implement Flash

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

@@ -8,6 +8,7 @@ import android.view.View;
 import android.view.ViewGroup;
 import android.view.Window;
 import android.view.WindowManager;
+import android.widget.ImageView;
 import android.widget.RelativeLayout;
 
 import butterknife.Bind;
@@ -17,9 +18,11 @@ import butterknife.OnClick;
 public class MainActivity extends AppCompatActivity {
     @Bind(R.id.viewHolder) RelativeLayout viewHolder;
     @Bind(R.id.toggle_camera) View toggleCameraBtn;
+    @Bind(R.id.toggle_flash) ImageView toggleFlashBtn;
 
     private Preview preview;
     private int currCamera;
+    private boolean isFlashEnabled;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -37,15 +40,33 @@ public class MainActivity extends AppCompatActivity {
 
     @OnClick(R.id.toggle_camera)
     public void toggleCamera() {
-        if (currCamera == Camera.CameraInfo.CAMERA_FACING_BACK)
+        if (currCamera == Camera.CameraInfo.CAMERA_FACING_BACK) {
             currCamera = Camera.CameraInfo.CAMERA_FACING_FRONT;
-        else
+        } else {
             currCamera = Camera.CameraInfo.CAMERA_FACING_BACK;
+        }
 
+        disableFlash();
         preview.releaseCamera();
         preview.setCamera(currCamera);
     }
 
+    @OnClick(R.id.toggle_flash)
+    public void toggleFlash() {
+        if (isFlashEnabled) {
+            disableFlash();
+        } else if (preview.enableFlash()) {
+            isFlashEnabled = preview.enableFlash();
+            toggleFlashBtn.setImageResource(R.mipmap.flash_on);
+        }
+    }
+
+    private void disableFlash() {
+        preview.disableFlash();
+        isFlashEnabled = false;
+        toggleFlashBtn.setImageResource(R.mipmap.flash_off);
+    }
+
     @OnClick(R.id.shutter)
     public void takePicture() {
         preview.takePicture();

app/src/main/java/com/simplemobiletools/camera/Preview.java

@@ -30,6 +30,8 @@ public class Preview extends ViewGroup implements SurfaceHolder.Callback, View.O
     private static boolean canTakePicture;
     private static Activity activity;
     private static int currCameraId;
+    private static boolean isFlashEnabled;
+    private static Camera.Parameters parameters;
 
     public Preview(Context context) {
         super(context);
@@ -66,15 +68,15 @@ public class Preview extends ViewGroup implements SurfaceHolder.Callback, View.O
         camera = newCamera;
 
         if (camera != null) {
-            supportedPreviewSizes = camera.getParameters().getSupportedPreviewSizes();
+            parameters = camera.getParameters();
+            supportedPreviewSizes = parameters.getSupportedPreviewSizes();
             requestLayout();
 
-            final Camera.Parameters params = camera.getParameters();
-            final List<String> focusModes = params.getSupportedFocusModes();
+            final List<String> focusModes = parameters.getSupportedFocusModes();
             if (focusModes.contains(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE))
-                params.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
+                parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
 
-            camera.setParameters(params);
+            camera.setParameters(parameters);
             setCameraDisplayOrientation(cameraId, camera);
 
             if (canTakePicture) {
@@ -119,6 +121,10 @@ public class Preview extends ViewGroup implements SurfaceHolder.Callback, View.O
 
     public void takePicture() {
         if (canTakePicture) {
+            if (isFlashEnabled) {
+                parameters.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
+                camera.setParameters(parameters);
+            }
             camera.takePicture(null, null, takePictureCallback);
         }
         canTakePicture = false;
@@ -139,6 +145,11 @@ public class Preview extends ViewGroup implements SurfaceHolder.Callback, View.O
 
             final Camera.CameraInfo info = Utils.getCameraInfo(currCameraId);
             new PhotoProcessor(getContext(), info.facing).execute(data);
+
+            if (isFlashEnabled) {
+                parameters.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
+                camera.setParameters(parameters);
+            }
         }
     };
 
@@ -148,7 +159,6 @@ public class Preview extends ViewGroup implements SurfaceHolder.Callback, View.O
 
         camera.cancelAutoFocus();
         final Rect focusRect = calculateFocusArea(event.getX(), event.getY());
-        final Camera.Parameters parameters = camera.getParameters();
         if (parameters.getMaxNumFocusAreas() > 0) {
             final List<Camera.Area> focusAreas = new ArrayList<>(1);
             focusAreas.add(new Camera.Area(focusRect, 1000));
@@ -211,7 +221,6 @@ public class Preview extends ViewGroup implements SurfaceHolder.Callback, View.O
     private void setupPreview() {
         canTakePicture = true;
         if (camera != null && previewSize != null) {
-            final Camera.Parameters parameters = camera.getParameters();
             parameters.setPreviewSize(previewSize.width, previewSize.height);
 
             requestLayout();
@@ -280,4 +289,17 @@ public class Preview extends ViewGroup implements SurfaceHolder.Callback, View.O
         focusArea(event);
         return false;
     }
+
+    public boolean enableFlash() {
+        if (!Utils.hasFlash(camera)) {
+            return false;
+        }
+
+        isFlashEnabled = true;
+        return true;
+    }
+
+    public void disableFlash() {
+        isFlashEnabled = false;
+    }
 }

app/src/main/java/com/simplemobiletools/camera/Utils.java

@@ -4,6 +4,8 @@ import android.content.Context;
 import android.hardware.Camera;
 import android.widget.Toast;
 
+import java.util.List;
+
 public class Utils {
     public static Camera.CameraInfo getCameraInfo(int cameraId) {
         final Camera.CameraInfo info = new android.hardware.Camera.CameraInfo();
@@ -14,4 +16,24 @@ public class Utils {
     public static void showToast(Context context, int resId) {
         Toast.makeText(context, context.getResources().getString(resId), Toast.LENGTH_SHORT).show();
     }
+
+    public static boolean hasFlash(Camera camera) {
+        if (camera == null) {
+            return false;
+        }
+
+        final Camera.Parameters parameters = camera.getParameters();
+
+        if (parameters.getFlashMode() == null) {
+            return false;
+        }
+
+        final List<String> supportedFlashModes = parameters.getSupportedFlashModes();
+        if (supportedFlashModes == null || supportedFlashModes.isEmpty() ||
+                supportedFlashModes.size() == 1 && supportedFlashModes.get(0).equals(Camera.Parameters.FLASH_MODE_OFF)) {
+            return false;
+        }
+
+        return true;
+    }
 }

app/src/main/res/layout/activity_main.xml

@@ -37,8 +37,7 @@
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_weight="1"
-            android:src="@mipmap/ic_launcher"
-            android:visibility="invisible"/>
+            android:src="@mipmap/flash_off"/>
 
     </LinearLayout>
 </RelativeLayout>