React native 如何在Android上使用react原生svg在屏幕上绘图?
我希望圆圈在移动时留下痕迹,但到目前为止它没有。圆圈会四处移动,但svg不会呈现在屏幕上。我似乎找不出哪里出了问题 代码如下:React native 如何在Android上使用react原生svg在屏幕上绘图?,react-native,react-native-android,React Native,React Native Android,我希望圆圈在移动时留下痕迹,但到目前为止它没有。圆圈会四处移动,但svg不会呈现在屏幕上。我似乎找不出哪里出了问题 代码如下: export default class App extends Component { constructor(props){ super(props); this._panResponder={}; this._previousLeft = 0; this._previousTop = 0; this._circleSty
export default class App extends Component {
constructor(props){
super(props);
this._panResponder={};
this._previousLeft = 0;
this._previousTop = 0;
this._circleStyles = {};
this.circle = null;
this.state={
coordinates: []
}
}
draw(x,y){
this.state.coordinates.push([x,y]);
var moves = "V" + this._previousLeft + " " + x + " H" + this._previousTop + " " + y;
console.log(moves)
return(
<Svg height={200} width={200}>
<Path
d = {moves}
fill = "blue"
stroke ="red"
strokeWidth={2}
/>
</Svg>
)
}
componentWillMount(){
this._panResponder = PanResponder.create({
onStartShouldSetPanResponder: this._handleStartShouldSetPanResponder,
onMoveShouldSetPanResponder: this._handleMoveShouldSetPanResponder,
onPanResponderGrant: this._handlePanResponderGrant,
onPanResponderMove: this._handlePanResponderMove,
onPanResponderRelease: this._handlePanResponderEnd,
onPanResponderTerminate: this._handlePanResponderEnd,
});
this._previousLeft = 20;
this._previousTop = 84;
this._circleStyles = {
style: {
left: this._previousLeft,
top: this._previousTop,
backgroundColor: 'green',
}
};
}
componentDidMount() {
this._updateNativeStyles();
}
render() {
return (
<View style={styles.container}>
<View style={styles.circle}
ref={(circle) => {
this.circle = circle;
}}
{ ...this._panResponder.panHandlers }
/>
</View>
);
}
_highlight = () => {
this._circleStyles.style.backgroundColor = 'blue';
this._updateNativeStyles();
}
_unHighlight = () => {
this._circleStyles.style.backgroundColor = 'green';
this._updateNativeStyles();
}
_updateNativeStyles() {
this.circle && this.circle.setNativeProps(this._circleStyles);
}
_handleStartShouldSetPanResponder() {
return true;
}
_handleMoveShouldSetPanResponder() {
return true;
}
_handlePanResponderGrant = () => {
this._highlight();
}
_handlePanResponderMove = (e, gestureState) => {
this._circleStyles.style.left = this._previousLeft + gestureState.dx;
this._circleStyles.style.top = this._previousTop + gestureState.dy;
this.draw(this._circleStyles.style.left, this._circleStyles.style.top)
this._updateNativeStyles();
}
_handlePanResponderEnd = (e, gestureState) => {
this._unHighlight();
this._previousLeft += gestureState.dx;
this._previousTop += gestureState.dy;
}
}
const styles = StyleSheet.create({
circle: {
width: CIRCLE_SIZE,
height: CIRCLE_SIZE,
borderRadius: CIRCLE_SIZE / 2,
position: 'absolute',
left: 0,
top: 0,
},
container: {
flex: 1,
paddingTop: 64,
},
});
导出默认类应用程序扩展组件{
建造师(道具){
超级(道具);
这个._panResponder={};
这个。_previousLeft=0;
这是.\u previousTop=0;
这个。_circleStyles={};
this.circle=null;
这个州={
坐标:[]
}
}
绘制(x,y){
这个.state.coordinates.push([x,y]);
var moves=“V”+此._previousLeft+“”+x+“H”+此._previousTop+“”+y;
console.log(移动)
返回(
)
}
组件willmount(){
这是.\u panResponder=panResponder.create({
onStartShouldSetPanResponder:这个。\你的手应该是SetPanResponder,
onMoveShouldSetPanResponder:此.\u handleMoveShouldSetPanResponder,
onPanResponderGrant:这个,
onPanResponderMove:这个。_handlePanResponderMove,
onPanResponderRelease:这个。\u handlePanResponderRend,
onPanResponderTerminate:这个。\u handlePanResponderRend,
});
这个。_先前左=20;
这个._previousTop=84;
这._circleStyles={
风格:{
左:这个,
上图:这个,
背景颜色:“绿色”,
}
};
}
componentDidMount(){
这是。_updatenavivestyles();
}
render(){
返回(
{
这个圆=圆;
}}
{…这个。_panResponder.panHandlers}
/>
);
}
_突出显示=()=>{
这个._circleStyles.style.backgroundColor='蓝色';
这是。_updatenavivestyles();
}
_不高亮度=()=>{
这个._circleStyles.style.backgroundColor='绿色';
这是。_updatenavivestyles();
}
_updateNativeStyles(){
this.circle&&this.circle.setNativeProps(this.\u circleStyles);
}
_handleStartShouldSetPanResponder(){
返回true;
}
_handleMoveShouldSetPanResponder(){
返回true;
}
_handlePanResponderGrant=()=>{
这个;
}
_handlePanResponderMove=(e,手势状态)=>{
this.\u circleStyles.style.left=this.\u previousLeft+gestureState.dx;
this.\u circleStyles.style.top=this.\u previousTop+gestureState.dy;
this.draw(this.\u circleStyles.style.left,this.\u circleStyles.style.top)
这是。_updatenavivestyles();
}
_HandlePanResponseRend=(e,手势状态)=>{
这个。_unHighlight();
这._previousLeft+=gestureState.dx;
这._previousTop+=gestureState.dy;
}
}
const styles=StyleSheet.create({
圆圈:{
宽度:圆圈大小,
高度:圆形尺寸,
边界半径:圆圈大小/2,
位置:'绝对',
左:0,,
排名:0,
},
容器:{
弹性:1,
paddingTop:64,
},
});