App Crash When Trying to Turn Flashlight On

Question

I'm trying to make a Flahlight app, but when I press the "Flashlight" button to turn the flashlight on, the app crashes. Here's my code:

Manifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="com.example.flashlight"
   android:versionCode="1"
   android:versionName="1.0" >

    <!-- Allows access to the flashlight -->
        <permission android:name="android.permission.FLASHLIGHT"
            android:permissionGroup="android.permission-group.HARDWARE_CONTROLS"
            android:protectionLevel="normal" />

        <uses-permission android:name="android.permission.CAMERA" />
        <uses-permission android:name="android.permission.FLASHLIGHT"/>
        <uses-feature android:name="android.hardware.camera" />
        <uses-feature android:name="android.hardware.camera.autofocus" />
        <uses-feature android:name="android.hardware.camera.flash" />

    <uses-sdk
       android:minSdkVersion="5"
       android:targetSdkVersion="16" />

    <application
       android:allowBackup="true"
       android:icon="@drawable/ic_launcher"
       android:label="@string/app_name"
       android:theme="@style/AppTheme" >
        <activity
           android:name="com.example.flashlight.MainActivity"
           android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>

</manifest>

java:

public class MainActivity extends Activity {

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

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

    public void toggleFlashlight() {
        Camera cam;
        cam = Camera.open();     
        Parameters p = cam.getParameters();
        p.setFlashMode(Parameters.FLASH_MODE_TORCH);
        cam.setParameters(p);
        cam.startPreview();
    }

}

I put the codes in images because I couldn't get the code block to work.

use a code uploading website like [pastie](http://pastie.org/) or [pastebin](http://pastebin.com/) — thepoosh, Jan 10 '13 at 09:47
You mean the LogCat? Here:http://img90.imageshack.us/img90/5706/logcat.png — Qruez, Jan 10 '13 at 09:54
You don't even call the `toggleFlashlight()` method anywhere... — Raghav Sood, Jan 10 '13 at 09:54
I didn't put the xml file, but I did call it. Here:http://pastebin.com/mEMdQdYL — Qruez, Jan 10 '13 at 09:56
Need more info. Are you trying to use this app in emulator. If yes, there is no hardware(Flashlight, Camera). Possibly because of that it might be crashing. — Ajay Kumar Meher, Jan 10 '13 at 09:55
It work now, after I added the "View" parameter. thanks anyway. — Qruez, Jan 10 '13 at 10:02

score 1 · Accepted Answer · answered Jan 10 '13 at 09:56

1

Add parameter View v to public void toggleFlashlight()

as

public void toggleFlashlight(View v)

answered Jan 10 '13 at 09:56

MysticMagicϡ

28,593
16
73
124

Now I try to turn the flashlight off, and it crashes hahaha. This is the new java file: http://pastebin.com/p3XdGKNb Do you have any idea? Thanks – Qruez Jan 10 '13 at 10:02
@OrelLazri, Please share new logcat output – MysticMagicϡ Jan 10 '13 at 10:03
@OrelLazri Try chacking condition if(cam != null) in else part first. – MysticMagicϡ Jan 10 '13 at 10:07
like this?: `} else if(cam != null) {` It still crashes. – Qruez Jan 10 '13 at 10:10
@OrelLazri, I m not able to understand the reason for this crash. Its saying "failed to connect to camera service" in logcat. But just try adding cam = null; after cam.release(); line. – MysticMagicϡ Jan 10 '13 at 10:18
Regarding to this: pastebin.com/NCdL7W6x You "open" the camera even if it is still open, which causes the crash. – lkdg Jan 10 '13 at 10:25

score 0 · Answer 2 · answered Jan 10 '13 at 09:55

Change:

public void toggleFlashlight() {
    Camera cam;
    cam = Camera.open();     
    Parameters p = cam.getParameters();
    p.setFlashMode(Parameters.FLASH_MODE_TORCH);
    cam.setParameters(p);
    cam.startPreview();
}

to

public void toggleFlashlight(View v) {
    Camera cam;
    cam = Camera.open();     
    Parameters p = cam.getParameters();
    p.setFlashMode(Parameters.FLASH_MODE_TORCH);
    cam.setParameters(p);
    cam.startPreview();
}

From your logcat, it is seen that you're setting the method for onClick in your XML to toggleFlashlight(). Due to being a method called on a View's click, it must match the signature of other onClick() methods, and have a View parameter.

Thanks, Shreya just said it. It works now :) Appreciate your help. — Qruez, Jan 10 '13 at 09:59
You should accept one of our answers if your problem is fixed. Click the check mark under the vote counts to accept it. — Raghav Sood, Jan 10 '13 at 10:01

score 0 · Answer 3 · answered Jan 10 '13 at 10:28

0

private void switchOn()
{
       if(getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH))
    {
        if(cam == null)
        {
            cam = Camera.open();
            Parameters p = cam.getParameters();
            p.setFlashMode(Parameters.FLASH_MODE_TORCH);
            cam.setParameters(p);
            cam.startPreview();
        }
    }
}

private void switchOff()
{
    if(cam != null)
    {
        cam.stopPreview();
        cam.release();
        cam = null;
    }
}

answered Jan 10 '13 at 10:28

lkdg

1,031
7
18

Thank you so much it works :) Wow I really appreciate your effort (all of you guys) Thanks again! – Qruez Jan 10 '13 at 10:34
Now you should overwrite onStop, onStart and onDestroy. Because if you switch your flashlight to on and click the "homebutton" of your device and open the camera of the device, this will crash and vice versa. – lkdg Jan 10 '13 at 10:39

App Crash When Trying to Turn Flashlight On

3 Answers3