Add methods to change the selected tab in the Shuffleboard app (#1448)

wpilibj/src/main/java/edu/wpi/first/wpilibj/shuffleboard/Shuffleboard.java

@@ -82,6 +82,25 @@ public final class Shuffleboard {
     return root.getTab(title);
   }
 
+  /**
+   * Selects the tab in the dashboard with the given index in the range [0..n-1], where <i>n</i>
+   * is the number of tabs in the dashboard at the time this method is called.
+   *
+   * @param index the index of the tab to select
+   */
+  public static void selectTab(int index) {
+    root.selectTab(index);
+  }
+
+  /**
+   * Selects the tab in the dashboard with the given title.
+   *
+   * @param title the title of the tab to select
+   */
+  public static void selectTab(String title) {
+    root.selectTab(title);
+  }
+
   /**
    * Enables user control of widgets containing actuators: speed controllers, relays, etc. This
    * should only be used when the robot is in test mode. IterativeRobotBase and SampleRobot are

wpilibj/src/main/java/edu/wpi/first/wpilibj/shuffleboard/ShuffleboardInstance.java

@@ -13,6 +13,7 @@ import java.util.Objects;
 import java.util.function.Consumer;
 
 import edu.wpi.first.networktables.NetworkTable;
+import edu.wpi.first.networktables.NetworkTableEntry;
 import edu.wpi.first.networktables.NetworkTableInstance;
 
 final class ShuffleboardInstance implements ShuffleboardRoot {
@@ -21,11 +22,13 @@ final class ShuffleboardInstance implements ShuffleboardRoot {
   private boolean m_tabsChanged = false; // NOPMD redundant field initializer
   private final NetworkTable m_rootTable;
   private final NetworkTable m_rootMetaTable;
+  private final NetworkTableEntry m_selectedTabEntry;
 
   ShuffleboardInstance(NetworkTableInstance ntInstance) {
     Objects.requireNonNull(ntInstance, "NetworkTable instance cannot be null");
     m_rootTable = ntInstance.getTable(Shuffleboard.kBaseTableName);
     m_rootMetaTable = m_rootTable.getSubTable(".metadata");
+    m_selectedTabEntry = m_rootMetaTable.getEntry("Selected");
   }
 
   @Override
@@ -64,6 +67,16 @@ final class ShuffleboardInstance implements ShuffleboardRoot {
     applyToAllComplexWidgets(ComplexWidget::disableIfActuator);
   }
 
+  @Override
+  public void selectTab(int index) {
+    m_selectedTabEntry.forceSetDouble(index);
+  }
+
+  @Override
+  public void selectTab(String title) {
+    m_selectedTabEntry.forceSetString(title);
+  }
+
   /**
    * Applies the function {@code func} to all complex widgets in this root, regardless of how they
    * are nested.

wpilibj/src/main/java/edu/wpi/first/wpilibj/shuffleboard/ShuffleboardRoot.java

@@ -38,4 +38,19 @@ interface ShuffleboardRoot {
    */
   void disableActuatorWidgets();
 
+  /**
+   * Selects the tab in the dashboard with the given index in the range [0..n-1], where <i>n</i>
+   * is the number of tabs in the dashboard at the time this method is called.
+   *
+   * @param index the index of the tab to select
+   */
+  void selectTab(int index);
+
+  /**
+   * Selects the tab in the dashboard with the given title.
+   *
+   * @param title the title of the tab to select
+   */
+  void selectTab(String title);
+
 }