Android Open Source - webview-gm Script Browser

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License

The source code is released under:

Apache License

Java Source Code

/*
 *    Copyright 2012 Werner Bayer//from w  w  w  . j a  va2 s  .c o  m
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

package at.pardus.android.webview.gm.store.ui;

import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import android.content.Context;
import android.graphics.Bitmap;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.inputmethod.EditorInfo;
import android.view.inputmethod.InputMethodManager;
import android.webkit.DownloadListener;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import at.pardus.android.webview.gm.model.Script;
import at.pardus.android.webview.gm.run.WebViewClientGm;
import at.pardus.android.webview.gm.run.WebViewGm;
import at.pardus.android.webview.gm.store.ScriptStore;
import at.pardus.android.webview.gm.util.UnicodeReader;
import at.pardus.webview.gm.R;

/**
 * Combines an address field and a WebView intercepting .user.js file downloads
 * to add them to a provided script store.
 */
public class ScriptBrowser {

  private static final String TAG = ScriptBrowser.class.getName();

  protected ScriptManagerActivity activity;

  protected ScriptStore scriptStore;

  private String startUrl;

  protected View browser;

  protected WebViewGm webView;

  protected EditText addressField;

  /**
   * Installs a new script.
   * 
   * Not to be run on the UI thread.
   * 
   * @param url
   *            the location of the script to install
   */
  protected void installScript(String url) {
    makeToastOnUiThread(activity.getString(R.string.starting_download_of)
        + " " + url, Toast.LENGTH_SHORT);
    String scriptStr = downloadScript(url);
    if (scriptStr == null) {
      makeToastOnUiThread(
          activity.getString(R.string.error_downloading_from) + " "
              + url, Toast.LENGTH_LONG);
      return;
    }
    Script script = Script.parse(scriptStr, url);
    if (script == null) {
      Log.d(TAG, "Error parsing script:\n" + scriptStr);
      makeToastOnUiThread(activity.getString(R.string.error_parsing_at)
          + " " + url, Toast.LENGTH_LONG);
      return;
    }
    scriptStore.add(script);
    makeToastOnUiThread(activity.getString(R.string.added_new_script) + " "
        + script, Toast.LENGTH_LONG);
  }

  /**
   * Downloads and returns a file as String.
   * 
   * Not to be run on the UI thread.
   * 
   * @param url
   *            the http address to get
   * @return the downloaded file as String or null on any error
   */
  protected String downloadScript(String url) {
    StringBuilder out = new StringBuilder();
    Reader in = null;
    HttpURLConnection con = null;
    char[] buffer = new char[4096];
    try {
      URL u = new URL(url);
      con = (HttpURLConnection) u.openConnection();
      con.setReadTimeout(5000);
      con.setRequestMethod("GET");
      con.setUseCaches(false);
      con.connect();
      InputStream is = con.getInputStream();
      in = new UnicodeReader(is, con.getContentEncoding());
      int bytesRead = 0;
      while ((bytesRead = in.read(buffer, 0, 4096)) != -1) {
        if (bytesRead > 0) {
          out.append(buffer, 0, bytesRead);
        }
      }
    } catch (MalformedURLException e) {
      Log.e(TAG, Log.getStackTraceString(e));
      return null;
    } catch (IOException e) {
      Log.e(TAG, Log.getStackTraceString(e));
      try {
        InputStream errorStream = con.getErrorStream();
        if (errorStream != null) {
          in = new UnicodeReader(errorStream, null);
          int bytesRead = 0;
          StringBuilder errorStr = new StringBuilder();
          while ((bytesRead = in.read(buffer, 0, 4096)) != -1) {
            if (bytesRead > 0) {
              errorStr.append(buffer, 0, bytesRead);
            }
          }
          in.close();
          Log.e(TAG, errorStr.toString());
        }
      } catch (Exception e1) {
      }
      return null;
    } catch (Exception e) {
      Log.e(TAG, Log.getStackTraceString(e));
      return null;
    } finally {
      try {
        in.close();
      } catch (Exception e) {
      }
      if (con != null) {
        con.disconnect();
      }
    }
    return out.toString();
  }

  /**
   * Inflates the WebViewGm from XML and sets up its WebViewClient,
   * WebChromeClient and DownloadListener. Also inflates and sets up the
   * address field EditText component.
   */
  private void init() {
    browser = (View) activity.getLayoutInflater().inflate(
        R.layout.script_browser, null);
    webView = (WebViewGm) browser.findViewById(R.id.webView);
    webView.setScriptStore(scriptStore);
    addressField = (EditText) browser.findViewById(R.id.addressField);
    addressField
        .setOnEditorActionListener(new EditText.OnEditorActionListener() {
          @Override
          public boolean onEditorAction(TextView v, int actionId,
              KeyEvent event) {
            if (actionId == EditorInfo.IME_ACTION_GO
                || actionId == EditorInfo.IME_NULL) {
              webView.loadUrl(v.getText().toString());
              webView.requestFocus();
              ((InputMethodManager) activity
                  .getSystemService(Context.INPUT_METHOD_SERVICE))
                  .hideSoftInputFromWindow(
                      v.getWindowToken(), 0);
              return true;
            }
            return false;
          }
        });
    webView.setWebViewClient(new ScriptBrowserWebViewClientGm(scriptStore,
        webView.getWebViewClient().getJsBridgeName(), webView
            .getWebViewClient().getSecret(), this));
    webView.setDownloadListener(new ScriptBrowserDownloadListener(this));
    webView.setWebChromeClient(new ScriptBrowserWebChromeClient(this));
    loadUrl(startUrl);
  }

