How do you set such value? For example the number field must be less than 50.
how to use with maxLength={2} property,
how to validate it.. i want input number should be less than 50
here is my code..
ShowMaxAlert = (EnteredValue) =>{
this.setState({number: EnteredValue});
if(EnteredValue > 50)
{
alert('Maximum number')
}
}
<TextInput style={styles.input}
keyboardType={"numeric"}
underlineColorAndroid='#fff'
placeholder={'num'}
maxLength={2}
placeholderTextColor={'#ccc'}
onChangeText={ EnteredValue => this.ShowMaxAlert(EnteredValue) }
value={this.state.number} />
The maxLength prop is used to validate the maximum length of the text that is entered, here your requirement is to validate against a max number. Your logic should be like below.
ShowMaxAlert = (EnteredValue) => {
if (EnteredValue < 50) {
this.setState({number: EnteredValue});
} else {
alert('Maximum number');
}
};
Here the function will alert if the value is greater than 50, otherwise it will set the state which will update the value in the textbox.
How can I excatly do a similar Date system like the one in the Whatsapp chat screen?
As you can see the messages are in a group by date, I mean they are separated by date.
Here is a ScreenShot that i found for better explanation:
I do this in a FlatList, while rendering the messages one by one.
Here is what i did
let previousDate = "";
if (index > 0) {
previousDate = moment(this.state.messages[index - 1].created_at).format(
"L"
);
} else {
previousDate = moment(this.state.messages.created_at).format("L");
}
let currentDate = moment(item.created_at).format("L");
So, i created a functional component for renderItem prop of the FlatList, so item and index comes from the actual data from the FlatList.
What i'm trying to do here is, basically grabbing the current rendering item's created_at and compare it with the previous item's created_at, and to do that, i'm using the original data which is stored in the state. But unfortunately when the FlatList rendering the very first item which has index number 0 there is no previous element to compare in the original data in state, that's why i checking if is greater than 0 go and grab date from previous indexed item. And in the Else case, which means when rendering the first item, do not look for previous item and just get the created_at.
And below i check if the currentDate and previousDates are NOT the same, render a custom component else do not render anything.
{previousDate && !moment(currentDate).isSame(previousDate, "day") ? ( // custom component) : null}
It's should work like that, but the major problem is, i used inverted FlatList for to able to messages go from bottom of the screen to the top. But now, becouse of it's a inverted flatlist the items being rendering from bottom to the top and it gives me result like this:
NOTE: At the beginning the messages were coming also reversed but i fixed this with sending them also reversed from the DB.
So, i don't know how do i able to achieve my goal, and do it like on the first picture.
Thank you!
I use a helper function (generateItems) to address the problem that you are describing. Here is the code that I use to group my messages by day and then render either a <Message /> or a <Day /> in the renderItem prop. This is using an inverted FlatList as you described.
import moment from 'moment';
function groupedDays(messages) {
return messages.reduce((acc, el, i) => {
const messageDay = moment(el.created_at).format('YYYY-MM-DD');
if (acc[messageDay]) {
return { ...acc, [messageDay]: acc[messageDay].concat([el]) };
}
return { ...acc, [messageDay]: [el] };
}, {});
}
function generateItems(messages) {
const days = groupedDays(messages);
const sortedDays = Object.keys(days).sort(
(x, y) => moment(y, 'YYYY-MM-DD').unix() - moment(x, 'YYYY-MM-DD').unix()
);
const items = sortedDays.reduce((acc, date) => {
const sortedMessages = days[date].sort(
(x, y) => new Date(y.created_at) - new Date(x.created_at)
);
return acc.concat([...sortedMessages, { type: 'day', date, id: date }]);
}, []);
return items;
}
export default generateItems;
For reference here is my list as well as the renderItem function:
<MessageList
data={generatedItems}
extraData={generatedItems}
inverted
keyExtractor={item => item.id.toString()}
renderItem={renderItem}
/>
function renderItem({ item }) {
if (item.type && item.type === 'day') {
return <Day {...item} />;
}
return <Message {...item} />;
}
This is how i did it in react,
Create a new Set() to store dates uniquely
const dates = new Set();
When looping through chats array, check if date already exists in unique Set before rendering date
chats.map((chat) => {
// For easier uniqueness check,
// Formated date string example '16082021'
const dateNum = format(chat.timestamp, 'ddMMyyyy');
return (
<React.Fragment key={chat.chat_key}>
// Do not render date if it already exists in set
{dates.has(dateNum) ? null : renderDate(chat, dateNum)}
<ChatroomChatBubble chat={chat} />
</React.Fragment>
);
});
Finally, when date has been rendered, add date num into array so it doesn't render again
const renderDate = (chat, dateNum) => {
const timestampDate = format(chat.timestamp, 'EEEE, dd/MM/yyyy');
// Add to Set so it does not render again
dates.add(dateNum);
return <Text>{timestampDate}</Text>;
};
I have a custom component that provides the rendered list of data when the data is available.
