Improve Preference highlighting

- use PreferenceFragment.onBindPreferences() to launch  highlighting
- improve SettingsPreferenceFragment code for highlighting: now we can
find the View to highlight thru its Tag if there is no ListAdapter available
- add HighlightingFragment for highlighting a View from its tag/key. This
is dealing with cases when the content is custom and not relying on
SettingsPreferenceFragment (like DataUsageSummary)

Also:

- improve DataUsageSummary so that onResume() is not recreating the
Tabs all the time
- add missing "android:keys" on some Security Settings preference files

Change-Id: Ib1dd8238fe2fb57c151d584c0810a0e0a5ad97c4

src/com/android/settings/HighlightingFragment.java

@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2014 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.settings;
+
+import android.app.Fragment;
+import android.graphics.drawable.Drawable;
+import android.os.Bundle;
+import android.text.TextUtils;
+import android.view.View;
+import android.view.ViewGroup;
+
+public class HighlightingFragment extends Fragment {
+
+    private static final String TAG = "HighlightSettingsFragment";
+
+    private static final int DELAY_HIGHLIGHT_DURATION_MILLIS = 300;
+    private static final String SAVE_HIGHLIGHTED_KEY = "android:view_highlighted";
+
+    private String mViewKey;
+    private boolean mViewHighlighted = false;
+
+    @Override
+    public void onCreate(Bundle icicle) {
+        super.onCreate(icicle);
+
+        if (icicle != null) {
+            mViewHighlighted = icicle.getBoolean(SAVE_HIGHLIGHTED_KEY);
+        }
+    }
+
+    @Override
+    public void onSaveInstanceState(Bundle outState) {
+        super.onSaveInstanceState(outState);
+
+        outState.putBoolean(SAVE_HIGHLIGHTED_KEY, mViewHighlighted);
+    }
+
+    @Override
+    public void onActivityCreated(Bundle savedInstanceState) {
+        super.onActivityCreated(savedInstanceState);
+
+        final Bundle args = getArguments();
+        if (args != null) {
+            mViewKey = args.getString(SettingsActivity.EXTRA_FRAGMENT_ARG_KEY);
+            highlightViewIfNeeded();
+        }
+    }
+
+    public void highlightViewIfNeeded() {
+        if (!mViewHighlighted &&!TextUtils.isEmpty(mViewKey)) {
+            highlightView(mViewKey);
+        }
+    }
+
+    private Drawable getHighlightDrawable() {
+        return getResources().getDrawable(R.drawable.preference_highlight);
+    }
+
+    private void highlightView(String key) {
+        final Drawable highlight = getHighlightDrawable();
+
+        // Try locating the View thru its Tag / Key
+        final View view = findViewForKey(getView(), key);
+        if (view != null ) {
+            view.setBackground(highlight);
+
+            getView().postDelayed(new Runnable() {
+                @Override
+                public void run() {
+                    final int centerX = view.getWidth() / 2;
+                    final int centerY = view.getHeight() / 2;
+                    highlight.setHotspot(0, centerX, centerY);
+                    highlight.clearHotspots();
+                }
+            }, DELAY_HIGHLIGHT_DURATION_MILLIS);
+
+            mViewHighlighted = true;
+        }
+    }
+
+    private View findViewForKey(View root, String key) {
+        if (checkTag(root, key)) {
+            return root;
+        }
+        if (root instanceof ViewGroup) {
+            final ViewGroup group = (ViewGroup) root;
+            final int count = group.getChildCount();
+            for (int n = 0; n < count; n++) {
+                final View child = group.getChildAt(n);
+                final View view = findViewForKey(child, key);
+                if (view != null) {
+                    return view;
+                }
+            }
+        }
+        return null;
+    }
+
+    private boolean checkTag(View view, String key) {
+        final Object tag = view.getTag();
+        if (tag == null || !(tag instanceof String)) {
+            return false;
+        }
+        final String viewKey = (String) tag;
+        return (!TextUtils.isEmpty(viewKey) && viewKey.equals(key));
+    }
+}