Android: Check whether camera supports auto-focus?

问题:

For the Android API version 2.1 and higher, we can use context:

getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_AUTOFOCUS)

But before version 2.1, how can we perform the same operation? Is there anything like this that does not involve invoking Camera.open and then getParameters?

回答1:

List<String> supportedFocusModes = camera.getParameters().getSupportedFocusModes();
boolean hasAutoFocus = supportedFocusModes != null && supportedFocusModes.contains(Camera.Parameters.FOCUS_MODE_AUTO)

回答2:

i'm guessing: Do not use the unknown constant.

getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_AUTOFOCUS)

Should be:

getPackageManager().hasSystemFeature("android.hardware.camera.autofocus")

It was a short sight of the developers to use constants here. It solves the problem of knowing if a device, running an API that knows about a feature has a feature. but fails on the case you just mentioned... they really make supporting multiple api levels difficult.

Updated: just tested it myself... PackageManager.hasSystemFeature() only showed up at API level 5. I was trying to add that check to my code that can very well support API level 3 (1.5) but which could benefit from camera's auto focus...seems like i have to choose support 1.5 or be able to use auto focus... or move my backward compatibility to level 5... or implement this http://www.java.net/forum/topic/java-tools/java-development-tools/wwyt-conditional-compilation-pre-process ...yeah, right.

they really make it difficult to support multiple versions. So sorry 1.5 and 1.6 and 2.0 users. since my device is on 2.2 that will be my bottom line.

回答3:

   private void getSuppourtedFocusedModes(Camera camera) 
   {
        final Camera.Parameters parameters = camera.getParameters();
        List<String> supportedFocusModes = parameters.getSupportedFocusModes();
        LogUtils.infoMsg("supportedFocusModes " + supportedFocusModes);
        for (String mode : supportedFocusModes) {
            LogUtils.infoMsg("supportedFocusModes " + mode);
        }
    }

回答4:

CameraManager cameraManager = (android.hardware.camera2.CameraManager) getSystemService(CAMERA_SERVICE);

int[] afModes = cameraManager.getCameraCharacteristics("0").get(CameraCharacteristics.CONTROL_AF_AVAILABLE_MODES);

if (afModes.length <= 1)
{Log.d(TAG, "Camera doesn't have autofocus");}
else
{Log.d(TAG, "Camera has autofocus");}

        Log.d(TAG, "CONTROL_AF_AVAILABLE_MODES:");
        for (int position : afModes) {
            switch (afModes[position]) {
                case 0:
                    Log.d(TAG, "CONTROL_AF_MODE_OFF (0)");
                    break;
                case 1:
                    Log.d(TAG, "CONTROL_AF_MODE_AUTO (1)");
                    break;
                case 2:
                    Log.d(TAG, "CONTROL_AF_MODE_MACRO (2)");
                    break;
                case 3:
                    Log.d(TAG, "CONTROL_AF_MODE_CONTINUOUS_VIDEO (3)");
                    break;
                case 4:
                    Log.d(TAG, "CONTROL_AF_MODE_CONTINUOUS_PICTURE (4)");
                    break;
                case 5:
                    Log.d(TAG, "CONTROL_AF_MODE_EDOF (5)");
                    break;
                default:
                    Log.d(TAG, String.valueOf(afModes[position]));
            }
        }

回答5:

There are a number of methods of the Camera.Parameters class added in API Level 5 (I believe that maps to Android 2.0) that will return a list of supported features. Call getSupportedFocusModes on the Camera.Parameters object retrieved from camera.getParameters()

http://developer.android.com/reference/android/hardware/Camera.Parameters.html