Refactored to make InstructionLoader more modular in preparation for adding exit signs

Author: Devota Aabel

libandroid-navigation-ui/src/main/java/com/mapbox/services/android/navigation/ui/v5/NavigationView.java

@@ -24,7 +24,7 @@
 import com.mapbox.mapboxsdk.maps.MapView;
 import com.mapbox.mapboxsdk.maps.MapboxMap;
 import com.mapbox.mapboxsdk.maps.OnMapReadyCallback;
-import com.mapbox.services.android.navigation.ui.v5.instruction.ImageCoordinator;
+import com.mapbox.services.android.navigation.ui.v5.instruction.ImageCreator;
 import com.mapbox.services.android.navigation.ui.v5.instruction.InstructionView;
 import com.mapbox.services.android.navigation.ui.v5.map.NavigationMapboxMap;
 import com.mapbox.services.android.navigation.ui.v5.map.NavigationMapboxMapInstanceState;
@@ -608,7 +608,7 @@ private void subscribeViewModels() {
   private void shutdown() {
     mapView.onDestroy();
     navigationViewModel.onDestroy(isChangingConfigurations());
-    ImageCoordinator.getInstance().shutdown();
+    ImageCreator.getInstance().shutdown();
     navigationMap = null;
   }
 }

libandroid-navigation-ui/src/main/java/com/mapbox/services/android/navigation/ui/v5/instruction/AbbreviationCoordinator.java renamed to libandroid-navigation-ui/src/main/java/com/mapbox/services/android/navigation/ui/v5/instruction/AbbreviationCreator.java

@@ -3,7 +3,6 @@
 import android.widget.TextView;
 
 import com.mapbox.api.directions.v5.models.BannerComponents;
-import com.mapbox.services.android.navigation.ui.v5.instruction.InstructionLoader.BannerComponentNode;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -17,18 +16,19 @@
  * BannerComponents containing abbreviation information and given a list of BannerComponentNodes,
  * constructed by InstructionLoader.
  */
-class AbbreviationCoordinator {
+class AbbreviationCreator extends NodeCreator<AbbreviationCreator.AbbreviationNode, AbbreviationVerifier> {
   private static final String SINGLE_SPACE = " ";
   private Map<Integer, List<Integer>> abbreviations;
   private TextViewUtils textViewUtils;
 
-  AbbreviationCoordinator(TextViewUtils textViewUtils) {
+  AbbreviationCreator(TextViewUtils textViewUtils, AbbreviationVerifier abbreviationVerifier) {
+    super(abbreviationVerifier);
     this.abbreviations = new HashMap<>();
     this.textViewUtils = textViewUtils;
   }
 
-  AbbreviationCoordinator() {
-    this(new TextViewUtils());
+  AbbreviationCreator() {
+    this(new TextViewUtils(), new AbbreviationVerifier());
   }
 
   /**
@@ -51,11 +51,11 @@ void addPriorityInfo(BannerComponents bannerComponents, int index) {
    * Using the abbreviations HashMap which should already be populated, abbreviates the text in the
    * bannerComponentNodes until the text fits the given TextView.
    *
-   * @param bannerComponentNodes containing the text to construct
    * @param textView to check the text fits
+   * @param bannerComponentNodes containing the text to construct
    * @return the properly abbreviated string that will fit in the TextView
    */
-  String abbreviateBannerText(List<BannerComponentNode> bannerComponentNodes, TextView textView) {
+  String abbreviateBannerText(TextView textView, List<BannerComponentNode> bannerComponentNodes) {
     String bannerText = join(bannerComponentNodes);
 
     if (abbreviations.isEmpty()) {
@@ -130,6 +130,18 @@ private String join(List<BannerComponentNode> tokens) {
     return stringBuilder.toString();
   }
 
+  @Override
+  AbbreviationNode setupNode(BannerComponents components, int index, int startIndex) {
+    addPriorityInfo(components, index);
+    return new AbbreviationCreator.AbbreviationNode(components, startIndex);
+  }
+
+  @Override
+  void preProcess(TextView textView, List<BannerComponentNode> bannerComponentNodes) {
+    String text = abbreviateBannerText(textView, bannerComponentNodes);
+    textView.setText(text);
+  }
+
   /**
    * Class used by InstructionLoader to determine that a BannerComponent contains an abbreviation
    */

libandroid-navigation-ui/src/main/java/com/mapbox/services/android/navigation/ui/v5/instruction/AbbreviationVerifier.java

