問題描述

我在Fragment的布局中放置了一個WebView，想監聽WebView的返回鍵，該如何實現？

@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; }}); }

這樣監聽沒用

問題解答

Fragment 本身是沒有 Activity#onBackPressed() 這樣的接口的, 所以需要 Activity 主動通知 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; }}