WEBVIEW: Add another webview - ANDROID only! (#387)

Moved the 'webview' script from DemoAndroidLNjScheme into a module of its own; this module is a bit of a stub. Might receive updates to become a nicer looking browser. Meanwhile still intended to showcase how to call Java via jScheme

modules/webview/ANDROID_application_attributes

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+android:usesCleartextTraffic="true"

modules/webview/ANDROID_java_additions

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+class SchemeWebView extends android.webkit.WebView {
+  LNjScheme.Scheme interpreter = null;
+  SchemeWebViewClient client = null;
+
+  public void ln_log(String msg) {
+    interpreter.eval(LNjScheme.Scheme.list(LNjScheme.Scheme.sym("log-message"), msg.toCharArray()));
+  }
+
+  private Object iapply(Object fn, Object arg1, Object args) {
+    return interpreter.eval(LNjScheme.Scheme.cons(fn, LNjScheme.Scheme.cons(arg1, args)));
+  }
+
+  private Object iapply(Object fn, Object arg1) { 
+    return iapply(fn, arg1, null);
+  }
+
+  class SchemeWebViewClient extends android.webkit.WebViewClient {
+    public Object onloadresource = null;
+    public Object onpagefinished = null;
+    public Object onpagecomplete = null;
+
+    // LNjScheme.Scheme interpreter = null;
+    /*
+    SchemeWebViewClient(LNjScheme.Scheme interp) {
+      interpreter = interp;
+    }
+    */
+    public Object eval(Object expr) { return interpreter.eval(expr); }
+
+    public void onLoadResource(final android.webkit.WebView view, final String url) {
+      Object fn = onloadresource;
+      if(fn!=null) { iapply(fn, view, LNjScheme.Scheme.list(url.toCharArray())); }
+    }
+
+    public void onPageFinished(final android.webkit.WebView view, final String url) {
+      Object fn = onpagefinished;
+      if(fn!=null) { iapply(fn, view, LNjScheme.Scheme.list(url.toCharArray())); }
+      @IF_ANDROIDAPI_GT_22@
+      if(onpagecomplete!=null) {
+        view.postVisualStateCallback
+          (0,
+           new android.webkit.WebView.VisualStateCallback() {
+             public void onComplete(long requestId) {
+               interpreter.eval
+                 (LNjScheme.Scheme.cons
+                  (onpagecomplete,
+                   (LNjScheme.Scheme.list (view, url.toCharArray()))));
+             }});
+      }
+      /* end of IF_ANDROIDAPI_GT_22 */
+    }
+
+    public boolean shouldOverrideUrlLoading(final android.webkit.WebView view, String url) {
+      return false;
+    }
+
+    //*  These suppress the "favicon.ico" request
+    @Override
+    public android.webkit.WebResourceResponse shouldInterceptRequest(android.webkit.WebView view, String url) {
+      if(url.toLowerCase().contains("/favicon.ico")) {
+        return new android.webkit.WebResourceResponse("image/png", null, null);
+      }
+      return null;
+    }
+
+    @IF_ANDROIDAPI_GT_22@
+    @Override
+    public android.webkit.WebResourceResponse shouldInterceptRequest(android.webkit.WebView view, android.webkit.WebResourceRequest request) {
+      if(!request.isForMainFrame() && request.getUrl().getPath().endsWith("/favicon.ico")) {
+        return new android.webkit.WebResourceResponse("image/png", null, null);
+      }
+      return null;
+    }
+    /* end of IF_ANDROIDAPI_GT_22 */
+    // end of suppressing the "favicon.ico" request */
