make prop nullable (commons-app#6073)

Signed-off-by: parneet-guraya <gurayaparneet@gmail.com>

Author: parneet-guraya

app/src/main/java/fr/free/nrw/commons/upload/UploadBaseFragment.kt

@@ -6,7 +6,7 @@ import fr.free.nrw.commons.di.CommonsDaggerSupportFragment
  * The base fragment of the fragments in upload
  */
 abstract class UploadBaseFragment : CommonsDaggerSupportFragment() {
-    lateinit var callback: Callback
+    var callback: Callback? = null
 
     protected open fun onBecameVisible() = Unit
 

app/src/main/java/fr/free/nrw/commons/upload/categories/UploadCategoriesFragment.kt

@@ -96,10 +96,10 @@ class UploadCategoriesFragment : UploadBaseFragment(), CategoriesContract.View {
         if (media == null) {
             if (callback != null) {
                 binding!!.tvTitle.text = getString(
-                    R.string.step_count, callback.getIndexInViewFlipper(
+                    R.string.step_count, callback!!.getIndexInViewFlipper(
                         this
                     ) + 1,
-                    callback.totalNumberOfSteps, getString(R.string.categories_activity_title)
+                    callback!!.totalNumberOfSteps, getString(R.string.categories_activity_title)
                 )
             }
         } else {
@@ -220,7 +220,7 @@ class UploadCategoriesFragment : UploadBaseFragment(), CategoriesContract.View {
     }
 
     override fun goToNextScreen() {
-        callback.onNextButtonClicked(callback.getIndexInViewFlipper(this))
+        callback!!.onNextButtonClicked(callback!!.getIndexInViewFlipper(this))
     }
 
     override fun showNoCategorySelected() {
@@ -322,7 +322,7 @@ class UploadCategoriesFragment : UploadBaseFragment(), CategoriesContract.View {
             mediaDetailFragment.onResume()
             goBackToPreviousScreen()
         } else {
-            callback.onPreviousButtonClicked(callback.getIndexInViewFlipper(this))
+            callback!!.onPreviousButtonClicked(callback!!.getIndexInViewFlipper(this))
         }
     }
 

app/src/main/java/fr/free/nrw/commons/upload/depicts/DepictsFragment.kt

@@ -97,10 +97,10 @@ class DepictsFragment : UploadBaseFragment(), DepictsContract.View {
         if (media == null) {
             binding.depictsTitle.text =
                 String.format(
-                    getString(R.string.step_count), callback.getIndexInViewFlipper(
+                    getString(R.string.step_count), callback!!.getIndexInViewFlipper(
                         this
                     ) + 1,
-                    callback.totalNumberOfSteps, getString(R.string.depicts_step_title)
+                    callback!!.totalNumberOfSteps, getString(R.string.depicts_step_title)
                 )
         } else {
             binding.depictsTitle.setText(R.string.edit_depictions)
@@ -173,11 +173,11 @@ class DepictsFragment : UploadBaseFragment(), DepictsContract.View {
     }
 
     override fun goToNextScreen() {
-        callback.onNextButtonClicked(callback.getIndexInViewFlipper(this))
+        callback!!.onNextButtonClicked(callback!!.getIndexInViewFlipper(this))
     }
 
     override fun goToPreviousScreen() {
-        callback.onPreviousButtonClicked(callback.getIndexInViewFlipper(this))
+        callback!!.onPreviousButtonClicked(callback!!.getIndexInViewFlipper(this))
     }
 
     override fun noDepictionSelected() {
@@ -338,7 +338,7 @@ class DepictsFragment : UploadBaseFragment(), DepictsContract.View {
             updateDepicts()
             goBackToPreviousScreen()
         } else {
-            callback.onPreviousButtonClicked(callback.getIndexInViewFlipper(this))
+            callback!!.onPreviousButtonClicked(callback!!.getIndexInViewFlipper(this))
         }
     }
 

app/src/main/java/fr/free/nrw/commons/upload/license/MediaLicenseFragment.kt

@@ -47,20 +47,20 @@ class MediaLicenseFragment : UploadBaseFragment(), MediaLicenseContract.View {
 
         binding.tvTitle.text = getString(
             R.string.step_count,
-            callback.getIndexInViewFlipper(this) + 1,
-            callback.totalNumberOfSteps,
+            callback!!.getIndexInViewFlipper(this) + 1,
+            callback!!.totalNumberOfSteps,
             getString(R.string.license_step_title)
         )
         setTvSubTitle()
         binding.btnPrevious.setOnClickListener {
-            callback.onPreviousButtonClicked(
-                callback.getIndexInViewFlipper(this)
+            callback!!.onPreviousButtonClicked(
+                callback!!.getIndexInViewFlipper(this)
             )
         }
 
         binding.btnSubmit.setOnClickListener {
-            callback.onNextButtonClicked(
-                callback.getIndexInViewFlipper(this)
+            callback!!.onNextButtonClicked(
+                callback!!.getIndexInViewFlipper(this)
             )
         }
 
@@ -201,6 +201,6 @@ class MediaLicenseFragment : UploadBaseFragment(), MediaLicenseContract.View {
          * Show the wlm info message if the upload is a WLM upload
          */
         binding.llInfoMonumentUpload.visibility =
-            if (callback.isWLMUpload && presenter.isWLMSupportedForThisPlace()) View.VISIBLE else View.GONE
+            if (callback!!.isWLMUpload && presenter.isWLMSupportedForThisPlace()) View.VISIBLE else View.GONE
     }
 }