JUCE: ComponentBuilder::TypeHandler Class Reference

JUCE

Public Member Functions | Public Attributes | List of all members
ComponentBuilder::TypeHandler Class Referenceabstract
juce_gui_basics » layout

The class is a base class for objects that manage the loading of a type of component from a ValueTree. More...

`#include <juce_ComponentBuilder.h>`

## Public Member Functions
| TypeHandler (const Identifier &valueTreeType)
| Creates a TypeHandler. More...
virtual | ~TypeHandler ()
| Destructor. More...
ComponentBuilder * | getBuilder () const noexcept
| Returns the builder that this type is registered with. More...
virtual Component * | addNewComponentFromState (const ValueTree &state, Component *parent)=0
| This method must create a new component from the given state, add it to the specified parent component (which may be null), and return it. More...
virtual void | updateComponentFromState (Component *component, const ValueTree &state)=0
| This method must update an existing component from a new ValueTree state. More...

## Public Attributes
const Identifier | type
| Returns the type of the ValueTrees that this handler can parse. More...

## Detailed Description

The class is a base class for objects that manage the loading of a type of component from a ValueTree.

To store and re-load a tree of components as a ValueTree, each component type must have a TypeHandler to represent it.

See also
  ComponentBuilder::registerTypeHandler(), Drawable::registerDrawableTypeHandlers()

## Constructor & Destructor Documentation

## ◆ TypeHandler()

ComponentBuilder::TypeHandler::TypeHandler | ( | const Identifier & | valueTreeType | ) |
| explicit

Creates a TypeHandler.

The valueTreeType must be the type name of the ValueTrees that this handler can parse.

## ◆ ~TypeHandler()

virtual ComponentBuilder::TypeHandler::~TypeHandler | ( |  | ) |
| virtual

Destructor.

## Member Function Documentation

## ◆ getBuilder()

ComponentBuilder * ComponentBuilder::TypeHandler::getBuilder | ( |  | ) | const
| noexcept

Returns the builder that this type is registered with.

## ◆ addNewComponentFromState()

virtual Component * ComponentBuilder::TypeHandler::addNewComponentFromState | ( | const ValueTree & | state,
|  | Component * | parent
| ) |  |
| pure virtual

This method must create a new component from the given state, add it to the specified parent component (which may be null), and return it.

The ValueTree will have been pre-checked to make sure that its type matches the type that this handler supports.

There's no need to set the new Component's ID to match that of the state - the builder will take care of that itself.

## ◆ updateComponentFromState()

virtual void ComponentBuilder::TypeHandler::updateComponentFromState | ( | Component * | component,
|  | const ValueTree & | state
| ) |  |
| pure virtual

This method must update an existing component from a new ValueTree state.

A component that has been created with addNewComponentFromState() may need to be updated if the ValueTree changes, so this method is used to do that. Your implementation must do whatever's necessary to update the component from the new state provided.

The ValueTree will have been pre-checked to make sure that its type matches the type that this handler supports, and the component will have been created by this type's addNewComponentFromState() method.

## Member Data Documentation

## ◆ type

const Identifier ComponentBuilder::TypeHandler::type

Returns the type of the ValueTrees that this handler can parse.

The documentation for this class was generated from the following file:

- juce_ComponentBuilder.h