Added loading show delay attribute

app/src/main/java/eu/faircode/email/ContentLoadingProgressBar.java

@@ -20,6 +20,7 @@ package eu.faircode.email;
 */
 
 import android.content.Context;
+import android.content.res.TypedArray;
 import android.util.AttributeSet;
 import android.widget.ProgressBar;
 
@@ -29,6 +30,7 @@ import androidx.annotation.Nullable;
 public class ContentLoadingProgressBar extends ProgressBar {
     private int visibility = VISIBLE;
     private boolean init = false;
+    private int delay = VISIBILITY_DELAY;
     private boolean delaying = false;
 
     private static final int VISIBILITY_DELAY = 1500; // milliseconds
@@ -39,14 +41,22 @@ public class ContentLoadingProgressBar extends ProgressBar {
 
     public ContentLoadingProgressBar(@NonNull Context context, @Nullable AttributeSet attrs) {
         super(context, attrs, 0);
+        getAttr(context, attrs);
     }
 
     public ContentLoadingProgressBar(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
+        getAttr(context, attrs);
     }
 
     public ContentLoadingProgressBar(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
         super(context, attrs, defStyleAttr, defStyleRes);
+        getAttr(context, attrs);
+    }
+
+    private void getAttr(Context context, AttributeSet attrs) {
+        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ContentLoadingProgressBar, 0, 0);
+        this.delay = a.getInt(R.styleable.ContentLoadingProgressBar_show_delay, VISIBILITY_DELAY);
     }
 
     @Override
@@ -59,7 +69,7 @@ public class ContentLoadingProgressBar extends ProgressBar {
             init = true;
             delaying = true;
             super.setVisibility(INVISIBLE);
-            ApplicationEx.getMainHandler().postDelayed(delayedShow, VISIBILITY_DELAY);
+            ApplicationEx.getMainHandler().postDelayed(delayedShow, delay);
         } else {
             ApplicationEx.getMainHandler().removeCallbacks(delayedShow);
             delaying = false;

app/src/main/res/layout/include_message_navigation.xml

@@ -20,6 +20,7 @@
         android:layout_width="36dp"
         android:layout_height="36dp"
         android:indeterminate="true"
+        app:show_delay="750"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toBottomOf="@id/vSeparator" />
 

app/src/main/res/values/attrs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <declare-styleable name="ContentLoadingProgressBar">
+        <attr name="show_delay" format="integer" />
+    </declare-styleable>
+</resources>