Back button in search always goes back or closes search

Before, the back button had different behavior depending on
which part of the search dialog had focus, and depending on
whether there were more suggestions than could fit in the
visible space in the drop-down.

This change makes the behavior of the BACK button more
predictable, by always going back to QSB when pivoted
into a source, and closing the search dialog when in
QSB.

Fixes http://b/issue?id=2126526
"One tap of back button when entering text to search
should always take you back to previous page"

Change-Id: I7b3553122eaa1a5d87ac966d5ab2a9f432063cc9

core/java/android/app/SearchDialog.java

@@ -30,7 +30,6 @@ import android.content.pm.ResolveInfo;
 import android.content.pm.PackageManager.NameNotFoundException;
 import android.content.res.Resources;
 import android.database.Cursor;
-import android.graphics.drawable.Animatable;
 import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.os.Bundle;
@@ -64,9 +63,9 @@ import android.widget.AutoCompleteTextView;
 import android.widget.Button;
 import android.widget.ImageButton;
 import android.widget.ImageView;
+import android.widget.LinearLayout;
 import android.widget.ListView;
 import android.widget.TextView;
-import android.widget.ListAdapter;
 import android.widget.AdapterView.OnItemClickListener;
 import android.widget.AdapterView.OnItemSelectedListener;
 
@@ -182,6 +181,9 @@ public class SearchDialog extends Dialog implements OnItemClickListener, OnItemS
         theWindow.setAttributes(lp);
 
         // get the view elements for local access
+        SearchBar searchBar = (SearchBar) findViewById(com.android.internal.R.id.search_bar);
+        searchBar.setSearchDialog(this);
+
         mBadgeLabel = (TextView) findViewById(com.android.internal.R.id.search_badge);
         mSearchAutoComplete = (SearchAutoComplete)
                 findViewById(com.android.internal.R.id.search_src_text);
@@ -205,8 +207,6 @@ public class SearchDialog extends Dialog implements OnItemClickListener, OnItemS
         mVoiceButton.setOnClickListener(mVoiceButtonClickListener);
         mVoiceButton.setOnKeyListener(mButtonsKeyListener);
 
-        mSearchAutoComplete.setSearchDialog(this);
-        
         // pre-hide all the extraneous elements
         mBadgeLabel.setVisibility(View.GONE);
 
@@ -1673,15 +1673,56 @@ public class SearchDialog extends Dialog implements OnItemClickListener, OnItemS
         }
         return result;
     }
-        
+
+    /**
+     * The root element in the search bar layout. This is a custom view just to override
+     * the handling of the back button.
+     */
+    public static class SearchBar extends LinearLayout {
+
+        private SearchDialog mSearchDialog;
+
+        public SearchBar(Context context, AttributeSet attrs) {
+            super(context, attrs);
+        }
+
+        public SearchBar(Context context) {
+            super(context);
+        }
+
+        public void setSearchDialog(SearchDialog searchDialog) {
+            mSearchDialog = searchDialog;
+        }
+
+        /**
+         * Overrides the handling of the back key to move back to the previous sources or dismiss
+         * the search dialog, instead of dismissing the input method.
+         */
+        @Override
+        public boolean dispatchKeyEventPreIme(KeyEvent event) {
+            if (DBG) Log.d(LOG_TAG, "onKeyPreIme(" + event + ")");
+            if (mSearchDialog != null && event.getKeyCode() == KeyEvent.KEYCODE_BACK) {
+                if (event.getAction() == KeyEvent.ACTION_DOWN
+                        && event.getRepeatCount() == 0) {
+                    getKeyDispatcherState().startTracking(event, this);
+                    return true;
+                } else if (event.getAction() == KeyEvent.ACTION_UP
+                        && !event.isCanceled() && getKeyDispatcherState().isTracking(event)) {
+                    mSearchDialog.onBackPressed();
+                    return true;
+                }
+            }
+            return super.dispatchKeyEventPreIme(event);
+        }
+    }
+
     /**
      * Local subclass for AutoCompleteTextView.
      */
     public static class SearchAutoComplete extends AutoCompleteTextView {
 
         private int mThreshold;
-        private SearchDialog mSearchDialog;
-        
+
         public SearchAutoComplete(Context context) {
             super(context);
             mThreshold = getThreshold();
@@ -1697,10 +1738,6 @@ public class SearchDialog extends Dialog implements OnItemClickListener, OnItemS
             mThreshold = getThreshold();
         }
 
-        private void setSearchDialog(SearchDialog searchDialog) {
-            mSearchDialog = searchDialog;
-        }
-        
         @Override
         public void setThreshold(int threshold) {
             super.setThreshold(threshold);
@@ -1754,46 +1791,6 @@ public class SearchDialog extends Dialog implements OnItemClickListener, OnItemS
             return mThreshold <= 0 || super.enoughToFilter();
         }
 
-        /**
-         * {@link AutoCompleteTextView#onKeyPreIme(int, KeyEvent)}) dismisses the drop-down on BACK,
-         * so we must override this method to modify the BACK behavior.
-         */
-        @Override
-        public boolean onKeyPreIme(int keyCode, KeyEvent event) {
-            if (DBG) Log.d(LOG_TAG, "onKeyPreIme(" + keyCode + "," + event + ")");
-            if (mSearchDialog.mSearchable == null) {
-                return false;
-            }
-            if (keyCode == KeyEvent.KEYCODE_BACK) {
-                if (event.getAction() == KeyEvent.ACTION_DOWN
-                        && event.getRepeatCount() == 0) {
-                    if (mSearchDialog.hasPreviousComponent() || isDismissingKeyboardPointless()) {
-                        getKeyDispatcherState().startTracking(event, this);
-                        return true;
-                    }
-                } else if (event.getAction() == KeyEvent.ACTION_UP
-                        && event.isTracking() && !event.isCanceled()) {
-                    if (mSearchDialog.backToPreviousComponent()) {
-                        return true;
-                    } else if (isDismissingKeyboardPointless()) {
-                        mSearchDialog.cancel();
-                        return true;
-                    }
-                }
-            }
-            return false;
-        }
-
-        // If the drop-down obscures the keyboard, or if the drop-down shows all suggestions,
-        // dismissing the keyboard is pointless, so we dismiss the entire dialog instead.
-        private boolean isDismissingKeyboardPointless() {
-            return (isInputMethodNotNeeded() || getDropDownChildCount() >= getAdapterCount());
-        }
-
-        private int getAdapterCount() {
-            final ListAdapter adapter = getAdapter();
-            return adapter == null ? 0 : adapter.getCount();
-        }
     }
 
     @Override

core/res/res/layout/search_bar.xml

@@ -17,8 +17,9 @@
 ** limitations under the License.
 */
 -->
-<LinearLayout
+<view
     xmlns:android="http://schemas.android.com/apk/res/android"
+    class="android.app.SearchDialog$SearchBar"
     android:id="@+id/search_bar"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
@@ -102,4 +103,4 @@
         
     </LinearLayout>
 
-</LinearLayout>
+</view>