Only Kitkat and up supports changing headers, disable on lower API versions

app/src/main/java/acr/browser/lightning/fragment/PrivacySettingsFragment.java

@@ -95,8 +95,11 @@ public class PrivacySettingsFragment extends LightningPreferenceFragment impleme
         cbcookiesexit.setChecked(mPreferenceManager.getClearCookiesExitEnabled());
         cb3cookies.setChecked(mPreferenceManager.getBlockThirdPartyCookiesEnabled());
         cbwebstorageexit.setChecked(mPreferenceManager.getClearWebStorageExitEnabled());
-        cbDoNotTrack.setChecked(mPreferenceManager.getDoNotTrackEnabled());
+        cbDoNotTrack.setChecked(mPreferenceManager.getDoNotTrackEnabled() && Utils.doesSupportHeaders());
-        cbIdentifyingHeaders.setChecked(mPreferenceManager.getRemoveIdentifyingHeadersEnabled());
+        cbIdentifyingHeaders.setChecked(mPreferenceManager.getRemoveIdentifyingHeadersEnabled() && Utils.doesSupportHeaders());
+
+        cbDoNotTrack.setEnabled(Utils.doesSupportHeaders());
+        cbIdentifyingHeaders.setEnabled(Utils.doesSupportHeaders());
 
         String identifyingHeadersSummary = LightningView.HEADER_REQUESTED_WITH + ", " + LightningView.HEADER_WAP_PROFILE;
         cbIdentifyingHeaders.setSummary(identifyingHeadersSummary);

app/src/main/java/acr/browser/lightning/utils/Utils.java

@@ -21,6 +21,7 @@ import android.graphics.Paint;
 import android.graphics.Path;
 import android.graphics.Shader;
 import android.net.Uri;
+import android.os.Build;
 import android.os.Environment;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
@@ -53,6 +54,10 @@ import acr.browser.lightning.preference.PreferenceManager;
 
 public final class Utils {
 
+    public static boolean doesSupportHeaders() {
+        return Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
+    }
+
     /**
      * Downloads a file from the specified URL. Handles permissions
      * requests, and creates all the necessary dialogs that must be

app/src/main/java/acr/browser/lightning/view/LightningWebClient.java

@@ -47,11 +47,9 @@ import acr.browser.lightning.utils.Utils;
 
 public class LightningWebClient extends WebViewClient {
 
-
     @NonNull private final Activity mActivity;
     @NonNull private final LightningView mLightningView;
     @NonNull private final UIController mUIController;
-    @NonNull private final Bus mEventBus;
     @NonNull private final IntentUtils mIntentUtils;
 
     @Inject ProxyUtils mProxyUtils;
@@ -65,7 +63,6 @@ public class LightningWebClient extends WebViewClient {
         mUIController = (UIController) activity;
         mLightningView = lightningView;
         mAdBlock.updatePreference();
-        mEventBus = BrowserApp.getBus(activity);
         mIntentUtils = new IntentUtils(activity);
     }
 
@@ -285,11 +282,11 @@ public class LightningWebClient extends WebViewClient {
 
         Map<String, String> headers = mLightningView.getRequestHeaders();
 
-        if (mLightningView.isIncognito()) {
+        if (mLightningView.isIncognito() && Utils.doesSupportHeaders()) {
             view.loadUrl(url, headers);
             return true;
         }
-        if (url.startsWith("about:")) {
+        if (url.startsWith("about:") && Utils.doesSupportHeaders()) {
             view.loadUrl(url, headers);
             return true;
         }
@@ -322,9 +319,9 @@ public class LightningWebClient extends WebViewClient {
             }
         }
 
-        if (!mIntentUtils.startActivityForUrl(view, url)) {
+        if (!mIntentUtils.startActivityForUrl(view, url) && Utils.doesSupportHeaders()) {
             view.loadUrl(url, headers);
         }
-        return true;
+        return Utils.doesSupportHeaders() || super.shouldOverrideUrlLoading(view, url);
     }
 }