从webview片段导航到不同的片段后，如何在webview中返回？

Question

I have been trying to figure out a way to go back within WebView after leaving the WebView fragment . The dilemma is as follows:

1. I load the WebView fragment page1.html
2. Then I navigate within it such that page1.html?navigate=page2.html .
3. Then I navigate to a different Fragment on click of some event in the WebView fragment , say I click a symbol that brings in "NotAwebviewfragment.java"
4. Then I click back from notawebviewfragment then it takes me to the WebView page I left from. However when I click back again it take me to the previous Fragment that was open before WebView .
5. Now If I stay within the WebViewFragment I can navigate back and forth as desired. However, once I leave it, it gives me access to the WebView only once.

Here's the code so far: Within the webview:

public boolean webViewSteppedBack() {       
        if (webview != null && webview.canGoBack()) {   
            webview.goBack();
            return true;
        }
        return false;
    }

public boolean backPressed(final MainActivity mainActivity) {
    if (webViewSteppedBack()) {
         if(!EikonUtils.isTablet(getActivity())) {
            getActivity().setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
          }
            return true;
     }
     return false;
}

MainActivity (which contains the fragment navigation code for back):

    @Override
    public void onBackPressed() {
    final FragmentManager manager = getSupportFragmentManager();
    Fragment topFragment = FragmentStackManager.getInstance().getTopFragment();

         if (backPressListener != null) {
             boolean b = false;
 
             //Making sure we trigger the backPressed event if the listener is the top fragment
             String bplTag = ((Fragment) backPressListener).getTag();

             String topFragemtnTag = "";


             if (topFragment != null) {

                 topFragemtnTag = topFragment.getTag();

                 if (bplTag != null && topFragemtnTag != null && bplTag.equals(topFragemtnTag)) {   

                      b = backPressListener.backPressed(this);


                 } 


             }
             if (b) { return;  }        


             if (!NotAWebViewFragment.TAG_NOT.equals(bplTag)) {

                 backPressListener = null;

             } 


        }

    } 

Answer 1

You need to override this method in your fragment in which you are defining the webView.

webView.setOnKeyListener(new View.OnKeyListener() {
    @Override
    public boolean onKey(View v, int keyCode, KeyEvent event) {
        if (event.getAction() == KeyEvent.ACTION_DOWN) {
            if (keyCode == KeyEvent.KEYCODE_BACK) {
                switch (keyCode) {
                    case KeyEvent.KEYCODE_BACK:
                        if (mWebView.canGoBack()) {
                            mWebView.goBack();
                            return true;
                        }

                }
            }
        }
        return false;
    }
});

Answer 2

You can add all the fragment to the back stack . In activity's onBackPressed method, you can get the current active fragment. You can check if the active fragment is the instance of Awebviewfragment and if the webview can navigate back otherwise pop the current active fragment from the stack using popBackStack () method of fragment manager. Here are the code snippet: 1. to add fragment

private void addNotAwebviewfragment() { supportFragmentManager.beginTransaction(); FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction(); notAwebviewfragment = NotAwebviewfragment.newInstance("test", "test");

    fragmentTransaction.add(R.id.contents, notAwebviewfragment, NotAwebviewfragment.TAG_NOT).addToBackStack(NotAwebviewfragment.TAG_NOT);
    fragmentTransaction.commit();
}

private void addFragWebview(){
    FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();
    webViewFragment = Awebviewfragment.newInstance("test", "test");
    webViewFragment.setFragmentListener(weblistener);
    backPressListener = webViewFragment;
    fragmentTransaction.add(R.id.contents, webViewFragment, Awebviewfragment.TAG).addToBackStack(Awebviewfragment.TAG);
    fragmentTransaction.commit();
}

2. In onBackPRessed() in main activity: @Override public void onBackPressed() {

    Fragment fragment = getActiveFragment(); if(fragment instanceof Awebviewfragment){ System.out.println("web view fragment"); if(backPressListener != null && backPressListener.backPressed(this)){ System.out.println("web view fragment will return"); return; } } int count = supportFragmentManager.getBackStackEntryCount(); if (count > 0 ){ supportFragmentManager.popBackStackImmediate(); }else { super.onBackPressed(); } 

   }

3. get active fragment: public Fragment getActiveFragment() { if (supportFragmentManager.getBackStackEntryCount() == 0) { return null; } String tag = supportFragmentManager.getBackStackEntryAt(supportFragmentManager.getBackStackEntryCount() - 1).getName(); return supportFragmentManager.findFragmentByTag(tag); }

you can check with the sample committed in the github .