Android: Fix taking photos for unavailable CONTINUOUS_PICTURE mode

It seems that auto-focus mode cannot be set to CONTINUOUS_PICTURE on
some devices. In such case, when trying to set AF_TRIGGER_START, Auto
Focus state will never change from INACTIVE[0]

If CONTROL_AF_MODE cannot be set to CONTINUOUS_PICTURE, just take a
photo without triggering auto-focus.

[0]https://developer.android.com/reference/android/hardware/camera2/CaptureResult#CONTROL_AE_STATE

Fixes: QTBUG-115842
Change-Id: I783e34c0971934904e7f19654cd5505ffc221f68
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>
Reviewed-by: Artem Dyomin <artem.dyomin@qt.io>
(cherry picked from commit 79cc5daf960a8ed293ec21da1744d5041af5230f)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 25 insertions, 4 deletions

diff --git a/src/android/jar/src/org/qtproject/qt/android/multimedia/QtCamera2.java b/src/android/jar/src/org/qtproject/qt/android/multimedia/QtCamera2.java
index 4076f42dd..5c46e486c 100644
--- a/src/android/jar/src/org/qtproject/qt/android/multimedia/QtCamera2.java
+++ b/src/android/jar/src/org/qtproject/qt/android/multimedia/QtCamera2.java
@@ -58,6 +58,7 @@ public class QtCamera2 {
     private static int MaxNumberFrames = 10;
     private int mFlashMode = CaptureRequest.CONTROL_AE_MODE_ON;
     private int mTorchMode = CameraMetadata.FLASH_MODE_OFF;
+    private int mAFMode = CaptureRequest.CONTROL_AF_MODE_OFF;
 
     native void onCameraOpened(String cameraId);
     native void onCameraDisconnect(String cameraId);
@@ -290,11 +291,18 @@ public class QtCamera2 {
             try {
                 mPreviewRequestBuilder = mCameraDevice.createCaptureRequest(template);
                 mPreviewRequestBuilder.addTarget(mImageReader.getSurface());
+                mAFMode = CaptureRequest.CONTROL_AF_MODE_OFF;
+                for (int mode : mVideoDeviceManager.getSupportedAfModes(mCameraId)) {
+                    if (mode == CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE) {
+                        mAFMode = mode;
+                        break;
+                    }
+                }
 
                 mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, mFlashMode);
                 mPreviewRequestBuilder.set(CaptureRequest.FLASH_MODE, mTorchMode);
                 mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_IDLE);
-                mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
+                mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, mAFMode);
                 mPreviewRequestBuilder.set(CaptureRequest.CONTROL_CAPTURE_INTENT, CameraMetadata.CONTROL_CAPTURE_INTENT_VIDEO_RECORD);
 
                 mPreviewRequest = mPreviewRequestBuilder.build();
@@ -366,9 +374,13 @@ public class QtCamera2 {
 
     public void takePhoto() {
         try {
-            mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_START);
-            mState = STATE_WAITING_LOCK;
-            mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback, mBackgroundHandler);
+            if (mAFMode == CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE) {
+                mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_START);
+                mState = STATE_WAITING_LOCK;
+                mCaptureSession.capture(mPreviewRequestBuilder.build(), mCaptureCallback, mBackgroundHandler);
+            } else {
+                capturePhoto();
+            }
         } catch (CameraAccessException e) {
             Log.w("QtCamera2", "Cannot get access to the camera: " + e);
         }
diff --git a/src/android/jar/src/org/qtproject/qt/android/multimedia/QtVideoDeviceManager.java b/src/android/jar/src/org/qtproject/qt/android/multimedia/QtVideoDeviceManager.java
index 5b0e730ec..255d1e504 100644
--- a/src/android/jar/src/org/qtproject/qt/android/multimedia/QtVideoDeviceManager.java
+++ b/src/android/jar/src/org/qtproject/qt/android/multimedia/QtVideoDeviceManager.java
@@ -155,6 +155,15 @@ public class QtVideoDeviceManager {
         }
     }
 
+    public int[] getSupportedAfModes(String cameraId) {
+
+        CameraCharacteristics characteristics = getCameraCharacteristics(cameraId);
+        if (characteristics == null)
+            return new int[0];
+
+        return characteristics.get(CameraCharacteristics.CONTROL_AF_AVAILABLE_MODES);
+    }
+
     public String[] getSupportedFlashModes(String cameraId) {
 
         CameraCharacteristics characteristics = getCameraCharacteristics(cameraId);