Customizing bootstrap-vue components - bootstrap-vue

Starting a large application with a handful of developers. Using webpack and bootstrap-vue. How would I default the style for <b-card> (and other components). In other words can I default:
<b-card>
to be the equivalent to:
<b-card style="max-width: 40rem;" header-bg-variant="primary" header-text-variant="white">
to make sure we keep our look consistent throughout the whole application.

You can either use SCSS/CSS overrides to control the b-card layout, or extend/wrap the component to default the props you want:
import { BCard } from 'bootstrap-vue'
export default {
name 'MyCard',
// Create as a functional component wrapper
functional: true,
// define our props (borrow from BCard)
props: {
...BCard.props,
},
render(h, { props, data, children }) {
return h(
BCard,
{
props: {
// Pass all props to BCard
...props,
// Override the following prop defaults (if not provided)
headerBgVariant: props.headerBgVariant || 'primary',
headerTextVariant: props.headerBgVariant || 'white'
},
// Pass any additional (optional) attributes down
attrs: data.attrs,
// Set the style
style: {
// merge in any styles manually applied
...data.style,
// Set the max-width if not explicitly set
maxWidth: data.style.maxWidth || '40rem'
}
}
)
}
}
For more info on functional components and render functions, see https://v2.vuejs.org/v2/guide/render-function.html#Functional-Components
For handling more complex data merges with functional components, check out https://github.com/alexsasharegan/vue-functional-data-merge

Related

MUI two AppBar in the same page as component = 'header' and component = 'footer'. How to override styles using createTheme()?

Having two appBars components in the same page is a good approach (one as header and the other one as footer)? Besides, I am using the MUI createTheme to override some styles. I am doing this to override the appBar component.
components: { ...
MuiAppBar: {
styleOverrides: {
root: {
minHeight: '4.375rem',
backgroundColor: appColors.aqua600,
},
},
}, ...
This works fine, but as was wondering how could I override the style of an AppBar that is renders as 'header' and style the other appBar that is rendered as 'footer'
The component usage:
<AppBar
component="header | footer" ...
</AppBar>
I know that can be easily done with CSS, but I was wondering if this can be done using the createTheme from MUI?
It can be done by overriding styles based on props using ownerState.
Overrides based on props
You can pass a callback as a value in each slot of the component's styleOverrides to apply styles based on props.
The ownerState prop is a combination of public props that you pass to the component + internal state of the component.
You can check more on docs.
So, the custom theme for MuiAppBar should be something like this:
components: {
MuiAppBar: {
styleOverrides: {
root: ({ ownerState }) => {
return {
...(ownerState.component === "header" && {
backgroundColor: "#202020"
})
};
}
}
}
}

How to pass a function to custom control

I have a question about custom controls in UI5. Say I want to use a formatter function in the custom control (see the snippet below). A colleague of mine insists that custom control should be as generic as possible (e.g. to be able to specify texts with commas, spaces and newlines in whichever way you need it to be). Thus my idea was to pass formatter function to the custom control. Is it possible and if yes how to do it?
sap.ui.define([
"pr/formatter/Formatter",
"sap/m/Popover",
"sap/m/Text"
], function(Formatter, Popover, Text) {
"use strict";
return Text.extend("pr.control.TextWithPopover", {
metadata: {
aggregations: {
_popover: {
type: "sap.m.Popover",
multiple: false,
visibility: "hidden"
}
}
},
init: function() {
const popover = new Popover({});
this.setAggregation("_popover", popover);
},
setText: function(text) {
if (this.getProperty("text") !== text) {
// How to make it generic?
const formattedText = Formatter.formatCommaListToNewLine(text);
const contentToAdd = new Text({ text: formattedText });
contentToAdd.addStyleClass("popoverContent");
// ...
}
},
renderer: "sap.m.TextRenderer",
});
});
UI5 introduced the standard type "function" to sap/ui/base/DataType in 1.46(Commit) which allows ManagedObject properties to receive functions as their values.
