open browser if login redirects to website

mastodon/src/main/java/org/joinmastodon/android/OAuthActivity.java

@@ -61,6 +61,9 @@ public class OAuthActivity extends Activity{
 					@Override
 					public void onSuccess(Token token){
 						new GetOwnAccount()
+								// in case the instance (looking at pixelfed) wants to redirect to a
+								// website, we need to pass a context so we can launch a browser
+								.setContext(OAuthActivity.this)
 								.setCallback(new Callback<>(){
 									@Override
 									public void onSuccess(Account account){

mastodon/src/main/java/org/joinmastodon/android/api/MastodonAPIController.java

@@ -17,6 +17,7 @@ import org.joinmastodon.android.api.gson.IsoInstantTypeAdapter;
 import org.joinmastodon.android.api.gson.IsoLocalDateTypeAdapter;
 import org.joinmastodon.android.api.session.AccountSession;
 import org.joinmastodon.android.model.Status;
+import org.joinmastodon.android.ui.utils.UiUtils;
 
 import java.io.BufferedReader;
 import java.io.IOException;
@@ -161,6 +162,11 @@ public class MastodonAPIController{
 											respObj=gson.fromJson(reader, req.respClass);
 									}
 								}catch(JsonIOException|JsonSyntaxException x){
+									if (req.context != null && response.body().contentType().subtype().equals("html")) {
+										UiUtils.launchWebBrowser(req.context, response.request().url().toString());
+										req.cancel();
+										return;
+									}
 									if(BuildConfig.DEBUG)
 										Log.w(TAG, "["+(session==null ? "no-auth" : session.getID())+"] "+response+" error parsing or reading body", x);
 									req.onError(x.getLocalizedMessage(), response.code(), x);

mastodon/src/main/java/org/joinmastodon/android/api/MastodonAPIRequest.java

@@ -2,6 +2,7 @@ package org.joinmastodon.android.api;
 
 import android.app.Activity;
 import android.app.ProgressDialog;
+import android.content.Context;
 import android.net.Uri;
 import android.util.Log;
 import android.util.Pair;
@@ -50,6 +51,7 @@ public abstract class MastodonAPIRequest<T> extends APIRequest<T>{
 	Map<String, String> headers;
 	private ProgressDialog progressDialog;
 	protected boolean removeUnsupportedItems;
+	@Nullable Context context;
 
 	public MastodonAPIRequest(HttpMethod method, String path, Class<T> respClass){
 		this.path=path;
@@ -181,6 +183,16 @@ public abstract class MastodonAPIRequest<T> extends APIRequest<T>{
 		return this;
 	}
 
+	public MastodonAPIRequest<T> setContext(Context context) {
+		this.context = context;
+		return this;
+	}
+
+	@Nullable
+	public Context getContext() {
+		return context;
+	}
+
 	@CallSuper
 	public void validateAndPostprocessResponse(T respObj, Response httpResponse) throws IOException{
 		if(respObj instanceof BaseModel){