Show scroll indicators in AlertDialog

BUG: 16353356
Change-Id: I0307283751ccb23b9d85b0c36cb78b01243e70dd

4 files changed, 126 insertions, 16 deletions

diff --git a/core/java/android/view/View.java b/core/java/android/view/View.java
index e7b98ca..801d9ad 100644
--- a/core/java/android/view/View.java
+++ b/core/java/android/view/View.java
@@ -3229,6 +3229,8 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
          */
         private ArrayList<OnLayoutChangeListener> mOnLayoutChangeListeners;
 
+        protected OnScrollChangeListener mOnScrollChangeListener;
+
         /**
          * Listeners for attach events.
          */
@@ -4606,6 +4608,17 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
     }
 
     /**
+     * Register a callback to be invoked when the scroll position of this view
+     * changed.
+     *
+     * @param l The callback that will run.
+     * @hide Only used internally.
+     */
+    public void setOnScrollChangeListener(OnScrollChangeListener l) {
+        getListenerInfo().mOnScrollChangeListener = l;
+    }
+
+    /**
      * Register a callback to be invoked when focus of this view changed.
      *
      * @param l The callback that will run.
@@ -9794,6 +9807,29 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
         if (ai != null) {
             ai.mViewScrollChanged = true;
         }
+
+        if (mListenerInfo != null && mListenerInfo.mOnScrollChangeListener != null) {
+            mListenerInfo.mOnScrollChangeListener.onScrollChange(this, l, t, oldl, oldt);
+        }
+    }
+
+    /**
+     * Interface definition for a callback to be invoked when the scroll
+     * position of a view changes.
+     *
+     * @hide Only used internally.
+     */
+    public interface OnScrollChangeListener {
+        /**
+         * Called when the scroll position of a view changes.
+         *
+         * @param v The view whose scroll position has changed.
+         * @param scrollX Current horizontal scroll origin.
+         * @param scrollY Current vertical scroll origin.
+         * @param oldScrollX Previous horizontal scroll origin.
+         * @param oldScrollY Previous vertical scroll origin.
+         */
+        void onScrollChange(View v, int scrollX, int scrollY, int oldScrollX, int oldScrollY);
     }
 
     /**
diff --git a/core/java/com/android/internal/app/AlertController.java b/core/java/com/android/internal/app/AlertController.java
index 0183e45..3630cc7 100644
--- a/core/java/com/android/internal/app/AlertController.java
+++ b/core/java/com/android/internal/app/AlertController.java
@@ -26,7 +26,6 @@ import android.content.DialogInterface;
 import android.content.res.TypedArray;
 import android.database.Cursor;
 import android.graphics.drawable.Drawable;
-import android.os.Build;
 import android.os.Handler;
 import android.os.Message;
 import android.text.TextUtils;
@@ -38,9 +37,11 @@ import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewGroup.LayoutParams;
+import android.view.ViewTreeObserver;
 import android.view.Window;
 import android.view.WindowInsets;
 import android.view.WindowManager;
+import android.widget.AbsListView;
 import android.widget.AdapterView;
 import android.widget.AdapterView.OnItemClickListener;
 import android.widget.ArrayAdapter;
@@ -449,11 +450,11 @@ public class AlertController {
     }
 
     private void setupView() {
-        final LinearLayout contentPanel = (LinearLayout) mWindow.findViewById(R.id.contentPanel);
+        final ViewGroup contentPanel = (ViewGroup) mWindow.findViewById(R.id.contentPanel);
         setupContent(contentPanel);
         final boolean hasButtons = setupButtons();
 
-        final LinearLayout topPanel = (LinearLayout) mWindow.findViewById(R.id.topPanel);
+        final ViewGroup topPanel = (ViewGroup) mWindow.findViewById(R.id.topPanel);
         final TypedArray a = mContext.obtainStyledAttributes(
                 null, R.styleable.AlertDialog, R.attr.alertDialogStyle, 0);
         final boolean hasTitle = setupTitle(topPanel);
@@ -521,13 +522,13 @@ public class AlertController {
         a.recycle();
     }
 
-    private boolean setupTitle(LinearLayout topPanel) {
+    private boolean setupTitle(ViewGroup topPanel) {
         boolean hasTitle = true;
 
         if (mCustomTitleView != null) {
             // Add the custom title view directly to the topPanel layout
-            LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
-                    LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
+            LayoutParams lp = new LayoutParams(
+                    LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
 
             topPanel.addView(mCustomTitleView, 0, lp);
 
@@ -571,7 +572,7 @@ public class AlertController {
         return hasTitle;
     }
 
-    private void setupContent(LinearLayout contentPanel) {
+    private void setupContent(ViewGroup contentPanel) {
         mScrollView = (ScrollView) mWindow.findViewById(R.id.scrollView);
         mScrollView.setFocusable(false);
 
