Action bar back button not working in webview

Question

In my android webView the back button present in the android action bar is not working whereas the hardware button works perfectly, I even have a menu button present in the action bar that works too.

Java file

    public class online extends AppCompatActivity{

    private WebView webView;
    private ImageButton btn_webview;

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

        String userAgent = "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.4) Gecko/20100101 Firefox/4.0";

        webView = (WebView) findViewById(R.id.webview);
        webView.setWebViewClient(new WebViewClient());
        webView.getSettings().setUserAgentString(userAgent);
        webView.getSettings().setJavaScriptEnabled(true);
        webView.getSettings().setJavaScriptCanOpenWindowsAutomatically(true);
        webView.loadUrl("https://kotlinlang.org/docs/reference/");

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    }

    @Override
    public void onBackPressed() {
        if(webView.canGoBack()){
            webView.goBack();
        }else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        int id = item.getItemId();

        if(id == R.id.btn_home)
        {
            Intent intent = new Intent(this, MainActivity.class);
            startActivity(intent);
            this.finish();
        }
        return super.onOptionsItemSelected(item);
    }
}

Answer 1

Try this Use android.R.id.home

@Override
    public boolean onOptionsItemSelected(MenuItem item) {

        int id = item.getItemId();

        if (id == android.R.id.home) {
            Toast.makeText(this, "Back Button clicked", Toast.LENGTH_SHORT).show();
            Intent intent = new Intent(this, MainActivity.class);
            startActivity(intent);
            this.finish();
        }
        return super.onOptionsItemSelected(item);
    }