Hierarchy
Ext.BaseExt.util.DelayedTaskFiles
The DelayedTask class provides a convenient way to "buffer" the execution of a method,
performing setTimeout
where a new timeout cancels the old timeout. When called, the
task will wait the specified time period before executing. If during that time period,
the task is called again, the original call will be canceled. This continues so that
the function is only called a single time for each iteration.
This method is especially useful for things like detecting whether a user has finished typing in a text field. An example would be performing validation on a keypress. You can use this class to buffer the keypress events for a certain number of milliseconds, and perform only if they stop for that amount of time.
Using Ext.util.DelayedTask is very simple:
//create the delayed task instance with our callback
var task = Ext.create('Ext.util.DelayedTask', {
fn: function() {
console.log('callback!');
}
});
task.delay(1500); //the callback function will now be called after 1500ms
task.cancel(); //the callback function will never be called now, unless we call delay() again
//create a textfield where we can listen to text
var field = Ext.create('Ext.field.Text', {
xtype: 'textfield',
label: 'Length: 0'
});
//add the textfield into a fieldset
Ext.Viewport.add({
xtype: 'formpanel',
items: [{
xtype: 'fieldset',
items: [field],
instructions: 'Type into the field and watch the count go up after 500ms.'
}]
});
//create our delayed task with a function that returns the fields length as the fields label
var task = Ext.create('Ext.util.DelayedTask', function() {
field.setLabel('Length: ' + field.getValue().length);
});
// Wait 500ms before calling our function. If the user presses another key
// during that 500ms, it will be canceled and we'll wait another 500ms.
field.on('keyup', function() {
task.delay(500);
});
Get the reference to the current class from which this object was instantiated. Unlike statics,
this.self
is scope-dependent and it's meant to be used for dynamic inheritance. See statics
for a detailed comparison
Ext.define('My.Cat', {
statics: {
speciesName: 'Cat' // My.Cat.speciesName = 'Cat'
},
constructor: function() {
alert(this.self.speciesName); // dependent on 'this'
},
clone: function() {
return new this.self();
}
});
Ext.define('My.SnowLeopard', {
extend: 'My.Cat',
statics: {
speciesName: 'Snow Leopard' // My.SnowLeopard.speciesName = 'Snow Leopard'
}
});
var cat = new My.Cat(); // alerts 'Cat'
var snowLeopard = new My.SnowLeopard(); // alerts 'Snow Leopard'
var clone = snowLeopard.clone();
alert(Ext.getClassName(clone)); // alerts 'My.SnowLeopard'
The parameters to this constructor serve as defaults and are not required.
The default function to call.
The default scope (The this
reference) in which the function is called. If
not specified, this
will refer to the browser window.
The default Array of arguments.
Call the original method that was previously overridden with override,
This method is deprecated as callParent does the same thing.
Ext.define('My.Cat', {
constructor: function() {
alert("I'm a cat!");
}
});
My.Cat.override({
constructor: function() {
alert("I'm going to be a cat!");
var instance = this.callOverridden();
alert("Meeeeoooowwww");
return instance;
}
});
var kitty = new My.Cat(); // alerts "I'm going to be a cat!"
// alerts "I'm a cat!"
// alerts "Meeeeoooowwww"
The arguments, either an array or the arguments
object
from the current method, for example: this.callOverridden(arguments)
Returns the result of calling the overridden method
Call the "parent" method of the current method. That is the method previously overridden by derivation or by an override (see Ext.define).
Ext.define('My.Base', {
constructor: function (x) {
this.x = x;
},
statics: {
method: function (x) {
return x;
}
}
});
Ext.define('My.Derived', {
extend: 'My.Base',
constructor: function () {
this.callParent([21]);
}
});
var obj = new My.Derived();
alert(obj.x); // alerts 21
This can be used with an override as follows:
Ext.define('My.DerivedOverride', {
override: 'My.Derived',
constructor: function (x) {
this.callParent([x*2]); // calls original My.Derived constructor
}
});
var obj = new My.Derived();
alert(obj.x); // now alerts 42
This also works with static methods.
Ext.define('My.Derived2', {
extend: 'My.Base',
statics: {
method: function (x) {
return this.callParent([x*2]); // calls My.Base.method
}
}
});
alert(My.Base.method(10)); // alerts 10
alert(My.Derived2.method(10)); // alerts 20
Lastly, it also works with overridden static methods.
Ext.define('My.Derived2Override', {
override: 'My.Derived2',
statics: {
method: function (x) {
return this.callParent([x*2]); // calls My.Derived2.method
}
}
});
alert(My.Derived2.method(10)); // now alerts 40
To override a method and replace it and also call the superclass method, use callSuper. This is often done to patch a method to fix a bug.
The arguments, either an array or the arguments
object
from the current method, for example: this.callParent(arguments)
Returns the result of calling the parent method
This method is used by an override to call the superclass method but bypass any overridden method. This is often done to "patch" a method that contains a bug but for whatever reason cannot be fixed directly.
Consider:
Ext.define('Ext.some.Class', {
method: function () {
console.log('Good');
}
});
Ext.define('Ext.some.DerivedClass', {
method: function () {
console.log('Bad');
// ... logic but with a bug ...
this.callParent();
}
});
To patch the bug in DerivedClass.method
, the typical solution is to create an
override:
Ext.define('App.paches.DerivedClass', {
override: 'Ext.some.DerivedClass',
method: function () {
console.log('Fixed');
// ... logic but with bug fixed ...
this.callSuper();
}
});
The patch method cannot use callParent
to call the superclass method
since
that would call the overridden method containing the bug. In other words, the
above patch would only produce "Fixed" then "Good" in the console log, whereas,
using callParent
would produce "Fixed" then "Bad" then "Good".
