java - OnActivityResult : Uri and getData is a null object during capture a photo

Question

我对 Uri 对象有疑问。用户应拍照，然后将其发送到 Firebase 存储。但是 onActivityResult 有问题。

我阅读了很多主题(https://developer.android.com/training/camera/photobasics.html，StackOverFlow 也是)，但此代码无效。

出现错误:

尝试在空对象引用上调用虚方法“java.lang.String android.net.Uri.getLastPathSegment()”

下面是一段代码:

 mUploadBtn.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {

      Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
      if (intent.resolveActivity(getPackageManager()) != null) {  

           startActivityForResult(intent, CAMERA_REQUEST_CODE);
               }
             }
         });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);


        if(requestCode == CAMERA_REQUEST_CODE && resultCode == RESULT_OK && data != null) {

            mProgress.setMessage("Uploading Image...");
            mProgress.show();

            Uri uri = data.getData();

            StorageReference filepath = mStorage.child("Photos").child(uri.getLastPathSegment());


            filepath.putFile(uri).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
                @Override
                public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {

                    mProgress.dismiss();

                    Uri downloadUri = taskSnapshot.getDownloadUrl();

                    Picasso.with(MainActivity.this).load(downloadUri).fit().centerCrop().into(mImageView);

                    Toast.makeText(MainActivity.this, "Upload Done.", Toast.LENGTH_LONG).show();
                }
            });

        }
    }
}

正如我检查的那样，onActivityResult 中的数据(Intent)等于 NULL，因此 uri 也为 null。

那么，我该如何解决这个挑战并使其可用呢？我应该使用位图来访问照片吗？

有人可以帮我解决这个问题吗？

问候

Answer 1

我想通了我的问题。 它现在有效。

    private ProgressDialog mProgress;
    private Button mUploadBtn;
    private ImageView mImageView;
    Uri picUri;
    private StorageReference mStorage;

    private static final int CAMERA_REQUEST_CODE = 1;

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


        mStorage = FirebaseStorage.getInstance().getReference();

        mUploadBtn = (Button) findViewById(R.id.uploadBtn);
        mImageView = (ImageView) findViewById(R.id.imageView);

        mProgress = new ProgressDialog(this);

        mUploadBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Intent i = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);

                File file=getOutputMediaFile(1);
                picUri = Uri.fromFile(file); // create
                i.putExtra(MediaStore.EXTRA_OUTPUT,picUri); // set the image file

                startActivityForResult(i, CAMERA_REQUEST_CODE);
            }
        });
    }

    /** Create a File for saving an image */
    private  File getOutputMediaFile(int type){
        File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_PICTURES), "MyApplication");

        /**Create the storage directory if it does not exist*/
        if (! mediaStorageDir.exists()){
            if (! mediaStorageDir.mkdirs()){
                return null;
            }
        }

        /**Create a media file name*/
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        File mediaFile;
        if (type == 1){
            mediaFile = new File(mediaStorageDir.getPath() + File.separator +
                    "IMG_"+ timeStamp + ".png");
        } else {
            return null;
        }

        return mediaFile;
    }


    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);


        if(requestCode == CAMERA_REQUEST_CODE && resultCode == RESULT_OK ) {

            mProgress.setMessage("Uploading Image...");
            mProgress.show();


            Uri uri = picUri;

            StorageReference filepath = mStorage.child("Photos").child(uri.getLastPathSegment());


            filepath.putFile(uri).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
                @Override
                public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {

                    mProgress.dismiss();

                    Uri downloadUri = taskSnapshot.getDownloadUrl();

                    Picasso.with(MainActivity.this).load(downloadUri).fit().centerCrop().into(mImageView);

                    Toast.makeText(MainActivity.this, "Upload Done.", Toast.LENGTH_LONG).show();
                }
            });
        }
    }