Add charts loading indicator

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/AbstractChartFragment.java

@@ -333,6 +333,7 @@ public abstract class AbstractChartFragment<D extends ChartsData> extends Abstra
         ChartsHost chartsHost = getChartsHost();
         if (chartsHost != null) {
             if (chartsHost.getDevice() != null) {
+                chartsHost.setLoading(true);
                 mChartDirty = false;
                 if (refreshTask != null && refreshTask.getStatus() != AsyncTask.Status.FINISHED) {
                     refreshTask.cancel(true);
@@ -372,6 +373,9 @@ public abstract class AbstractChartFragment<D extends ChartsData> extends Abstra
                 LOG.info("Not rendering charts because activity is not available anymore");
                 return;
             }
+
+            getChartsHost().setLoading(false);
+
             if (getTaskError() != null) {
                 // Async task failed - we will have no data, so avoid NPE crashes
                 // a log + toast were already displayed by the DBAccess class

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/ActivityChartsActivity.java

@@ -28,6 +28,7 @@ import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.Button;
+import android.widget.ProgressBar;
 import android.widget.TextView;
 import android.widget.Toast;
 
@@ -88,6 +89,8 @@ public class ActivityChartsActivity extends AbstractGBActivity implements Charts
     public static final String EXTRA_TIMESTAMP = "timestamp";
     public static final String EXTRA_MODE = "mode";
 
+    private ProgressBar mLoadingProgressBar;
+
     private TextView mDateControl;
 
     private Date mStartDate;
@@ -214,6 +217,7 @@ public class ActivityChartsActivity extends AbstractGBActivity implements Charts
             }
         }
 
+        mLoadingProgressBar = findViewById(R.id.loading_progressbar);
         dateBar = findViewById(R.id.charts_date_bar);
         mDateControl = findViewById(R.id.charts_text_date);
         mDateControl.setOnClickListener(v -> {
@@ -378,6 +382,11 @@ public class ActivityChartsActivity extends AbstractGBActivity implements Charts
         mDateControl.setText(dateInfo);
     }
 
+    @Override
+    public void setLoading(boolean loading) {
+        mLoadingProgressBar.setVisibility(loading ? View.VISIBLE : View.INVISIBLE);
+    }
+
     @Override
     public ViewGroup getDateBar() {
         return dateBar;

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/ChartsHost.java

@@ -45,6 +45,8 @@ public interface ChartsHost {
 
     void setDateInfo(String dateInfo);
 
+    void setLoading(boolean loading);
+
     ViewGroup getDateBar();
 
     void enableSwipeRefresh(boolean enable);

app/src/main/res/layout/activity_charts.xml

@@ -27,10 +27,23 @@
             tools:context="nodomain.freeyourgadget.gadgetbridge.activities.charts.ActivityChartsActivity">
         </androidx.viewpager2.widget.ViewPager2>
 
+        <ProgressBar
+            android:id="@+id/loading_progressbar"
+            style="?android:attr/progressBarStyleHorizontal"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:layout_marginBottom="-8dp"
+            android:layout_marginTop="-4dp"
+            android:layout_gravity="center_horizontal"
+            android:indeterminate="true"
+            android:indeterminateOnly="true"
+            android:visibility="invisible" />
+
     <LinearLayout
         android:id="@+id/charts_date_bar"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
+        android:paddingTop="2dp"
         android:gravity="fill_horizontal"
         android:orientation="horizontal">