Android 我在安卓4.0+；但2.2中没有

我正在用手电筒，当一个朋友试着用时，他撞车了。 他有v4.0+ 这是我的日志：

我是新手，但我读到4.0+版本中带有线程的应用程序崩溃了，所以。。我不太懂，但是，我怎么能把我所有的代码都放在没有线程的地方呢？ 这是我的应用程序代码：

package flash.light.app;


import com.google.ads.AdRequest;
import com.google.ads.AdView;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.ActivityNotFoundException;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.Toast;

public class MainActivity extends Activity {

public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        exitByBackKey();

        //moveTaskToBack(false);

        return true;
    }
    return super.onKeyDown(keyCode, event);
}

protected void exitByBackKey() {

    AlertDialog alertbox = new AlertDialog.Builder(this)
    .setMessage("Do you want to Exit?")
    .setPositiveButton("Yes", new DialogInterface.OnClickListener() {

        // do something when the button is clicked
        public void onClick(DialogInterface arg0, int arg1) {

            finish();
            //close();


        }
    })

    .setNeutralButton("Rate us!", new DialogInterface.OnClickListener() {

        // do something when the button is clicked
        public void onClick(DialogInterface arg0, int arg1) {

             {
                Uri uri = Uri.parse("market://details?id=" + getPackageName());
                Intent goToMarket = new Intent(Intent.ACTION_VIEW, uri);
                try {
                    startActivity(goToMarket);
                } catch (ActivityNotFoundException e) {
                    Toast.makeText(getApplicationContext(), "Couldn´t launch Google Play", 
                            Toast.LENGTH_LONG).show();
                }
            }


        }
    })

    .setNegativeButton("No", new DialogInterface.OnClickListener() {

        // do something when the button is clicked
        public void onClick(DialogInterface arg0, int arg1) {
                       }
    })
      .show();

}

ImageButton btnSwitch;
 private Camera camera;
 private boolean isFlashOn;
 private boolean hasFlash;
 Parameters params;
 MediaPlayer mp;




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

    final AdView adView = (AdView) findViewById(R.id.adView);
    adView.loadAd(new AdRequest());

    ImageView ButtonScr = (ImageView) findViewById(R.id.imageView1);
    ButtonScr.setOnClickListener(new OnClickListener(){

        @Override
        public void onClick(View arg0) {
            Intent Screen = new Intent (MainActivity.this, ScreenActivity.class);
            startActivity(Screen);
        }});


    // flash switch button
    btnSwitch = (ImageButton) findViewById(R.id.imageButton1);


    // First check if device is supporting flashlight or not        
    hasFlash = getApplicationContext().getPackageManager()
            .hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH);

    if (!hasFlash) {
        // device doesn't support flash
        // Show alert message and close the application
        AlertDialog alert = new AlertDialog.Builder(MainActivity.this)
                .create();
        alert.setTitle("Error");
        alert.setMessage("Sorry, your device doesn't support flash light!");
        alert.setButton(AlertDialog.BUTTON_POSITIVE,"OK", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {

                Intent Screen = new Intent (MainActivity.this, ScreenActivity.class);
                startActivity(Screen);
                Toast.makeText(MainActivity.this, "You can use our Screen Light :)", 
                        Toast.LENGTH_LONG).show();

                // closing the application
               // finish();
            }
        });


        alert.show();
        return;
    }

    // get the camera
    getCamera();

    // displaying button image
    toggleButtonImage();

    //Orientación de la APP Vertical
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
    //Codigo para que no se apague la pantalla :D
    getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);


    // Switch button click event to toggle flash on/off
    btnSwitch.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            if (isFlashOn) {
                // turn off flash
                turnOffFlash();
             //  RelativeLayout layout = (RelativeLayout)findViewById(R.id.background);
            //  layout.setBackgroundResource(R.drawable.image6);
            } else {
                // turn on flash
                turnOnFlash();
              //  RelativeLayout layout =(RelativeLayout)findViewById(R.id.background);
                //layout.setBackgroundResource(R.drawable.slender);
            }
        }
    });
}


