how implement the back button in webview?

Question

I have a simple webview to shows a forum..i need "mapping" the back button to go back in the webpages of the forum of course. I tryied in This way but gets me a fatal error

public class MainActivity extends Activity
{
protected WebView webview;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    WebView webview = (WebView) findViewById(R.id.webview);
    WebSettings websettings = webview.getSettings();
    websettings.setJavaScriptEnabled(true);
    webview.setWebViewClient(new WebViewClient());
    if (savedInstanceState == null)
    {
        webview.loadUrl("http://www.proboards.com/");
    }

}

@Override
protected void onSavedInstanceState(Bundle outState) {
    //super.onSavedInstanceState(outState);

    webview.saveState(outState);
}

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    switch (keyCode) {
        case KeyEvent.KEYCODE_BACK:
            if(webview.canGoBack() == true)

                webview.goBack();
            else finish();
            break;

        default:
            break;
    }
    return super.onKeyDown(keyCode, event);
}
}

The error is onKeyDown line 42.

Answer 1

Change this

 WebView webview = (WebView) findViewById(R.id.webview); 
 // webview becomes local

To

 webview = (WebView) findViewById(R.id.webview); 

You have already declared

 WebView webview;

as a class member

Answer 2

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    switch (keyCode) {
        case KeyEvent.KEYCODE_BACK:
            if(webview.canGoBack() == true)

                webview.goBack();
            else finish();
            return true;
    }
    return super.onKeyDown(keyCode, event);
}

this is the duplicate of: How to go back to previous page if back button is pressed in WebView?

in any case you have to return true if you handled the key down action

Answer 3

Try this way

Do not override onKeyDown() method

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