Add/Fix Animation

README.md

@@ -55,6 +55,23 @@ expandableLayout.setCollapseListener(new ExpandCollapseListener.CollapseListener
     }
 });
 ```
+
+## Set animations
+<img src="https://raw.githubusercontent.com/iammert/ExpandableLayout/master/art/animation1.gif"/>
+
+```java
+sectionLinearLayout.setExpandableAnimation(new ExpendableScaleAnimation(2000));    
+```
+
+or create custom animation
+```java
+        sectionLinearLayout.setExpandableAnimation(new ExpandableAnimation(2000) {
+            @Override
+            public Animation generateAnimation(View parentView, View childView, ExpandableState expandableState) {
+                return null;
+            }
+        });
+```
 ## Add section or children
 ```java
 Section<FruitCategory, Fruit> section = new Section<>();

app/src/main/java/iammert/com/expandablelayout/MainActivity.java

@@ -11,6 +11,7 @@
 import iammert.com.expandablelib.ExpandCollapseListener;
 import iammert.com.expandablelib.ExpandableLayout;
 import iammert.com.expandablelib.Section;
+import iammert.com.expandablelib.animations.ExpendableScaleAnimation;
 
 public class MainActivity extends AppCompatActivity {
 
@@ -27,7 +28,7 @@ protected void onCreate(Bundle savedInstanceState) {
 
         EditText editText = (EditText) findViewById(R.id.edittext);
         ExpandableLayout sectionLinearLayout = (ExpandableLayout) findViewById(R.id.el);
-
+        sectionLinearLayout.setExpandableAnimation(new ExpendableScaleAnimation(2000));
         sectionLinearLayout.setRenderer(new ExpandableLayout.Renderer<FruitCategory, Fruit>() {
             @Override
             public void renderParent(View view, FruitCategory model, boolean isExpanded, int parentPosition) {

expandablelib/src/main/java/iammert/com/expandablelib/ExpandableAnimation.java

@@ -0,0 +1,23 @@
+package iammert.com.expandablelib;
+
+import android.view.View;
+import android.view.animation.Animation;
+
+/**
+ * Created by T0173711 on 13/12/2017.
+ */
+
+public abstract class ExpandableAnimation {
+
+    private int mExpandableAnimationDuration;
+
+    public int getExpandableAnimationDuration() {
+        return mExpandableAnimationDuration;
+    }
+
+    public ExpandableAnimation(int expandableAnimationDuration){
+        this.mExpandableAnimationDuration=expandableAnimationDuration;
+    }
+
+    public abstract Animation generateAnimation(View parentView, View childView, ExpandableState expandableState);
+}

expandablelib/src/main/java/iammert/com/expandablelib/ExpandableLayout.java

@@ -57,6 +57,16 @@ public boolean apply(Object obj) {
 
     private Operation currentFilter = DEFAULT_FILTER;
 
+    public ExpandableAnimation getExpandableAnimation() {
+        return mExpandableAnimation;
+    }
+
+    public void setExpandableAnimation(ExpandableAnimation expandableAnimation) {
+        mExpandableAnimation = expandableAnimation;
+    }
+
+    private ExpandableAnimation mExpandableAnimation;
+
     public ExpandableLayout(Context context) {
         super(context);
         init(context, null);
@@ -252,9 +262,14 @@ private <P> void expand(@NonNull P parent) {
                 for (int j = 1; j < sectionView.getChildCount(); j++) {
                     final View childView = sectionView.getChildAt(j);
                     final Object childType = sections.get(i).children.get(j - 1);
-                    childView.setVisibility(currentFilter.apply(childType) ? View.VISIBLE : View.GONE);
+                    sectionViewAnimateVisibility(sectionView,childView,currentFilter.apply(childType) ?
+                            ExpandableState.EXPAND
+                            : ExpandableState.COLLAPSE);
                 }
                 sections.get(i).expanded = true;
+
+                // re-render parent for "arrow" animation
+                notifyParentChanged(i);
                 if (expandListener != null)
                     expandListener.onExpanded(i, sections.get(i).parent, sectionView.getChildAt(0));
                 break;
@@ -269,13 +284,23 @@ private <P> void collapse(@NonNull P parent) {
                 sections.get(i).expanded = false;
 
                 for (int j = 1; j < sectionView.getChildCount(); j++) {
-                    sectionView.getChildAt(j).setVisibility(View.GONE);
+                    sectionViewAnimateVisibility(sectionView,sectionView.getChildAt(j),ExpandableState.COLLAPSE);
                 }
-
+                // re-render parent for "arrow" animation
+                notifyParentChanged(i);
                 if (collapseListener != null)
                     collapseListener.onCollapsed(i, sections.get(i).parent, sectionView.getChildAt(0));
                 break;
             }
         }
     }
+
+    private void sectionViewAnimateVisibility(final View parentView,final View childView,final ExpandableState expandableState){
+        if (mExpandableAnimation !=null){
+            childView.startAnimation(mExpandableAnimation.generateAnimation(parentView,childView,expandableState));
+        }else {
+            childView.setVisibility(expandableState == ExpandableState.EXPAND ? VISIBLE : GONE);
+        }
+
+    }
 }

expandablelib/src/main/java/iammert/com/expandablelib/ExpandableState.java

@@ -0,0 +1,9 @@
+package iammert.com.expandablelib;
+
+/**
+ * Created by T0173711 on 13/12/2017.
+ */
+
+public enum  ExpandableState {
+    EXPAND, COLLAPSE
+}

expandablelib/src/main/java/iammert/com/expandablelib/animations/ExpendableScaleAnimation.java