+  }
+
+  public SchemeWebView(android.content.Context context, LNjScheme.Scheme interp) {
+    super(context);
+    interpreter = interp;
+    client = new SchemeWebViewClient();
+    String http_proxy=java.lang.System.getenv("http_proxy");
+    String https_proxy=java.lang.System.getenv("https_proxy");
+    if(http_proxy!=null || https_proxy!=null) {
+      try {
+      ln_log("webview setting proxy to " + http_proxy /* + " and " + https_proxy*/);
+      int i = http_proxy.indexOf(':', 7);
+      String host = http_proxy.substring(7, i);
+      int port = Integer.parseInt(http_proxy.substring(i+1, http_proxy.length()));
+      if(!ProxySettings.setProxy(context, host, port)) {
+        ln_log("webview setting proxy FAILED");
+      }
+      /*
+      androidx.webkit.ProxyConfig.Builder pcb = new androidx.webkit.ProxyConfig.Builder();
+      if(http_proxy!=null) { pcb.addProxyRule(http_proxy); }
+      if(https_proxy!=null) { pcb.addProxyRule(https_proxy); }
+      // pcb.addDirect(); // if desired as fallback
+      */
+      } catch (Exception e) {
+        ln_log("Setting proxy failed: " + e);
+      }
+    }
+    setWebViewClient(client);
+  }
+
+  public Object SchemeSetProxy(Object args) {
+    return true; //NYI
+  }
+
+  public Object apply(LNjScheme.Scheme interpreter, Object args) {
+    Object key0 = LNjScheme.Scheme.first(args);
+    String key = null;
+    if(key0 instanceof String) { key = (String)key0; }
+    if(key == null) {
+      return LNjScheme.Scheme.error("webview: dispatch key missing");
+    } else if( key == "load" ) {
+      setVisibility(android.view.View.VISIBLE);
+      Object a1 = LNjScheme.Scheme.second(args);
+      if(a1 instanceof char[]) { loadUrl(new String((char[])a1)); return true; }
+      else { return LNjScheme.Scheme.error("webview: not a URL " + a1); }
+    } else if( key == "redraw" ) {
+      ln_log("webview redraw");
+      setVisibility(android.view.View.VISIBLE); //onResume();// onDraw(); // that might have to be something else!
+      onPause();
+      onResume();
+      return true;
+    } else if( key == "setproxy" ) {
+      return SchemeSetProxy(LNjScheme.Scheme.rest(args));
+    } else if( key == "onloadresource" ) {
+      client.onloadresource = LNjScheme.Scheme.second(args);
+      return true;
+    } else if( key=="onpagecomplete" ) {
+      client.onpagecomplete = LNjScheme.Scheme.second(args);
+      return true;
+    } else if( key=="onpagefinished" ) {
+      client.onpagefinished = LNjScheme.Scheme.second(args);
+      return true;
+    } else {
+      return LNjScheme.Scheme.error("webview: unknown key: " + key);
+    }
+  }
+
+  private static LNMethod lnmethod = new LNMethod("webview!") {
+      public Object apply(LNjScheme.Scheme interpreter, Object args) {
+        if(args instanceof LNjScheme.Pair) {
+          Object a1 = LNjScheme.Scheme.first(args);
+          if(a1 instanceof SchemeWebView) {
+            SchemeWebView obj = (SchemeWebView)a1;
+            return obj.apply(obj.interpreter, LNjScheme.Scheme.rest(args));
+          } else {
+            return LNjScheme.Scheme.error("webview: not a webview " + a1);
+          }
+        } else { return LNjScheme.Scheme.error("webview: mising arguments"); }
+      }};
+
+  public static LNMethod proc() { return lnmethod; }
+}

