I am translating views to follow a move gesture, with least possible latency.
I am investigating a couple of options and one of which is - if possible - to send the setValue action to UI thread, rather than the JS thread.
Even though in the documentations it is stated that the Animated.timing, Animated.spring, etc type of functions can be offloaded to the UI thread with useNativeDriver: true directive, there is no reference - at least that I could have found - on if it is possible to send the direct setValue action to the UI thread or not.
My question is; is it possible to use animated setValue with useNativeDriver and how if possible.
Below is the rough example of the code that I am using:
export default class App extends React.Component {
constructor(props) {
super(props);
this.state = {};
this.spaceAnimatedTranslations = new Animated.ValueXY();
this._animatedStyle = {
transform: [
{ translateX: this.spaceAnimatedTranslations.x },
{ translateY: this.spaceAnimatedTranslations.y }
]
};
}
onSpaceMove(event) {
this.spaceAnimatedTranslations.setValue({x: event.nativeEvent.translationX, y: event.nativeEvent.translationY});
}
render(){
return <PanGestureHandler
key={`test`}
onGestureEvent={e => this.onSpaceMove(e)}>
<Animated.View
ref={ref => {
this.testAnimatedView = ref;
}}
style={[this._animatedStyle]}>
<View style={styles._box_content}>
{someContent}
</View>
</Animated.View>
</PanGestureHandler>
}
}
You have to use Animated.event to do the mapping directly in native thread. See Tracking gestures. Other possibility would be to use react-native-reanimated with react-native-gesture-handler.
Related
In my app, I have a function which calls every 2s a bluetooth command to ask the current temperature of a device with a setInterval function.
The bluetooth response is given by monitored function. I use react native-ble-plx library for that.
I have no problem with this process.
The temperature is returned via a property which is dispatched via redux in an action file.
But when I "dispatch" (via redux) the function to my screen, I have a short interrupt which causes a laggy/jerky behavior. In my case, I have a slide to unlock button, and on my device when the dispatch is call, the touch operation is interrupted, and become not intuitive and annoying. It's difficult to explain the problem, but my question is simple, how I have to set react-redux not to be laggy, or not interrupt current user interaction on redux dispatch ?
My app, is based on this project structure (for react-redux with Ble) : https://github.com/momolarson/BLEServiceDiscovery
Environement:
react-native: 0.63.3
react-native-ble-plx: 2.0.2
react-redux: 7.2.1
This is pseudo code of my app (the code is more longer, but I have excluded all other by remove them) :
HomeScreen.js
import stuff[...]
class HomeScreen extends Component {
componentDidMount() {
this.timer = setInterval(() => {
this.props.readTemp();
}, 2000);
}
render() {
const { value } = this.state
return (
<>
<ScrollView>
<Text>{this.props.temperatture}"></Text>
<Slide2Unlock/>
</ScrollView>
</>
);
}
}
function mapStateToProps(state) {
return {
temperature: state.temperature,
};
}
const mapDispatchToProps = dispatch => ({
readTemp: () => bluetooth.readTemp(),
})
export default connect(mapStateToProps, mapDispatchToProps())(HomeScreen);
redux's action file : actionBt.js (my file is based on this https://github.com/momolarson/BLEServiceDiscovery/blob/master/actions/index.js)
[...]
device.monitorCharacteristicForService(
characteristicData.serviceUUID,
characteristicData.uuid,
(error, characteristic) => {
if (characteristic != null && characteristic.value != null) {
dispatch(formatTemperature(characteristic.value));
}
},
);
thanks for your help
Update 1
I make a specific version of my app, without bluetooth, just the slide to unlock module and a watcher with setInterval, and still have a laggy behavior, when the state is dispatched. I have done tests with button only, when I tap then show the value via dispatch, it's still the same trouble.
this my test code, index.js (redux action file)
export const readTemp = () => {
return (dispatch, getState, DeviceManager) => {
const state = getState();
console.log("READ TEMP");
dispatch(temperatureSensor( Math.random(0,9) ))
}
}
function BLEservices(BLEServices) {
setInterval(() => {
BLEServices.readTemp();
}, 2500);
return (
<SafeAreaView style={styles.container}>
<Slider
childrenContainer={{ }}
onEndReached={() => {
console.log('REACHED')
}}
containerStyle={{
height:40,
margin: 8,
backgroundColor: "#EEEEEE",
overflow: 'hidden',
alignItems: 'center',
justifyContent: 'center',
width: '50%',
}}
sliderElement={
<Text style={{color:"#FFF"}}>TEST</Text>
}
>
<Text style={{color: "#D5BD9E"}}>unlock</Text>
</Slider>
<Text>Temperature: {BLEServices.temperatureSensor}</Text>
</SafeAreaView>
);
}
thanks for your advice, and your help
Update 2
Solution found, see my answer below. The problem was type of var user in dispatch and some side effect due to previous test I have done on app and not clean them.
