之前因為Fragment，不能監聽返回鍵，所以把Fragment返回監聽，放在了FragmentActivity上。

FragmentActivity.java

 @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {
            if (fragment instanceof RechargeSuccessFragment
                    || fragment instanceof
 
 HuifuWithdrawalSuccessFragment) {
                finish();
            } else {
                popBackStack();
            }
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }

後來又加上要監聽webview返回，對之前程式碼不太滿意。後修改如下：

Fragment.java

mWebView.setOnKeyListener(new View.OnKeyListener() {
            @Override
            public
 
 boolean onKey(View v, int keyCode, KeyEvent event) {
                if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {
                    if (mWebView != null && mWebView.canGoBack()) {
                        mWebView.goBack();
                    } else {
                        mActivity.popBackStack();
                    }
                    return
 
 true;
                }
                return  false;
            }
        });

搞定！