android - Fragment中的WebView如何监听其返回监听事件？

Question

我在Fragment的布局中放置了一个WebView，想监听WebView的返回键，该如何实现？

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        getView().setOnKeyListener(new View.OnKeyListener() {
            @Override
            public boolean onKey(View v, int keyCode, KeyEvent event) {
                if ((keyCode == KeyEvent.KEYCODE_BACK) && webview.canGoBack()) {
                    webview.goBack();
                    return true;
                }
                return false;
            }
        });
    }

这样监听没用

Answer 1

Fragment sendiri tidak mempunyai antara muka seperti Activity#onBackPressed(), jadi Activity perlu memaklumkan secara proaktif Fragment :

public class ActivityA extends Activity {
    ... ...
    
    @Override
    public void onBackPressed() {
        FragmentA fragment = findFragmentA();
        if (fragment.onBackPressed()) {
            return ;
        }
        
        super.onBackPressed();
    }
}

public class FragmentA extends Fragment {
    public boolean onBackPressed() {
        if (webview.canGoBack()) {
            webview.goBack();
            return true;
        }
        
        return false;
    }
}