I solved my problem, by finding multiple var who are contains objects. I have a var which contain four attributes, I update and use one of them. And this object was update by my watcher. When I dispatch object to get a part of this object, I have to read the whole object, and this one is fully updated by my watchern which cause laggy render. So i have splitted that, to update only per var.
Another thing I've done, I split my interface elements in multi component, before, I has a lot of code in one screen, because I didn't need to reuse them elsewhere.
I'm having an issue with React-native where I have a component TouchTimer which uses an AnimatedTimer component. This timer is supposed to start and stop when it is tapped, which it does, however all of the TouchTimer components I add to a page will start and stop whenever any of them are tapped, rather than only affecting the tapped component.
Below is a snippet of my component:
TouchTimer.tsx
export class TouchTimer extends React.Component<TouchTimerProps> {
state: {
...
paused: boolean,
}
constructor(props) {
super(props);
...
this.state = {
...
paused: true,
}
}
startStop() {
this.setState({paused: !this.state.paused});
}
render() {
const { time } = this.props;
return (
<TouchableHighlight onPress={() => this.startStop()}>
<View>
<AnimatedTimer
...
time={time}
pause={this.state.paused}
/>
<View style={styles.timeContainer}>
<Text style={styles.time}>{this.state.remaining}</Text>
</View>
</View>
</TouchableHighlight>
)
}
}
And here is a snippet of the screen containing these components:
Details.tsx
import { TouchTimer } from '../components/TouchTimer';
...
export class RecipeDetailsScreen extends React.Component<NavigationInjectedProps> {
...
{this.state.steps.map(step => (
<List.Item
key={step.id}
title={"Step " + step.index}
style={styles.step}
description={step.short_desc}
right={() => (step.time > 0 &&
<TouchTimer
time={step.time * 60000}
/>
)}
/>
)
}
I have tried wrapping the TouchTimer components in a View and changing the paused boolean to a prop, to no avail.
I have also tested to see if this issue appears when the components are not siblings, and when they are not produced as the result of a callback, and the issue still persists in both these cases.
If anybody has any advice or answers on how to make these timers independent I would very much appreciate it!
Curiously that component seems to be implemented with a global pauseFlag that applies to all component instances. See https://github.com/dalisalvador/react-native-animated-timer/blob/master/src/Components/AnimatedTimer.js#L34
So I don't think you're doing anything wrong here, this is a limitation of the library code that is coupling all instances of your timer to the same pauseFlag value.
I created a very simple page in react native. However, I'm getting the warning:
Warning: Unsafe legacy lifecycles will not be called for components using new component APIs.
%s uses %s but also contains the following legacy lifecycles:%s%s%s
The above lifecycles should be removed. Learn more about this warning here:
https://reactjs.org/blog/2018/03/27/update-on-async-rendering.html, Styled(PickerNB), getDerivedStateFromProps(), ,
UNSAFE_componentWillReceiveProps,
It is happening because the native-base Picker. If I remove the picker, I do not receive the warning.
...
class ChangeProperty extends Component {
constructor(props) {
super(props);
this.state = {
selectedProperty: '1'
};
}
componentDidMount() {
this.props.getProperties(); // It just loads a properties data from action component
}
onChangeProperty(value) {
this.setState({
selectedProperty: value
});
}
updatePropertyBTN = async () => {
await AsyncStorage.setItem('CurrentPropertyID', this.state.selectedProperty);
NavigationService.navigate('iRent');
}
...
<Picker
mode="dropdown"
iosHeader="Select Property"
placeholder="Property"
iosIcon={<Icon name="arrow-down" />}
selectedValue={this.state.selectedProperty}
textStyle={{ color: '#C0C0C0' }}
style={{ width: '100%' }}
onValueChange={(text) => this.onChangeProperty(text)}
>
{Object.keys(this.props.properties).map((key) => {
return (
<Picker.Item
label={this.props.properties[key]}
value={key}
key={key}
/>
);
})}
</Picker>
}
It is not causing any error in my code, but the warning message in the terminal is disturbing me because I do not know what is causing it.
