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.

score 3 · Accepted Answer · answered Sep 03 '13 at 11:57

3

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

answered Sep 03 '13 at 11:57

Raghunandan

132,755
26
225
256

Yeah it works!! You're right i've forgotten to remove `WebView`. Thank you so much – David_D Sep 03 '13 at 12:05

score 0 · Answer 2 · edited May 23 '17 at 12:29

0

@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

edited May 23 '17 at 12:29

Community

1
1

answered Sep 03 '13 at 11:57

kjurkovic

4,044
2
23
28

1

He's getting a NPE as webView is null. – gunar Sep 03 '13 at 11:57
see what Raghunandan (http://stackoverflow.com/a/18591751/508126) wrote.. that is your solution – kjurkovic Sep 03 '13 at 12:02

score 0 · Answer 3 · answered Sep 03 '13 at 11:58

0

Try this way

Do not override onKeyDown() method

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

answered Sep 03 '13 at 11:58

Biraj Zalavadia

28,348
10
61
77

how implement the back button in webview?

3 Answers3