网页视图片段:后退按钮和下载侦听器

Question

我使用Webview片段制作简单的Webview应用程序。应用程序工作正常。但问题是我单击后退按钮应用程序关闭。第二个问题是我点击HTML页面链接。链接未在默认浏览器中打开。错误显示网页未打开。我希望在相同的Web视图中打开所有选项卡，然后返回按钮和下载链接正常工作。 我的代码是

我的网络视图片段.java

package com.example.com;
import android.app.Fragment;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
public class MyWebViewFragment extends Fragment {
    ProgressDialog mProgress;
    WebView webview;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.web_fragment, container,
                false);
        Bundle bundle = getArguments();
        String url = bundle.getString("url");
        webview = (WebView) rootView.findViewById(R.id.webview1);
        WebSettings settings = webview.getSettings();
        settings.setJavaScriptEnabled(true);
        mProgress = ProgressDialog.show(getActivity(), "Loading",
                "Please wait for a moment...");
        webview.loadUrl(url);
        webview.setWebViewClient(new WebViewClient() {
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                view.loadUrl(url);
                return true;
            }
            @Override
            public void onPageFinished(WebView view, String url) {
                super.onPageFinished(view, url);
                if (mProgress.isShowing()) {
                    mProgress.dismiss();
                }
            }
        });
        return rootView;
    }
}

主要活动.java

package com.example.com;
import java.util.ArrayList;
import java.util.List;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.content.res.Configuration;
import android.content.res.TypedArray;
import android.os.Bundle;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.widget.DrawerLayout;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
public class MainActivity extends Activity {
    String[] menutitles;
    TypedArray menuIcons;
    String[] pageUrl;
    // nav drawer title
    private CharSequence mDrawerTitle;
    private CharSequence mTitle;
    private DrawerLayout mDrawerLayout;
    private ListView mDrawerList;
    private ActionBarDrawerToggle mDrawerToggle;
    private List<RowItem> rowItems;
    private CustomAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mTitle = mDrawerTitle = getTitle();
        menutitles = getResources().getStringArray(R.array.titles);
        menuIcons = getResources().obtainTypedArray(R.array.icons);
        pageUrl = getResources().getStringArray(R.array.pageurl);
        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
        mDrawerList = (ListView) findViewById(R.id.slider_list);
        rowItems = new ArrayList<RowItem>();
        for (int i = 0; i < menutitles.length; i++) {
            RowItem items = new RowItem(menutitles[i], menuIcons.getResourceId(
                    i, -1), pageUrl[i]);
            rowItems.add(items);
        }
        menuIcons.recycle();
        adapter = new CustomAdapter(getApplicationContext(), rowItems);
        mDrawerList.setAdapter(adapter);
        mDrawerList.setOnItemClickListener(new SlideitemListener());
        // enabling action bar app icon and behaving it as toggle button
        getActionBar().setDisplayHomeAsUpEnabled(true);
        getActionBar().setHomeButtonEnabled(true);
        mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
                R.drawable.ic_drawer, R.string.app_name,
                R.string.app_name) {
            public void onDrawerClosed(View view) {
                getActionBar().setTitle(mTitle);
                // calling onPrepareOptionsMenu() to show action bar icons
                invalidateOptionsMenu();
            }
            public void onDrawerOpened(View drawerView) {
                getActionBar().setTitle(mDrawerTitle);
                // calling onPrepareOptionsMenu() to hide action bar icons
                invalidateOptionsMenu();
            }
        };
        mDrawerLayout.setDrawerListener(mDrawerToggle);
        if (savedInstanceState == null) {
            // on first time display view for first nav item
            updateDisplay(0);
        }
    }
    class SlideitemListener implements ListView.OnItemClickListener {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position,
                long id) {
            updateDisplay(position);
        }
    }
    private void updateDisplay(int position) {
        String url = rowItems.get(position).getPageUrl();
        Fragment fragment = new MyWebViewFragment();
        Bundle bundle = new Bundle();
        bundle.putString("url", url);
        fragment.setArguments(bundle);
        FragmentManager fragmentManager = getFragmentManager();
        fragmentManager.beginTransaction()
                .replace(R.id.frame_container, fragment).commit();
        setTitle(menutitles[position]);
        mDrawerLayout.closeDrawer(mDrawerList);
    }
    @Override
    public void setTitle(CharSequence title) {
        mTitle = title;
        getActionBar().setTitle(mTitle);
    }
    @Override
   public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // toggle nav drawer on selecting action bar app icon/title
        if (mDrawerToggle.onOptionsItemSelected(item)) {
            return true;
        }
        // Handle action bar actions click
        switch (item.getItemId()) {
           case R.id.action_settings:
                return true;
          default:
             return super.onOptionsItemSelected(item);
        }
    }
    /***
     * Called when invalidateOptionsMenu() is triggered
     */
    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        // if nav drawer is opened, hide the action items
        boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
        menu.findItem(R.id.action_settings).setVisible(!drawerOpen);
        return super.onPrepareOptionsMenu(menu);
    }
    /**
     * When using the ActionBarDrawerToggle, you must call it during
     * onPostCreate() and onConfigurationChanged()...
     */
    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        // Sync the toggle state after onRestoreInstanceState has occurred.
        mDrawerToggle.syncState();
    }
    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        // Pass any configuration change to the drawer toggles
        mDrawerToggle.onConfigurationChanged(newConfig);
    }
}

