How do I access the camera on Android phones?

Google is your best friend, here are some tutorials:

Using the camera

How-To Program The Google Android Camera To Take Pictures

Take Picture from Camera Emulator

camera

First edit your AndroidManifest.xml, add the camera permission:

<uses-permission android:name=”android.permission.CAMERA”/>

Camera service has to be opened and closed:

Camera camera = Camera.open();
 //Do things with the camera
camera.release();

You can set camera settings, e.g.:

Camera.Parameters parameters = camera.getParameters();
parameters.setPictureFormat(PixelFormat.JPEG); 
camera.setParameters(parameters);

To take a picture:

private void takePicture() {
  camera.takePicture(shutterCallback, rawCallback, jpegCallback); 
}

ShutterCallback shutterCallback = new ShutterCallback() {
  public void onShutter() {
    // TODO Do something when the shutter closes.
  }
};

PictureCallback rawCallback = new PictureCallback() {
  public void onPictureTaken(byte[] _data, Camera _camera) {
    // TODO Do something with the image RAW data.
  }
};

PictureCallback jpegCallback = new PictureCallback() {
  public void onPictureTaken(byte[] _data, Camera _camera) {
    // TODO Do something with the image JPEG data.
  }
};

Do not forget to add the camera layout to your main layout xml.