modules/webview/ANDROID_java_oncreate

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+LNjSchemeEvaluate
+    (LNjScheme.Scheme.cons
+     (LNjScheme.Scheme.sym("define"),
+      LNjScheme.Scheme.list
+      (LNjScheme.Scheme.sym("webview!"), SchemeWebView.proc())));
+
+LNjSchemeEvaluate
+    (LNjScheme.Scheme.cons
+     (LNjScheme.Scheme.sym("define"),
+      LNjScheme.Scheme.list
+      (LNjScheme.Scheme.sym("make-webview"),
+       new LNMethod("make-webview") {
+           public Object apply(LNjScheme.Scheme interpreter, Object args) {
+               if(args instanceof LNjScheme.Pair) {
+                   Object a1 = null;
+                   a1 = LNjScheme.Scheme.first(args);
+                   if(a1 instanceof android.content.Context) {
+                       return new SchemeWebView((android.content.Context)a1, LNjSchemeSession);
+                   }
+               }
+               return LNjScheme.Scheme.error("make-webview" + args);
+           }}
+       )));
+
+LNjSchemeEvaluate
+// Dummy
+    (LNjScheme.Scheme.cons
+     (LNjScheme.Scheme.sym("define"),
+      LNjScheme.Scheme.list
+      (LNjScheme.Scheme.sym("webview-set-proxy!"), LNjScheme.Scheme.sym("list"))));
+
+/*
+    (lnjscheme-eval
+          `(let ((String (lambda (x) (new "java.lang.String" x)))
+                 (setProperty (method "setProperty" "java.lang.System" "java.lang.String" "java.lang.String")))
+             (let ((host (String ,(if (= v 0) "" "127.0.0.1")))
+                   (port (String ,(if (= v 0) "" (number->string v)))))
+               (setProperty (String "http.ProxyHost") host)
+               (setProperty (String "http.ProxyPort") port)
+               (setProperty (String "https.ProxyHost") host)
+               (setProperty (String "https.ProxyPort") port))))
+*/

