Javascript 无法在React native中显示本机Android视图
我正试图在我的Javascript视图中显示一个简单的Javascript 无法在React native中显示本机Android视图,javascript,java,android,react-native,react-native-android,Javascript,Java,Android,React Native,React Native Android,我正试图在我的Javascript视图中显示一个简单的文本视图。但是,应用程序会无声地失败,我只看到默认的“Hello World” RCTScannerViewManager.java public class RCTScannerViewManager extends SimpleViewManager<TextView> { public static final String REACT_CLASS = "RCTScannerView"; @Overrid
文本视图
。但是,应用程序会无声地失败,我只看到默认的“Hello World”
RCTScannerViewManager.java
public class RCTScannerViewManager extends SimpleViewManager<TextView> {
public static final String REACT_CLASS = "RCTScannerView";
@Override
public String getName() {
return REACT_CLASS;
}
@Override
protected TextView createViewInstance(ThemedReactContext reactContext) {
TextView tv = new TextView(reactContext);
tv.setText("hello from android !");
return tv;
}
}
public class RCTScannerViewPackage implements ReactPackage {
@Override
public List<NativeModule> createNativeModules(ReactApplicationContext reactContext) {
return Collections.emptyList();
}
@Override
public List<Class<? extends JavaScriptModule>> createJSModules() {
return Collections.emptyList();
}
@Override
public List<ViewManager> createViewManagers(ReactApplicationContext reactContext) {
return Arrays.<ViewManager> asList(
new RCTScannerViewManager()
);
}
}
@Override
protected List<ReactPackage> getPackages() {
return Arrays.<ReactPackage>asList(
new MainReactPackage(),
new RCTScannerViewPackage()
);
}
};
公共类RCTScannerViewManager扩展了SimpleViewManager{
公共静态最终字符串REACT\u CLASS=“RCTScannerView”;
@凌驾
公共字符串getName(){
返回一个类;
}
@凌驾
受保护的TextView createViewInstance(主题reactContext reactContext){
TextView tv=新的TextView(反应上下文);
tv.setText(“安卓你好!”);
返回电视;
}
}
RCTScannerViewPackage.java
public class RCTScannerViewManager extends SimpleViewManager<TextView> {
public static final String REACT_CLASS = "RCTScannerView";
@Override
public String getName() {
return REACT_CLASS;
}
@Override
protected TextView createViewInstance(ThemedReactContext reactContext) {
TextView tv = new TextView(reactContext);
tv.setText("hello from android !");
return tv;
}
}
public class RCTScannerViewPackage implements ReactPackage {
@Override
public List<NativeModule> createNativeModules(ReactApplicationContext reactContext) {
return Collections.emptyList();
}
@Override
public List<Class<? extends JavaScriptModule>> createJSModules() {
return Collections.emptyList();
}
@Override
public List<ViewManager> createViewManagers(ReactApplicationContext reactContext) {
return Arrays.<ViewManager> asList(
new RCTScannerViewManager()
);
}
}
@Override
protected List<ReactPackage> getPackages() {
return Arrays.<ReactPackage>asList(
new MainReactPackage(),
new RCTScannerViewPackage()
);
}
};
公共类RCTScannerViewPackage实现了ReactPackage{
@凌驾
公共列表createNativeModules(ReactApplicationContext reactContext){
返回集合。emptyList();
}
@凌驾
public List我怀疑这与您忘记为组件添加布局属性有关
据我所知,React Native仅通过其定制的Flexbox布局引擎(目前为Yoga)进行布局。因此,如果您不指定任何Flexbox属性,它将不会附加任何本机视图,或者附加宽度/高度/x/y为0的视图
帮助了我很多,并且有一个有效的解决方案
更具体地说,我认为这样做应该会起到作用:
import React, { Component } from 'react'
import { AppRegistry, Text, View } from 'react-native';
import ScannerView from './ScannerView';
class AwesomeProject extends Component {
render() {
return (
<View style={styles.container}>
<Text style={styles.hello}> Hello world </Text>
<ScannerView style={styles.scannerview}></ScannerView>
</View>
);
}
}
var styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
},
hello: {
fontSize: 20,
textAlign: 'center',
margin: 10
},
scannerview: {
height: 100,
width: 100,
},
});
AppRegistry.registerComponent('AwesomeProject', () => AwesomeProject)
import React,{Component}来自“React”
从“react native”导入{AppRegistry,Text,View};
从“/ScannerView”导入ScannerView;
类AwesomeProject扩展组件{
render(){
返回(
你好,世界
);
}
}
var styles=StyleSheet.create({
容器:{
弹性:1,
为内容辩护:“中心”,
},
您好:{
尺寸:20,
textAlign:'中心',
差额:10
},
scannerview:{
身高:100,
宽度:100,
},
});
AppRegistry.registerComponent('AwesomeProject',()=>AwesomeProject)
成功了,非常感谢!这些样式是否覆盖了视图中设置的维度。onDraw
?您指的是本机Android布局属性(LayoutParams)?如果是这样,那么是的,您在ViewManager的本机端设置的值将被React本机框架覆盖。正如我所写的,RN使用一个完全独立的布局系统,本机Android LayoutParams与此无关。明白了,非常感谢!我在这方面已经坚持了近一个月,并转到了其他项目ts.你在我被放回RN的那天回答:)