Open Camera in Android Studio

<Button
    android:id="@+id/camerabtn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:text="Camera" />

<ImageView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/imageview"
    android:layout_below="@+id/camerabtn"
    />

public class MainActivity extends AppCompatActivity {

Button camrebtn;
ImageView imageView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    camrebtn = (Button)findViewById(R.id.camerabtn);
    imageView = (ImageView)findViewById(R.id.imageview);

    camrebtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
            startActivityForResult(cameraIntent,123);
        }
    });


}

protected void onActivityResult(int requestCode, int resultCode, Intent data){
    if(requestCode == 123){
        Bitmap photo = (Bitmap)data.getExtras().get("data");
        imageView.setImageBitmap(photo);
    }
}
}