The arguments, either an array or the arguments
object
from the current method, for example: this.callSuper(arguments)
Returns the result of calling the superclass method
Cancels any pending timeout and queues a new one.
The milliseconds to delay
Overrides the original function passed when instantiated.
Overrides the original scope
passed when instantiated. Remember that if no scope
is specified, this
will refer to the browser window.
Overrides the original args
passed when instantiated.
Initialize configuration for this class. a typical example:
Ext.define('My.awesome.Class', {
// The default config
config: {
name: 'Awesome',
isAwesome: true
},
constructor: function(config) {
this.initConfig(config);
}
});
var awesome = new My.awesome.Class({
name: 'Super Awesome'
});
alert(awesome.getName()); // 'Super Awesome'
mixins The mixin prototypes as key - value pairs
Get the reference to the class from which this object was instantiated. Note that unlike self,
this.statics()
is scope-independent and it always returns the class from which it was called, regardless of what
this
points to during run-time
Ext.define('My.Cat', {
statics: {
totalCreated: 0,
speciesName: 'Cat' // My.Cat.speciesName = 'Cat'
},
constructor: function() {
var statics = this.statics();
alert(statics.speciesName); // always equals to 'Cat' no matter what 'this' refers to
// equivalent to: My.Cat.speciesName
alert(this.self.speciesName); // dependent on 'this'
statics.totalCreated++;
},
clone: function() {
var cloned = new this.self(); // dependent on 'this'
cloned.groupName = this.statics().speciesName; // equivalent to: My.Cat.speciesName
return cloned;
}
});
Ext.define('My.SnowLeopard', {
extend: 'My.Cat',
statics: {
speciesName: 'Snow Leopard' // My.SnowLeopard.speciesName = 'Snow Leopard'
},
constructor: function() {
this.callParent();
}
});
var cat = new My.Cat(); // alerts 'Cat', then alerts 'Cat'
var snowLeopard = new My.SnowLeopard(); // alerts 'Cat', then alerts 'Snow Leopard'
var clone = snowLeopard.clone();
alert(Ext.getClassName(clone)); // alerts 'My.SnowLeopard'
alert(clone.groupName); // alerts 'Cat'
alert(My.Cat.totalCreated); // alerts 3
Add methods / properties to the prototype of this class.
Ext.define('My.awesome.Cat', {
constructor: function() {
// ...
}
});
My.awesome.Cat.addMembers({
meow: function() {
alert('Meowww...');
}
});
var kitty = new My.awesome.Cat();
kitty.meow();
Add / override static properties of this class.
Ext.define('My.cool.Class', {
// this.se
});
My.cool.Class.addStatics({
someProperty: 'someValue', // My.cool.Class.someProperty = 'someValue'
method1: function() { }, // My.cool.Class.method1 = function() { ... };
method2: function() { } // My.cool.Class.method2 = function() { ... };
});
this
Borrow another class' members to the prototype of this class.
Ext.define('Bank', {
money: '$$$',
printMoney: function() {
alert('$$$$$$$');
}
});
Ext.define('Thief', {
// ...
});
Thief.borrow(Bank, ['money', 'printMoney']);
var steve = new Thief();
alert(steve.money); // alerts '$$$'
steve.printMoney(); // alerts '$$$$$$$'
The class to borrow members from
The names of the members to borrow
this
Create a new instance of this Class.
Ext.define('My.cool.Class', {
// ...
});
My.cool.Class.create({
someConfig: true
});
All parameters are passed to the constructor of the class.
the created instance.
Create aliases for existing prototype methods. Example:
Ext.define('My.cool.Class', {
method1: function() { },
method2: function() { }
});
var test = new My.cool.Class();
My.cool.Class.createAlias({
method3: 'method1',
method4: 'method2'
});
test.method3(); // test.method1()
My.cool.Class.createAlias('method5', 'method3');
test.method5(); // test.method3() -> test.method1()
The new method name, or an object to set multiple aliases. See flexSetter
The original method name
Get the current class' name in string format.
Ext.define('My.cool.Class', {
constructor: function() {
alert(this.self.getName()); // alerts 'My.cool.Class'
}
});
My.cool.Class.getName(); // 'My.cool.Class'
className
Override members of this class. Overridden methods can be invoked via callParent.
Ext.define('My.Cat', {
constructor: function() {
alert("I'm a cat!");
}
});
My.Cat.override({
constructor: function() {
alert("I'm going to be a cat!");
var instance = this.callParent(arguments);
alert("Meeeeoooowwww");
return instance;
}
});
var kitty = new My.Cat(); // alerts "I'm going to be a cat!"
// alerts "I'm a cat!"
// alerts "Meeeeoooowwww"
As of 2.1, direct use of this method is deprecated. Use Ext.define instead:
Ext.define('My.CatOverride', {
override: 'My.Cat',
constructor: function() {
alert("I'm going to be a cat!");
var instance = this.callParent(arguments);
alert("Meeeeoooowwww");
return instance;
}
});
The above accomplishes the same result but can be managed by the Ext.Loader which can properly order the override and its target class and the build process can determine whether the override is needed based on the required state of the target class (My.Cat).
This method has been deprecated since 2.1.0
Please use Ext.define instead
The properties to add to this class. This should be specified as an object literal containing one or more properties.
this class