[camerax] Implements setFocusMode (#6176)

Implements `setFocusMode` (also adds support for disabling auto-cancel to `FocusMeteringAction` host API implementation to accomplish this) + some minor documentation improvements based on discoveries I made while working on this :)

Fixes flutter/flutter#120467.

~To be landed after: #6110 Done :)

Author: camsim99

packages/camera/camera_android_camerax/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.6.0
+
+* Implements `setFocusMode`, which makes this plugin reach feature parity with camera_android.
+* Fixes `setExposureCompensationIndex` return value to use index returned by CameraX.
+
 ## 0.5.0+36
 
 * Implements `setExposureMode`.

packages/camera/camera_android_camerax/README.md

@@ -3,7 +3,7 @@
 An Android implementation of [`camera`][1] that uses the [CameraX library][2].
 
 *Note*: This package is under development, so please note the
-[missing features and limitations](#missing-features-and-limitations), but
+[missing features and limitations](#limitations), but
 otherwise feel free to try out the current implementation and provide any
 feedback by filing issues under [`flutter/flutter`][5] with `[camerax]` in
 the title, which will be actively triaged.
@@ -22,18 +22,14 @@ dependencies:
   camera_android_camerax: ^0.5.0
 ```
 
-## Missing features and limitations
+## Limitations
 
 ### 240p resolution configuration for video recording
 
 240p resolution configuration for video recording is unsupported by CameraX,
 and thus, the plugin will fall back to 480p if configured with a
 `ResolutionPreset`.
 
-### Focus mode configuration \[[Issue #120467][120467]\]
-
-`setFocusMode` is unimplemented.
-
 ### Setting maximum duration and stream options for video capture
 
 Calling `startVideoCapturing` with `VideoCaptureOptions` configured with

packages/camera/camera_android_camerax/android/src/main/java/io/flutter/plugins/camerax/FocusMeteringActionHostApiImpl.java

@@ -5,6 +5,7 @@
 package io.flutter.plugins.camerax;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.annotation.VisibleForTesting;
 import androidx.camera.core.FocusMeteringAction;
 import androidx.camera.core.MeteringPoint;
@@ -29,7 +30,9 @@ public class FocusMeteringActionHostApiImpl implements FocusMeteringActionHostAp
   public static class FocusMeteringActionProxy {
     /** Creates an instance of {@link FocusMeteringAction}. */
     public @NonNull FocusMeteringAction create(
-        @NonNull List<MeteringPoint> meteringPoints, @NonNull List<Integer> meteringPointModes) {
+        @NonNull List<MeteringPoint> meteringPoints,
+        @NonNull List<Integer> meteringPointModes,
+        @Nullable Boolean disableAutoCancel) {
       if (meteringPoints.size() >= 1 && meteringPoints.size() != meteringPointModes.size()) {
         throw new IllegalArgumentException(
             "One metering point must be specified and the number of specified metering points must match the number of specified metering point modes.");
@@ -59,6 +62,10 @@ public static class FocusMeteringActionProxy {
         }
       }
 
+      if (disableAutoCancel != null && disableAutoCancel == true) {
+        focusMeteringActionBuilder.disableAutoCancel();
+      }
+
       return focusMeteringActionBuilder.build();
     }
 
@@ -100,7 +107,9 @@ public FocusMeteringActionHostApiImpl(@NonNull InstanceManager instanceManager)
 
   @Override
   public void create(
-      @NonNull Long identifier, @NonNull List<MeteringPointInfo> meteringPointInfos) {
+      @NonNull Long identifier,
+      @NonNull List<MeteringPointInfo> meteringPointInfos,
+      @Nullable Boolean disableAutoCancel) {
     final List<MeteringPoint> meteringPoints = new ArrayList<MeteringPoint>();
     final List<Integer> meteringPointModes = new ArrayList<Integer>();
     for (MeteringPointInfo meteringPointInfo : meteringPointInfos) {
@@ -110,6 +119,6 @@ public void create(
     }
 
     instanceManager.addDartCreatedInstance(
-        proxy.create(meteringPoints, meteringPointModes), identifier);
+        proxy.create(meteringPoints, meteringPointModes, disableAutoCancel), identifier);
   }
 }

packages/camera/camera_android_camerax/android/src/main/java/io/flutter/plugins/camerax/GeneratedCameraXLibrary.java

@@ -3796,7 +3796,10 @@ protected void writeValue(@NonNull ByteArrayOutputStream stream, Object value) {
   /** Generated interface from Pigeon that represents a handler of messages from Flutter. */
   public interface FocusMeteringActionHostApi {
 
-    void create(@NonNull Long identifier, @NonNull List<MeteringPointInfo> meteringPointInfos);
+    void create(
+        @NonNull Long identifier,
+        @NonNull List<MeteringPointInfo> meteringPointInfos,
+        @Nullable Boolean disableAutoCancel);
 
     /** The codec used by FocusMeteringActionHostApi. */
     static @NonNull MessageCodec<Object> getCodec() {
@@ -3822,10 +3825,12 @@ static void setup(
                 Number identifierArg = (Number) args.get(0);
                 List<MeteringPointInfo> meteringPointInfosArg =
                     (List<MeteringPointInfo>) args.get(1);
+                Boolean disableAutoCancelArg = (Boolean) args.get(2);
                 try {
                   api.create(
                       (identifierArg == null) ? null : identifierArg.longValue(),
-                      meteringPointInfosArg);
+                      meteringPointInfosArg,
+                      disableAutoCancelArg);
                   wrapped.add(0, null);