Thanks
The warning is occurring because the NativeBase picker appears to be using legacy life cycle methods (eg componentWillReceiveProps like was mentioned in the warning) that are no longer supported by React - this has nothing to do with your code.
Ensure your NativeBase is updated to the latest package version and if it is you can raise an issue on their repo here
I'm trying to call a function that will fire upon onFoucs on TextInput that will scroll the scrollView all the way down (using scrollToEnd())
so this is my class component
class MyCMP extends Component {
constructor(props) {
super(props);
this.onInputFocus = this.onInputFocus.bind(this);
}
onInputFocus() {
setTimeout(() => {
this.refs.scroll.scrollToEnd();
console.log('done scrolling');
}, 1);
}
render() {
return (
<View>
<ScrollView ref="scroll">
{ /* items */ }
</ScrollView>
<TextInput onFocus={this.onInputFocus} />
</View>
);
}
}
export default MyCMP;
the component above works and it does scroll but it takes a lot of time ... I'm using setTimeout because without it its just going down the screen without calculating the keybaord's height so it not scrolling down enough, even when I keep typing (and triggering that focus on the input) it still doesn't scroll all the way down.
I'm dealing with it some good hours now, I did set the windowSoftInputMode to adjustResize and I did went through some modules like react-native-keyboard-aware-scroll-view or react-native-auto-scroll but none of them really does the work as I need it.
any direction how to make it done the right way would be really appreciated. thanks!
Rather than using a setTimeout you use Keyboard API of react-native. You add an event listener for keyboard show and then scroll the view to end. You might need to create some logic on which input is focused if you have more than one input in your component but if you only have one you can just do it like the example below.
Another good thing to do is changing your refs to functional ones since string refs are considered as legacy and will be removed in future releases of react. More info here.
class MyCMP extends Component {
constructor(props) {
super(props);
this.scroll = null;
this.keyboardDidShowListener = Keyboard.addListener('keyboardDidShow', this._keyboardDidShow.bind(this));
}
componentWillUnmount () {
this.keyboardDidShowListener.remove();
}
_keyboardDidShow() {
this.scroll.scrollToEnd();
}
render() {
return (
<View>
<ScrollView ref={(scroll) => {this.scroll = scroll;}}>
{ /* items */ }
</ScrollView>
<TextInput />
</View>
);
}
}
export default MyCMP;
If you have a large dataset React Native docs is telling you to go with FlatList.
To get it to scroll to bottom this is what worked for me
<FlatList
ref={ref => (this.scrollView = ref)}
onContentSizeChange={() => {
this.scrollView.scrollToEnd({ animated: true, index: -1 }, 200);
}}
/>
I have a component in React Native which updates it's state once it knows what size it is.
Example:
class MyComponent extends Component {
...
render() {
...
return (
<View onLayout={this.onLayout.bind(this)}>
<Image source={this.state.imageSource} />
</View>
);
}
onLayout(event) {
...
this.setState({
imageSource: newImageSource
});
}
...
}
This gives the following error:
Warning: setState(...): Cannot update during an existing state transition (such as within render or another component's constructor). Render methods should be a pure function of props and state; constructor side-effects are an anti-pattern, but can be moved to componentWillMount.
I guess the onLayout function is called while still rendering (which can be good, the sooner the update, the better). What is the correct way to solve this problem?
Thanks in advance!
We got around this by using the measure function, you will have to wait until the scene is fully complete before measuring to prevent incorrect values (i.e. in componentDidMount/componentDidUpdate). Here's an example:
measureComponent = () => {
if (this.refs.exampleRef) {
this.refs.exampleRef.measure(this._logLargestSize);
}
}
_logLargestSize = (ox, oy, width, height, px, py) => {
if (height > this.state.measureState) {
this.setState({measureState:height});
}
}
render() {
return (
<View ref = 'exampleRef' style = {{minHeight: this.props.minFeedbackSize}}/>
);
}
Here is a solution from documentation for such cases
class MyComponent extends Component {
...
render() {
...
return (
<View>
<Image ref="image" source={this.state.imageSource} />
</View>
);
}
componentDidMount() {
//Now you can get your component from this.refs.image
}
...
}
But for my opinion it's better to do such things onload