Removed donate link in Transdrone version to meet Play Store regulations

app/src/lite/res/values/strings.xml

@@ -18,7 +18,7 @@
 
 	<string name="app_name" translatable="false">Transdrone</string>
 
-	<string name="donate_text">Donate via transdroid.org</string>
+	<string name="donate_text"></string>
-	<string name="donate_url">https://transdroid.org</string>
+	<string name="donate_url"></string>
 
 </resources>

app/src/main/java/org/transdroid/core/gui/settings/MainSettingsActivity.java

@@ -178,6 +178,7 @@ public class MainSettingsActivity extends PreferenceCompatActivity {
 
 		boolean enableSearchUi = navigationHelper.enableSearchUi();
 		boolean enableRssUi = navigationHelper.enableRssUi();
+		boolean enableDonateLink = !getString(R.string.donate_url).isEmpty();
 
 		// Load the preference menu and attach actions
 		addPreferencesFromResource(R.xml.pref_main);
@@ -191,7 +192,11 @@ public class MainSettingsActivity extends PreferenceCompatActivity {
 		findPreference("header_background").setOnPreferenceClickListener(onBackgroundSettings);
 		findPreference("header_system").setOnPreferenceClickListener(onSystemSettings);
 		findPreference("header_help").setOnPreferenceClickListener(onHelpSettings);
+		if (enableDonateLink) {
 			findPreference("header_donate").setOnPreferenceClickListener(onDonate);
+		} else {
+			getPreferenceScreen().removePreference(findPreference("header_donate"));
+		}
 
 		// Keep a list of the server codes and names (for default server selection)
 		List<String> serverCodes = new ArrayList<>();