[DataUsage] Adjusting the control of display sequence

Showing a usage graph before end of statistic would lead to incorrect
height of usage graph, and another update would lead to layout moved a
little bit.

This change tries to improve it through:
1. Start the loading animation earlier, and stop animation when
   statistics loaded.
   (Only effective when UI re-create.)
2. Update the UI only when statistics are ready.

Bug: 187019210
Test: robotest ChartDataUsagePreferenceTest DataUsageListTest
Change-Id: Ic83f2422b6c6d55948110d652ee24234f43b6445

src/com/android/settings/datausage/ChartDataUsagePreference.java

@@ -48,8 +48,8 @@ public class ChartDataUsagePreference extends Preference {
     // Set to half a meg for now.
     private static final long RESOLUTION = DataUnit.MEBIBYTES.toBytes(1) / 2;
 
-    private final int mWarningColor;
-    private final int mLimitColor;
+    private int mWarningColor;
+    private int mLimitColor;
 
     private Resources mResources;
     private NetworkPolicy mPolicy;
@@ -58,24 +58,25 @@ public class ChartDataUsagePreference extends Preference {
     private NetworkCycleChartData mNetworkCycleChartData;
     private int mSecondaryColor;
     private int mSeriesColor;
+    private UsageView mUsageView;
+    private boolean mSuspendUiUpdate;  // Suppress UI updates to save some CPU time.
 
     public ChartDataUsagePreference(Context context, AttributeSet attrs) {
         super(context, attrs);
-        mResources = context.getResources();
         setSelectable(false);
-        mLimitColor = Utils.getColorAttrDefaultColor(context, android.R.attr.colorError);
-        mWarningColor = Utils.getColorAttrDefaultColor(context, android.R.attr.textColorSecondary);
-        setLayoutResource(R.layout.data_usage_graph);
     }
 
     @Override
     public void onBindViewHolder(PreferenceViewHolder holder) {
         super.onBindViewHolder(holder);
-        final UsageView chart = (UsageView) holder.findViewById(R.id.data_usage);
-        if (mNetworkCycleChartData == null) {
+        mUsageView = (UsageView) holder.findViewById(R.id.data_usage);
+    }
+
+    private void onUpdateView() {
+        UsageView chart = mUsageView;
+        if ((chart == null) || (mNetworkCycleChartData == null)) {
             return;
         }
-
         final int top = getTop();
         chart.clearPaths();
         chart.configureGraph(toInt(mEnd - mStart), top);
@@ -291,9 +292,16 @@ public class ChartDataUsagePreference extends Preference {
         return new SpannableStringBuilder().append(label, new ForegroundColorSpan(mLimitColor), 0);
     }
 
+    public void onPreparingChartData() {
+        mSuspendUiUpdate = true;
+    }
+
     public void setNetworkPolicy(NetworkPolicy policy) {
         mPolicy = policy;
-        notifyChanged();
+        if ((!mSuspendUiUpdate) && (mResources != null)) {
+            onUpdateView();
+            notifyChanged();
+        }
     }
 
     public long getInspectStart() {
@@ -305,15 +313,31 @@ public class ChartDataUsagePreference extends Preference {
     }
 
     public void setNetworkCycleData(NetworkCycleChartData data) {
+        if (data == null) {
+            return;
+        }
         mNetworkCycleChartData = data;
         mStart = data.getStartTime();
         mEnd = data.getEndTime();
+        if (mResources == null) {
+            Context context = getContext();
+            mResources = context.getResources();
+            mLimitColor = Utils.getColorAttrDefaultColor(context, android.R.attr.colorError);
+            mWarningColor = Utils.getColorAttrDefaultColor(context,
+                    android.R.attr.textColorSecondary);
+            setLayoutResource(R.layout.data_usage_graph);
+        }
+        onUpdateView();
         notifyChanged();
+        mSuspendUiUpdate = false;
     }
 
     public void setColors(int seriesColor, int secondaryColor) {
         mSeriesColor = seriesColor;
         mSecondaryColor = secondaryColor;
-        notifyChanged();
+        if ((!mSuspendUiUpdate) && (mResources != null)) {
+            onUpdateView();
+            notifyChanged();
+        }
     }
 }

src/com/android/settings/datausage/DataUsageList.java

@@ -151,7 +151,20 @@ public class DataUsageList extends DataUsageBaseFragment
     public void onViewCreated(View v, Bundle savedInstanceState) {
         super.onViewCreated(v, savedInstanceState);
 
+        // Show loading
+        mLoadingViewController = new LoadingViewController(
+                v.findViewById(R.id.loading_container), getListView());
+        mLoadingViewController.showLoadingViewDelayed();
+    }
+
+    private void onEndOfLoading() {
+        if (mHeader != null) {
+            return;
+        }
         mHeader = setPinnedHeaderView(R.layout.apps_filter_spinner);
+
+        mCycleSpinner = mHeader.findViewById(R.id.filter_spinner);
+
         mHeader.findViewById(R.id.filter_settings).setOnClickListener(btn -> {
             final Bundle args = new Bundle();
             args.putParcelable(DataUsageList.EXTRA_NETWORK_TEMPLATE, mTemplate);
@@ -162,8 +175,6 @@ public class DataUsageList extends DataUsageBaseFragment
                     .setArguments(args)
                     .launch();
         });
-        mCycleSpinner = mHeader.findViewById(R.id.filter_spinner);
-        mCycleSpinner.setVisibility(View.GONE);
         mCycleAdapter = new CycleAdapter(mCycleSpinner.getContext(), new SpinnerInterface() {
             @Override
             public void setAdapter(CycleAdapter cycleAdapter) {
@@ -195,10 +206,6 @@ public class DataUsageList extends DataUsageBaseFragment
                 super.sendAccessibilityEvent(host, eventType);
             }
         });
-
-        mLoadingViewController = new LoadingViewController(
-                getView().findViewById(R.id.loading_container), getListView());
-        mLoadingViewController.showLoadingViewDelayed();
     }
 
     @Override
@@ -206,6 +213,10 @@ public class DataUsageList extends DataUsageBaseFragment
         super.onResume();
         mDataStateListener.start(mSubId);
 
+        if (mChart != null) {
+            mChart.onPreparingChartData();
+        }
+
         // kick off loader for network history
         // TODO: consider chaining two loaders together instead of reloading
         // network history when showing app detail.
@@ -526,11 +537,13 @@ public class DataUsageList extends DataUsageBaseFragment
         @Override
         public void onLoadFinished(Loader<List<NetworkCycleChartData>> loader,
                 List<NetworkCycleChartData> data) {
-            mLoadingViewController.showContent(false /* animate */);
+            onEndOfLoading();
+            if (mLoadingViewController != null) {
+                mLoadingViewController.showContent(false /* animate */);
+            }
             mCycleData = data;
             // calculate policy cycles based on available data
             updatePolicy();
-            mCycleSpinner.setVisibility(View.VISIBLE);
         }
 
         @Override