// Get the camera
private void getCamera() {
    if (camera == null) {
        try {
            camera = Camera.open();
            params = camera.getParameters();
        } catch (RuntimeException e) {
            Log.e("Camera Error. Failed to Open. Error: ", e.getMessage());
        }
    }
}


 // Turning On flash
private void turnOnFlash() {
    if (!isFlashOn) {
        if (camera == null || params == null) {
            return;
        }
        // play sound
     //   playSound();

        params = camera.getParameters();
        params.setFlashMode(Parameters.FLASH_MODE_TORCH);
        camera.setParameters(params);
        camera.startPreview();
        isFlashOn = true;

        // changing button/switch image
        toggleButtonImage();
    }

}


// Turning Off flash
private void turnOffFlash() {
    if (isFlashOn) {
        if (camera == null || params == null) {
            return;
        }
        // play sound
      //  playSound();

        params = camera.getParameters();
        params.setFlashMode(Parameters.FLASH_MODE_OFF);
        camera.setParameters(params);
        camera.stopPreview();
        isFlashOn = false;

        // changing button/switch image
        toggleButtonImage();
    }
}


 // Playing sound
 // will play button toggle sound on flash on / off
// private void playSound(){
 //   if(isFlashOn){
 //       mp = MediaPlayer.create(MainActivity.this, R.raw.light_switch_off);
 //   }else{
  //      mp = MediaPlayer.create(MainActivity.this, R.raw.light_switch_on);
 //   }
 //   mp.setOnCompletionListener(new OnCompletionListener() {

   //     @Override
    //    public void onCompletion(MediaPlayer mp) {
            // TODO Auto-generated method stub
     //       mp.release();
     //   }
  //  }); 
 //   mp.start();
// }

/*
 * Toggle switch button images
 * changing image states to on / off
 * */
private void toggleButtonImage(){
    if(isFlashOn){
        btnSwitch.setImageResource(R.drawable.on);

    }else{
        btnSwitch.setImageResource(R.drawable.off);

    }
}

@Override
protected void onDestroy() {
    super.onDestroy();
}

@Override
protected void onPause() {
    super.onPause();

    // on pause turn off the flash
    turnOffFlash();
}

@Override
protected void onRestart() {
    super.onRestart();
}

@Override
protected void onResume() {
    super.onResume();

    // on resume turn on the flash 
    //CREO QUE ES PARA QUE SE ENCIENDA APENAS SE ABRE.
    if (hasFlash){
        turnOnFlash();
} else { 
    Toast.makeText(MainActivity.this, "You can use our Screen Light :)", 
            Toast.LENGTH_LONG).show();
    }

}
@Override
protected void onStart() {
    super.onStart();

    // on starting the app get the camera params
   getCamera();
}

@Override
protected void onStop() {
    super.onStop();

    // on stop release the camera
    if (camera != null) {
        camera.release();
        camera = null;
    }





}

}

我该怎么做，在所有或几乎所有的设备上运行一个简单的应用程序（像这样，它是一个简单的手电筒）？

---

感谢并对我的英语表示歉意

您的问题出现在

getCamera（）

中的

Log.e行（“Camera Error.Failed to Open.Error:，e.getMessage（））

看起来
e.getMessage（）
正在返回
null
，因此崩溃

您可能应该使用格式
Log.e（标记“getCamera”，e）将打印异常的堆栈跟踪（并且不会使应用程序崩溃）
替换

Log.e("Camera Error. Failed to Open. Error: ", e.getMessage());

与

然后找出相机不工作的原因。
如果你能发布堆栈跟踪，那会有帮助。哇，1分钟后我得到了回复lol好的，如果我没有收到错误，我会尝试，但请稍候。。我把Log.e（标签“getCamera”，e）放在哪里？在第一部分：//获取摄影机getCamera（）？？？？您应该替换Log.e（“摄像头错误。无法打开。错误：”，e.getMessage（））；我建议的那个。然后告诉你是什么导致了你的错误omgggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg！谢谢，谢谢！
Log.e("MainActivity", "Camera Error. Failed to Open. Error: " + e.getMessage());