I have a simple application with a button to turn on/off camera flash:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button)findViewById(R.id.btnFlash);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
if(!isLight)
{
switchON();
}
else
{
switchOFF();
}
}
});
}
If the flash was off, it will turn on and else, turn off. Yes, it works well.
The problem is:
- Firstly, I pressed the button to turn on, after that, I rotate my device and then pressing again to turn off -> Application crash.
Fatal Exception: main - Runtime Exception: Fail to connect to camera
service
These are 2 functions to turn on/off
public void switchON()
{
camera = Camera.open();
Parameters p = camera.getParameters();
p.setFlashMode(Parameters.FLASH_MODE_TORCH);
camera.setParameters(p);
camera.startPreview();
isLight = true;
}
public void switchOFF()
{
Parameters p = camera.getParameters();
p.setFlashMode(Parameters.FLASH_MODE_OFF);
camera.setParameters(p);
camera.stopPreview();
camera.release();
isLight = false;
}
Try This (I re-wrote the code):
public class YourClass extends Activity {
private Button button;
private Camera camera;
private boolean isLight=false;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
button = (Button)findViewById(R.id.btnFlash);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
if(!isLight)
{
switchON();
}
else
{
switchOFF();
}
}
});
}
#Override
protected void onResume() {
super.onResume();
try{
camera = Camera.open();
} catch( Exception e ){
e.printStackTrace();
}
}
#Override
protected void onPause() {
if( camera != null ){
camera.release();
camera = null;
}
super.onPause();
}
private void switchOFF(){
if( mCamera != null ){
Parameters p = camera.getParameters();
p.setFlashMode(Parameters.FLASH_MODE_OFF);
camera.setParameters(p);
isLight = false;
}
}
private void switchON(){
if( mCamera != null ){
Parameters p = camera.getParameters();
p.setFlashMode(Parameters.FLASH_MODE_TORCH);
camera.setParameters(p);
isLight=true;
}
}
}
Try:
public void switchOFF()
{
if(camera == null)
{
camera = Camera.open();
}
Parameters p = camera.getParameters();
p.setFlashMode(Parameters.FLASH_MODE_OFF);
camera.setParameters(p);
camera.stopPreview();
camera.release();
isLight = false;
}
Related
i am implementing flashlight, and i have called all the functions i,e onDestroy() onBackpressed() to remain my flash light on. but i have bug that if i pressed on back and after that screen is locked the flashlight switches off after few seconds. kindly help me with the code.
public class MainActivity extends AppCompatActivity {
ImageButton btnSwitch;
Camera camera;
Camera.Parameters parameters;
boolean isflash = false;
boolean ison = false;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
btnSwitch = (ImageButton) findViewById(R.id.btnSwitch);
if(getApplicationContext().getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH));
{
try {
camera = Camera.open();
parameters = camera.getParameters();
isflash = true;
}catch (Exception e ){
Log.e(getString(R.string.app_name), "failed to open Camera");
e.printStackTrace();
}
}
btnSwitch.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(isflash)
{
if (!ison)
{
btnSwitch.setImageResource(R.drawable.off);
parameters.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
camera.setParameters(parameters);
camera.startPreview();
ison = true;
}
else {
btnSwitch.setImageResource(R.drawable.btn_switch_on);
parameters.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
camera.setParameters(parameters);
camera.stopPreview();
ison = false;
}
}
else
{
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder.setTitle("Error.....");
builder.setMessage("FlashLight is not available on this device....");
builder.setPositiveButton("ok", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
finish();
}
});
AlertDialog alertDialog = builder.create();
alertDialog.show();
}
}
});
}
#Override
protected void onStop() {
super.onStop();
if(!ison){
if (camera!=null)
{
camera.release();
camera = null;
}
}
}
#Override
public void onBackPressed() {
super.onBackPressed();
if(!ison){
if (camera!=null)
{
camera.release();
camera = null;
}
}
}
#Override
protected void onPause() {
super.onPause();
if(!ison){
if (camera!=null)
{
camera.release();
camera = null;
}
}
}
#Override
protected void onDestroy() {
super.onDestroy();
if(!ison) {
if (camera != null) {
camera.release();
camera = null;
}
}
}
}
I have a Flashlight Activity. Normally it works fine but When I go to any other activity, it stop working!
