How to implement curved-start only bottom navigation bar in react/react-native?

Question

I want to make such bottom navigation bar, the curve is fixed there and does not move when you press the tab buttons, tried both svg paths and d3-shapes But could not manage to find the correct points/dimensions to make the end curve

Edit: The provided answer does not suit my case, as it heavily uses absolutely positioned elements and its not flexible with different screens, following that way will cause the bottom navigation bar (which heavily needs a relative layout) to have a-lot of layout and visual bugs

Answer 1

You should use react-native-svg

import React, { Component } from "react";
import {
  Text,
  StyleSheet,
  View,
  Dimensions,
  TouchableHighlight,
} from "react-native";
import Svg, { Circle, Path } from "react-native-svg";

const tabs = [1, 2, 3, 4, 5];
export default class App extends Component {
  constructor(props) {
    super(props);
    this.state = {
      pathX: "357",
      pathY: "675",
      pathA: "689",
      pathB: "706",
    };
  }
  render() {
    return (
      <View style={[styles.container]}>
        <View style={[styles.content]}>
          <View style={styles.subContent}>
            {tabs.map((_tabs, i) => {
              return (
                <TouchableHighlight
                  key={i}
                  underlayColor={"transparent"}
                  onPress={() => console.log("onPress")}
                >
                  <View>
                  </View>
                </TouchableHighlight>
              );
            })}
          </View>
          <Svg
            version="1.1"
            id="bottom-bar"
            x="0px"
            y="0px"
            width="100%"
            height="100"
            viewBox="0 0 1092 260"
            space="preserve"
          >
            <Path
              fill={"#373A50"}
              stroke={"#373A50"}
              d={`M30,60h${this.state.pathX}.3c17.2,0,31,14.4,30,31.6c-0.2,2.7-0.3,5.5-0.3,8.2c0,71.2,58.1,129.6,129.4,130c72.1,0.3,130.6-58,130.6-130c0-2.7-0.1-5.4-0.2-8.1C${this.state.pathY}.7,74.5,${this.state.pathA}.5,60,${this.state.pathB}.7,60H1062c16.6,0,30,13.4,30,30v94c0,42-34,76-76,76H76c-42,0-76-34-76-76V90C0,73.4,13.4,60,30,60z`}
            />
            <Circle
              fill={"#7EE6D2"}
              stroke={"#7EE6D2"}
              cx="546"
              cy="100"
              r="100"
            />
          </Svg>
        </View>
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    overflow: "hidden",
  },
  content: {
    flexDirection: "column",
    zIndex: 0,
    width: Dimensions.get("window").width - 30,
    marginBottom: "4%",
    left: "4%",
    right: "4%",
    position: "absolute",
    bottom: "1%",
  },
  subContent: {
    flexDirection: "row",
    marginLeft: 15,
    marginRight: 15,
    marginBottom: 10,
    zIndex: 1,
    position: "absolute",
    bottom: 5,
  }
});

The above code will make a rounded view you can update it according to your requirement.