Fixes #3506: Image height remains zero for some time on bad network (#3513)

* optimise width loading

* amending as per the reviews

* aspect ratio updates after layout completion

* MediaDetailFragment: update aspect ratio using onGlobalLayoutListener

* remove unnecessary imports

Author: kbhardwaj123

app/src/main/java/fr/free/nrw/commons/media/MediaDetailFragment.java

@@ -9,11 +9,11 @@
 import android.os.Bundle;
 import android.text.Editable;
 import android.text.TextWatcher;
-import android.util.TypedValue;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewTreeObserver;
+import android.view.ViewTreeObserver.OnGlobalLayoutListener;
 import android.widget.ArrayAdapter;
 import android.widget.Button;
 import android.widget.EditText;
@@ -33,7 +33,6 @@
 
 import org.apache.commons.lang3.StringUtils;
 import org.wikipedia.util.DateUtil;
-import org.wikipedia.util.StringUtil;
 
 import java.util.ArrayList;
 import java.util.Date;
@@ -224,7 +223,15 @@ public void onResume() {
                     .setVisibility(View.GONE);
         }
         media = detailProvider.getMediaAtPosition(index);
-        displayMediaDetails();
+        scrollView.getViewTreeObserver().addOnGlobalLayoutListener(
+            new OnGlobalLayoutListener() {
+                @Override
+                public void onGlobalLayout() {
+                    scrollView.getViewTreeObserver().removeOnGlobalLayoutListener(this);
+                    displayMediaDetails();
+                }
+            }
+        );
     }
 
     private void displayMediaDetails() {
@@ -243,7 +250,8 @@ private void displayMediaDetails() {
 
     private void updateAspectRatio(ImageInfo imageInfo) {
         if (imageInfo != null) {
-            int finalHeight = (scrollView.getWidth()*imageInfo.getHeight()) / imageInfo.getWidth();
+            int screenWidth = scrollView.getWidth();
+            int finalHeight = (screenWidth*imageInfo.getHeight()) / imageInfo.getWidth();
             ViewGroup.LayoutParams params = image.getLayoutParams();
             params.height = finalHeight;
             image.setLayoutParams(params);