adding modelpath and tokenizerpath placeholder to load models

Author: cmodi-meta

examples/demo-apps/android/LlamaDemo/app/src/main/java/com/example/executorchllamademo/SettingsActivity.java

@@ -422,13 +422,17 @@ private void setXNNPACKSettingMode() {
     requireViewById(R.id.tokenizerLayout).setVisibility(View.VISIBLE);
     requireViewById(R.id.parametersView).setVisibility(View.VISIBLE);
     requireViewById(R.id.temperatureLayout).setVisibility(View.VISIBLE);
+    mModelFilePath="";
+    mTokenizerFilePath="";
   }
 
   private void setMediaTekSettingMode() {
     requireViewById(R.id.modelLayout).setVisibility(View.GONE);
     requireViewById(R.id.tokenizerLayout).setVisibility(View.GONE);
     requireViewById(R.id.parametersView).setVisibility(View.GONE);
     requireViewById(R.id.temperatureLayout).setVisibility(View.GONE);
+    mModelFilePath="/in/mtk/llama/runner";
+    mTokenizerFilePath="/in/mtk/llama/runner";
   }
 
   private void loadSettings() {