The problem you're facing is that the injectJavaScript method in your React Native WebView isn't executing the showMiddlemarker and hideMiddlemarker functions as expected. This is a common issue when working with WebView and JavaScript injection, and it usually boils down to timing, scope, or communication issues between React Native and the WebView.

• Use onMessage to debug and confirm the functions are being called.
• Use onLoadEnd instead of onLoad to ensure the WebView is fully loaded.
• Try adding more logs to where is the issue exactly share logs here