解决react-native软键盘弹出挡住输入框的问题

import React, {Component} from 'react';
import { View, Text, Button, StyleSheet, TextInput, ScrollView, KeyboardAvoidingView, Dimensions } from 'react-native';
import { StackActions, NavigationActions, withNavigation } from 'react-navigation';
const {width, height} = Dimensions.get('window');
class ChangePassword extends Component {
static navigationOptions = {
headerStyle: {
elevation: 0, //去除安卓手机header的样式
},
};
constructor(props) {
super(props);
this.state = {
isTrue: false,
text: '',
text1: '',
};
}
onChangeText = (text1) =  {
this.setState({
text1
},()=  {
if (this.state.text1.length  = 8) {
this.setState({
isTrue: true
})
} else if (this.state.text1.length < 8) {
this.setState({
isTrue: false
})
}
})
}
render() {
return (
<ScrollView style={styles.container} 
<KeyboardAvoidingView behavior="position" keyboardVerticalOffset = {120}  
<Text style={styles.title} 修改密码</Text 
<Text style={styles.totst} 密码为8-16位，须包含数字、字母2中元素</Text 
<TextInput
style={styles.textinput}
placeholder="请输入初始密码"
placeholderTextColor = "#cccccc"
maxLength = {16}
value={this.state.value}
secureTextEntry = {true}
onChangeText={(text) =  this.setState({text})}
/ 
<Text style={styles.Line} </Text 
<TextInput
style={styles.textinput}
placeholder="请输入新密码"
placeholderTextColor = "#cccccc"
maxLength = {16}
secureTextEntry = {true}
onChangeText={this.onChangeText}
/ 
<Text style={styles.Line} </Text 
{
this.state.isTrue == true ? <Text style={styles.errorconfirm} onPress={() =  {
alert('你点击了确认，该跳转了！~')
// this.props.navigation.navigate('ChangePassword')
}} 确认</Text  : <Text style={styles.confirm} 确认</Text 
}
</KeyboardAvoidingView 
</ScrollView 
);
}
}
const styles = StyleSheet.create({
container: {
height: height,
padding: 16,
},
title: {
color: '#4a4a4a',
fontSize: 23,
fontFamily: 'PingFangSC-Semibold',
},
totst: {
color: '#999999',
fontFamily: 'PingFang-SC-Medium',
fontSize: 13,
marginTop: 16,
},
Line: {
height: 1,
backgroundColor: '#d8d8d8',
},
textinput: {
marginTop: 50,
color: '#4a4a4a',
fontSize: 18,
},
errorconfirm: {
marginTop: 44,
height: 44,
lineHeight: 44,
textAlign: 'center',
fontSize: 16,
color: '#ffffff',
backgroundColor: '#25A3FF',
borderRadius: 4,
},
confirm: {
marginTop: 44,
height: 44,
lineHeight: 44,
textAlign: 'center',
fontSize: 16,
color: '#ffffff',
backgroundColor: '#cccccc',
borderRadius: 4,
}
})
export default withNavigation(ChangePassword);