未捕獲的錯誤：未定義不是物件（評估“_this.setState”）

經過大量研究后，每次在訊息框中輸入文本時都會出現此錯誤。

我洗掉了很多代碼 - 所以問題在于文本 Input 和 var state{ ... }

我不知道該怎么做

我計劃將來將資料提交到 SQLite 資料庫，但現在我只是試圖捕獲按鈕按下時的文本輸入 - 我在網上找到了一個腳本，但它不起作用。

  const JournalNewEntryScreen = ({navigation}) => {
  const messageImage = require('./images/Imatter-icons-13.png');
  const homeImage = require('./images/Imatter-icons-14.png');
  const settingsImage = require('./images/Imatter-icons-11.png');
  const journalHomeImage = require('./images/Imatter-icons-09.png');
  const cancelAlert = () =>
    Alert.alert(
      "Are You Sure?",
      "Any content will be deleted and cannot be recovered",
      [
        {
          text: "Cancel",
          style: "cancel"
        },
        { text: "Yes, I'm Sure", 
          onPress: () => navigation.navigate("JournalHome") }
      ]
    );
    var state = {
      message: '',
    }
    const getValues = () => {
      console.log(this.state.message);
    }
    
    
  return (
    <>
    
      <StatusBar barStyle='dark-content' />
      
         <SafeAreaView style={homePage.flexContainer}>
         <View style={{ flex: 1 }}>
            <ScrollView>
             <View style={JournalNewEntryPage.container}>
                <Image
                  source={require("./assets/images/cropped-img_1619-1-e1610564001477.png")}
                  resizeMode="contain"
                  style={JournalNewEntryPage.image}>

                </Image>
                <Text style={JournalNewEntryPage.myJournal}>New Journal Entry</Text>
                <Text style={JournalNewEntryPage.descriptionText}>
                  Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s
                </Text>
                <Text style={JournalNewEntryPage.messageText}>
                  Type a message
                </Text>
                <TextInput
                  multiline
                  editable
                  numberOfLines={4}
                  style={JournalNewEntryPage.textBox}
                  onChangeText={(text) => this.setState({ message: text })}
                />
                <Text style={JournalNewEntryPage.messageText}>
                  Attach a file:
                </Text>
                <Text style={JournalNewEntryPage.upload}>
                    Add a photo, audio or video file
                </Text>
                <TouchableOpacity onPress={() => this.getValues()}>
                  <Text style = {JournalNewEntryPage.journalButton}>
                    Save Entry
                  </Text>
                </TouchableOpacity>
                <TouchableOpacity onPress={cancelAlert}>
                  <Text style = {JournalNewEntryPage.journalButton}>
                    Cancel
                  </Text>
                </TouchableOpacity>
                <View style = {custom.spacer10}></View>
              </View>
             </ScrollView>
         </View>
         {/* <Button title="Reload" onPress={() => navigation.navigate('Home')}/> */}
         <View style={homePage.tabBarContainer}>
             <View style={homePage.column}>
             <TouchableOpacity onPress={hide ? dataButtonHandler : onPress1}>
                 <Text style={hide ? homePage.button : homePage.codeButton}>{hide ? "Data" : "XXXXXX"}</Text>
             </TouchableOpacity>
             </View>
             
             <View style={homePage.column}>
             <TouchableOpacity onPress={() => navigation.navigate('Home')}>
                 <Image style={homePage.navImage} source={homeImage}/>
             </TouchableOpacity>
             </View>
             <View style={homePage.column}>
             <TouchableOpacity onPress={() => navigation.navigate('JournalHome')}>
                 <Image style={homePage.navImage} source={journalHomeImage}/>
             </TouchableOpacity>
             </View>
             <View style={homePage.column}>
             <TouchableOpacity onPress={messagesButtonHandler}>
                 <Image style={homePage.navImage} source={messageImage}/>
             </TouchableOpacity>
             </View>
             <View style={homePage.column}>
             <TouchableOpacity onPress={() => navigation.navigate('Settings')}>
                 <Image style={homePage.navImage} source={settingsImage}/>
             </TouchableOpacity>
             </View>
             <View style={homePage.column}>
             <TouchableOpacity onPress={hide ? logButtonHandler : onPress3}>
                 <Text style={hide ? homePage.button : homePage.codeButton}>{hide ? "Logs" : "XXXXXX"}</Text>
             </TouchableOpacity>
             </View>
         </View>
         <View style={homePage.tabBarContainerText}>
             <View style={homePage.column}>
             </View>
             
             <View style={homePage.column}>
             <TouchableOpacity onPress={() => navigation.navigate('Home')}>
                 <Text style={homePage.button}>Home</Text>
             </TouchableOpacity>
             </View>
             <View style={homePage.column}>
             <TouchableOpacity onPress={() => navigation.navigate('JournalHome')}>
                 <Text style={homePage.button}>Journal</Text>
             </TouchableOpacity>
             </View>
             <View style={homePage.column}>
             <TouchableOpacity onPress={messagesButtonHandler}>
                 <Text style={homePage.button}>Messages</Text>
             </TouchableOpacity>
             </View>
             <View style={homePage.column}>
             <TouchableOpacity onPress={() => navigation.navigate('Settings')}>
                 <Text style={homePage.button}>Settings</Text>
             </TouchableOpacity>
             </View>
             <View style={homePage.column}>
             </View>
         </View>
         </SafeAreaView>
     </>      
  );


};

錯誤圖片

uj5u.com熱心網友回復：

您使用的不是基于類的功能組件，因此這不是宣告and的方法，這僅適用于基于類的組件。statessetState

因此，您需要查看此檔案以使用React Hooks https://reactnative.dev/docs/state處理狀態

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