  /**
   * Load the given URL.
   * 
   * @param url
   *            the address to load
   */
  public void loadUrl(String url) {
    addressField.setText(url);
    webView.loadUrl(url);
  }

  /**
   * @return the browser's last loaded address
   */
  public String getUrl() {
    return webView.getUrl();
  }

  /**
   * Constructor.
   * 
   * @param activity
   *            the application's activity
   * @param scriptStore
   *            the database to use
   */
  public ScriptBrowser(ScriptManagerActivity activity,
      ScriptStore scriptStore, String startUrl) {
    this.activity = activity;
    this.scriptStore = scriptStore;
    this.startUrl = startUrl;
    init();
  }

  /**
   * Goes back to the previous browser page.
   * 
   * @return false if the browser history is empty
   */
  public boolean back() {
    if (webView.canGoBack()) {
      webView.goBack();
      return true;
    }
    return false;
  }

  /**
   * Stops any browser activity.
   */
  public void pause() {
    webView.stopLoading();
    webView.pauseTimers();
  }

  /**
   * Resumes browser timers.
   */
  public void resume() {
    webView.resumeTimers();
  }

  /**
   * @return the browser view group
   */
  public View getBrowser() {
    return browser;
  }

  /**
   * @return the webView
   */
  public WebViewGm getWebView() {
    return webView;
  }

  /**
   * Displays a message created on the UI thread.
   * 
   * @param message
   *            the message to show
   * @param length
   *            the duration (use Toast.LENGTH_ constants)
   */
  private void makeToastOnUiThread(final String message, final int length) {
    activity.runOnUiThread(new Runnable() {
      public void run() {
        Toast.makeText(activity, message, length).show();
      }
    });
  }

  /**
   * WebViewClientGm component for the ScriptBrowser intercepting .user.js
   * downloads.
   */
  public static class ScriptBrowserWebViewClientGm extends WebViewClientGm {

    private ScriptBrowser scriptBrowser;

    /**
     * Constructor.
     * 
     * @param scriptStore
     *            the script database to query for scripts to run when a
     *            page starts/finishes loading
     * @param jsBridgeName
     *            the variable name to access the webview GM functions from
     *            javascript code
     * @param secret
     *            a random string that is added to calls of the GM API
     * @param scriptBrowser
     *            reference to its enclosing ScriptBrowser
     */
    public ScriptBrowserWebViewClientGm(ScriptStore scriptStore,
        String jsBridgeName, String secret, ScriptBrowser scriptBrowser) {
      super(scriptStore, jsBridgeName, secret);
      this.scriptBrowser = scriptBrowser;
    }

    @Override
    public boolean shouldOverrideUrlLoading(WebView view, final String url) {
      if (url.endsWith(".user.js")) {
        // TODO ask before installing new script
        new Thread() {
          public void run() {
            scriptBrowser.installScript(url);
          }
        }.start();
        return true;
      }
      return false;
    }

    @Override
    public void onPageStarted(WebView view, String url, Bitmap favicon) {
      scriptBrowser.addressField.setText(url);
      super.onPageStarted(view, url, favicon);
    }

    @Override
    public void onReceivedError(WebView view, int errorCode,
        String description, String failingUrl) {
      Toast.makeText(
          scriptBrowser.activity,
          scriptBrowser.activity
              .getString(R.string.error_while_loading)
              + " "
              + failingUrl + ": " + errorCode + " " + description,
          Toast.LENGTH_LONG).show();
    }

  }

  /**
   * DownloadListener for .user.js downloads.
   */
  public static class ScriptBrowserDownloadListener implements
      DownloadListener {

    private ScriptBrowser scriptBrowser;

    /**
     * Constructor.
     * 
     * @param scriptBrowser
     *            reference to its enclosing ScriptBrowser
     */
    public ScriptBrowserDownloadListener(ScriptBrowser scriptBrowser) {
      this.scriptBrowser = scriptBrowser;
    }

    @Override
    public void onDownloadStart(final String url, String userAgent,
        String contentDisposition, String mimetype, long contentLength) {
      if (url.endsWith(".user.js")) {
        // TODO ask before installing new script
        new Thread() {
          public void run() {
            scriptBrowser.installScript(url);
          }
        }.start();
      }
    }

  }

  /**
   * WebChromeClient setting the app's title and progress.
   */
  public static class ScriptBrowserWebChromeClient extends WebChromeClient {

    private ScriptBrowser scriptBrowser;

    /**
     * Constructor.
     * 
     * @param scriptBrowser
     *            reference to its enclosing ScriptBrowser
     */
    public ScriptBrowserWebChromeClient(ScriptBrowser scriptBrowser) {
      this.scriptBrowser = scriptBrowser;
    }

    @Override
    public void onProgressChanged(WebView view, int progress) {
      scriptBrowser.activity.setProgress(progress * 100);
    }

    @Override
    public void onReceivedTitle(WebView view, String title) {
      scriptBrowser.activity.setTitle(title);
    }

  }

}

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