Created
November 30, 2018 05:47
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Sample of custom analog of KeyboardAvoidingView in "padding" mode, that actually works.
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import React from 'react' | |
import { | |
EmitterSubscription, | |
Keyboard, | |
LayoutAnimation, | |
LayoutChangeEvent, | |
LayoutRectangle, | |
Platform, | |
StyleSheet, | |
View, | |
ViewProps, | |
} from 'react-native' | |
// iOS: all events: | |
// keyboardWillChangeFrame, keyboardDidChangeFrame, | |
// keyboardWillShow, keyboardDidShow, | |
// keyboardWillHide and keyboardDidHide | |
// all events contains all data | |
// Android: only two events keyboardDidShow and keyboardDidHide | |
// keyboardDidShow - only data is endCoordinates | |
// keyboardDidHide - data is null | |
interface IKeyboardEvent { | |
easing?: string | |
duration?: number | |
startCoordinates?: IKeyboardRectangle | |
endCoordinates?: IKeyboardRectangle | |
} | |
interface IKeyboardRectangle { | |
screenX: number | |
screenY: number | |
width: number | |
height: number | |
} | |
interface IState { | |
padding: number | |
} | |
/** | |
* View that moves out of the way when the keyboard appears by automatically | |
* adjusting its height, position, or bottom padding. | |
*/ | |
export class KeyboardAvoidingView extends React.Component<ViewProps, IState> { | |
state: IState = { padding: 0 } | |
private _subscriptions: EmitterSubscription[] = [] | |
private viewRef: View | null | undefined = undefined | |
private viewFrame: LayoutRectangle | undefined = undefined | |
private keyboardFrame: IKeyboardRectangle | undefined = undefined | |
componentDidMount(): void { | |
if (Platform.OS === 'ios') { | |
this._subscriptions = [Keyboard.addListener('keyboardWillChangeFrame', this.onKeyboardChange)] | |
} else if (Platform.OS === 'android') { | |
this._subscriptions = [ | |
Keyboard.addListener('keyboardDidShow', this.onKeyboardChange), | |
Keyboard.addListener('keyboardDidHide', this.onKeyboardChange), | |
] | |
} else { | |
throw new Error('KeyboardAvoidingView supports only ios and android platforms') | |
} | |
} | |
componentWillUnmount(): void { | |
this._subscriptions.forEach((subscription) => { | |
subscription.remove() | |
}) | |
} | |
render() { | |
return ( | |
<View | |
ref={this.setViewRef} | |
{...this.props} | |
style={StyleSheet.flatten([this.props.style, { paddingBottom: this.state.padding }])} | |
onLayout={this.onViewLayout} | |
/> | |
) | |
} | |
private setViewRef: React.Ref<View> = (ref) => { | |
this.viewRef = ref | |
} | |
private onViewLayout = (ev: LayoutChangeEvent) => { | |
if (!this.viewRef) return | |
this.viewRef.measureInWindow(this.onViewMeasure) | |
} | |
private onViewMeasure = (x: number, y: number, width: number, height: number) => { | |
this.viewFrame = { x, y, width, height } | |
this.updatePadding() | |
} | |
private updatePadding() { | |
const padding = this.calculatePadding() | |
if (this.state.padding !== padding) { | |
this.setState({ padding }) | |
} | |
} | |
private calculatePadding() { | |
if (!this.viewFrame || !this.keyboardFrame) return 0 | |
const keyboardTop = this.keyboardFrame.screenY | |
const viewBottom = this.viewFrame.y + this.viewFrame.height | |
return keyboardTop < viewBottom ? viewBottom - keyboardTop : 0 | |
} | |
private onKeyboardChange = (ev: IKeyboardEvent) => { | |
// KeyboardDidHide on android | |
if (!ev) { | |
this.keyboardFrame = undefined | |
this.updatePadding() | |
return | |
} | |
this.keyboardFrame = ev.endCoordinates | |
if (ev.duration) { | |
LayoutAnimation.configureNext({ | |
duration: ev.duration, | |
update: { duration: ev.duration, type: ev.easing || 'keyboard' }, | |
}) | |
} | |
this.updatePadding() | |
} | |
} |
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