}
}
}
It sounds like you want to use a for statement. I've also used a multi-dimensional array to store the instance names, and the text that they contain. I like to use the variable _path to define the scope of my code.
var _path = this;
var text_ar:Array = new Array(['instance_1',''],['instance_2',''],['instance_3','']); //instance name, instance text.
for(var i=0; i<ar.length; i++)
{
text_ar[i][1] = _path[text_ar[i][0]].text
}
trace( text_ar[1][1] ); //Traces the text that's entered in instance_1.
I am using jqgrid in my new project.
In a specific case I need to use a select element in the grid. No problem.
I define the colModel and the column for example like (from wiki)
colModel : [
...
{name:'myname', edittype:'select', editoptions:{value:{1:'One',2:'Two'}} },
...
]
But now when I load my data I would prefer the column "myname" to contain the value 1.
This won't work for me instead it has to contain the value "One".
The problem with this is that the text-part of the select element is in my case localized in the business layer where the colModel is dynamically generated. Also the datatype for the entity which generates the data via EF 4 may not be a string. Then I have to find the correct localized text and manipulate the data result so that the column "myname" does not containt an integer which is typically the case but a string instead with the localized text.
There is no option you can use so that when the data contains the value which match an option in the select list then the grid finds that option and presents the text.
Now the grid presents the value as a text and first when I click edit it finds the matching option and presents the text. When I undo the edit it returns to present the value again.
I started to think of a solution and this is what I came up with. Please if you know a better solution or if you know there is a built in option don't hesitate to answer.
Otherwise here is what I did:
loadComplete: function (data) {
var colModel = grid.getGridParam('colModel');
$.each(colModel, function (index, col) {
if (col.edittype === 'select') {
$.each(grid.getDataIDs(), function (index, id) {
var row = grid.getRowData(id);
var value = row[col.name];
var editoptions = col.editoptions.value;
var startText = editoptions.indexOf(value + ':') + (value + ':').length;
var endText = editoptions.indexOf(';', startText);
if (endText === -1) { endText = editoptions.length; }
var text = editoptions.substring(startText, endText);
row[col.name] = text;
grid.setRowData(id, row);
});
}
});
}
It works and I will leave it like this if nobody comes up with a better way.
You should just include additional formatter:'select' option in the definition of the column. See the documentation for more details.