Apply TopBar buttons only if they are different than current buttons (#…

…5314)

Like all other options, buttons are applied when a screen becomes visible. This means that in a BottomTabs layout,
options are applied when a tab is selected. Since tab change happens involves only changing view visibility, and button creation take a bit long,
the buttons appear to flicker some times.

lib/android/app/src/main/java/com/reactnativenavigation/parse/Component.java

@@ -44,4 +44,11 @@ public void mergeWithDefault(Component defaultOptions) {
     public boolean hasValue() {
         return name.hasValue();
     }
+
+    public boolean equals(Component other) {
+        return name.equals(other.name) &&
+               componentId.equals(other.componentId) &&
+               alignment.equals(other.alignment) &&
+               waitForRender.equals(other.waitForRender);
+    }
 }

lib/android/app/src/main/java/com/reactnativenavigation/parse/params/Button.java

@@ -16,6 +16,7 @@
 import org.json.JSONObject;
 
 import java.util.ArrayList;
+import java.util.Objects;
 
 public class Button {
     public String instanceId = "btn" + CompatUtils.generateViewId();
@@ -34,6 +35,22 @@ public class Button {
     public Text testId = new NullText();
     public Component component = new Component();
 
+    public boolean equals(Button other) {
+        return Objects.equals(id, other.id) &&
+               text.equals(other.text) &&
+               enabled.equals(other.enabled) &&
+               disableIconTint.equals(other.disableIconTint) &&
+               showAsAction.equals(other.showAsAction) &&
+               color.equals(other.color) &&
+               disabledColor.equals(other.disabledColor) &&
+               fontSize.equals(other.fontSize) &&
+               fontWeight.equals(other.fontWeight) &&
+               Objects.equals(fontFamily, other.fontFamily) &&
+               icon.equals(other.icon) &&
+               testId.equals(other.testId) &&
+               component.equals(other.component);
+    }
+
     private static Button parseJson(JSONObject json, TypefaceLoader typefaceManager) {
         Button button = new Button();
         button.id = json.optString("id");

lib/android/app/src/main/java/com/reactnativenavigation/parse/params/Param.java

@@ -1,5 +1,7 @@
 package com.reactnativenavigation.parse.params;
 
+import static com.reactnativenavigation.utils.ObjectUtils.equalsNotNull;
+
 public abstract class Param<T> {
     protected T value;
 
@@ -21,4 +23,8 @@ public T get(T defaultValue) {
     public boolean hasValue() {
         return value != null;
     }
+
+    public boolean equals(Param other) {
+        return value == other.value || equalsNotNull(value, other.value);
+    }
 }

lib/android/app/src/main/java/com/reactnativenavigation/utils/CollectionUtils.java

@@ -2,13 +2,16 @@
 
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
+import android.support.v4.util.Pair;
 
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 public class CollectionUtils {
     public interface Apply<T> {
@@ -136,4 +139,23 @@ public static <T> Boolean reduce(@Nullable Collection<T> items, boolean initialV
         return t == null ? Collections.EMPTY_LIST : t.values();
     }
 
+    public static <T> boolean equals(@Nullable Collection<T> a, @Nullable Collection<T> b) {
+        if (size(a) != size(b)) return false;
+        return reduce(zip(a, b), true, (p, currentValue) -> currentValue && Objects.equals(p.first, p.second));
+    }
+
+    public static int size(@Nullable Collection items) {
+        return items == null ? 0 : items.size();
+    }
+
+    public static <T> Collection<Pair<T, T>> zip(@Nullable Collection<T> a, @Nullable Collection<T> b) {
+        if (a == null || b == null) return new ArrayList<>();
+        Iterator iter1 = a.iterator();
+        Iterator iter2 = b.iterator();
+        ArrayList<Pair<T,T>> result = new ArrayList<>();
+        while (iter1.hasNext() && iter2.hasNext()) {
+            result.add(new Pair(iter1.next(), iter2.next()));
+        }
+        return result;
+    }
 }

lib/android/app/src/main/java/com/reactnativenavigation/utils/ViewUtils.java

@@ -16,7 +16,7 @@
 
 public class ViewUtils {
     @Nullable
-    public static <T> T findChildByClass(ViewGroup root, Class clazz) {
+    public static <T extends View> T findChildByClass(ViewGroup root, Class<T> clazz) {
         for (int i = 0; i < root.getChildCount(); i++) {
             View view = root.getChildAt(i);
             if (clazz.isAssignableFrom(view.getClass())) {

lib/android/app/src/main/java/com/reactnativenavigation/views/topbar/TopBar.java

@@ -20,7 +20,6 @@
 import android.widget.RelativeLayout;
 import android.widget.TextView;
 
-import com.reactnativenavigation.BuildConfig;
 import com.reactnativenavigation.R;
 import com.reactnativenavigation.anim.TopBarAnimator;
 import com.reactnativenavigation.anim.TopBarCollapseBehavior;
@@ -29,13 +28,15 @@
 import com.reactnativenavigation.parse.AnimationOptions;
 import com.reactnativenavigation.parse.params.Colour;
 import com.reactnativenavigation.parse.params.Number;
+import com.reactnativenavigation.utils.CollectionUtils;
 import com.reactnativenavigation.utils.CompatUtils;
 import com.reactnativenavigation.utils.UiUtils;
 import com.reactnativenavigation.viewcontrollers.TitleBarButtonController;
 import com.reactnativenavigation.views.StackLayout;
 import com.reactnativenavigation.views.titlebar.TitleBar;
 import com.reactnativenavigation.views.toptabs.TopTabs;
 
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
@@ -52,6 +53,7 @@ public class TopBar extends AppBarLayout implements ScrollEventListener.ScrollAw
     private View border;
     private View component;
     private float elevation = -1;
+    private List<TitleBarButtonController> rightButtons = new ArrayList<>();
 
     public TopBar(final Context context, StackLayout parentView) {
         super(context);
@@ -218,6 +220,8 @@ public void clearLeftButtons() {
     }
 
     public void setRightButtons(List<TitleBarButtonController> rightButtons) {
+        if (CollectionUtils.equals(this.rightButtons, rightButtons)) return;
+        this.rightButtons = rightButtons;
         titleBar.setRightButtons(rightButtons);
     }
 

lib/android/app/src/test/java/com/reactnativenavigation/views/TopBarTest.java

@@ -26,7 +26,6 @@ public class TopBarTest extends BaseTest {
     private TopBarAnimator animator;
     private Activity activity;
 
-    @SuppressWarnings("Convert2Lambda")
     @Override
     public void beforeEach() {
         activity = newActivity();