制作目录时保存从相机拍摄的照片（Android应用程序）

所以我试着做4件事： 1） 拍照 2） 将其加载到ImageView中 3） 创建一个新目录 4） 将图像保存在该目录中

问题在于：

    File path =  Environment.getExternalStoragePublicDirectory
                 (Environment.DIRECTORY_PICTURES);

    File mediaStorageDir = new File(path, "MyCameraApp");

出于某种原因，它没有生成一个名为MyCameraApp的新文件

及

我一直得到threadid=1：线程以未捕获异常退出（组=0x41631ba8）

这是我的密码：

public class Main extends Activity {

private Uri fileUri;
ImageView iv;
private Camera mCamera;
public static final int MEDIA_TYPE_IMAGE = 1;
private static final int CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE = 100;

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

    iv = (ImageView) findViewById(R.id.imageView);

    fileUri = getOutputMediaFileUri(MEDIA_TYPE_IMAGE); // create a file to save the image

    Button btn = (Button) findViewById(R.id.takePhoto);
    btn.setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View arg0) {
    Intent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
    intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri); // set the image file name
    startActivityForResult(intent, CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE);            
    }
 });      
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data){
    if (requestCode == CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE)

        {
            // Image captured and saved to fileUri specified in the Intent
            Toast.makeText(this, "Image saved to:\n" + data.getData(), Toast.LENGTH_LONG).show();
            Bitmap theImage = (Bitmap) data.getExtras().get("data");
            iv.setImageBitmap(theImage);

    } 
}
   /** Create a file Uri for saving an image or video */
private static Uri getOutputMediaFileUri(int type){
     return Uri.fromFile(getOutputMediaFile(type));
}

/** Create a File for saving an image or video */
private static File getOutputMediaFile(int type){
    // To be safe, you should check that the SDCard is mounted
    // using Environment.getExternalStorageState() before doing this.

    File path = Environment.getExternalStoragePublicDirectory(
            Environment.DIRECTORY_PICTURES);

    File mediaStorageDir = new File(path, "MyCameraApp");
    // This location works best if you want the created images to be shared
    // between applications and persist after your app has been uninstalled.


    // Create the storage directory if it does not exist
    if (!mediaStorageDir.exists()){
        if (!mediaStorageDir.mkdirs()){
            Log.d("MyCameraApp", "failed to create directory");
            return null;
        }
    }
    // Create a media file name


    File mediaFile = null;
    if (type == MEDIA_TYPE_IMAGE){
        mediaFile = new File(mediaStorageDir.getPath() + /*File.separator +*/ "IMG_1" +".tif");
        Log.d("MyCameraApp", "DONE");
   }
    else {
        Log.d("MyCameraApp", "NOT DONE!");
        return null;
    }
    return mediaFile;
}

protected void onPause(){

    super.onPause();
    releaseCamera();              // release the camera immediately on pause event
}       

private void releaseCamera(){
        if (mCamera != null){
            mCamera.release();        // release the camera for other applications
            mCamera = null;
        }
    }
}

堆栈跟踪：

 03-10 17:14:39.708: I/Process(9786): Sending signal. PID: 9786 SIG: 9

 03-10 18:04:04.248: D/MyCameraApp(13459): failed to create directory

 03-10 18:04:04.248: D/AndroidRuntime(13459): Shutting down VM

 03-10 18:04:04.248: W/dalvikvm(13459): threadid=1: thread exiting with uncaught    exception(group=0x41631ba8)

03-10 18:04:04.258: E/AndroidRuntime(13459): FATAL EXCEPTION: main

03-10 18:04:04.258: E/AndroidRuntime(13459): Process: com.example.irisrec, PID: 13459

03-10 18:04:04.258: E/AndroidRuntime(13459): java.lang.RuntimeException: Unable to start 
activity ComponentInfo{com.example.irisrec/com.example.irisrec.Main}: java.lang.NullPointerException: file

03-10 18:04:04.258: E/AndroidRuntime(13459):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at 
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at android.app.ActivityThread.access$800(ActivityThread.java:135)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at android.os.Handler.dispatchMessage(Handler.java:102)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at android.os.Looper.loop(Looper.java:136)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at android.app.ActivityThread.main(ActivityThread.java:5017)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at java.lang.reflect.Method.invokeNative(Native Method)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at java.lang.reflect.Method.invoke(Method.java:515)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at dalvik.system.NativeStart.main(Native Method)

03-10 18:04:04.258: E/AndroidRuntime(13459): Caused by: java.lang.NullPointerException: file

03-10 18:04:04.258: E/AndroidRuntime(13459):    at android.net.Uri.fromFile(Uri.java:444)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at com.example.irisrec.Main.getOutputMediaFileUri(Main.java:80)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at  com.example.irisrec.Main.onCreate(Main.java:38)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at android.app.Activity.performCreate(Activity.java:5231)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)

03-10 18:04:04.258: E/AndroidRuntime(13459):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)

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谢谢你的帮助

你已经给出了要求，你已经粘贴了大量的代码，你希望我们为你做调试…缩小代码范围，这是最有可能的问题点，并提供更多的延迟，以便我们能够更轻松地回答。发布整个stacktrace。你的清单中有读写权限吗？我有写权限，在安道尔开发网站上说，如果它能写，它也应该能读。所有权限都是正确的。