can someone help me with this error? I click a button to go to a page with video(webview) E FATAL EXCEPTION: main Process: com.example.markethub, PID: 7025 java.lang.IllegalStateException: Could not execute method for android:onClick at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:473) at android.view.View.performClick(View.java:8028) at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1131) at android.view.View.performClickInternal(View.java:8005) at android.view.View.-$$Nest$mperformClickInternal(Unknown Source:0) at android.view.View$PerformClick.run(View.java:31229) at android.os.Handler.handleCallback(Handler.java:959) at android.os.Handler.dispatchMessage(Handler.java:100) at android.os.Looper.loopOnce(Looper.java:232) at android.os.Looper.loop(Looper.java:317) at android.app.ActivityThread.main(ActivityThread.java:8705) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:580) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:886) Caused by: java.lang.reflect.InvocationTargetException at java.lang.reflect.Method.invoke(Native Method) at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:468) at android.view.View.performClick(View.java:8028) at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1131) at android.view.View.performClickInternal(View.java:8005) at android.view.View.-$$Nest$mperformClickInternal(Unknown Source:0) at android.view.View$PerformClick.run(View.java:31229) at android.os.Handler.handleCallback(Handler.java:959) at android.os.Handler.dispatchMessage(Handler.java:100) at android.os.Looper.loopOnce(Looper.java:232) at android.os.Looper.loop(Looper.java:317) at android.app.ActivityThread.main(ActivityThread.java:8705) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:580) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:886) Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.markethub/com.example.markethub.VideoActivity}; have you declared this activity in your AndroidManifest.xml, or does your intent not match its declared <intent-filter>? at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:2427) at android.app.Instrumentation.execStartActivity(Instrumentation.java:2005) at android.app.Activity.startActivityForResult(Activity.java:5874) at androidx.activity.ComponentActivity.startActivityForResult(ComponentActivity.java:728) at android.app.Activity.startActivityForResult(Activity.java:5832) at androidx.activity.ComponentActivity.startActivityForResult(ComponentActivity.java:709) at android.app.Activity.startActivity(Activity.java:6329) at android.app.Activity.startActivity(Activity.java:6296) at com.example.markethub.MainActivity.onSafeClick(MainActivity.java:38) at java.lang.reflect.Method.invoke(Native Method) at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:468) at android.view.View.performClick(View.java:8028) at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1131) at android.view.View.performClickInternal(View.java:8005) at android.view.View.-$$Nest$mperformClickInternal(Unknown Source:0) at android.view.View$PerformClick.run(View.java:31229) at android.os.Handler.handleCallback(Handler.java:959) at android.os.Handler.dispatchMessage(Handler.java:100) at android.os.Looper.loopOnce(Looper.java:232) at android.os.Looper.loop(Looper.java:317) at android.app.ActivityThread.main(ActivityThread.java:8705) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:580) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:886) ::::: the code of the video activity is:

package com.example.markethub;
import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.view.View;

public class VideoActivity extends AppCompatActivity {
private WebView webView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_video);

        WebView webView = findViewById(R.id.webView);
        String video ="<iframe width=\"100\" height=\"100\" src=\"<https://www.youtube.com/embed/ouPe8uEuC-k?si=VB-MaVo19lrkmqFy>\" title=\"YouTube video player\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen></iframe>";
        webView.loadData(video, "text/html","utf-8");
        webView.getSettings().setJavaScriptEnabled(true);
        webView.setWebChromeClient(new WebChromeClient());
    }

    public void onBackClick(View view) {
        finish();
}
}

Please don't post such walls of text to the main channel, that makes following the channel hard, especially on mobile. Better start with a short message and add details or longer snippets to the thread. Regarding the question, why do you at all ask it here? It has nothing at all to do with Gradle.

Looks like a problem with code, not Gradle.