@@ -0,0 +1,64 @@
+package iammert.com.expandablelib.animations;
+
+import android.view.View;
+import android.view.animation.Animation;
+
+import iammert.com.expandablelib.ExpandableAnimation;
+import iammert.com.expandablelib.ExpandableState;
+
+/**
+ * Created by T0173711 on 13/12/2017.
+ */
+
+public class ExpendableScaleAnimation extends ExpandableAnimation {
+    public ExpendableScaleAnimation(int duration) {
+        super(duration);
+    }
+
+    @Override
+    public Animation generateAnimation(View parentView, final View childView, ExpandableState expandableState) {
+        float startScale;
+        float endScale;
+        final int visibility;
+        switch (expandableState) {
+            case COLLAPSE:
+                startScale = 1.F;
+                endScale = 0.F;
+                visibility = View.GONE;
+                break;
+            case EXPAND:
+                startScale = 0.F;
+                endScale = 1.F;
+                visibility = View.VISIBLE;
+                // prevent from animation to be "GONE"
+                childView.setVisibility(visibility);
+                break;
+            default:
+                return null;
+        }
+        Animation mAnimation =new android.view.animation.ScaleAnimation(
+                1f, 1f, // Start and end values for the X axis scaling
+                startScale, endScale, // Start and end values for the Y axis scaling
+                Animation.RELATIVE_TO_SELF, 0f, // Pivot point of X scaling
+                Animation.ABSOLUTE, 1f);
+        mAnimation.setFillAfter(true); // Needed to keep the result of the animation
+        mAnimation.setDuration(1000);
+        mAnimation.setAnimationListener(new Animation.AnimationListener() {
+            @Override
+            public void onAnimationStart(Animation animation) {
+
+            }
+
+            @Override
+            public void onAnimationEnd(Animation animation) {
+                childView.setVisibility(visibility);
+            }
+
+            @Override
+            public void onAnimationRepeat(Animation animation) {
+
+            }
+        });
+        return mAnimation;
+    }
+}

expandablelib/src/main/java/iammert/com/expandablelib/animations/ExpendableScaleAnimationAdvanced.java

@@ -0,0 +1,79 @@
+package iammert.com.expandablelib.animations;
+
+import android.view.View;
+import android.view.animation.Animation;
+import android.view.animation.Transformation;
+import android.widget.LinearLayout;
+
+import iammert.com.expandablelib.ExpandableAnimation;
+import iammert.com.expandablelib.ExpandableState;
+
+import static iammert.com.expandablelib.ExpandableState.COLLAPSE;
+import static iammert.com.expandablelib.ExpandableState.EXPAND;
+
+/**
+ * Created by T0173711 on 13/12/2017.
+ */
+
+public class ExpendableScaleAnimationAdvanced extends ExpandableAnimation {
+
+    private int mExpendHeight;
+    private LinearLayout.LayoutParams mLayoutParams;
+
+    public ExpendableScaleAnimationAdvanced(int duration) {
+        super(duration);
+    }
+
+
+    @Override
+    public Animation generateAnimation(View parentView, final View childView, final ExpandableState expandableState) {
+        // FIXME little trick to save height don't work if childViews don't have same height
+        if (expandableState == COLLAPSE) {
+            mExpendHeight = childView.getHeight();
+        }
+        return new CustomAnimation(childView, expandableState);
+    }
+
+    class CustomAnimation extends Animation {
+        private View mView;
+        private ExpandableState mState;
+        private int mEndHeight;
+
+        CustomAnimation(final View childView, final ExpandableState expandableState) {
+            setDuration(getExpandableAnimationDuration());
+            mView = childView;
+            mView.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
+            mEndHeight = mView.getMeasuredHeight();
+            mState = expandableState;
+            mLayoutParams = ((LinearLayout.LayoutParams) childView.getLayoutParams());
+            if (mState == EXPAND) {
+                mLayoutParams.height = 0;
+            } else {
+                mLayoutParams.height = LinearLayout.LayoutParams.WRAP_CONTENT;
+            }
+            mView.setVisibility(View.VISIBLE);
+        }
+
+        @Override
+        protected void applyTransformation(float interpolatedTime, Transformation t) {
+
+            super.applyTransformation(interpolatedTime, t);
+            if (interpolatedTime < 1.0f) {
+                if (mState == EXPAND) {
+                    mLayoutParams.height = (int) (mEndHeight * (interpolatedTime));
+                } else {
+                    mLayoutParams.height = (int) (mEndHeight * (1 - interpolatedTime));
+                }
+                mView.requestLayout();
+            } else {
+                if (mState == EXPAND) {
+                    mLayoutParams.height = LinearLayout.LayoutParams.WRAP_CONTENT;
+                    mView.requestLayout();
+                } else {
+                    mView.setVisibility(View.GONE);
+                }
+            }
+        }
+    }
+}
+