android - 相机预览在低光 android 中太暗

Question

我的相机应用程序预览在低光下太暗。如果我打开我的谷歌相机，它会增加预览中的亮度，这样我们的脸就可以看到拍照了。但是我的预览是完全黑暗的。我已经处理了亮度和光传感器。我的光传感器在光线充足时工作。我需要使预览可见。让我有什么需要处理的？

 public void initialBrightness() {
        try {
            brightnessMode = Settings.System.getInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE);
        } catch (Settings.SettingNotFoundException e) {
            e.printStackTrace();
        }
        if (brightnessMode == Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC) {
            Settings.System.putInt(getContentResolver(), Settings.System.SCREEN_BRIGHTNESS_MODE,
                    Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
            brightnessModeAuto = true;
        }
        Settings.System.putInt(this.getContentResolver(), Settings.System.SCREEN_BRIGHTNESS, 95);
        WindowManager.LayoutParams lp = getWindow().getAttributes();
        lp.screenBrightness = 100;
        getWindow().setAttributes(lp);

    } 

我在调用相机预览类之前在 onCreate 方法中调用此方法。

Answer 1

要解决此问题，您必须解锁自动曝光补偿 并设置为最大值:

Camera.Parameters params = mCamera.getParameters();
 
params.setExposureCompensation(params.getMaxExposureCompensation());
 
if(params.isAutoExposureLockSupported()) {
 params.setAutoExposureLock(false);
}

mCamera.setParameters(params);

根据 Android Develop > Reference > Camera.Parameters

Changing the white balance mode with setWhiteBalance(String) will release the auto-white balance lock if it is set.

Exposure compensation, AE lock, and AWB lock can be used to capture an exposure-bracketed burst of images, for example. Auto-white balance state, including the lock state, will not be maintained after camera release() is called.

Locking auto-white balance after open() but before the first call to startPreview() will not allow the auto-white balance routine to run at all, and may result in severely incorrect color in captured images.

所以要小心，在第一次调用 startPreview() 之后使用提到的代码