So I want to refresh the code when I back to the Flashlight Activity.
I think refreshing using onResume() would help me best, But how to do it?
public class FlashLightActivity extends Activity {
//flag to detect flash is on or off
private boolean isLighOn = false;
private Camera camera;
private Button next1, next2;
#Override
protected void onStop() {
super.onStop();
if (camera != null) {
camera.release();
}
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
next1 = (Button) findViewById(R.id.ebtn28_answer);
next1.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Intent myIntent = new Intent(view.getContext(), FullScreen.class);
startActivityForResult(myIntent, 0);
}
});
next2 = (Button) findViewById(R.id.buttonFlashlight);
Context context = this;
PackageManager pm = context.getPackageManager();
// if device support camera?
if (!pm.hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
Log.e("err", "Device has no camera!");
return;
}
camera = Camera.open();
final Parameters p = camera.getParameters();
next2.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
if (isLighOn) {
Log.i("info", "torch is turn off!");
p.setFlashMode(Parameters.FLASH_MODE_OFF);
camera.setParameters(p);
camera.stopPreview();
isLighOn = false;
} else {
Log.i("info", "torch is turn on!");
p.setFlashMode(Parameters.FLASH_MODE_TORCH);
camera.setParameters(p);
camera.startPreview();
isLighOn = true;
}
}
});
}
}
You need to override onPause and onResume. In onPause, you need to release the Camera. In onResume, you need to re-request it. Camera doesn't like it if you try to hold it when you aren't the active activity.
public void onPause(){
super.onPause();
if(camera != null){
camera.release();
camera = null;
}
}
public void onResume(){
super.onResume();
//Need to release if we already have one, or we won't get the camera
if(camera != null){
camera.release();
camera = null;
}
try {
camera = Camera.open();
}
catch (Exception e){
}
}
I am working with camera flashlight project.
It load on the emulator but when I click on the "On" button it has stopped unexpectedly. Here is the cat-log https://dl.dropbox.com/u/15065300/logcat1.png
Here is the code:
public class FlashLight extends Activity {
private final static String LOG_TAG = "FlashLight";
private Button mOnBtn;
private Camera mCamera;
private boolean isActive;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//this will be inside your onCreate...
mOnBtn = (Button) findViewById(R.id.on_btn);
mOnBtn.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
flipSwitch();
processClick();
}
});
}
//these will be outside your onCreate
public void flipSwitch() {
isActive = !isActive;
}
#Override
protected void onResume() {
super.onResume();
try{
mCamera = Camera.open();
mCamera.startPreview();
Toast.makeText(getApplicationContext(),"Camera is present", Toast.LENGTH_LONG).show();
} catch( Exception e ){
Log.e(LOG_TAG, "Impossible d'ouvrir la camera");
}
}
#Override
protected void onPause() {
if( mCamera != null ){
mCamera.release();
mCamera = null;
}
super.onPause();
}
public void processClick() {
if(isActive) {
Parameters params = mCamera.getParameters();
params.set("flash-mode", "torch");
mCamera.setParameters( params );
mCamera.startPreview();
}
else {
Parameters params = mCamera.getParameters();
params.set("flash-mode", "off");
mCamera.setParameters( params );
mCamera.stopPreview();
}
}
}
You have a NullPointerException on line 74 of Flashlight.java in your code.
It's probably that mCamera or params is being used while it's value is null. Check the initializations/assignments to these values.
i have made a flashlight app and i want to try to make add-on to allow a strobe light feature.
