How to turn on FlashLight in Lollipop programmatically Android

Question

Camera cam = Camera.open();     
Parameters p = cam.getParameters();
p.setFlashMode(Parameters.FLASH_MODE_TORCH);
cam.setParameters(p);
cam.startPreview();

Answer 1

mCam = Camera.open();
Camera.Parameters p = mCam.getParameters();
p.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
mCam.setParameters(p);
mPreviewTexture = new SurfaceTexture(0);
try {
   mCam.setPreviewTexture(mPreviewTexture);
} catch (IOException ex) {
   // Ignore
}
mCam.startPreview();

It works for me on Android 5.0.x. And don't forget to add permission in manifest for camera usage.