                 } catch (Throwable exception) {
                   ArrayList<Object> wrappedError = wrapError(exception);

packages/camera/camera_android_camerax/android/src/test/java/io/flutter/plugins/camerax/FocusMeteringActionTest.java

@@ -6,6 +6,7 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
@@ -43,7 +44,7 @@ public void tearDown() {
   }
 
   @Test
-  public void hostApiCreatecreatesExpectedFocusMeteringActionWithInitialPointThatHasMode() {
+  public void hostApiCreate_createsExpectedFocusMeteringActionWithInitialPointThatHasMode() {
     FocusMeteringActionHostApiImpl.FocusMeteringActionProxy proxySpy =
         spy(new FocusMeteringActionHostApiImpl.FocusMeteringActionProxy());
     FocusMeteringActionHostApiImpl hostApi =
@@ -89,7 +90,7 @@ public void hostApiCreatecreatesExpectedFocusMeteringActionWithInitialPointThatH
     List<MeteringPointInfo> mockMeteringPointInfos =
         Arrays.asList(fakeMeteringPointInfo1, fakeMeteringPointInfo2, fakeMeteringPointInfo3);
 
-    hostApi.create(focusMeteringActionIdentifier, mockMeteringPointInfos);
+    hostApi.create(focusMeteringActionIdentifier, mockMeteringPointInfos, null);
 
     verify(mockFocusMeteringActionBuilder).addPoint(mockMeteringPoint2, mockMeteringPoint2Mode);
     verify(mockFocusMeteringActionBuilder).addPoint(mockMeteringPoint3);
@@ -98,7 +99,8 @@ public void hostApiCreatecreatesExpectedFocusMeteringActionWithInitialPointThatH
   }
 
   @Test
-  public void hostApiCreatecreatesExpectedFocusMeteringActionWithInitialPointThatDoesNotHaveMode() {
+  public void
+      hostApiCreate_createsExpectedFocusMeteringActionWithInitialPointThatDoesNotHaveMode() {
     FocusMeteringActionHostApiImpl.FocusMeteringActionProxy proxySpy =
         spy(new FocusMeteringActionHostApiImpl.FocusMeteringActionProxy());
     FocusMeteringActionHostApiImpl hostApi =
@@ -142,11 +144,49 @@ public void hostApiCreatecreatesExpectedFocusMeteringActionWithInitialPointThatD
     List<MeteringPointInfo> mockMeteringPointInfos =
         Arrays.asList(fakeMeteringPointInfo1, fakeMeteringPointInfo2, fakeMeteringPointInfo3);
 
-    hostApi.create(focusMeteringActionIdentifier, mockMeteringPointInfos);
+    hostApi.create(focusMeteringActionIdentifier, mockMeteringPointInfos, null);
 
     verify(mockFocusMeteringActionBuilder).addPoint(mockMeteringPoint2, mockMeteringPoint2Mode);
     verify(mockFocusMeteringActionBuilder).addPoint(mockMeteringPoint3);
     assertEquals(
         testInstanceManager.getInstance(focusMeteringActionIdentifier), focusMeteringAction);
   }
+
+  @Test
+  public void hostApiCreate_disablesAutoCancelAsExpected() {
+    FocusMeteringActionHostApiImpl.FocusMeteringActionProxy proxySpy =
+        spy(new FocusMeteringActionHostApiImpl.FocusMeteringActionProxy());
+    FocusMeteringActionHostApiImpl hostApi =
+        new FocusMeteringActionHostApiImpl(testInstanceManager, proxySpy);
+
+    FocusMeteringAction.Builder mockFocusMeteringActionBuilder =
+        mock(FocusMeteringAction.Builder.class);
+    final MeteringPoint mockMeteringPoint = mock(MeteringPoint.class);
+    final Long mockMeteringPointId = 47L;
+
+    MeteringPointInfo fakeMeteringPointInfo =
+        new MeteringPointInfo.Builder()
+            .setMeteringPointId(mockMeteringPointId)
+            .setMeteringMode(null)
+            .build();
+
+    testInstanceManager.addDartCreatedInstance(mockMeteringPoint, mockMeteringPointId);
+
+    when(proxySpy.getFocusMeteringActionBuilder(mockMeteringPoint))
+        .thenReturn(mockFocusMeteringActionBuilder);
+    when(mockFocusMeteringActionBuilder.build()).thenReturn(focusMeteringAction);
+
+    List<MeteringPointInfo> mockMeteringPointInfos = Arrays.asList(fakeMeteringPointInfo);
+
+    // Test not disabling auto cancel.
+    hostApi.create(73L, mockMeteringPointInfos, /* disableAutoCancel */ null);
+    verify(mockFocusMeteringActionBuilder, never()).disableAutoCancel();
+
+    hostApi.create(74L, mockMeteringPointInfos, /* disableAutoCancel */ false);
+    verify(mockFocusMeteringActionBuilder, never()).disableAutoCancel();
+
+    // Test disabling auto cancel.
+    hostApi.create(75L, mockMeteringPointInfos, /* disableAutoCancel */ true);
+    verify(mockFocusMeteringActionBuilder).disableAutoCancel();
+  }
 }

packages/camera/camera_android_camerax/example/lib/main.dart

@@ -477,8 +477,9 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
                 children: <Widget>[
                   TextButton(
                     style: styleAuto,
-                    onPressed:
-                        () {}, // TODO(camsim99): Add functionality back here.
+                    onPressed: controller != null
+                        ? () => onSetFocusModeButtonPressed(FocusMode.auto)
+                        : null,
                     onLongPress: () {
                       if (controller != null) {
                         CameraPlatform.instance
@@ -490,8 +491,9 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
                   ),
                   TextButton(
                     style: styleLocked,
-                    onPressed:
-                        () {}, // TODO(camsim99): Add functionality back here.
+                    onPressed: controller != null
+                        ? () => onSetFocusModeButtonPressed(FocusMode.locked)
+                        : null,
                     child: const Text('LOCKED'),
                   ),
                 ],