I want to set it up on a different button thought, not the same one. i think i need to use a timer , but i have never used a timer because im new to java.
here is my code for the flashlight:
public class FlashLightActivity extends Activity {
private boolean isLighOn = false;
private Camera camera;
private Button button;
#Override
protected void onStop() {
super.onStop();
if (camera != null) {
camera.release();
}
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
button = (Button) findViewById(R.id.buttonFlashlight);
Context context = this;
PackageManager pm = context.getPackageManager();
if (!pm.hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
Log.e("err", "Device has no camera!");
return;
}
camera = Camera.open();
final Parameters p = camera.getParameters();
button.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
if (isLighOn) {
Log.i("info", "torch is turn off!");
p.setFlashMode(Parameters.FLASH_MODE_OFF);
camera.setParameters(p);
camera.stopPreview();
isLighOn = false;
} else {
Log.i("info", "torch is turn on!");
p.setFlashMode(Parameters.FLASH_MODE_TORCH);
camera.setParameters(p);
camera.startPreview();
isLighOn = true;
}
}
});
}
}
You could use a Handler
public class Strobe extends Activity {
private LinearLayout mLinearLayout;
private Handler mHander = new Handler();
private boolean mActive = false;
private boolean mSwap = true;
private final Runnable mRunnable = new Runnable() {
public void run() {
if (mActive) {
if (mSwap) {
mLinearLayout.setBackgroundColor(Color.WHITE);
mSwap = false;
mHander.postDelayed(mRunnable, 20);
} else {
mLinearLayout.setBackgroundColor(Color.BLACK);
mSwap = true;
mHander.postDelayed(mRunnable, 100);
}
}
}
};
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mLinearLayout = (LinearLayout) findViewById(R.id.strobe);
startStrobe();
}
private void startStrobe() {
mActive = true;
mHander.post(mRunnable);
}
}
Set a Theme to the Activity to make it full screen.
android:theme="#android:style/Theme.NoTitleBar.Fullscreen"
I have a button on my camera preview screen to toggle the camera's flash. The camera starts on auto-flash which works then when the button is pressed the flash turns off but when i try to turn the flash back on it doesn't turn on and i don't know why?
Log.d("flash",mCamera.getParameters().getFlashMode());
Displays on off and auto as i press it. But it doesn't turn back on. Here is my full code
public void flashPressed(View v)
{
ImageButton flashButton = (ImageButton)findViewById(R.id.flash);
Camera.Parameters myP = mCamera.getParameters();
if(flashOn == 0)
{
flashButton.setImageResource(R.drawable.device_access_flash_off);
myP.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
flashOn = 1;
}
else if(flashOn == 1)
{
myP.setFlashMode(Camera.Parameters.FLASH_MODE_ON);
flashButton.setImageResource(R.drawable.device_access_flash_on);
flashOn=2;
}else{
myP.setFlashMode(Camera.Parameters.FLASH_MODE_AUTO);
flashButton.setImageResource(R.drawable.device_access_flash_automatic);
flashOn =0;
}
mCamera.setParameters(myP);
Log.d("flash",mCamera.getParameters().getFlashMode());
}
This is how I used to create a Flash app.
public class Flash extends Activity {
boolean cameraOpened;
static Camera camFlash = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
#Override
public void onPause() {
super.onPause();
if (camFlash != null) {
camFlash.stopPreview();
camFlash.release();
camFlash = null;
}
}
public void turnOnFlash(View view) {
if (camFlash == null) {
camFlash = Camera.open();
}
if (camFlash != null) {
Parameters params = camFlash.getParameters();
params.setFlashMode(Parameters.FLASH_MODE_TORCH);
camFlash.setParameters(params);
camFlash.startPreview();
camFlash.autoFocus(new AutoFocusCallback() {
public void onAutoFocus(boolean success, Camera camera) {
}
});
}
}
public void turnOffFlash(View view) {
if (camFlash != null) {
camFlash.stopPreview();
camFlash.release();
camFlash = null;
}
}
}
the methods turnOnFlash() and turnOffFlash are called from xml android:onClick.
To avoid this problem I just created a new camera each time the flash option changes