move the functionality to an interface

app/src/main/java/flashlight/simplemobiletools/com/MainActivity.java

@@ -1,18 +1,13 @@
 package flashlight.simplemobiletools.com;
 
-import android.graphics.Color;
-import android.graphics.PorterDuff;
-import android.hardware.Camera;
 import android.os.Bundle;
 import android.support.v7.app.AppCompatActivity;
 import android.view.View;
 import android.widget.ImageView;
 
-public class MainActivity extends AppCompatActivity {
-    private Camera camera;
-    private Camera.Parameters params;
-    private boolean isFlashlightOn;
+public class MainActivity extends AppCompatActivity implements MyCamera {
     private ImageView toggleBtn;
+    private MyCameraImpl cameraImpl;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -20,8 +15,13 @@ public class MainActivity extends AppCompatActivity {
         setContentView(R.layout.activity_main);
 
         setupToggleButton();
-        setupCamera();
-        toggleFlashlight();
+        setupCameraImpl();
+    }
+
+    private void setupCameraImpl() {
+        cameraImpl = new MyCameraImpl(this);
+        cameraImpl.setupCamera();
+        cameraImpl.toggleFlashlight();
     }
 
     private void setupToggleButton() {
@@ -29,73 +29,42 @@ public class MainActivity extends AppCompatActivity {
         toggleBtn.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
-                toggleFlashlight();
+                cameraImpl.toggleFlashlight();
             }
         });
     }
 
-    private void toggleFlashlight() {
-        isFlashlightOn = !isFlashlightOn;
-
-        if (isFlashlightOn) {
-            enableFlashlight();
-        } else {
-            disableFlashlight();
-        }
-    }
-
-    private void setupCamera() {
-        if (camera == null) {
-            camera = Camera.open();
-            params = camera.getParameters();
-            params.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
-            camera.setParameters(params);
-
-            if (isFlashlightOn)
-                enableFlashlight();
-        }
-    }
-
-    private void enableFlashlight() {
-        params.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
-        camera.setParameters(params);
-        toggleBtn.setBackground(getResources().getDrawable(R.mipmap.flashlight_big_on));
-    }
-
-    private void disableFlashlight() {
-        params.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
-        camera.setParameters(params);
-        toggleBtn.setBackground(getResources().getDrawable(R.mipmap.flashlight_big_off));
-    }
-
-    private void releaseCamera() {
-        if (camera != null) {
-            camera.release();
-            camera = null;
-        }
-    }
-
     @Override
     protected void onStart() {
         super.onStart();
-        setupCamera();
+        cameraImpl.setupCamera();
     }
 
     @Override
     protected void onResume() {
         super.onResume();
-        setupCamera();
+        cameraImpl.setupCamera();
     }
 
     @Override
     protected void onPause() {
         super.onPause();
-        releaseCamera();
+        cameraImpl.releaseCamera();
     }
 
     @Override
     protected void onStop() {
         super.onStop();
-        releaseCamera();
+        cameraImpl.releaseCamera();
+    }
+
+    @Override
+    public void enableFlashlight() {
+        toggleBtn.setBackground(getResources().getDrawable(R.mipmap.flashlight_big_on));
+    }
+
+    @Override
+    public void disableFlashlight() {
+        toggleBtn.setBackground(getResources().getDrawable(R.mipmap.flashlight_big_off));
     }
 }

app/src/main/java/flashlight/simplemobiletools/com/MyCamera.java

@@ -0,0 +1,7 @@
+package flashlight.simplemobiletools.com;
+
+public interface MyCamera {
+    void enableFlashlight();
+
+    void disableFlashlight();
+}

app/src/main/java/flashlight/simplemobiletools/com/MyCameraImpl.java

@@ -0,0 +1,53 @@
+package flashlight.simplemobiletools.com;
+
+public class MyCameraImpl {
+    private android.hardware.Camera camera;
+    private android.hardware.Camera.Parameters params;
+    private boolean isFlashlightOn;
+    private MyCamera callback;
+
+    public MyCameraImpl(MyCamera camera) {
+        callback = camera;
+    }
+
+    public void toggleFlashlight() {
+        isFlashlightOn = !isFlashlightOn;
+
+        if (isFlashlightOn) {
+            enableFlashlight();
+        } else {
+            disableFlashlight();
+        }
+    }
+
+    public void setupCamera() {
+        if (camera == null) {
+            camera = android.hardware.Camera.open();
+            params = camera.getParameters();
+            params.setFlashMode(android.hardware.Camera.Parameters.FLASH_MODE_OFF);
+            camera.setParameters(params);
+
+            if (isFlashlightOn)
+                enableFlashlight();
+        }
+    }
+
+    private void enableFlashlight() {
+        params.setFlashMode(android.hardware.Camera.Parameters.FLASH_MODE_TORCH);
+        camera.setParameters(params);
+        callback.enableFlashlight();
+    }
+
+    private void disableFlashlight() {
+        params.setFlashMode(android.hardware.Camera.Parameters.FLASH_MODE_OFF);
+        camera.setParameters(params);
+        callback.disableFlashlight();
+    }
+
+    public void releaseCamera() {
+        if (camera != null) {
+            camera.release();
+            camera = null;
+        }
+    }
+}