重构代码，在4.4中将回收多余的Surface，已提升性能

Author: Issac

library/src/main/java/me/imid/swipebacklayout/lib/SwipeBackLayout.java

@@ -14,6 +14,9 @@
 import android.view.ViewGroup;
 import android.widget.FrameLayout;
 
+import java.util.ArrayList;
+import java.util.List;
+
 public class SwipeBackLayout extends FrameLayout {
     /**
      * Minimum velocity that will be detected as a fling
@@ -93,7 +96,10 @@ public class SwipeBackLayout extends FrameLayout {
 
     private int mContentTop;
 
-    private SwipeListener mSwipeListener;
+    /**
+     * The set of listeners to be sent events through.
+     */
+    private List<SwipeListener> mListeners;
 
     private Drawable mShadowLeft;
 
@@ -210,9 +216,35 @@ public void setEdgeSize(int size) {
      * view.
      * 
      * @param listener the swipe listener to attach to this view
+     * @deprecated use {@link #addSwipeListener} instead
      */
+    @Deprecated
     public void setSwipeListener(SwipeListener listener) {
-        mSwipeListener = listener;
+        addSwipeListener(listener);
+    }
+
+    /**
+     * Add a callback to be invoked when a swipe event is sent to this view.
+     * 
+     * @param listener the swipe listener to attach to this view
+     */
+    public void addSwipeListener(SwipeListener listener) {
+        if (mListeners == null) {
+            mListeners = new ArrayList<SwipeListener>();
+        }
+        mListeners.add(listener);
+    }
+
+    /**
+     * Removes a listener from the set of listeners
+     * 
+     * @param listener
+     */
+    public void removeSwipeListener(SwipeListener listener) {
+        if (mListeners == null) {
+            return;
+        }
+        mListeners.remove(listener);
     }
 
     public static interface SwipeListener {
@@ -442,8 +474,10 @@ public boolean tryCaptureView(View view, int i) {
                 } else if (mDragHelper.isEdgeTouched(EDGE_BOTTOM, i)) {
                     mTrackingEdge = EDGE_BOTTOM;
                 }
-                if (mSwipeListener != null) {
-                    mSwipeListener.onEdgeTouch(mTrackingEdge);
+                if (mListeners != null && !mListeners.isEmpty()) {
+                    for (SwipeListener listener : mListeners) {
+                        listener.onEdgeTouch(mTrackingEdge);
+                    }
                 }
                 mIsScrollOverValid = true;
             }
@@ -479,10 +513,13 @@ public void onViewPositionChanged(View changedView, int left, int top, int dx, i
             if (mScrollPercent < mScrollThreshold && !mIsScrollOverValid) {
                 mIsScrollOverValid = true;
             }
-            if (mSwipeListener != null && mDragHelper.getViewDragState() == STATE_DRAGGING
+            if (mListeners != null && !mListeners.isEmpty()
+                    && mDragHelper.getViewDragState() == STATE_DRAGGING
                     && mScrollPercent >= mScrollThreshold && mIsScrollOverValid) {
                 mIsScrollOverValid = false;
-                mSwipeListener.onScrollOverThreshold();
+                for (SwipeListener listener : mListeners) {
+                    listener.onScrollOverThreshold();
+                }
             }
 
             if (mScrollPercent >= 1) {
@@ -535,8 +572,10 @@ public int clampViewPositionVertical(View child, int top, int dy) {
         @Override
         public void onViewDragStateChanged(int state) {
             super.onViewDragStateChanged(state);
-            if (mSwipeListener != null) {
-                mSwipeListener.onScrollStateChange(state, mScrollPercent);
+            if (mListeners != null && !mListeners.isEmpty()) {
+                for (SwipeListener listener : mListeners) {
+                    listener.onScrollStateChange(state, mScrollPercent);
+                }
             }
         }
     }

library/src/main/java/me/imid/swipebacklayout/lib/app/SwipeBackActivityHelper.java

@@ -3,7 +3,6 @@
 
 import android.app.Activity;
 import android.graphics.drawable.ColorDrawable;
-import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 
@@ -29,11 +28,28 @@ public void onActivityCreate() {
         mActivity.getWindow().getDecorView().setBackgroundDrawable(null);
         mSwipeBackLayout = (SwipeBackLayout) LayoutInflater.from(mActivity).inflate(
                 me.imid.swipebacklayout.lib.R.layout.swipeback_layout, null);
+        mSwipeBackLayout.addSwipeListener(new SwipeBackLayout.SwipeListener() {
+            @Override
+            public void onScrollStateChange(int state, float scrollPercent) {
+                if (state == SwipeBackLayout.STATE_IDLE && scrollPercent == 0) {
+                    convertActivityFromTranslucent();
+                }
+            }
+
+            @Override
+            public void onEdgeTouch(int edgeFlag) {
+                convertActivityToTranslucent();
+            }
+
+            @Override
+            public void onScrollOverThreshold() {
+
+            }
+        });
     }
 
     public void onPostCreate() {
         mSwipeBackLayout.attachToActivity(mActivity);
-        convertActivityFromTranslucent();
     }
 
     public View findViewById(int id) {
@@ -85,11 +101,8 @@ public void convertActivityToTranslucent() {
             Class<?>[] classes = Activity.class.getDeclaredClasses();
             Class<?> translucentConversionListenerClazz = null;
             for (Class clazz : classes) {
-                if (clazz.getName().contains("TranslucentConversionListener")) {
+                if (clazz.getSimpleName().contains("TranslucentConversionListener")) {
                     translucentConversionListenerClazz = clazz;
-                    Log.e("class ",
-                            clazz.getName() + "," + clazz.getCanonicalName() + ","
-                                    + clazz.getSimpleName());
                 }
             }
             Method method = Activity.class.getDeclaredMethod("convertToTranslucent",

samples/src/main/java/me/imid/swipebacklayout/demo/DemoActivity.java

@@ -62,7 +62,7 @@ public void onCheckedChanged(RadioGroup group, int checkedId) {
                 saveTrackingMode(edgeFlag);
             }
         });
-        mSwipeBackLayout.setSwipeListener(new SwipeBackLayout.SwipeListener() {
+        mSwipeBackLayout.addSwipeListener(new SwipeBackLayout.SwipeListener() {
             @Override
             public void onScrollStateChange(int state, float scrollPercent) {