Answer 1

要在 Web 视图中打开 URL，请使用代码

  protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
     webView = (WebView) findViewById(R.id.webView);
                WebSettings webSettings = webView.getSettings();
                webSettings.setJavaScriptEnabled(true);
                webSettings.setPluginState(WebSettings.PluginState.OFF);
                webSettings.setSupportMultipleWindows(true);
                webSettings.setBuiltInZoomControls(true);
                webSettings.setAppCacheMaxSize(1);
                webSettings.setCacheMode(WebSettings.LOAD_NO_CACHE);
                webSettings.setAppCacheEnabled(false);
        //        webView.setVerticalScrollBarEnabled(false);
        //        webView.setHorizontalScrollBarEnabled(false);
                webView.setWebChromeClient(new WebChromeClient());
                webView.clearCache(true);
        //        webView.setInitialScale(100);
        //        webView.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY);
                webView.setBackgroundColor(0);
                webView.setWebViewClient(new WebViewClient() {
                    @Override
                    public boolean shouldOverrideUrlLoading(WebView view, String url) {
                        view.loadUrl(url);
                        Log.e("", "shouldOverrideUrlLoading load url" + url);
                        return false;
                    }
                    public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
                        super.onReceivedError(view, errorCode, description, failingUrl);
                        isLoaded = false;
                        progressDialog.setMessage("Unknown Error!");
                        Handler handler = new Handler();
                        handler.postDelayed(new Runnable() {
                            public void run() {
                                try {
                                    progressDialog.dismiss();
                                } catch (Exception e) {
                                }
                            }
                        }, 1500);
                    }
                    public void onPageStarted(WebView view, String url, Bitmap favicon) {
                        super.onPageStarted(view, url, favicon);
                        displayProgress(getString(R.string.loading), getString(R.string.loading));
                        Log.e("onPageStarted",url);
                    }
                    public void onPageFinished(WebView view, String url) {
                        isLoaded = true;
                        super.onPageFinished(view, url);
                        Handler handler = new Handler();
                        handler.postDelayed(new Runnable() {
                            public void run() {
                                try {
                                    progressDialog.dismiss();
                                } catch (Exception e) {
                                }
                            }
                        }, 1500);
                    }
                });
    web_link = "https://twitter.com";
                        webView.loadUrl(web_link);
}
 public void displayProgress(String title,String mes){
        if (progressDialog!=null)
            progressDialog.dismiss();
        progressDialog = new ProgressDialog(MainActivity.this);
        //          progressDialog.setTitle(title);
        progressDialog.setMessage(mes);
        progressDialog.setIndeterminate(false);
        progressDialog.setCancelable(true);
        try {
            progressDialog.show();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

返回 Web 视图，请将此方法覆盖到您的活动

public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            if (web_link!=null && !webView.getUrl().equals(web_link))
                webView.goBack();
            else{
                AlertDialog.Builder builder = new AlertDialog.Builder(this);
                builder.setMessage(R.string.to_exit)
                        .setCancelable(false)
                        .setPositiveButton(getString(android.R.string.yes), new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int id) {
                                MainActivity.this.finish();
                            }
                        })
                        .setNegativeButton(getString(android.R.string.no), new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int id) {
                                dialog.cancel();
                            }
                        });
                AlertDialog alert = builder.create();
                alert.show();
            }
        }
        return super.onKeyDown(keyCode, event);
    }