Changed PageChangeListener to add/remove

It's the right way to indicate and handle multiple listener

Author: massimobio

demo/src/main/java/com/daimajia/slider/demo/MainActivity.java

@@ -66,7 +66,7 @@ protected void onCreate(Bundle savedInstanceState) {
         mDemoSlider.setPresetIndicator(SliderLayout.PresetIndicators.Center_Bottom);
         mDemoSlider.setCustomAnimation(new DescriptionAnimation());
         mDemoSlider.setDuration(4000);
-        mDemoSlider.setOnPageChangeListener(this);
+        mDemoSlider.addOnPageChangeListener(this);
         ListView l = (ListView)findViewById(R.id.transformers);
         l.setAdapter(new TransformerAdapter(this));
         l.setOnItemClickListener(new AdapterView.OnItemClickListener() {

library/src/main/java/com/daimajia/slider/library/Indicators/PagerIndicator.java

@@ -328,7 +328,7 @@ public void setViewPager(ViewPagerEx pager){
             throw new IllegalStateException("Viewpager does not have adapter instance");
         }
         mPager = pager;
-        mPager.setOnPageChangeListener(this);
+        mPager.addOnPageChangeListener(this);
         ((InfinitePagerAdapter)mPager.getAdapter()).getRealAdapter().registerDataSetObserver(dataChangeObserver);
     }
 

library/src/main/java/com/daimajia/slider/library/SliderLayout.java

@@ -213,12 +213,16 @@ public boolean onTouch(View v, MotionEvent event) {
         }
     }
 
-    public void setOnPageChangeListener(ViewPagerEx.OnPageChangeListener onPageChangeListener){
-        if(onPageChangeListener!=null){
-            mViewPager.setOnPageChangeListener(onPageChangeListener);
+    public void addOnPageChangeListener(ViewPagerEx.OnPageChangeListener onPageChangeListener){
+        if(onPageChangeListener != null){
+            mViewPager.addOnPageChangeListener(onPageChangeListener);
         }
     }
 
+    public void removeOnPageChangeListener(ViewPagerEx.OnPageChangeListener onPageChangeListener) {
+        mViewPager.removeOnPageChangeListener(onPageChangeListener);
+    }
+
     public void setCustomIndicator(PagerIndicator indicator){
         if(mIndicator != null){
             mIndicator.destroySelf();

library/src/main/java/com/daimajia/slider/library/Tricks/ViewPagerEx.java

@@ -589,17 +589,27 @@ private void scrollToItem(int item, boolean smoothScroll, int velocity,
     }
 
     /**
-     * Set a listener that will be invoked whenever the page changes or is incrementally
+     * Add a listener that will be invoked whenever the page changes or is incrementally
      * scrolled. See {@link OnPageChangeListener}.
      *
-     * @param listener Listener to set
+     * @param listener Listener to add
      */
-    public void setOnPageChangeListener(OnPageChangeListener listener) {
+    public void addOnPageChangeListener(OnPageChangeListener listener) {
         if (!mOnPageChangeListeners.contains(listener)) {
             mOnPageChangeListeners.add(listener);
         }
     }
 
+    /**
+     * Remove a listener that was added with addOnPageChangeListener
+     * See {@link OnPageChangeListener}.
+     *
+     * @param listener Listener to remove
+     */
+    public void removeOnPageChangeListener(OnPageChangeListener listener) {
+        mOnPageChangeListeners.remove(listener);
+    }
+
     /**
      * Set a {@link PageTransformer} that will be called for each attached page whenever
      * the scroll position is changed. This allows the application to apply custom property