Control
return ControlToExtend.extend("MyControl", {
metadata: {
properties: {
/**
* This function will contain foo and bar as parameters.
* Applications should return xyz.
*/
doSomethingWith: {
type: "function",
},
},
},
// ...
getXYZ: function(/*...*/) {
const doSomethingWith = this.getDoSomethingWith(); // function from the application
if (typeof doSomethingWith == "function") {
const [foo, bar] = [/*...*/];
return doSomethingWith(foo, bar);
} else {
/*default behavior*/;
}
},
});
Application
<MyControl doSomethingWith=".myControllerMethod" /> <!-- or -->
<MyControl doSomethingWith="some.globally.available.function" /> <!-- or -->
<!-- Since 1.69: -->
<MyControl
xmlns:core="sap.ui.core"
core:require="{
'myRequiredFunction': 'mynamespace/myApplicationFunction'
}"
doSomethingWith="myRequiredFunction"
/>
Note: XMLTemplateProcessor (XML-view / -fragment) supports function properties only as of 1.56. (Commit)
myApplicationFunction: function(foo, bar) {
// create and return xyz however the application wants;
},
This way, the control has no hard dependency to the application while keeping the flexibility to allow changing the default output or behavior.
The above option is one of the many solutions to reduce tight couplings in UI5. Another solution would be to add a control property which can be then manipulated by applications via binding and formatter.
Generally, controls (or control libraries) and control consumers (e.g. applications) should be always developed independently; with an interface in between (e.g. MenagedObjectMetadata) and the controls being still open for extensions without disclosing how they're implemented internally.

Can you manipulate the DOM directly while using Preactjs?

I am looking into Preact for my next project.
Since it has no virtual DOM I am wondering if it, like React, prefers you to let the framework manipulate the DOM instead of doing so yourself directly.
Would Preact bump heads with another library that manipulates the DOM such as SVGjs?
Preact is non-destructive when it comes to DOM updates. The official guide already explains how to integrate external DOM manipulations into the preact component:
If using class-based component:
import { h, Component } from 'preact';
class Example extends Component {
shouldComponentUpdate() {
// IMPORTANT: do not re-render via diff:
return false;
}
componentWillReceiveProps(nextProps) {
// you can do something with incoming props here if you need
}
componentDidMount() {
// now mounted, can freely modify the DOM:
const thing = document.createElement('maybe-a-custom-element');
this.base.appendChild(thing);
}
componentWillUnmount() {
// component is about to be removed from the DOM, perform any cleanup.
}
render() {
return <div class="example" />;
}
}
If using hooks, then use memo function from preact/compat:
import { h } from 'preact';
import { useEffect } from 'preact/hooks';
import { memo } from 'preact/compat';
function Example(props) {
const [node, setNode] = setState(null);
useEffect(() => {
const elm = document.createElement('maybe-a-custom-element');
setNode(elm);
// Now do anything with the elm.
// Append to body or <div class="example"></div>
}, []);
return <div class="example" />;
}
// Usage with default comparison function
const Memoed = memo(Example);
// Usage with custom comparison function
const Memoed2 = memo(Example, (prevProps, nextProps) => {
// Only re-render when `name' changes
return prevProps.name === nextProps.name;
});
Also, note that Preact's render() function always diffs DOM children inside of the container. So if your container contains DOM that was not rendered by Preact, Preact will try to diff it with the elements you pass it. - Thus the meaning non-destructive.

How to provide a background color for an entire row in ag grid based on a certain value in a column?

I need to provide a background color for an entire row in ag grid based on a condition in a column. I found no such examples where entire row is colored based on a certain value in a column..
