App Freezes and Crashes when trying to Blink the Flashlight

Question

there Folks! And Here it goes another Question.. from me..

I'm making a flashlight app. In the app there are two buttons, one is for turning on/off flash (flashlight_switch) and the other one is for blinking the flash With a single tap on the Button (sos_switch) at medium speed. The flash on/off works perfectly, but when i press the SOS button the app freezes and crashes. And also how can I turn off the SOS. I'm a beginner so it would be very nice that you explain the answer in depth. Please ignore Any typos if there are. The App is tested on Galaxy S3 and LG G3 and no luck on both of them.

Here is the complete code:

Java:

FlashlightActivity:

public class FlashlightActivity extends Activity {
    ImageButton flashlight_switch;
    ImageButton sos_switch;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_flashlight);
        flashlight_switch = (ImageButton) findViewById(R.id.flashlight_switch);
        sos_switch = (ImageButton) findViewById(R.id.sos_switch);

        flashlight_switch.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                view.performHapticFeedback(HapticFeedbackConstants.VIRTUAL_KEY);

                if (Flash.getTorch()) {
                    flashlight_switch.setImageResource(R.drawable.flashlight_switch_on);
                } else {
                    flashlight_switch.setImageResource(R.drawable.flashlight_switch_off);
                }
            }
        });

        sos_switch.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (SOS.getSOS()) {
                    sos_switch.setImageResource(R.drawable.sos_on);
                } else {
                    sos_switch.setImageResource(R.drawable.sos_off);
                }
            }
        });
    }
}

Flash:

class Flash {
private static boolean flashOnOff = false;
private static boolean sosOnOff = false;
public static Camera camera;
private static Camera.Parameters params;


public static boolean getTorch() {
    if (flashOnOff)
        off();
    else
        on();
    return flashOnOff;

}

public static boolean getSOS() {
    if (sosOnOff)
        offSOS();
    else
        onSOS();
    return sosOnOff;

}

private static void on()  {
    if (!flashOnOff) {
        if (camera == null || params == null) {
            try {
                camera = Camera.open();
                params = camera.getParameters();
            } catch (RuntimeException e) {
                int a = 10;
            }
        }
        try {
            camera.setPreviewTexture(new SurfaceTexture(0));
            params = camera.getParameters();
            params.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
            camera.setParameters(params);
            camera.startPreview();
            flashOnOff = true;

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

private static void off() {
    if (camera == null || params == null)
        return;
    params = camera.getParameters();
    params.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
    camera.setParameters(params);
    camera.stopPreview();
    camera.release();
    camera = null;
    flashOnOff = false;
}

private static void onSOS() {
    Thread t = new Thread() {
        public void run() {
            try {

                int delay = 50;
                int times = 10;
                for (int i=0; i < times*2; i++) {
                    if (flashOnOff) {
                        on();
                    } else {
                        off();
                    }
                    sleep(delay);
                }

            } catch (Exception e){
                e.printStackTrace();
            }
        }
    };
    t.start();
}
private static void offSOS() {
    Thread t = new Thread();
    t.stop();}}

Thanks In Advance!

Update:

I have updated my flash.java. It does not crash now but still the SOS don't work and also the sos switch freezes. I can't figure it out now. Please help!!!! as soon as possible!

Answer 1

You should not sleep Thread.sleep(blinkDelay); the thread because it is main thread need to update UI.you should use a different thread for SOS on

And Your SOS on function is in recursive infinite loop plz edit it. You are calling ON infinite time recursivly

Make Flash class ON / OFF method to public and make few changes in SOS's on method on(); to Flash.on and off to Flash .off

Flash.java

class Flash {
private static boolean flashOnOff = false;
public static Camera camera;
private static Camera.Parameters params;
static Thread t;
    public static boolean getTorch() {
        if (flashOnOff)  // turn off flash
            off();
        else              // turn on flash
            on();
        return flashOnOff;

    }

private static void on() {
    if (!flashOnOff) {
        if (camera == null || params == null) {
            try {
                camera = Camera.open();
                params = camera.getParameters();
            } catch (RuntimeException e) {
                int a = 10;
            }
        }
        try {
            params = camera.getParameters();
            params.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
            camera.setParameters(params);
            camera.setPreviewTexture(new SurfaceTexture(0));
            camera.startPreview();
            flashOnOff = true;
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

private static void off() {
    if (camera == null || params == null)
        return;
    params = camera.getParameters();
    params.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
    camera.setParameters(params);
    camera.stopPreview();
    flashOnOff = false;
}
public static void onSOS() {
    t = new Thread() {
        public void run() {
            try {
                int delay = 50;
                while (true) {
                    if (t.isInterrupted())
                        break;
                    getTorch();
                    sleep(delay);
                }

            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    };
    t.start();

}

public static void offSOS() {
    if (!t.isInterrupted()) {
        t.interrupt();
        off();
    }
}}

FlashlightActivity.java

public class FlashlightActivity extends Activity {
ImageButton flashlight_switch;
ImageButton sos_switch;
boolean isStart = false;
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_flashlight);
        flashlight_switch = (ImageButton) findViewById(R.id.flashlight_switch);
        sos_switch = (ImageButton) findViewById(R.id.sos_switch);
    flashlight_switch.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            view.performHapticFeedback(HapticFeedbackConstants.VIRTUAL_KEY);

            if (Flash.getTorch()) {
                flashlight_switch.setImageResource(R.drawable.flashlight_switch_on);
            } else {
                flashlight_switch.setImageResource(R.drawable.flashlight_switch_off);
            }
        }
    });

    sos_switch.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if (!isStart){
        Flash.onSOS();
        isStart = true;
        sos_switch.setImageResource(R.drawable.sos_off);
    }else{
        Flash.offSOS();
        isStart = false;
        sos_switch.setImageResource(R.drawable.sos_on);
    }
        }
    });
}

}