small fix to avoid unnecessary calls to the CTS API

src/pages/corpus-detail/corpus-detail.ts

@@ -24,6 +24,7 @@ export class CorpusDetailPage {
     private noTextRangeChosenString: string;
     public CitationLevel = CitationLevel;
     private invalidTextRangeString: string;
+    public isTransitioningToTextPage: boolean = false;
 
     constructor(public navCtrl: NavController, public navParams: NavParams,
                 public corpusProvider: CorpusProvider,
@@ -50,28 +51,30 @@ export class CorpusDetailPage {
     }
 
     showFurtherReferences(urn: string, currentCitationLevel: number, isStart: boolean) {
-        if (currentCitationLevel === 1 &&
-            this.corpusProvider.currentCorpus.citation_level_2 !== CitationLevel[CitationLevel.default]) {
-            // change display for further references
-            if (isStart) {
-                this.corpusProvider.currentTextRange.start[currentCitationLevel] = "";
-            }
-            else {
-                this.corpusProvider.currentTextRange.end[currentCitationLevel] = "";
-            }
-            this.checkFurtherReferences(urn, isStart, false);
+        if (!this.isTransitioningToTextPage) {
+            if (currentCitationLevel === 1 &&
+                this.corpusProvider.currentCorpus.citation_level_2 !== CitationLevel[CitationLevel.default]) {
+                // change display for further references
+                if (isStart) {
+                    this.corpusProvider.currentTextRange.start[currentCitationLevel] = "";
+                }
+                else {
+                    this.corpusProvider.currentTextRange.end[currentCitationLevel] = "";
+                }
+                this.checkFurtherReferences(urn, isStart, false);
 
-        }
-        else if (currentCitationLevel === 2 &&
-            this.corpusProvider.currentCorpus.citation_level_3 !== CitationLevel[CitationLevel.default]) {
-            // change display for further references
-            if (isStart) {
-                this.corpusProvider.currentTextRange.start[currentCitationLevel] = "";
             }
-            else {
-                this.corpusProvider.currentTextRange.end[currentCitationLevel] = "";
+            else if (currentCitationLevel === 2 &&
+                this.corpusProvider.currentCorpus.citation_level_3 !== CitationLevel[CitationLevel.default]) {
+                // change display for further references
+                if (isStart) {
+                    this.corpusProvider.currentTextRange.start[currentCitationLevel] = "";
+                }
+                else {
+                    this.corpusProvider.currentTextRange.end[currentCitationLevel] = "";
+                }
+                this.checkFurtherReferences(urn, isStart, true);
             }
-            this.checkFurtherReferences(urn, isStart, true);
         }
     }
 
@@ -108,6 +111,7 @@ export class CorpusDetailPage {
             toast.present().then();
         }
         else {
+            this.isTransitioningToTextPage = true;
             this.adjustCurrentTextRange();
             let startNumber: number = +this.corpusProvider.currentTextRange.start.join("");
             let endNumber: number = +this.corpusProvider.currentTextRange.end.join("");