Android运行时错误：打开跟踪文件时出错：没有这样的文件或目录（2）

Question

I did some search and found people who ended up with the same error as I did, but in a completely different context :(

So, I'm trying to get my app to gracefully exit when something critical happens. It's an android app that uses camera, and I want the app to quit after showing a toast text, so the users don't get a random crash. (And yes, theoretically I shouldn't end up in the if statement because I require a camera hardware in my manifest, but I like handling error as much as possible)

Here's a snippet of the manifest file:

<uses-permission android:name="android.permission.CAMERA" />

<uses-feature
    android:name="android.hardware.camera"
    android:required="true" />

And here's my code:

public class MainActivity extends Activity {
/* member variables... */

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // Create an instance of Camera
    // I forced this to true for testing because the devices I'm testing
    // against won't reach inside the if statement
    if (/*!(checkCameraHardware(this) || checkFrontFacingCameraHardware(this))*/ true)  {
        Toast.makeText(getBaseContext(), "Shutting Down! No Camera Detected!", Toast.LENGTH_SHORT).show();
        System.exit(0); // This is the last code it reaches
    }
    mCamera = getCameraInstance(); // This code isn't reached

As you can see, I would like the code to make a toast, then shut down, but it gets stuck in a blank (black) screen instead (at or right after System.exit(0) ), repeating the following error in Log Cat instead.

Tag: Trace, Text: error opening trace file: No such file or directory (2)

Did I miss something? Can I not exit or toast in the OnCreate() function?

Answer 1

Do not use System.exit(0)

Quoting Romain Guy from https://groups.google.com/forum/#!topic/android-developers/G_D3pKnGLt0

The user doesn't, the system handles this automatically. That's what the activity lifecycle (especially onPause/onStop/onDestroy) is for. No matter what you do, do not put a "quit" or "exit" application. It is useless with Android's application model. This is also contrary to how core applications work.

There is detailed answer about the same @

Is quitting an application frowned upon?

You can also read related threads @

https://groups.google.com/forum/#!topic/android-developers/G_D3pKnGLt0