undefined is not a function(evaluating '_this2.AlertButton()')? - react-native

Question

I create touchableopacity for every item in map. it works well but when I give function to TouchableOpacity like below, it gives me error which is on title. How can I fix this ?
it gives error when I write this.AlertButton()
{section.subcategory.map((item, key) => (
<View key={key} style={styles.item}>
<TouchableOpacity
onPress={() =>this.AlertButton()}>
</TouchableOpacity>
<View style={styles.separator} />
</View>
))}
This is my alert function :
AlertButton() {
const number = 'TelNo';
Alert.alert(
'',
'Test',
[
{text: 'NO'},
{text: 'Yes', onPress: () => Linking.openURL(`tel:${number}`)},
],
);
}
Here is render. And my map function which is above is in renderContent
render() {
CONTENT2 =[];
CONTENT2 = this.state.fromPage1;
return (
<View style={styles.container}>
<View style={{height: this.state.yuksek, width: this.state.genis, justifyContent: 'center', alignItems: 'center',position:'absolute'}}>
<Text style={{fontWeight: 'bold', color:'#856F6F'}}>Yukarıdaki menü butonlarına tıklayınız.</Text>
</View>
<View style={{height: this.state.yuksek2, width: this.state.genis2, justifyContent: 'center', alignItems: 'center'}}>
<Text style={{fontWeight: 'bold', color:'#856F6F'}}>String</Text>
</View>
<ScrollView contentContainerStyle={{}}>
<Accordion
activeSections={this.state.activeSections}
sections={CONTENT2}
touchableComponent={TouchableOpacity}
expandMultiple={false}
renderHeader={this.renderHeader}
renderContent={this.renderContent}
duration={400}
onChange={this.setSections}
/>
</ScrollView>
<View style={{height:85, width:85,position:'absolute',bottom:5,right:5}}>
<TouchableOpacity style={{flex:1}} onPress={() => this.AlertButton()}>
<ImageBackground source={require('../../image/phoneCall.png')} style={{flex:1}}>
</ImageBackground>
</TouchableOpacity>
</View>
</View>
);
}
}

Answer 1

just change the following line
renderContent={this.renderContent}
to
renderContent={this.renderContent.bind(this)}
because when you are using the class method directly as callback then its not definitely bound to its class when called from inside the component