Add null check for worker

Add null check to avoid crash when worker cannot get through uri.

Bug: 128492874
Test: make -j42 RunSettingsRoboTests
Change-Id: I789ce0bfa98c0b0b145a8605c58c88a77eeb76a9

src/com/android/settings/media/MediaOutputSlice.java

@@ -76,6 +76,11 @@ public class MediaOutputSlice implements CustomSliceable {
             return null;
         }
 
+        if (getWorker() == null) {
+            Log.d(TAG, "getSlice() Can not get worker through uri!");
+            return null;
+        }
+
         final List<MediaDevice> devices = getMediaDevices();
         @ColorInt final int color = Utils.getColorAccentDefaultColor(mContext);
 
@@ -115,13 +120,15 @@ public class MediaOutputSlice implements CustomSliceable {
     private MediaDeviceUpdateWorker getWorker() {
         if (mWorker == null) {
             mWorker = (MediaDeviceUpdateWorker) SliceBackgroundWorker.getInstance(getUri());
-            mWorker.setPackageName(mPackageName);
+            if (mWorker != null) {
+                mWorker.setPackageName(mPackageName);
+            }
         }
         return mWorker;
     }
 
     private List<MediaDevice> getMediaDevices() {
-        List<MediaDevice> devices = getWorker().getMediaDevices();
+        final List<MediaDevice> devices = getWorker().getMediaDevices();
         return devices;
     }
 

tests/robotests/src/com/android/settings/media/MediaOutputSliceTest.java

@@ -93,6 +93,13 @@ public class MediaOutputSliceTest {
         mMediaOutputSlice.init(TEST_PACKAGE_NAME, mMediaDeviceUpdateWorker);
     }
 
+    @Test
+    public void getSlice_workerIsNull_shouldNotCrash() {
+        mMediaOutputSlice.init(TEST_PACKAGE_NAME, null);
+
+        mMediaOutputSlice.getSlice();
+    }
+
     @Test
     public void getSlice_shouldHaveActiveDeviceName() {
         mDevices.clear();