Merge pull request #450 from AppDevNext/KotlinOnChartGestureListener

Kotlin on chart gesture listener

Author: hannesa2

MPChartLib/src/main/java/com/github/mikephil/charting/listener/BarLineChartTouchListener.kt

@@ -0,0 +1,122 @@
+package com.github.mikephil.charting.listener
+
+import android.view.GestureDetector
+import android.view.GestureDetector.SimpleOnGestureListener
+import android.view.MotionEvent
+import android.view.View.OnTouchListener
+import com.github.mikephil.charting.charts.Chart
+import com.github.mikephil.charting.highlight.Highlight
+import kotlin.math.sqrt
+
+abstract class ChartTouchListener<T : Chart<*>?>(
+    @JvmField protected var chart: T?) : SimpleOnGestureListener(), OnTouchListener {
+    enum class ChartGesture {
+        NONE, DRAG, X_ZOOM, Y_ZOOM, PINCH_ZOOM, ROTATE, SINGLE_TAP, DOUBLE_TAP, LONG_PRESS, FLING
+    }
+
+    /**
+     * Returns the last gesture that has been performed on the chart.
+     *
+     * @return
+     */
+    /**
+     * the last touch gesture that has been performed
+     */
+    var lastGesture: ChartGesture = ChartGesture.NONE
+        protected set
+
+    /**
+     * returns the touch mode the listener is currently in
+     *
+     * @return
+     */
+    /**
+     * integer field that holds the current touch-state
+     */
+    var touchMode: Int = NONE
+        protected set
+
+    /**
+     * the last highlighted object (via touch)
+     */
+    protected var mLastHighlighted: Highlight? = null
+
+    /**
+     * the gesturedetector used for detecting taps and longpresses, ...
+     */
+    @JvmField
+    protected var gestureDetector: GestureDetector? = GestureDetector(chart!!.getContext(), this)
+
+    /**
+     * Calls the OnChartGestureListener to do the start callback
+     *
+     * @param me
+     */
+    fun startAction(me: MotionEvent) {
+        val l = chart!!.getOnChartGestureListener()
+
+        if (l != null) l.onChartGestureStart(me, this.lastGesture)
+    }
+
+    /**
+     * Calls the OnChartGestureListener to do the end callback
+     *
+     * @param me
+     */
+    fun endAction(me: MotionEvent) {
+        val l = chart!!.getOnChartGestureListener()
+
+        if (l != null) l.onChartGestureEnd(me, this.lastGesture)
+    }
+
+    /**
+     * Sets the last value that was highlighted via touch.
+     *
+     * @param high
+     */
+    fun setLastHighlighted(high: Highlight?) {
+        mLastHighlighted = high
+    }
+
+    /**
+     * Perform a highlight operation.
+     *
+     * @param motionEvent
+     */
+    protected fun performHighlight(highlight: Highlight?, motionEvent: MotionEvent?) {
+        if (highlight == null || highlight.equalTo(mLastHighlighted)) {
+            chart!!.highlightValue(null, true)
+            mLastHighlighted = null
+        } else {
+            chart!!.highlightValue(highlight, true)
+            mLastHighlighted = highlight
+        }
+    }
+
+    companion object {
+        // states
+        protected const val NONE: Int = 0
+        protected const val DRAG: Int = 1
+        protected const val X_ZOOM: Int = 2
+        protected const val Y_ZOOM: Int = 3
+        protected const val PINCH_ZOOM: Int = 4
+        protected const val POST_ZOOM: Int = 5
+        protected const val ROTATE: Int = 6
+
+        /**
+         * returns the distance between two points
+         *
+         * @param eventX
+         * @param startX
+         * @param eventY
+         * @param startY
+         * @return
+         */
+        @JvmStatic
+        protected fun distance(eventX: Float, startX: Float, eventY: Float, startY: Float): Float {
+            val dx = eventX - startX
+            val dy = eventY - startY
+            return sqrt((dx * dx + dy * dy).toDouble()).toFloat()
+        }
+    }
+}

MPChartLib/src/main/java/com/github/mikephil/charting/listener/ChartTouchListener.java

@@ -1,50 +1,48 @@
-package com.github.mikephil.charting.listener;
+package com.github.mikephil.charting.listener
 
-import android.view.MotionEvent;
+import android.view.MotionEvent
+import com.github.mikephil.charting.listener.ChartTouchListener.ChartGesture
 
 /**
  * Listener for callbacks when doing gestures on the chart.
- *
- * @author Philipp Jahoda
  */
-public interface OnChartGestureListener {
-
+interface OnChartGestureListener {
     /**
      * Callbacks when a touch-gesture has started on the chart (ACTION_DOWN)
      *
      * @param me
      * @param lastPerformedGesture
      */
-    void onChartGestureStart(MotionEvent me, ChartTouchListener.ChartGesture lastPerformedGesture);
+    fun onChartGestureStart(me: MotionEvent, lastPerformedGesture: ChartGesture?)
 
     /**
      * Callbacks when a touch-gesture has ended on the chart (ACTION_UP, ACTION_CANCEL)
      *
      * @param me
      * @param lastPerformedGesture
      */
-    void onChartGestureEnd(MotionEvent me, ChartTouchListener.ChartGesture lastPerformedGesture);
+    fun onChartGestureEnd(me: MotionEvent, lastPerformedGesture: ChartGesture?)
 
     /**
      * Callbacks when the chart is longpressed.
      *
      * @param me
      */
-    void onChartLongPressed(MotionEvent me);
+    fun onChartLongPressed(me: MotionEvent)
 
     /**
      * Callbacks when the chart is double-tapped.
      *
      * @param me
      */
-    void onChartDoubleTapped(MotionEvent me);
+    fun onChartDoubleTapped(me: MotionEvent)
 
     /**
      * Callbacks when the chart is single-tapped.
      *
      * @param me
      */
-    void onChartSingleTapped(MotionEvent me);
+    fun onChartSingleTapped(me: MotionEvent)
 
     /**
      * Callbacks then a fling gesture is made on the chart.
@@ -54,7 +52,7 @@ public interface OnChartGestureListener {
      * @param velocityX
      * @param velocityY
      */
-    void onChartFling(MotionEvent me1, MotionEvent me2, float velocityX, float velocityY);
+    fun onChartFling(me1: MotionEvent?, me2: MotionEvent, velocityX: Float, velocityY: Float)
 
     /**
      * Callbacks when the chart is scaled / zoomed via pinch zoom / double-tap gesture.
@@ -63,7 +61,7 @@ public interface OnChartGestureListener {
      * @param scaleX scalefactor on the x-axis
      * @param scaleY scalefactor on the y-axis
      */
-    void onChartScale(MotionEvent me, float scaleX, float scaleY);
+    fun onChartScale(me: MotionEvent, scaleX: Float, scaleY: Float)
 
     /**
      * Callbacks when the chart is moved / translated via drag gesture.
@@ -72,5 +70,5 @@ public interface OnChartGestureListener {
      * @param dX translation distance on the x-axis
      * @param dY translation distance on the y-axis
      */
-    void onChartTranslate(MotionEvent me, float dX, float dY);
+    fun onChartTranslate(me: MotionEvent, dX: Float, dY: Float)
 }