The previous answer is somewhat outdated (although still correct and working) and now we have some more control over the styling of the grid. You could use getRowStyle(params) for this job, just like this:
gridOptions.getRowStyle(params) {
if (params.data.myColumnToCheck === myValueToCheck) {
return {'background-color': 'yellow'}
}
return null;
}
Obviously, myColumnToCheck would be the column you're checking your value against (the same name you input in the id/field property of the colDef object), and myValueToCheck would be the value you want said column to have to make the row all yellow.
I hope this helps others. A very common use case in any table or grid including AG Grid is going to be to set the even/odd background color of the whole row of the entire table in a performant way. ALSO, this needs to still work when SORTING.
ALL OF THESE WAYS OF DOING THIS IN AG-GRID ARE WRONG. Even though they WILL work without sort, they will not update properly when you go to use sorting. This is due to something the ag-grid team refers to in this issue https://github.com/ag-grid/ag-grid-react/issues/77 as initialization time properties.
// Initialization problem
getRowClass = (params) => {
if (params.node.rowIndex % 2 === 0) {
return this.props.classes.rowEven;
}
};
<AgGridReact
getRowClass={this.getRowClass}
>
// Initialization problem
getRowStyle = (params) => {
if (params.node.rowIndex % 2 === 0) {
return this.props.classes.rowEven;
}
};
<AgGridReact
getRowStyle={this.getRowStyle}
>
// Initialization problem
rowClassRules = {
rowEven: 'node.rowIndex % 2 === 0',
}
rowClassRules = {
rowEven: (params) => params.node.rowIndex % 2 === 0,
}
<AgGridReact
rowClassRules={this.rowClassRules}
>
// Trying to change the key so a rerender happens
// Grid also listens to this so an infinite loop is likely
sortChanged = (data) => {
this.setState({ sort: Math.random()})
}
<AgGridReact
key={this.state.sort}
onSortChanged={this.sortChanged}
>
Basically, most stuff in grid is just read once and not again, probably for performance reasons to save rerenders.
You end up with this problem when sorting when doing any of the above:
THE FOLLOWIUNG IS THE RIGHT WAY TO ACHIEVE EVEN ODD COLORING:
The correct way to add even/odd functionality in ag-grid is to apply custom css styles as follows:
You will need to overwrite/use ag variables as mentioned in the docs here:https://www.ag-grid.com/javascript-grid-styling/#customizing-sass-variables
The names of the variables in our case are
.ag-grid-even class name, or the .ag-grid-odd class name. You of course only need one if you just want an alternating color to help with visibility. For our purposes we only needed one.
Here is how this process looked in our repo:
1. Make a custom css file that overwrites/uses some of these ag- class variable names. We call it ag-theme-custom.css (I believe it needs to be a css file).
Note: We also have sass variables so this file just has a comment that this color I am adding in css is the value for our variable $GREY_100 so you don't need that part
You now will get the same result but it will still work when sorting.
Answer 2 is correct, but the syntax used is wrong, and caused me several problems trying to sort it out. Trying to minify the answer 2 code barfed, for example. It did work, but it's not proper syntax as far as I can see.
Note, this can be done inline, or with an external
function. For example an external function.
vm.gridOptions = {
columnDefs: columnDefs,
getRowStyle: getRowStyleScheduled
}
function getRowStyleScheduled(params) {
if (params.selected && params.data.status === 'SCHEDULED') {
return {
'background-color': '#455A64',
'color': '#9AA3A8'
}
} else if (params.data.status === 'SCHEDULED') {
return {
'background-color': '#4CAF50',
'color': '#F4F8F5'
};
}
return null;
};
You can add CSS classes to each row in the following ways:
rowClass: Property to set CSS class for all rows. Provide either a string (class name) or array of strings (array of class names).
getRowClass: Callback to set class for each row individually.
<ag-grid-angular
[rowClass]="rowClass"
[getRowClass]="getRowClass"
/* other grid options ... */>
</ag-grid-angular>
// all rows assigned CSS class 'my-green-class'
this.rowClass = 'my-green-class';
// all even rows assigned 'my-shaded-effect'
this.getRowClass = params => {
if (params.node.rowIndex % 2 === 0) {
return 'my-shaded-effect';
}
};
You can define rules which can be applied to include certain CSS classes via the grid option rowClassRules.