modules/webview/ANDROID_java_public_ProxySettings

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+import android.annotation.TargetApi;
+import android.content.Context;
+import android.content.Intent;
+import android.net.Proxy;
+import android.os.Build;
+import android.os.Parcelable;
+import android.util.ArrayMap;
+//import org.apache.http.HttpHost;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+/**
+ * Utility class for setting WebKit proxy used by Android WebView
+ */
+@SuppressWarnings({"unchecked", "ConstantConditions"})
+public class ProxySettings {
+
+  private static final String TAG = "ProxySettings";
+  public static final String LOG_TAG = TAG;
+
+  static final int PROXY_CHANGED = 193;
+
+  private static Object getDeclaredField(Object obj, String name) throws
+    SecurityException, NoSuchFieldException,
+    IllegalArgumentException, IllegalAccessException {
+    Field f = obj.getClass().getDeclaredField(name);
+    f.setAccessible(true);
+    // System.out.println(obj.getClass().getName() + "." + name + " = "+
+    // out);
+    return f.get(obj);
+  }
+
+  public static Object getRequestQueue(Context ctx) throws Exception {
+    Object ret = null;
+    Class networkClass = Class.forName("android.webkit.Network");
+    if (networkClass != null) {
+      Object networkObj = invokeMethod(networkClass, "getInstance", new Object[]{ctx},
+                                       Context.class);
+      if (networkObj != null) {
+        ret = getDeclaredField(networkObj, "mRequestQueue");
+      }
+    }
+    return ret;
+  }
+
+  private static Object invokeMethod(Object object, String methodName, Object[] params,
+                                     Class... types) throws Exception {
+    Object out = null;
+    Class c = object instanceof Class ? (Class) object : object.getClass();
+    if (types != null) {
+      Method method = c.getMethod(methodName, types);
+      out = method.invoke(object, params);
+    } else {
+      Method method = c.getMethod(methodName);
+      out = method.invoke(object);
+    }
+    // System.out.println(object.getClass().getName() + "." + methodName +
+    // "() = "+ out);
+    return out;
+  }
+
+  public static void resetProxy(Context ctx) throws Exception {
+    Object requestQueueObject = getRequestQueue(ctx);
+    if (requestQueueObject != null) {
+      setDeclaredField(requestQueueObject, "mProxyHost", null);
+    }
+  }
+
+  private static void setDeclaredField(Object obj, String name, Object value)
+    throws SecurityException, NoSuchFieldException, IllegalArgumentException,
+           IllegalAccessException {
+    Field f = obj.getClass().getDeclaredField(name);
+    f.setAccessible(true);
+    f.set(obj, value);
+  }
+
+  /**
+   * Override WebKit Proxy settings
+   *
+   * @param ctx  Android ApplicationContext
+   * @param host
+   * @param port
+   * @return true if Proxy was successfully set
+   */
+  public static boolean setProxy(Context ctx, String host, int port) {
+    boolean ret = false;
+    setSystemProperties(host, port);
+
+    try {
+      if (Build.VERSION.SDK_INT > 18) {
+        ret = setKitKatProxy(ctx, host, port);
+      } else if (Build.VERSION.SDK_INT > 13) {
+        ret = setICSProxy(host, port);
+      } else {
+        /*
+          Object requestQueueObject = getRequestQueue(ctx);
+          if (requestQueueObject != null) {
+          // Create Proxy config object and set it into request Q
+          HttpHost httpHost = new HttpHost(host, port, "http");
+
+          setDeclaredField(requestQueueObject, "mProxyHost", httpHost);
+          ret = true;
+        */
+        return false;
+      }
+    }
+    catch (Exception e) {
+      e.printStackTrace();
+    }
+    return ret;
+  }
+
+  private static boolean setICSProxy(String host, int port) throws
+    ClassNotFoundException, NoSuchMethodException,
+    IllegalArgumentException, InstantiationException,
+    IllegalAccessException, InvocationTargetException {
+    Class webViewCoreClass = Class.forName("android.webkit.WebViewCore");
+    Class proxyPropertiesClass = Class.forName("android.net.ProxyProperties");
+    if (webViewCoreClass != null && proxyPropertiesClass != null) {
+      Method m = webViewCoreClass.getDeclaredMethod("sendStaticMessage", Integer.TYPE,
+                                                    Object.class);
+      Constructor c = proxyPropertiesClass.getConstructor(String.class, Integer.TYPE,
+                                                          String.class);
+      m.setAccessible(true);
+      c.setAccessible(true);
+      Object properties = c.newInstance(host, port, null);
+      m.invoke(null, PROXY_CHANGED, properties);
+      return true;
+    }
+    return false;
+
+  }
+
+  @TargetApi(Build.VERSION_CODES.KITKAT)
+  private static boolean setKitKatProxy(Context context, String host, int port) {
+    Context appContext = context.getApplicationContext();
+    try {
+      Class applictionCls = appContext.getClass();
+      Field loadedApkField = applictionCls.getField("mLoadedApk");
+      loadedApkField.setAccessible(true);
+      Object loadedApk = loadedApkField.get(appContext);
+      Class loadedApkCls = Class.forName("android.app.LoadedApk");
+      Field receiversField = loadedApkCls.getDeclaredField("mReceivers");
+      receiversField.setAccessible(true);
+      ArrayMap receivers = (ArrayMap) receiversField.get(loadedApk);
+      for (Object receiverMap : receivers.values()) {
+        for (Object rec : ((ArrayMap) receiverMap).keySet()) {
+          Class clazz = rec.getClass();
+          if (clazz.getName().contains("ProxyChangeListener")) {
+            Method onReceiveMethod = clazz.getDeclaredMethod("onReceive", Context.class, Intent.class);
+            Intent intent = new Intent(Proxy.PROXY_CHANGE_ACTION);
+
+            /*********** optional, may be need in future ************* /
+            final String CLASS_NAME = "android.net.ProxyProperties";
+            Class cls = Class.forName(CLASS_NAME);
+            Constructor constructor = cls.getConstructor(String.class, Integer.TYPE, String.class);
+            constructor.setAccessible(true);
+            Object proxyProperties = constructor.newInstance(host, port, null);
+            intent.putExtra("proxy", (Parcelable) proxyProperties);
+            //*********** optional, may be need in future *************/
+
+            onReceiveMethod.invoke(rec, appContext, intent);
+          }
+        }
+      }
+      return true;
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+    return false;
+  }
+
+  private static void setSystemProperties(String host, int port) {
+
+    java.lang.System.setProperty("http.proxyHost", host);
+    java.lang.System.setProperty("http.proxyPort", port + "");
+
+    java.lang.System.setProperty("https.proxyHost", host);
+    java.lang.System.setProperty("https.proxyPort", port + "");
+
+  }
+}

modules/webview/MODULES

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+ln_core ln_jscheme