1 files changed, 76 insertions, 0 deletions
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/ViewLinker.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/ViewLinker.java
new file mode 100644
index 0000000..48457c6
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/ViewLinker.java
@@ -0,0 +1,76 @@
+package com.android.systemui.statusbar.phone;
+
+import android.view.View;
+
+/*
+    Allows mirroring of view states such as alpha, translation...etc
+ */
+public class ViewLinker<T extends View & ViewLinker.ViewLinkerParent> {
+
+    public static final int LINK_ALPHA = 0x1;
+    public static final int LINK_TRANSLATION = 0x2;
+
+    private final LinkInfo[] mLinkedViews;
+    private final T mParent;
+
+    public interface ViewLinkerCallback {
+        void onAlphaChanged(float alpha);
+        void onTranslationXChanged(float translationX);
+    }
+
+    public interface ViewLinkerParent {
+        void registerLinker(ViewLinkerCallback callback);
+    }
+
+    public static class LinkInfo {
+        private View mView;
+        private int mFlags;
+        public LinkInfo(View v, int linkFlags) {
+            mView = v;
+            mFlags = linkFlags;
+        }
+        private boolean supportsFlag(int flag) {
+            return (mFlags & flag) != 0;
+        }
+    }
+
+    private ViewLinkerCallback mCallback = new ViewLinkerCallback() {
+        @Override
+        public void onAlphaChanged(float alpha) {
+            for (LinkInfo v : mLinkedViews) {
+                if (v.supportsFlag(LINK_ALPHA)) {
+                    v.mView.setAlpha(alpha);
+                }
+            }
+        }
+
+        @Override
+        public void onTranslationXChanged(float translationX) {
+            for (LinkInfo v : mLinkedViews) {
+                if (v.supportsFlag(LINK_TRANSLATION)) {
+                    v.mView.setTranslationX(translationX);
+                }
+            }
+        }
+    };
+
+    public ViewLinker(T parent, LinkInfo... viewsToLink) {
+        mLinkedViews = viewsToLink;
+        mParent = parent;
+        ensureParentNotInLink();
+        parent.registerLinker(mCallback);
+    }
+
+    private void ensureParentNotInLink() {
+        for (LinkInfo v : mLinkedViews) {
+            if (v.mView == mParent) {
+                throw new IllegalStateException("Parent cannot be" +
+                        "one of the linked views");
+            }
+        }
+    }
+
+    public View getParent() {
+        return mParent;
+    }
+}