The following snippet shows rowClassRules that use functions and the value from the year column:
<ag-grid-angular
[rowClassRules]="rowClassRules"
/* other grid options ... */>
</ag-grid-angular>
this.rowClassRules = {
// apply green to 2008
'rag-green-outer': function(params) { return params.data.year === 2008; },
// apply amber 2004
'rag-amber-outer': function(params) { return params.data.year === 2004; },
// apply red to 2000
'rag-red-outer': function(params) { return params.data.year === 2000; }
};
You can't change the background color of an entire row in one command. You need to do it through the cellStyle callback setup in the columnDefs. This callback will be called per each cell in the row. You need to change the color of the row by changing the color of all the cells.
See the following column definition
{
headerName: "Street Address", field: "StreetAddress", cellStyle: changeRowColor
}
You need to do this for all your columns.
Here is your changeRowColor function.
function changeRowColor(params) {
if(params.node.data[4] === 100){
return {'background-color': 'yellow'};
}
}
It changes the color of a row if the value of the third cell is 100.
I set different color for even and odd rows you can do it in any way..
$scope.gridOptions.getRowStyle = function getRowStyleScheduled(params){
if(parseInt(params.node.id)%2==0) {
return {'background-color': 'rgb(87, 90, 90)'}
}else {
return {'background-color': 'rgb(74, 72, 72)'}
}
};
If you don't need to set the background color conditionally(based on the row data), it is not recommended to use rowStyle, as written on the row style documentation page:
// set background color on even rows
// again, this looks bad, should be using CSS classes
gridOptions.getRowStyle = function(params) {
if (params.node.rowIndex % 2 === 0) {
return { background: 'red' };
}
}
Instead, you can change the row colors using css:
#import "~ag-grid-community/dist/styles/ag-grid.css";
#import "~ag-grid-community/dist/styles/ag-theme-alpine.css";
#import "~ag-grid-community/dist/styles/ag-theme-balham.css";
#import "~ag-grid-community/src/styles/ag-theme-balham/sass/ag-theme-balham-mixin";
.ag-theme-balham {
#include ag-theme-balham((
// use theme parameters where possible
odd-row-background-color: red
));
}
If you are using AdapTable then the simplest way is to use a Conditional Style and apply it to a whole row.
The advantage of this is that it can be at run-time easily by users also.
https://demo.adaptabletools.com/style/aggridconditionalstyledemo

How to create custom ExtJS form field component?

I want to create custom ExtJS form field components using other ExtJS components in it (e.g. TreePanel). How can I do it most easily?
I've read docs of Ext.form.field.Base but I don't want to define field body by fieldSubTpl. I just want to write code which creates ExtJS components and maybe some other code which gets and sets values.
Update: Summarized purposes are the followings:
This new component should fit in the
form GUI as a field. It should have
label and the same alignment (label,
anchor) of other fields without need
of further hacking.
Possibly, I have
to write some getValue, setValue
logic. I'd rather embed it into this component than making separated code which copies things into further hidden form fields that I also have to manage.
To extend #RobAgar 's answer, following a really simple Date Time field that I wrote for ExtJS 3 and it's quickport that I made for ExtJS 4. The important thing is the use of the Ext.form.field.Field mixin. This mixin provides a common interface for the logical behavior and state of form fields, including:
Getter and setter methods for field values
Events and methods for tracking value and validity changes
Methods for triggering validation
This can be used for combining multiple fields and let act them as one. For a total custom fieldtype I recommend to extend Ext.form.field.Base
Here is the example that I mentioned above. It should shoe how easy this can be done even for something like a date object where we need to format the data within the getter and setter.
