Question

我有一个webview片段，我想使用内置的Android后退按钮返回上一页。

package kyfb.android.kyfb.com.kyfb;

import android.app.Fragment;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.ProgressBar;
import android.widget.Toast;

/**
 * Created by Adam Rayborn on 8/25/14.
 */
public class MyKYFB extends Fragment {

    public WebView web;
    private ProgressBar progressBar;

    private String url;

    private static final String SP_LAST_WEBVIEW_URL = "com.app.kyfb.LASTWEBVIEWURL";

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        super.onCreateView(inflater, container, savedInstanceState);
        View rootView = inflater.inflate(R.layout.fragment_my_kyfb, null);

        url = "https://my.kyfb.com";

        web = (WebView)rootView.findViewById(R.id.kyfb_web);
        progressBar = (ProgressBar)rootView.findViewById(R.id.prgPageLoading);

        web.getSettings().setDomStorageEnabled(true);
        web.getSettings().setJavaScriptEnabled(true);
        web.getSettings().setSupportZoom(true);
        web.getSettings().setBuiltInZoomControls(true);
        web.getSettings().setRenderPriority(WebSettings.RenderPriority.HIGH);
        web.getSettings().setCacheMode(WebSettings.LOAD_NO_CACHE);
        web.getSettings().setDefaultZoom(WebSettings.ZoomDensity.FAR);


        SharedPreferences sharedPrefs = getActivity().getPreferences(Context.MODE_PRIVATE);
        String savedUrl = sharedPrefs.getString("URL", null);
        if (savedUrl != null) {
            web.loadUrl(savedUrl);
        }
        else {
            web.loadUrl(url);
        }

        web.setWebChromeClient(new WebChromeClient() {
            public void onProgressChanged(WebView webView, int progress) {
                getActivity().setProgress(progress * 100);  
                progressBar.setProgress(progress);
            }
        });

        // this.getView().setFocusableInTouchMode(true);
        rootView.setFocusableInTouchMode(true);

        web.setWebViewClient(new WebViewClient() {
            @Override
            public void onPageStarted(WebView view, String url, Bitmap favicon) {
                super.onPageStarted(web, url, favicon);
                progressBar.setVisibility(View.VISIBLE);
            }

            @Override
            public void onPageFinished(WebView view, String url) {
                super.onPageFinished(web, url);
                progressBar.setProgress(0);
                progressBar.setVisibility(View.GONE);

                SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);
                SharedPreferences.Editor editor = sharedPref.edit();
                editor.putString("URL", web.getUrl());
                editor.apply();
            }

            public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
                Toast.makeText(getActivity(), description, Toast.LENGTH_SHORT).show();
            }



            public boolean shouldOverrideUrlLoading(WebView view, String url)
            {
                if(url.endsWith(".mp4") || url.endsWith(".3gp") || url.endsWith(".avi") || url.endsWith(".flv") || url.endsWith(".pdf")){
                    Intent i = new Intent(Intent.ACTION_VIEW);
                    i.setData(Uri.parse(url));
                    startActivity(i); //warning no error handling will cause force close if no media player on phone.
                    return true;
                }

                view.loadUrl(url);
                return true;
            }
        });

        this.getActivity().onBackPressed();

        return rootView;
    }
}

在我加载此片段的主要活动中，我已覆盖onBackPressed（）

@Override
    public void onBackPressed() {
        Fragment webview = getFragmentManager().findFragmentByTag("webview");
        if (webview instanceof MyKYFB) {
            boolean goback = ((MyKYFB) webview).web.canGoBack();
            if (!goback) {
                super.onBackPressed();
            } else {
                ((MyKYFB) webview).web.goBack();
            }
        }
    }

通过这样做并调用this.getActivity.onBackPressed（）;在片段中，后退按钮不做任何事情，但如果有的话，它不会转到上一页。

Answer 1

According to this link

For Fragment

@Override
 public void onBackPressed() {
       Fragment webview = getSupportFragmentManager().findFragmentByTag("webview");
       if (webview instanceof MyWebViewFragment) {
              boolean goback = ((MyWebViewFragment)webview).canGoBack();
              if (!goback)
                super.onBackPressed();
       }
 }

对于活动，不要为rootView设置setOnKeyListener，只需在onCreate方法之外和类内放置onKeyDown方法

    imports ....;

    public WebView myWebView;

    public class MainActivity extends AppcompatActivity {
    ..
    protected void onCreate(Bundle savedInstanceState) {
WebView myWebView = (WebView) findViewById(R.id.webview);

    ..}


    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        // Check if the key event was the Back button and if there's history
        if ((keyCode == KeyEvent.KEYCODE_BACK) && myWebView.canGoBack()) {
            myWebView.goBack();
            return true;
        }
        // If it wasn't the Back key or there's no web page history, bubble up to the default
        // system behavior (probably exit the activity)
        return super.onKeyDown(keyCode, event);
    }
    }

返回Web视图中的上一页

1 个答案: