每次当 kotlin 中的 webview url 更改时，都需要使用 url 更新 textview

Question

Trying make a simple browser, and can't set a fild that will showing current webview's url. Tried override functions, but always says that "name of function" overrides nothing. Also can add that webview is within fragment. Maybe i can call this from mainactivity, but idk how. webview_fragment.kt

 package com.example.webviewapp import android.content.ContentValues.TAG import android.graphics.Bitmap import android.os.Bundle import android.util.Log import android.view.LayoutInflater import android.view.View import android.view.ViewGroup import android.webkit.WebView import android.webkit.WebViewClient import android.widget.TextView import android.widget.Toast import androidx.activity.OnBackPressedCallback import androidx.fragment.app.Fragment class webview_fragment : Fragment(){ override fun onCreateView( inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle? ): View? { val view : View = inflater.inflate(R.layout.layout_webview_fragment, container, false) val mWebView : WebView = view.findViewById(R.id.webViewMain) mWebView.loadUrl("https://google.com") val webSettings = mWebView.getSettings() webSettings.setJavaScriptEnabled(true) mWebView.setWebViewClient(WebViewClient()) requireActivity() .onBackPressedDispatcher .addCallback(viewLifecycleOwner, object : OnBackPressedCallback(true) { override fun handleOnBackPressed() { Log.d(TAG, "Fragment back pressed invoked") if (mWebView.canGoBack()){ mWebView.goBack() } else { requireActivity().finishAndRemoveTask() } } } ) mWebView.webViewClient = object : WebViewClient(){ override fun onPageFinished(view: WebView?, url: String?) { super.onPageFinished(view, url) val urlText: TextView? = view?.findViewById(R.id.urlText) val mWebView : WebView? = view?.findViewById(R.id.webViewMain) urlText?.setText(mWebView?.getUrl()) } } return view } }

mainactivity.kt

 package com.example.webviewapp import android.content.ContentValues.TAG import android.content.Context import androidx.appcompat.app.AppCompatActivity import android.os.Bundle import android.util.Log class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) if (getSharedPreferences("app", Context.MODE_PRIVATE).getBoolean("Boolean", false) == false) { supportFragmentManager .beginTransaction() .replace(R.id.fullcreen_holder, start_fragment()) .commit() } else { supportFragmentManager .beginTransaction() .replace(R.id.fullcreen_holder, webview_fragment()) .commit() } } }

Answer 1

You can simply get the web url from the webView like this

binding.webView.webViewClient = object : WebViewClient() {
            override fun onPageStarted(view: WebView?, url: String?, favicon: Bitmap?) {
                super.onPageStarted(view, url, favicon)
                Log.d("onPageStarted ","${view?.url} ")
            }

            override fun onPageFinished(view: WebView?, url: String?) {
                super.onPageFinished(view, url)
                Log.d("onPageFinished ","${view?.url} ")
            }
        }

There are few issues in your code

val view : View = inflater.inflate(R.layout.layout_webview_fragment, container, false)

mWebView.webViewClient = object : WebViewClient(){
        override fun onPageFinished(view: WebView?, url: String?) {
            super.onPageFinished(view, url)
            val urlText: TextView? = view?.findViewById(R.id.urlText)
            val  mWebView : WebView? = view?.findViewById(R.id.webViewMain)
            urlText?.setText(mWebView?.getUrl())
        }
    }

In the above code the textView you are trying to access it from the WebView's view instead from your fragment's view that's why you are facing the issue, you should rename the reference to the webView in override fun onPageFinished(view: WebView?, url: String?) to resolve the conflict.

Answer 2

You can simply do it like this,

YOUR_WEBVIEW.apply {
        webChromeClient = object : WebChromeClient() {
            override fun onReceivedTitle(view: WebView?, title: String?) {
                super.onReceivedTitle(view, title)
                YOUR_TEXTVIEW.text = title.toString()
            }
        }
}

it will update the text view automatically every time you move to another web page.