Ext.define('QWA.form.field.DateTime', {
extend: 'Ext.form.FieldContainer',
mixins: {
field: 'Ext.form.field.Field'
},
alias: 'widget.datetimefield',
layout: 'hbox',
width: 200,
height: 22,
combineErrors: true,
msgTarget: 'side',
submitFormat: 'c',
dateCfg: null,
timeCfg: null,
initComponent: function () {
var me = this;
if (!me.dateCfg) me.dateCfg = {};
if (!me.timeCfg) me.timeCfg = {};
me.buildField();
me.callParent();
me.dateField = me.down('datefield')
me.timeField = me.down('timefield')
me.initField();
},
//#private
buildField: function () {
var me = this;
me.items = [
Ext.apply({
xtype: 'datefield',
submitValue: false,
format: 'd.m.Y',
width: 100,
flex: 2
}, me.dateCfg),
Ext.apply({
xtype: 'timefield',
submitValue: false,
format: 'H:i',
width: 80,
flex: 1
}, me.timeCfg)]
},
getValue: function () {
var me = this,
value,
date = me.dateField.getSubmitValue(),
dateFormat = me.dateField.format,
time = me.timeField.getSubmitValue(),
timeFormat = me.timeField.format;
if (date) {
if (time) {
value = Ext.Date.parse(date + ' ' + time, me.getFormat());
} else {
value = me.dateField.getValue();
}
}
return value;
},
setValue: function (value) {
var me = this;
me.dateField.setValue(value);
me.timeField.setValue(value);
},
getSubmitData: function () {
var me = this,
data = null;
if (!me.disabled && me.submitValue && !me.isFileUpload()) {
data = {},
value = me.getValue(),
data[me.getName()] = '' + value ? Ext.Date.format(value, me.submitFormat) : null;
}
return data;
},
getFormat: function () {
var me = this;
return (me.dateField.submitFormat || me.dateField.format) + " " + (me.timeField.submitFormat || me.timeField.format)
}
});
Now that's cool. The other day, I created a fiddle to answer another question before realizing I was off-topic. And here your are, finally bringing to my attention the question to my answer. Thanks!
So, here are the steps required in implementing a custom field from another component:
Creating the child component
Render the child component
Ensuring the child component is sized and resized correctly
Getting and setting value
Relaying events
Creating the child component
The first part, creating the component, is easy. There's nothing particular compared to creating a component for any other usage.
However, you must create the child in the parent field's initComponent method (and not at rendering time). This is because external code can legitimately expect that all dependent objects of a component are instantiated after initComponent (e.g. to add listeners to them).
Furthermore, you can be kind to yourself and create the child before calling the super method. If you create the child after the super method, you may get a call to your field's setValue method (see bellow) at a time when the child is not yet instantiated.
initComponent: function() {
this.childComponent = Ext.create(...);
this.callParent(arguments);
}
As you see, I am creating a single component, which is what you'll want in most case. But you can also want to go fancy and compose multiple child components. In this case, I think it would be clever to back to well known territories as quickly as possible: that is, create one container as the child component, and compose in it.
Rendering
Then comes the question of rendering. At first I considered using fieldSubTpl to render a container div, and have the child component render itself in it. However, we don't need the template features in that case, so we can as well bypass it completely using the getSubTplMarkup method.
I explored other components in Ext to see how they manage the rendering of child components. I found a good example in BoundList and its paging toolbar (see the code). So, in order to obtain the child component's markup, we can use Ext.DomHelper.generateMarkup in combination with the child's getRenderTree method.
So, here's the implementation of getSubTplMarkup for our field:
getSubTplMarkup: function() {
// generateMarkup will append to the passed empty array and return it
var buffer = Ext.DomHelper.generateMarkup(this.childComponent.getRenderTree(), []);
// but we want to return a single string
return buffer.join('');
}
Now, that's not enough. The code of BoundList learns us that there's another important part in component rendering: calling the finishRender() method of the child component. Fortunately, our custom field will have its own finishRenderChildren method called just when that needs to be done.
finishRenderChildren: function() {
this.callParent(arguments);
this.childComponent.finishRender();
}
Resizing
Now our child will be rendered in the right place, but it will not respect its parent field size. That is especially annoying in the case of a form field, because that means it won't honor the anchor layout.
