1 files changed, 99 insertions, 0 deletions
diff --git a/src/com/android/gallery3d/ui/ScrollView.java b/src/com/android/gallery3d/ui/ScrollView.java
new file mode 100644
index 000000000..f7628335c
--- /dev/null
+++ b/src/com/android/gallery3d/ui/ScrollView.java
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.gallery3d.ui;
+
+import com.android.gallery3d.R;
+import com.android.gallery3d.common.Utils;
+
+import android.content.Context;
+import android.view.GestureDetector;
+import android.view.MotionEvent;
+import android.view.View.MeasureSpec;
+
+// The current implementation can only scroll vertically.
+public class ScrollView extends GLView {
+
+    private static final int MIN_SCROLLER_HEIGHT = 20;
+
+    private NinePatchTexture mScroller;
+    private int mScrollLimit = 0;
+    private int mScrollerHeight = MIN_SCROLLER_HEIGHT;
+    private GestureDetector mGestureDetector;
+
+    public ScrollView(Context context) {
+        mScroller = new NinePatchTexture(context, R.drawable.scrollbar_handle_holo_dark);
+        mGestureDetector = new GestureDetector(context, new MyGestureListener());
+    }
+
+    private GLView getContentView() {
+        return getComponentCount() == 0 ? null : getComponent(0);
+    }
+
+    @Override
+    public void onLayout(boolean sizeChange, int l, int t, int r, int b) {
+        GLView content = getContentView();
+        int width = getWidth();
+        int height = getHeight();
+        content.measure(MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY),
+                MeasureSpec.UNSPECIFIED);
+        int contentHeight = content.getMeasuredHeight();
+        content.layout(0, 0, width, contentHeight);
+        if (height < contentHeight) {
+            mScrollLimit = contentHeight - height;
+            mScrollerHeight = Math.max(MIN_SCROLLER_HEIGHT,
+                    height * height / contentHeight);
+        } else {
+            mScrollLimit = 0;
+        }
+        mScrollY = Utils.clamp(mScrollY, 0, mScrollLimit);
+    }
+
+    @Override
+    public void render(GLCanvas canvas) {
+        GLView content = getContentView();
+        if (content == null) return;
+        int width = getWidth();
+        int height = getHeight();
+
+        canvas.save(GLCanvas.SAVE_FLAG_CLIP);
+        canvas.clipRect(0, 0, width, height);
+        super.render(canvas);
+        if (mScrollLimit > 0) {
+            int x = getWidth() - mScroller.getWidth();
+            int y = (height - mScrollerHeight) * mScrollY / mScrollLimit;
+            mScroller.draw(canvas, x, y, mScroller.getWidth(), mScrollerHeight);
+        }
+        canvas.restore();
+    }
+
+    @Override
+    public boolean onTouch(MotionEvent event) {
+        mGestureDetector.onTouchEvent(event);
+        return true;
+    }
+
+    private class MyGestureListener
+            extends GestureDetector.SimpleOnGestureListener {
+        @Override
+        public boolean onScroll(MotionEvent e1,
+                MotionEvent e2, float distanceX, float distanceY) {
+            mScrollY = Utils.clamp(mScrollY + (int) distanceY, 0, mScrollLimit);
+            invalidate();
+            return true;
+        }
+    }
+}