But when the data is not available in the example case below where data=[], I want to apply a different style to it.
return (
<FollowableArticleListTemplate
style={hasData}
title={ title }
data={ [] }
isFollowing={ isFollowing }
onToggleFollow={ id ? () => toggleSourceFollow(id, isFollowing, title) : null }
setListRef={ this.setListRef }
contentType="source"
/>
);
What I'm looking for is something like this:
style={hasData}
i.e if the data.length > 0
use this style for this component: style={hasData}
otherwise use this style component: style={noData}
This is easily achieved by using the ternary operator. First, you have to conditionally use data using state, not by giving its value directly into the component.
return (
<FollowableArticleListTemplate
style={myData.length > 0 ? hasData : noData}
title={ title }
data={myData}//this is your state
isFollowing={ isFollowing }
onToggleFollow={ id ? () => toggleSourceFollow(id, isFollowing, title) : null }
setListRef={ this.setListRef }
contentType="source"
/>
);
```
So basically I want to be able to collect all the values from multiple inputs and set that array as a state. Here is what I am currently working with:
this.state.basket.map(b => {
return (
<View>
<InputSpinner
style={styles.spinnerQty}
max={50}
min={1}
step={1}
rounded={false}
showBorder
colorMax={"#2a292d"}
colorMin={"#2a292d"}
value={b.qty}
onChange={num => {
this.setState({ popUpQty: num });
}}
/>
<View style={styles.hrLine}></View>
</View>
);
});
So I am iterating my basket and setting a spinner with a value from axios output. So there are now multiple InputSpinner with multiple values.
My question is, how can I collect all the values of the onChange, and push it to an array which will eventually become a state. Something like QuantityState: [] would be the values of all the InputSpinner. Hope that made sense. Any help is appreciated. Thanks!
PS. InputSpinner is an npm package from here.
Through this code you can dynamically add/update onChange number on it's particular array instance. num key will be added when a particular onChange trigger so at the end you will get its values which placed on it's index and if key not found that means onChange never triggered for that index
state = {
spinnerData : {},
basket: []
}
this.state.basket.map((b, index) => {
return (
<View>
<InputSpinner
style={styles.spinnerQty}
max={50}
min={1}
step={1}
rounded={false}
showBorder
colorMax={"#2a292d"}
colorMin={"#2a292d"}
value={b.qty}
onChange={num => {
const newbasket = [...this.state.basket];
newbasket[index]["num"] = num;
this.setState({ basket:newbasket });
}}
/>
<View style={styles.hrLine}></View>
</View>
);
});
Hi as shown in the picture you canno't see the full text however I don't want to decrease the fonsize for all other items.
Only if it they're greater that 16 in length.
Can I return the fontSize in my renderTitleStyle method or can I do in within the ListItem props e.g {infoText.length > 16 ? (fontSize: 12) : (fontSize: 32)} However I don't think this works.
renderTitleStyle = item => {
const infoText = item.location_from + item.location_to;
if (infoText.length > 12) {
// Return fontSize ???
}
console.warn(infoText.length);
};
<ListItem
style={styles.activeUser}
onPress={() => this.toggleModalConfirmTrip(item)}
roundAvatar
subtitle={item.user[0].name}
titleStyle={this.renderTitleStyle(item)}
title={`${item.location_from} to ${item.location_to} `}
....[![Example of text not fitting][1]][1]
You should be able to set styles dynamically by passing an array of styles with a style array element that depends on a state or a conditional.
<Text style={[styles.mainStyles, {fontSize: ((infoText && infoText.length) > 16 ? 12 :32) }]}>
{/*other elements*/}
</Text>
In your specific case i would try passing that condictional as property for ListItem Component.
titleStyle={this._renderItemTitleStyle(item)}
dont forget to create the function.
_renderItemTitleStyle = (item) => {
if (item && Object.keys(item).length) {
const infoText = item.location_from + item.location_to;
return {fontSize: (infoText.length > 16 ? 12 :32)}
}
console.warn("param item has no properties");
}