That's very straightforward to fix, we just need to resize the child when the parent field is resized. From my experience, this is something that was greatly improved since Ext3. Here, we just need to not forget the extra space for the label:
onResize: function(w, h) {
this.callParent(arguments);
this.childComponent.setSize(w - this.getLabelWidth(), h);
}
Handling value
This part will, of course, depend on your child component(s), and the field you're creating. Moreover, from now on, it's just a matter of using your child components in a regular way, so I won't detail this part too much.
A minima, you also need to implement the getValue and setValue methods of your field. That will make the getFieldValues method of the form work, and that will be enough to load/update records from the form.
To handle validation, you must implement getErrors. To polish this aspect, you may want to add a handful of CSS rules to visually represent the invalid state of your field.
Then, if you want your field to be usable in a form that will be submitted as an actual form (as opposed to with an AJAX request), you'll need getSubmitValue to return a value that can be casted to a string without damage.
Apart from that, as far as I know, you don't have to worry about the concept or raw value introduced by Ext.form.field.Base since that's only used to handle the representation of the value in an actual input element. With our Ext component as input, we're way off that road!
Events
Your last job will be to implement the events for your fields. You will probably want to fire the three events of Ext.form.field.Field, that is change, dirtychange and validitychange.
Again, the implementation will be very specific to the child component you use and, to be honest, I haven't explored this aspect too much. So I'll let you wire this for yourself.
My preliminary conclusion though, is that Ext.form.field.Field offers to do all the heavy lifting for you, provided that (1) you call checkChange when needed, and (2) isEqual implementation is working with your field's value format.
Example: TODO list field
Finally, here's a complete code example, using a grid to represent a TODO list field.
You can see it live on jsFiddle, where I tries to show that the field behaves in an orderly manner.
Ext.define('My.form.field.TodoList', {
// Extend from Ext.form.field.Base for all the label related business
extend: 'Ext.form.field.Base'
,alias: 'widget.todolist'
// --- Child component creation ---
,initComponent: function() {
// Create the component
// This is better to do it here in initComponent, because it is a legitimate
// expectationfor external code that all dependant objects are created after
// initComponent (to add listeners, etc.)
// I will use this.grid for semantical access (value), and this.childComponent
// for generic issues (rendering)
this.grid = this.childComponent = Ext.create('Ext.grid.Panel', {
hideHeaders: true
,columns: [{dataIndex: 'value', flex: 1}]
,store: {
fields: ['value']
,data: []
}
,height: this.height || 150
,width: this.width || 150
,tbar: [{
text: 'Add'
,scope: this
,handler: function() {
var value = prompt("Value?");
if (value !== null) {
this.grid.getStore().add({value: value});
}
}
},{
text: "Remove"
,itemId: 'removeButton'
,disabled: true // initial state
,scope: this
,handler: function() {
var grid = this.grid,
selModel = grid.getSelectionModel(),
store = grid.getStore();
store.remove(selModel.getSelection());
}
}]
,listeners: {
scope: this
,selectionchange: function(selModel, selection) {
var removeButton = this.grid.down('#removeButton');
removeButton.setDisabled(Ext.isEmpty(selection));
}
}
});
// field events
this.grid.store.on({
scope: this
,datachanged: this.checkChange
});
this.callParent(arguments);
}
// --- Rendering ---
// Generates the child component markup and let Ext.form.field.Base handle the rest
,getSubTplMarkup: function() {
// generateMarkup will append to the passed empty array and return it
var buffer = Ext.DomHelper.generateMarkup(this.childComponent.getRenderTree(), []);
// but we want to return a single string
return buffer.join('');
}
// Regular containers implements this method to call finishRender for each of their
// child, and we need to do the same for the component to display smoothly
,finishRenderChildren: function() {
this.callParent(arguments);
this.childComponent.finishRender();
}
// --- Resizing ---
// This is important for layout notably
,onResize: function(w, h) {
this.callParent(arguments);
this.childComponent.setSize(w - this.getLabelWidth(), h);
}
// --- Value handling ---
// This part will be specific to your component of course
,setValue: function(values) {
var data = [];
if (values) {
Ext.each(values, function(value) {
data.push({value: value});
});
}
this.grid.getStore().loadData(data);
}
,getValue: function() {
var data = [];
this.grid.getStore().each(function(record) {
data.push(record.get('value'));
});
return data;
}
,getSubmitValue: function() {
return this.getValue().join(',');
}
});
Heh. After posting the bounty I found out that Ext.form.FieldContainer isn't just a field container, but a fully fledged component container, so there is a simple solution.
