【问题标题】:When i want to delete one item in my list, everything gets deleted Expo, React Native当我想删除列表中的一项时,一切都会被删除 Expo, React Native
【发布时间】:2021-02-02 06:29:36
【问题描述】:
This is my app.js

我的应用程序的主体。 ... 导入反应,{ useState } 从“反应”; 进口 { 样式表, 文本, 看法, 按钮, 文本输入, 平面列表, } 来自“反应原生”; 从“./components/GoalItem”导入 GoalItem; 从“./components/GoalInput”导入GoalInput;

export default function App() {
  const [lifeGoals, setLifeGoals] = useState([]);

  const addGoalHandler = (goalTitle) => {
    setLifeGoals((currentGoals) => [
      ...currentGoals,
      { key: Math.random().toString(), value: goalTitle },
    ]);
  };

  const removeGoalHandler = (goalId) => {
    setLifeGoals((currentGoals) => {
      return currentGoals.filter((goal) => goal.id !== goalId);
    });
  };
  return (
    <View style={styles.Screen}>
      <GoalInput onAddGoal={addGoalHandler} />
      <FlatList
        keyExtractor={(item, index) => item.id}
        data={lifeGoals}
        renderItem={(itemData) => (
          <GoalItem
            id={itemData.item.id}
            onDelete={removeGoalHandler}
            title={itemData.item.value}
          />
        )}
      />
    </View>
  );
}

const styles = StyleSheet.create({
  Screen: {
    padding: 50,
  },
});
...
This is my GoalItem which houses my list
...
import React from "react";
import { StyleSheet, View, Text, TouchableOpacity } from "react-native";

const GoalItem = (props) => {
  return (
    <TouchableOpacity onPress={props.onDelete.bind(this, props.id)}>
      <View style={styles.ListItem}>
        <Text>{props.title}</Text>
      </View>
    </TouchableOpacity>
  );
};

const styles = StyleSheet.create({
  ListItem: {
    padding: 10,
    marginVertical: 10,
    backgroundColor: "#CCFFFF",
    borderRadius: 15,
  },
});

export default GoalItem;
...
This is my GoalInput which handles the userinput and appending onto the list
...
import React, { useState } from "react";
import { View, TextInput, Button, Stylesheet, StyleSheet } from "react-native";

const GoalInput = (props) => {
  const [enteredGoal, setEnteredGoal] = useState("");

  const InputGoalHandler = (enteredText) => {
    setEnteredGoal(enteredText);
  };

  return (
    <View style={styles.inputContainer}>
      <TextInput
        placeholder="Enter Task Here"
        style={styles.InputBox}
        onChangeText={InputGoalHandler}
        value={enteredGoal}
      />
      <Button title="add" onPress={props.onAddGoal.bind(this, enteredGoal)} />
    </View>
  );
};

const styles = StyleSheet.create({
  InputBox: {
    borderColor: "black",
    borderWidth: 0,
    padding: 10,
    width: "80%",
  },
  inputContainer: {
    flexDirection: "row",
    justifyContent: "space-between",
    alignItems: "center",
  },
});

export default GoalInput;

... 我相信关键可能是问题,但我真的不确定。应该发生的是,当您单击列表中的某个项目时,它应该被删除,但是它正在删除我的整个列表。我该如何解决这个问题?

【问题讨论】:

  • 尝试拼接而不是过滤看看w3schools.com/js/js_array_methods.asp。过滤器只返回那些匹配大小写的元素。在您上面的代码中,您正在设置过滤产品,以防给您选择(比如说已删除)项目

标签: javascript react-native expo


【解决方案1】:
const removeGoalHandler = (goalId) => {
    setLifeGoals(lifeGoals.filter((m) => m.id !== goalId.id));
  };

  <FlatList
        keyExtractor={(item) => item.id}
        data={lifeGoals}
        renderItem={(itemData) => (
          <GoalItem
            onDelete={removeGoalHandler}
            title={itemData.item.value}
          />
        )}
      />

const GoalItem = ({onDelete, title}) => {
  return (
    <TouchableOpacity onPress={onDelete}>
      <View style={styles.ListItem}>
        <Text>{title}</Text>
      </View>
    </TouchableOpacity>
  );
};


试试这个

【讨论】:

  • 您的 GoalItems 只是您想在平面列表中使用的组件,对吧?
  • 它似乎不起作用,因为它说缺少返回语句
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