Fix bugs related to ActionBar

This commit fixes two bugs:

1. NPE due to a race condition where clear() was called in the
   ReplForm before the FrameLayout was initialized.
2. setImageTintMode on an internal Widget wasn't supported on
   Android 4.x, resulting in a crash on connection.

Change-Id: Ia28f9eaa404fa0b8f830d5a809d77226a611b36c

appinventor/components/src/com/google/appinventor/components/runtime/Form.java

@@ -2033,8 +2033,10 @@ public class Form extends AppCompatActivity
   // This is called from clear-current-form in runtime.scm.
   public void clear() {
     viewLayout.getLayoutManager().removeAllViews();
+    if (frameLayout != null) {
       frameLayout.removeAllViews();
       frameLayout = null;
+    }
     // Set all screen properties to default values.
     defaultPropertyValues();
     onStopListeners.clear();

appinventor/components/src/com/google/appinventor/components/runtime/ReplForm.java

@@ -30,6 +30,7 @@ import com.google.appinventor.components.annotations.SimpleProperty;
 import com.google.appinventor.components.common.ComponentConstants;
 import com.google.appinventor.components.runtime.util.AppInvHTTPD;
 import com.google.appinventor.components.runtime.util.ErrorMessages;
+import com.google.appinventor.components.runtime.util.ImageViewUtil;
 import com.google.appinventor.components.runtime.util.RetValManager;
 
 import dalvik.system.DexClassLoader;
@@ -64,7 +65,6 @@ public class ReplForm extends Form {
   private String replResultFormName = null;
   private List<String> loadedExternalDexs; // keep a track of loaded dexs to prevent reloading and causing crash in older APIs
   private String currentTheme = ComponentConstants.DEFAULT_THEME;
-  private TintImageView overflowMenuView = null;
 
   public ReplForm() {
     super();
@@ -331,42 +331,15 @@ public class ReplForm extends Form {
   protected void updateTitle() {
     final ActionBar actionBar = getSupportActionBar();
     if (actionBar != null) {
-      findOverflowMenuView();
-      ColorStateList stateList;
       if ("AppTheme.Light".equals(currentTheme)) {
         actionBar.setTitle(Html.fromHtml("<font color=\"black\">" + title + "</font>"));
-        stateList = new ColorStateList(new int[][] { new int[] {} }, new int[] { Color.BLACK });
+        ImageViewUtil.setMenuButtonColor(this, Color.BLACK);
       } else {
         actionBar.setTitle(title);
-        stateList = new ColorStateList(new int[][] { new int[] {} }, new int[] { Color.WHITE });
+        ImageViewUtil.setMenuButtonColor(this, Color.WHITE);
       }
-      if (overflowMenuView != null) {
-        overflowMenuView.setImageTintMode(PorterDuff.Mode.MULTIPLY);
-        overflowMenuView.setImageTintList(stateList);
     }
   }
-  }
-
-  private TintImageView findOverflowMenuView() {
-    if (overflowMenuView == null) {
-      ViewGroup vg = (ViewGroup) getWindow().getDecorView();
-      Queue<ViewGroup> children = new LinkedList<ViewGroup>();
-      children.add(vg);
-      while (children.size() > 0) {
-        vg = children.poll();
-        for (int i = 0; i < vg.getChildCount(); i++) {
-          View child = vg.getChildAt(i);
-          if (child instanceof TintImageView) {
-            overflowMenuView = (TintImageView) child;
-            return overflowMenuView;
-          } else if (child instanceof ViewGroup) {
-            children.add((ViewGroup) child);
-          }
-        }
-      }
-    }
-    return overflowMenuView;
-  }
 
   private String genReportId() {
     String [] words = { "A","ABE","ACE","ACT","AD","ADA","ADD",

appinventor/components/src/com/google/appinventor/components/runtime/util/ImageViewUtil.java

+// -*- mode: java; c-basic-offset: 2; -*-
+// Copyright 2017 MIT, All rights reserved
+// Released under the Apache License, Version 2.0
+// http://www.apache.org/licenses/LICENSE-2.0
+
+package com.google.appinventor.components.runtime.util;
+
+import android.content.res.ColorStateList;
+import android.graphics.PorterDuff;
+import android.support.v7.app.AppCompatActivity;
+import android.support.v7.internal.widget.TintImageView;
+import android.view.View;
+import android.view.ViewGroup;
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+public final class ImageViewUtil {
+
+  /**
+   * We will determine when this class is first referenced whether we can update the color of
+   * the menu button. If true, we will attempt to update. Otherwise, the button will get out of
+   * sync, but this will only happen in the companion so it shouldn't be too much of a problem.
+   */
+  private static final boolean canUpdate;
+
+  static {
+    boolean updateable = false;
+    try {
+      TintImageView.class.getMethod("setImageTintMode", PorterDuff.Mode.class);
+      updateable = true;
+    } catch(NoSuchMethodException e) {
+    }
+    canUpdate = updateable;
+  }
+
+  private ImageViewUtil() {}
+
+  public static void setMenuButtonColor(AppCompatActivity activity, int color) {
+    if (canUpdate) {
+      TintImageView overflowMenuView = findOverflowMenuView(activity);
+      if (overflowMenuView != null) {
+        ColorStateList stateList = new ColorStateList(new int[][]{new int[]{}}, new int[]{color});
+        try {
+          overflowMenuView.setImageTintMode(PorterDuff.Mode.MULTIPLY);
+          overflowMenuView.setImageTintList(stateList);
+        } catch (NoSuchMethodError e) {
+          // extra insurance in case the canUpdate flag is lying...
+        }
+      }
+    }
+  }
+
+  private static TintImageView findOverflowMenuView(AppCompatActivity activity) {
+    TintImageView overflowMenuView = null;
+    ViewGroup vg = (ViewGroup) activity.getWindow().getDecorView();
+    Queue<ViewGroup> children = new LinkedList<ViewGroup>();
+    children.add(vg);
+    while (children.size() > 0) {
+      vg = children.poll();
+      for (int i = 0; i < vg.getChildCount(); i++) {
+        View child = vg.getChildAt(i);
+        if (child instanceof TintImageView) {
+          overflowMenuView = (TintImageView) child;
+          return overflowMenuView;
+        } else if (child instanceof ViewGroup) {
+          children.add((ViewGroup) child);
+        }
+      }
+    }
+    return overflowMenuView;
+  }
+}