All you need to do is extend FieldContainer, overriding initComponent to add the child components, and implement setValue, getValue and the validation methods as appropriate for your value data type.
Here's an example with a grid whose value is a list of name/value pair objects:
Ext.define('MyApp.widget.MyGridField', {
extend: 'Ext.form.FieldContainer',
alias: 'widget.mygridfield',
layout: 'fit',
initComponent: function()
{
this.callParent(arguments);
this.valueGrid = Ext.widget({
xtype: 'grid',
store: Ext.create('Ext.data.JsonStore', {
fields: ['name', 'value'],
data: this.value
}),
columns: [
{
text: 'Name',
dataIndex: 'name',
flex: 3
},
{
text: 'Value',
dataIndex: 'value',
flex: 1
}
]
});
this.add(this.valueGrid);
},
setValue: function(value)
{
this.valueGrid.getStore().loadData(value);
},
getValue: function()
{
// left as an exercise for the reader :P
}
});
I've done this a few times. Here is the general process/pseudo-code I use:
Create an extension of field that provides the most useful re-use (typically Ext.form.TextField if you just want to get/set a string value)
In the afterrender of the field, hide the textfield, and create a wrapping element around this.el with this.wrap = this.resizeEl = this.positionEl = this.el.wrap()
Render any components to this.wrap (e.g. using renderTo: this.wrap in the config)
Override getValue and setValue to talk to the component(s) you rendered manually
You may need to do some manually sizing in a resize listener if your form's layout changes
Don't forget to cleanup any components you create in the beforeDestroy method!
I can't wait to switch our codebase to ExtJS 4, where these kinds of things are easy.
Good luck!
Since the question was asked rather vague - I only can provide the basic pattern for ExtJS v4.
Even if it's not too specific, it has the advance that it's rather universal like this:
Ext.define('app.view.form.field.CustomField', {
extend: 'Ext.form.field.Base',
requires: [
/* require further components */
],
/* custom configs & callbacks */
getValue: function(v){
/* override function getValue() */
},
setValue: function(v){
/* override function setValue() */
},
getSubTplData: [
/* most likely needs to be overridden */
],
initComponent: function(){
/* further code on event initComponent */
this.callParent(arguments);
}
});
The file /ext/src/form/field/Base.js provides the names of all configs and functions that can be overridden.
