Issue 4399 - Add WebView inheritor with ad blocking

libadblockplus-android-webviewapp/src/org/adblockplus/libadblockplus/android/webviewapp/MainActivity.java

+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-2016 Eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.adblockplus.libadblockplus.android.webviewapp;
+
+import org.adblockplus.libadblockplus.android.settings.Adblock;
+import org.adblockplus.libadblockplus.android.webview.AdblockWebView;
+
+import android.app.Activity;
+import android.content.Intent;
+import android.graphics.Bitmap;
+import android.os.Bundle;
+import android.view.View;
+import android.view.inputmethod.InputMethodManager;
+import android.webkit.WebChromeClient;
+import android.webkit.WebView;
+import android.webkit.WebViewClient;
+import android.widget.Button;
+import android.widget.EditText;
+import android.widget.ProgressBar;
+
+public class MainActivity extends Activity
+{
+  public static final boolean DEVELOPMENT_BUILD = true;
+
+  // webView can create AdblockEngine instance itself if not passed with `webView.setAdblockEngine()`
+  public static final boolean USE_EXTERNAL_ADBLOCKENGINE = true;
+
+  // adblock retain() may be long-running, pass `true` to do it in background thread
+  public static final boolean ADBLOCKENGINE_RETAIN_ASYNC = true;
+
+  private ProgressBar progress;
+  private EditText url;
+  private Button ok;
+  private Button back;
+  private Button forward;
+  private Button settings;
+
+  private AdblockWebView webView;
+
+  @Override
+  protected void onCreate(Bundle savedInstanceState)
+  {
+    super.onCreate(savedInstanceState);
+    setContentView(R.layout.activity_main);
+
+    bindControls();
+    initControls();
+  }
+
+  private void bindControls()
+  {
+    url = (EditText) findViewById(R.id.main_url);
+    ok = (Button) findViewById(R.id.main_ok);
+    back = (Button) findViewById(R.id.main_back);
+    forward = (Button) findViewById(R.id.main_forward);
+    settings = (Button) findViewById(R.id.main_settings);
+    progress = (ProgressBar) findViewById(R.id.main_progress);
+    webView = (AdblockWebView) findViewById(R.id.main_webview);
+  }
+
+  private void setProgressVisible(boolean visible)
+  {
+    progress.setVisibility(visible ? View.VISIBLE : View.INVISIBLE);
+  }
+
+  private WebViewClient webViewClient = new WebViewClient()
+  {
+    @Override
+    public void onPageStarted(WebView view, String url, Bitmap favicon)
+    {
+      setProgressVisible(true);
+
+      // show updated URL (because of possible redirection)
+      MainActivity.this.url.setText(url);
+    }
+
+    @Override
+    public void onPageFinished(WebView view, String url)
+    {
+      setProgressVisible(false);
+      updateButtons();
+    }
+
+    @Override
+    public void onReceivedError(WebView view, int errorCode, String description, String failingUrl)
+    {
+      updateButtons();
+    }
+  };
+
+  private void updateButtons()
+  {
+    back.setEnabled(webView.canGoBack());
+    forward.setEnabled(webView.canGoForward());
+  }
+
+  private WebChromeClient webChromeClient = new WebChromeClient()
+  {
+    @Override
+    public void onProgressChanged(WebView view, int newProgress)
+    {
+      progress.setProgress(newProgress);
+    }
+  };
+
+  private void initControls()
+  {
+    ok.setOnClickListener(new View.OnClickListener()
+    {
+      @Override
+      public void onClick(View view)
+      {
+        loadUrl();
+      }
+    });
+
+    back.setOnClickListener(new View.OnClickListener()
+    {
+      @Override
+      public void onClick(View v)
+      {
+        loadPrev();
+      }
+    });
+
+    forward.setOnClickListener(new View.OnClickListener()
+    {
+      @Override
+      public void onClick(View v)
+      {
+        loadForward();
+      }
+    });
+
+    if (USE_EXTERNAL_ADBLOCKENGINE)
+    {
+      settings.setOnClickListener(new View.OnClickListener()
+      {
+        @Override
+        public void onClick(View v)
+        {
+          navigateSettings();
+        }
+      });
+    }
+    else
+    {
+      /*
+      We're able to show settings if we're using Adblock facade only.
+      Otherwise pass AdblockEngine instance to the fragments and not it's neither Serializable nor Parcelable.
+       */
+      settings.setVisibility(View.GONE);
+    }
+
+    initAdblockWebView();
+
+    setProgressVisible(false);
+    updateButtons();
+
+    // to get debug/warning log output
+    webView.setDebugMode(DEVELOPMENT_BUILD);
+
+    // render as fast as we can
+    webView.setAllowDrawDelay(0);
+
+    // to show that external WebViewClient is still working
+    webView.setWebViewClient(webViewClient);
+
+    // to show that external WebChromeClient is still working
+    webView.setWebChromeClient(webChromeClient);
+  }
+
+  private void navigateSettings()
+  {
+    startActivity(new Intent(this, SettingsActivity.class));
+  }
+
+  private void initAdblockWebView()
+  {
+    if (USE_EXTERNAL_ADBLOCKENGINE)
+    {
+      // external adblockEngine
+      Adblock.get().retain(ADBLOCKENGINE_RETAIN_ASYNC);
+
+      if (!ADBLOCKENGINE_RETAIN_ASYNC)
+      {
+        webView.setAdblockEngine(Adblock.get().getEngine());
+      }
+    }
+    else
+    {
+      // AdblockWebView will create internal AdblockEngine instance
+    }
+  }
+
+  private void hideSoftwareKeyboard()
+  {
+    InputMethodManager imm = (InputMethodManager)getSystemService(INPUT_METHOD_SERVICE);
+    imm.hideSoftInputFromWindow(url.getWindowToken(), 0);
+  }
+
+  private void loadPrev()
+  {
+    hideSoftwareKeyboard();
+    if (webView.canGoBack())
+    {
+      webView.goBack();
+    }
+  }
+
+  private void loadForward()
+  {
+    hideSoftwareKeyboard();
+    if (webView.canGoForward())
+    {
+      webView.goForward();
+    }
+  }
+
+  private String prepareUrl(String url)
+  {
+    if (!url.startsWith("http"))
+      url = "http://" + url;
+
+    // make sure url is valid URL
+    return url;
+  }
+
+  private void loadUrl()
+  {
+    hideSoftwareKeyboard();
+
+    // if retained with `true` we need to make sure it's ready now
+    if (USE_EXTERNAL_ADBLOCKENGINE && ADBLOCKENGINE_RETAIN_ASYNC)
+    {
+      Adblock.get().waitForReady();
+      webView.setAdblockEngine(Adblock.get().getEngine());
+    }
+    webView.loadUrl(prepareUrl(url.getText().toString()));
+  }
+
+  @Override
+  protected void onDestroy()
+  {
+    webView.dispose(new Runnable()
+    {
+      @Override
+      public void run()
+      {
+        if (USE_EXTERNAL_ADBLOCKENGINE)
+        {
+          Adblock.get().release();
+        }
+      }
+    });
+
+    super.onDestroy();
+  }
+}