@@ -0,0 +1,15 @@
+package com.mapbox.services.android.navigation.ui.v5.instruction;
+
+import com.mapbox.api.directions.v5.models.BannerComponents;
+import com.mapbox.core.utils.TextUtils;
+
+class AbbreviationVerifier extends NodeVerifier {
+  @Override
+  boolean isNodeType(BannerComponents bannerComponents) {
+    return hasAbbreviation(bannerComponents);
+  }
+
+  private boolean hasAbbreviation(BannerComponents components) {
+    return !TextUtils.isEmpty(components.abbreviation());
+  }
+}

libandroid-navigation-ui/src/main/java/com/mapbox/services/android/navigation/ui/v5/instruction/BannerComponentNode.java

@@ -0,0 +1,25 @@
+package com.mapbox.services.android.navigation.ui.v5.instruction;
+
+import com.mapbox.api.directions.v5.models.BannerComponents;
+
+/**
+ * Class used to construct a list of BannerComponents to be populated into a TextView
+ */
+class BannerComponentNode {
+  BannerComponents bannerComponents;
+  int startIndex;
+
+  BannerComponentNode(BannerComponents bannerComponents, int startIndex) {
+    this.bannerComponents = bannerComponents;
+    this.startIndex = startIndex;
+  }
+
+  @Override
+  public String toString() {
+    return bannerComponents.text();
+  }
+
+  void setStartIndex(int startIndex) {
+    this.startIndex = startIndex;
+  }
+}

libandroid-navigation-ui/src/main/java/com/mapbox/services/android/navigation/ui/v5/instruction/BannerComponentTree.java

@@ -0,0 +1,72 @@
+package com.mapbox.services.android.navigation.ui.v5.instruction;
+
+import android.support.annotation.NonNull;
+import android.widget.TextView;
+
+import com.mapbox.api.directions.v5.models.BannerComponents;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class BannerComponentTree {
+  private final NodeCreator[] nodeCreators;
+  private List<BannerComponentNode> bannerComponentNodes;
+
+  /**
+   * Creates a master coordinator to make sure the coordinators passed in are used appropriately
+   *
+   * @param nodeCreators coordinators in the order that they should process banner components
+   */
+  BannerComponentTree(@NonNull List<BannerComponents> bannerComponents, NodeCreator... nodeCreators) {
+    this.nodeCreators = nodeCreators;
+    bannerComponentNodes = parseBannerComponents(bannerComponents);
+  }
+
+  /**
+   * Parses the banner components and processes them using the nodeCreators in the order they
+   * were originally passed
+   *
+   * @param bannerComponents to parse
+   * @return the list of nodes representing the bannerComponents
+   */
+  List<BannerComponentNode> parseBannerComponents(List<BannerComponents> bannerComponents) {
+    int length = 0;
+    List<BannerComponentNode> bannerComponentNodes = new ArrayList<>();
+
+    for (BannerComponents components : bannerComponents) {
+      BannerComponentNode node = null;
+
+      for (NodeCreator nodeCreator : nodeCreators) {
+        if (nodeCreator.isNodeType(components)) {
+          node = nodeCreator.setupNode(components, bannerComponentNodes.size(), length - 1);
+          break;
+        }
+      }
+
+      if (node != null) {
+        bannerComponentNodes.add(node);
+        length += components.text().length() + 1;
+      }
+    }
+
+    return bannerComponentNodes;
+  }
+
+  /**
+   * Loads the instruction into the given text view. If things have to be done in a particular order,
+   * the coordinator methods preProcess and postProcess can be used. PreProcess should be used to
+   * load text into the textView (so there should only be one coordinator calling this method), and
+   * postProcess should be used to make changes to that text, i.e., to load images into the textView.
+   *
+   * @param textView in which to load text and images
+   */
+  void loadInstruction(TextView textView) {
+    for (NodeCreator nodeCreator : nodeCreators) {
+      nodeCreator.preProcess(textView, bannerComponentNodes);
+    }
+
+    for (NodeCreator nodeCreator : nodeCreators) {
+      nodeCreator.postProcess(textView, bannerComponentNodes);
+    }
+  }
+}

libandroid-navigation-ui/src/main/java/com/mapbox/services/android/navigation/ui/v5/instruction/ImageCoordinator.java renamed to libandroid-navigation-ui/src/main/java/com/mapbox/services/android/navigation/ui/v5/instruction/ImageCreator.java

@@ -3,15 +3,13 @@
 import android.content.Context;
 import android.text.Spannable;
 import android.text.SpannableString;
-import android.text.TextUtils;
 import android.text.style.ImageSpan;
 import android.widget.TextView;
 
 import com.mapbox.api.directions.v5.models.BannerComponents;
 import com.mapbox.api.directions.v5.models.BannerInstructions;
 import com.mapbox.api.directions.v5.models.BannerText;
 import com.mapbox.api.directions.v5.models.LegStep;
-import com.mapbox.services.android.navigation.ui.v5.instruction.InstructionLoader.BannerComponentNode;
 import com.squareup.picasso.Picasso;
 
 import java.util.ArrayList;
@@ -27,26 +25,55 @@
  * If a shield URL is found, {@link Picasso} is used to load the image.  Then, once the image is loaded,
  * a new {@link ImageSpan} is created and set to the appropriate position of the {@link Spannable}
  */
-public class ImageCoordinator {
+public class ImageCreator extends NodeCreator<ImageCreator.ImageNode, ImageVerifier> {
 
