Callback and Handlers

Callback and Handlers#

✅ 1. Button Callbacks

ElevatedButton, TextButton, IconButton, FloatingActionButton

  • onPressed

  • onLongPress

  • onHover

  • onFocusChange

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✅ 2. Gesture Callbacks (GestureDetector / InkWell / InkResponse)

Tap gestures

  • onTap

  • onTapDown

  • onTapUp

  • onTapCancel

Double-tap

  • onDoubleTap

Long press

  • onLongPress

  • onLongPressStart

  • onLongPressMoveUpdate

  • onLongPressEnd

  • onLongPressUp

Pan / Drag

  • onPanStart

  • onPanUpdate

  • onPanEnd

  • onHorizontalDragStart

  • onHorizontalDragUpdate

  • onHorizontalDragEnd

  • onVerticalDragStart

  • onVerticalDragUpdate

  • onVerticalDragEnd

Force press

  • onForcePressStart

  • onForcePressPeak

  • onForcePressEnd

Scale / Pinch

  • onScaleStart

  • onScaleUpdate

  • onScaleEnd

Other gestures

  • onSecondaryTap

  • onSecondaryTapUp

  • onSecondaryTapDown

  • onTertiaryTapDown

  • onTertiaryTapUp

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✅ 3. TextField / TextFormField Callbacks

  • onChanged

  • onEditingComplete

  • onSubmitted

  • onTap

  • onTapOutside

  • onSaved ⚠️ (in forms)

  • validator (returns String?)

  • onFieldSubmitted

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✅ 4. Checkbox / Switch / Radio Callbacks

  • onChanged

Checkbox:

  • onChanged

Switch:

  • onChanged

Radio:

  • onChanged

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✅ 5. Slider Callbacks

  • onChanged

  • onChangeStart

  • onChangeEnd

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✅ 6. Scroll Callbacks

ListView, ScrollController

  • onNotification (using NotificationListener)

  • ScrollController listeners via:

  • addListener()

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✅ 7. Form Callbacks

  • onWillPop (using WillPopScope)

  • onSaved

  • validator

  • onChanged (FormField)

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✅ 8. Page and Navigation Callbacks

PageView

  • onPageChanged

Navigator

You register callbacks (not properties) by:

  • .then() when popping a route

  • using RouteObserver for:

  • didPush

  • didPop

  • didReplace

  • didRemove

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✅ 9. Animation Callbacks

AnimationController

  • addListener

  • addStatusListener

Status options:

  • AnimationStatus.forward

  • AnimationStatus.reverse

  • AnimationStatus.completed

  • AnimationStatus.dismissed

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✅ 10. Lifecycle Callbacks

StatefulWidget lifecycle

  • initState

  • didChangeDependencies

  • didUpdateWidget

  • setState (handler to update UI)

  • dispose

  • build

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✅ 11. Focus & Keyboard Callbacks

FocusNode

  • addListener

Shortcuts/Actions (like your app)

  • onInvoke

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✅ 12. App Lifecycle Callbacks

Using WidgetsBindingObserver

  • didChangeAppLifecycleState

  • resumed

  • inactive

  • paused

  • detached

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✅ 13. Miscellaneous Widget Callbacks

Switches, Toggles, Pickers:

  • onDateChanged

  • onTimeChanged

  • onSelectedItemChanged (CupertinoPicker)

Drawer:

  • onDrawerOpened

  • onDrawerClosed

ExpansionTile:

  • onExpansionChanged

RefreshIndicator:

  • onRefresh

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⭐ SUMMARY

Here is the clean shortest summary:

Most common callbacks in Flutter:

  • onPressed

  • onTap

  • onChanged

  • onSubmitted

  • onLongPress

  • onHover

  • onSaved

  • validator

  • onPageChanged

  • addListener (for controllers)

  • onWillPop

  • onRefresh

  • onInvoke

Most common handlers:

  • Tap handler → onTap

  • Press handler → onPressed

  • Change handler → onChanged

  • Drag handler → onPanUpdate, etc.

  • Keyboard handler → onSubmitted

  • Scroll handler → ScrollController listener

  • Animation handler → AnimationController listeners