@@ -588,14 +589,76 @@ public class AlertController {
             mScrollView.removeView(mMessageView);
 
             if (mListView != null) {
-                contentPanel.removeView(mWindow.findViewById(R.id.scrollView));
-                contentPanel.addView(mListView,
-                        new LinearLayout.LayoutParams(MATCH_PARENT, MATCH_PARENT));
-                contentPanel.setLayoutParams(new LinearLayout.LayoutParams(MATCH_PARENT, 0, 1.0f));
+                final int childIndex = mScrollView.indexOfChild(mScrollView);
+                contentPanel.removeViewAt(childIndex);
+                contentPanel.addView(mListView, childIndex,
+                        new LayoutParams(MATCH_PARENT, MATCH_PARENT));
             } else {
                 contentPanel.setVisibility(View.GONE);
             }
         }
+
+        // Set up scroll indicators (if present).
+        final View indicatorUp = mWindow.findViewById(R.id.scrollIndicatorUp);
+        final View indicatorDown = mWindow.findViewById(R.id.scrollIndicatorDown);
+        if (indicatorUp != null || indicatorDown != null) {
+            if (mMessage != null) {
+                // We're just showing the ScrollView, set up listener.
+                mScrollView.setOnScrollChangeListener(new View.OnScrollChangeListener() {
+                        @Override
+                        public void onScrollChange(View v, int scrollX, int scrollY,
+                                int oldScrollX, int oldScrollY) {
+                            manageScrollIndicators(v, indicatorUp, indicatorDown);
+                        }
+                    });
+                // Set up the indicators following layout.
+                mScrollView.post(new Runnable() {
+                     @Override
+                     public void run() {
+                             manageScrollIndicators(mScrollView, indicatorUp, indicatorDown);
+                         }
+                     });
+
+            } else if (mListView != null) {
+                // We're just showing the AbsListView, set up listener.
+                mListView.setOnScrollListener(new AbsListView.OnScrollListener() {
+                        @Override
+                        public void onScrollStateChanged(AbsListView view, int scrollState) {
+                            // That's cool, I guess?
+                        }
+
+                        @Override
+                        public void onScroll(AbsListView v, int firstVisibleItem,
+                                int visibleItemCount, int totalItemCount) {
+                            manageScrollIndicators(v, indicatorUp, indicatorDown);
+                        }
+                    });
+                // Set up the indicators following layout.
+                mListView.post(new Runnable() {
+                        @Override
+                        public void run() {
+                            manageScrollIndicators(mListView, indicatorUp, indicatorDown);
+                        }
+                    });
+            } else {
+                // We don't have any content to scroll, remove the indicators.
+                if (indicatorUp != null) {
+                    contentPanel.removeView(indicatorUp);
+                }
+                if (indicatorDown != null) {
+                    contentPanel.removeView(indicatorDown);
+                }
+            }
+        }
+    }
+
+    private static void manageScrollIndicators(View v, View upIndicator, View downIndicator) {
+        if (upIndicator != null) {
+            upIndicator.setVisibility(v.canScrollVertically(-1) ? View.VISIBLE : View.INVISIBLE);
+        }
+        if (downIndicator != null) {
+            downIndicator.setVisibility(v.canScrollVertically(1) ? View.VISIBLE : View.INVISIBLE);
+        }
     }
 
     private boolean setupButtons() {
diff --git a/core/res/res/layout/alert_dialog_material.xml b/core/res/res/layout/alert_dialog_material.xml
index 89a47af..5627a2c 100644
--- a/core/res/res/layout/alert_dialog_material.xml
+++ b/core/res/res/layout/alert_dialog_material.xml
@@ -51,12 +51,17 @@
         <!-- If the client uses a customTitle, it will be added here. -->
     </LinearLayout>
 
-    <LinearLayout android:id="@+id/contentPanel"
+    <FrameLayout android:id="@+id/contentPanel"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_weight="1"
-        android:orientation="vertical"
         android:minHeight="48dp">
+        <View android:id="@+id/scrollIndicatorUp"
+            android:visibility="gone"
+            android:layout_width="match_parent"
+            android:layout_height="1dp"
+            android:layout_gravity="top"
+            android:background="@drawable/list_divider_material"/>
         <ScrollView android:id="@+id/scrollView"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
@@ -78,7 +83,13 @@
                        android:layout_height="@dimen/alert_dialog_padding_top_material" />
             </LinearLayout>
         </ScrollView>
-    </LinearLayout>
+        <View android:id="@+id/scrollIndicatorDown"
+            android:visibility="gone"
+            android:layout_width="match_parent"
+            android:layout_height="1dp"
+            android:layout_gravity="bottom"
+            android:background="@drawable/list_divider_material"/>
+    </FrameLayout>
 
     <FrameLayout android:id="@+id/customPanel"
         android:layout_width="match_parent"
diff --git a/core/res/res/values/symbols.xml b/core/res/res/values/symbols.xml
index d86413f..3cdc1ac 100644
--- a/core/res/res/values/symbols.xml
+++ b/core/res/res/values/symbols.xml
@@ -2090,7 +2090,7 @@
   <java-symbol type="bool" name="config_switch_phone_on_voice_reg_state_change" />
   <java-symbol type="string" name="whichHomeApplicationNamed" />
   <java-symbol type="bool" name="config_sms_force_7bit_encoding" />
-
-  <!-- From MSIM Account -->
   <java-symbol type="layout" name="simple_account_item" />
+  <java-symbol type="id" name="scrollIndicatorUp" />
+  <java-symbol type="id" name="scrollIndicatorDown" />
 </resources>