Following the documentation at http://docs.sencha.com/ext-js/4-0/#/api/Ext.form.field.Base
This code will create a reusable TypeAhead/Autocomplete style field for selecting a language.
var langs = Ext.create( 'Ext.data.store', {
fields: [ 'label', 'code' ],
data: [
{ code: 'eng', label: 'English' },
{ code: 'ger', label: 'German' },
{ code: 'chi', label: 'Chinese' },
{ code: 'ukr', label: 'Ukranian' },
{ code: 'rus', label: 'Russian' }
]
} );
Ext.define( 'Ext.form.LangSelector', {
extend: 'Ext.form.field.ComboBox',
alias: 'widget.LangSelector',
allowBlank: false,
hideTrigger: true,
width: 225,
displayField: 'label',
valueField: 'code',
forceSelection: true,
minChars: 1,
store: langs
} );
You can use the field in a form simply by setting the xtype to the widget name:
{
xtype: 'LangSelector'
fieldLabel: 'Language',
name: 'lang'
}
Many of the answers either use the Mixin Ext.form.field.Field or just extends on some already made class that suits their needs - which is fine.
But I do not recommend fully overwriting the setValue method, that is IMO really bad form!
A lot more happens than just setting and getting the value, and if you fully overwrite it - well you will for instance mess up the dirty state, processing of rawValue etc..
Two options here I guess, one is to callParent(arguments) inside the method you declare to keep things streamlined, or to at the end when you are done apply the inherited method from where ever you got it (mixin or extend).
But do not just overwrite it with no regards for what that already made method does behind the scenes.
Also remember that if you use other field types in your new class - then do set the isFormField property to false - otherwise your getValues method on the form will take those values and run with em!
Another solution could be this tree-field implementation.
It behaves just like a normal form field:
https://github.com/wencywww/Ext.ux.form.field.Tree
Here is an example of a custom panel that extends an Ext Panel. You can extend any component, check the docs for the fields, methods and events you can play with.
Ext.ns('yournamespace');
yournamespace.MyPanel = function(config) {
yournamespace.MyPanel.superclass.constructor.call(this, config);
}
Ext.extend(yournamespace.MyPanel, Ext.Panel, {
myGlobalVariable : undefined,
constructor : function(config) {
yournamespace.MyPanel.superclass.constructor.apply(this, config);
},
initComponent : function() {
this.comboBox = new Ext.form.ComboBox({
fieldLabel: "MyCombo",
store: someStore,
displayField:'My Label',
typeAhead: true,
mode: 'local',
forceSelection: true,
triggerAction: 'all',
emptyText:'',
selectOnFocus:true,
tabIndex: 1,
width: 200
});
// configure the grid
Ext.apply(this, {
listeners: {
'activate': function(p) {
p.doLayout();
},
single:true
},
xtype:"form",
border: false,
layout:"absolute",
labelAlign:"top",
bodyStyle:"padding: 15px",
width: 350,
height: 75,
items:[{
xtype:"panel",
layout:"form",
x:"10",
y:"10",
labelAlign:"top",
border:false,
items:[this.comboBox]
},
{
xtype:"panel",
layout:"form",
x:"230",
y:"26",
labelAlign:"top",
border:false,
items:[{
xtype:'button',
handler: this.someAction.createDelegate(this),
text: 'Some Action'
}]
}]
}); // eo apply
yournamespace.MyPanel.superclass.initComponent.apply(this, arguments);
this.comboBox.on('select', function(combo, record, index) {
this.myGlobalVariable = record.get("something");
}, this);
}, // eo function initComponent
someAction : function() {
//do something
},
getMyGlobalVariable : function() {
return this.myGlobalVariable;
}
}); // eo extend
Ext.reg('mypanel', yournamespace.MyPanel);
Could you describe the UI requirements that you have a bit more? Are you sure that you even need to do build an entire field to support the TreePanel? Why not set the value of a hidden field (see the "hidden" xtype in the API) from a click handler on a normal tree panel?
To answer your question more fully, you can find many tutorials on how to extend ExtJS components. You do this by leveraging the Ext.override() or Ext.Extend() methods.
But my feeling is that you may be over-complicating your design. You can achieve what you need to do by setting a value to this hidden field. If you have complex data, you can set the value as some XML or JSON string.
EDIT Here's a few tutorials. I highly recommend going with the KISS rule when it comes to your UI design. Keep It Simple Stupid!
Extending components using panels