-  private static ImageCoordinator instance;
+  private static ImageCreator instance;
   private boolean isInitialized;
   private Picasso picassoImageLoader;
   private List<InstructionTarget> targets;
   private UrlDensityMap urlDensityMap;
   private List<BannerShield> bannerShieldList;
 
-  private ImageCoordinator() {
+  private ImageCreator(ImageVerifier imageVerifier) {
+    super(imageVerifier);
+  }
+
+  @Override
+  ImageCreator.ImageNode setupNode(BannerComponents components, int index, int startIndex) {
+    addShieldInfo(components, index);
+    return new ImageCreator.ImageNode(components, startIndex);
+  }
+
+  /**
+   * Uses the given BannerComponents object to construct a BannerShield object containing the
+   * information needed to load the proper image into the TextView where appropriate.
+   *
+   * @param bannerComponents containing image info
+   * @param index of the BannerComponentNode which refers to the given BannerComponents
+   */
+  public void addShieldInfo(BannerComponents bannerComponents, int index) {
+    bannerShieldList.add(new BannerShield(bannerComponents, index));
+  }
+
+  static class ImageNode extends BannerComponentNode {
+
+    ImageNode(BannerComponents bannerComponents, int startIndex) {
+      super(bannerComponents, startIndex);
+    }
   }
 
   /**
    * Primary access method (using singleton pattern)
    *
    * @return InstructionLoader
    */
-  public static synchronized ImageCoordinator getInstance() {
+  public static ImageCreator getInstance() {
+    return getInstance(new ImageVerifier());
+  }
+
+  public static synchronized ImageCreator getInstance(ImageVerifier imageVerifier) {
     if (instance == null) {
-      instance = new ImageCoordinator();
+      instance = new ImageCreator(imageVerifier);
     }
 
     return instance;
@@ -68,16 +95,7 @@ public void initialize(Context context) {
     }
   }
 
-  /**
-   * Uses the given BannerComponents object to construct a BannerShield object containing the
-   * information needed to load the proper image into the TextView where appropriate.
-   *
-   * @param bannerComponents containing image info
-   * @param index of the BannerComponentNode which refers to the given BannerComponents
-   */
-  public void addShieldInfo(BannerComponents bannerComponents, int index) {
-    bannerShieldList.add(new BannerShield(bannerComponents, index));
-  }
+
 
   /**
    * Will pre-fetch images for a given {@link LegStep}.
@@ -164,16 +182,12 @@ private boolean hasImages() {
    */
   private void fetchImageBaseUrls(BannerText bannerText) {
     for (BannerComponents components : bannerText.components()) {
-      if (hasImageUrl(components)) {
+      if (nodeVerifier.hasImageUrl(components)) {
         picassoImageLoader.load(urlDensityMap.get(components.imageBaseUrl())).fetch();
       }
     }
   }
 
-  private boolean hasImageUrl(BannerComponents components) {
-    return !TextUtils.isEmpty(components.imageBaseUrl());
-  }
-
   private void createTargets(TextView textView) {
     Spannable instructionSpannable = new SpannableString(textView.getText());
     for (final BannerShield bannerShield : bannerShieldList) {
@@ -201,10 +215,8 @@ private void checkIsInitialized() {
     }
   }
 
-  static class ImageNode extends BannerComponentNode {
-
-    ImageNode(BannerComponents bannerComponents, int startIndex) {
-      super(bannerComponents, startIndex);
-    }
+  @Override
+  void postProcess(TextView textView, List<BannerComponentNode> bannerComponentNodes) {
+    loadImages(textView, bannerComponentNodes);
   }
 }

libandroid-navigation-ui/src/main/java/com/mapbox/services/android/navigation/ui/v5/instruction/ImageVerifier.java

@@ -0,0 +1,17 @@
+package com.mapbox.services.android.navigation.ui.v5.instruction;
+
+import android.text.TextUtils;
+
+import com.mapbox.api.directions.v5.models.BannerComponents;
+
+public class ImageVerifier extends NodeVerifier {
+
+  @Override
+  boolean isNodeType(BannerComponents bannerComponents) {
+    return hasImageUrl(bannerComponents);
+  }
+
+  protected boolean hasImageUrl(BannerComponents components) {
+    return !TextUtils.isEmpty(components.imageBaseUrl());
+  }
+}