尝试在空对象引用上调用虚拟方法'java.lang.String java.lang.Integer.toString()'

Question

我正在尝试解决此问题两天，但仍然无法弄清楚为什么我会收到 NullPointException。

我尝试更改模型类的参数，但这无济于事。

//call the task api
private void taskuploadArt(String name,String width,String height,String year, String technique, String price,String contact)
{
String currency_code = currency.getText().toString().trim();
String tags = painting_tags.getText().toString().trim();
String info = painting_story.getText().toString().trim();
String wishtosell;
if(wisht_to_sell)
{
wishtosell="1";
//Toast.makeText(this, "Done here", Toast.LENGTH_SHORT).show();
}
else
{
wishtosell="0";
}
String sellprints;
if(sell_prints)
{
sellprints="1";
}
else {
sellprints="0";
}
String createdby_me;
if(createdbyme)
{
createdby_me="1";
}
else
{
createdby_me="0";
}

UploadArtApiInterface uploadartapiInterface;
//API call
uploadartapiInterface = ApiClient.getApiClient().create(UploadArtApiInterface.class);
Call<TaskNew> call = uploadartapiInterface.uploadtask(api_key,
name,
info,
year,
technique,
createdby_me,
wishtosell,
price,
contact,
dimen_unit,
width,
height,
currency_code,
sellprints,
tags);
call.enqueue(new Callback<TaskNew>() {
//show progress dialog
final ProgressDialog progressDialog = ProgressDialogPopup.showProgressDialog(UploadArt.this,
getResources().getString(R.string.loading), "");
@Override
public void onResponse(@NonNull Call<TaskNew> call, @NonNull Response<TaskNew> response) {
//on response successful
if(response.isSuccessful())
{
//Toast.makeText(UploadArt.this,"upload task successful",Toast.LENGTH_SHORT).show();
//call image upload api
try
{
//Toast.makeText(UploadArt.this, "here", Toast.LENGTH_SHORT).show();
assert response.body() != null;
if(uploadArtImage(response.body().getTaskId().toString().trim(),response.body().getUserId().toString().trim()))
{
Toast.makeText(UploadArt.this, "Uploaded", Toast.LENGTH_SHORT).show();
//successfully image uploaded
progressDialog.dismiss();
UploadArt.super.onBackPressed();
//Toast.makeText(UploadArt.this, "Success", Toast.LENGTH_SHORT).show();
//AlertPopup.alertDialogShow(UploadArt.this, response.body().getMessage().toString(), "");
//Log.d("ImageUploadq123",response.body().toString());
}
else {
Toast.makeText(UploadArt.this, "Not uploaded", Toast.LENGTH_SHORT).show();
//image upload unsuccessful
progressDialog.dismiss();
//Log.d("ImageUploadq123",response.body().toString());
}
}
catch (Exception e)
{
progressDialog.dismiss();
AlertPopup.alertDialogShow(UploadArt.this, e.getMessage(), "");
}
}
else
{
//Toast.makeText(UploadArt.this,"Upload task failed",Toast.LENGTH_SHORT).show();
progressDialog.dismiss();
//AlertPopup.alertDialogShow(UploadArt.this, "Some error occurred 2", "");
Toast.makeText(UploadArt.this, "Something wrong with your internet connection. Please try again.", Toast.LENGTH_SHORT).show();
}
}
@Override
public void onFailure(@NonNull Call<TaskNew> call, @NonNull Throwable t) {
progressDialog.dismiss();
//Toast.makeText(UploadArt.this,"upload task failed",Toast.LENGTH_SHORT).show();
AlertPopup.alertDialogShow(UploadArt.this, "Some error occurred 3", "");
Toast.makeText(UploadArt.this, "Something wrong with your internet connection. Please try again.", Toast.LENGTH_SHORT).show();
}
});
}


//image upload api
private boolean uploadArtImage(String task_Id, String user_Id)
{
// Build and send an Event.
mTracker.send(new HitBuilders.EventBuilder()
.setCategory(getString(R.string.ga_upload_action))
.setAction(getString(R.string.ga_upload_action))
.build());
//check if pic is properly set to the imageview
final Boolean[] imageresonse = new Boolean[1];
if(imageadded)
{
//get the bytes
Bitmap bitmap = ((BitmapDrawable) previewImage.getDrawable()).getBitmap();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
byte[] imageInByte = baos.toByteArray();
RequestBody requestFile = RequestBody.create(MediaType.parse("image/png"), imageInByte);
MultipartBody.Part body = MultipartBody.Part.createFormData("image", "image"+"_"+user_Id+"_"+task_Id+".jpg", requestFile);
RequestBody userId = RequestBody.create(MediaType.parse("text/plain"), user_Id);
RequestBody taskId = RequestBody.create(MediaType.parse("text/plain"), task_Id);
UploadArtApiInterface uploadArtApiInterface = ApiClient.getApiClient().create(UploadArtApiInterface.class);
Call<ProfilePicUploadResponse> call = uploadArtApiInterface.uploadArt(body,userId,taskId);
final ProgressDialog progressDialog = ProgressDialogPopup.showProgressDialog(UploadArt.this,
getResources().getString(R.string.loading), "");
call.enqueue(new Callback<ProfilePicUploadResponse>() {
@Override
public void onResponse(@NonNull Call<ProfilePicUploadResponse> call, @NonNull Response<ProfilePicUploadResponse> response) {
progressDialog.dismiss();
//                    ProfilePicUploadResponse profilePicUploadResponse = response.body();
//                    if (profilePicUploadResponse.getError() != null){
//                        AlertPopup.alertDialogShow(UploadArt.this, response.body().getMessage(), "");
//                    }
//                    else {
//                        AlertPopup.alertDialogShow(UploadArt.this, profilePicUploadResponse.getMessage(), "");
//                    }
if(response.isSuccessful())
{
imageresonse[0] =true;
//Toast.makeText(UploadArt.this,response.body().getMessage(),Toast.LENGTH_SHORT).show();
//AlertPopup.alertDialogShow(UploadArt.this, response.body().getMessage(), "");
Intent intent = new Intent();
intent.putExtra("message","message");
setResult(12);
finish();
//UploadArt.super.onBackPressed();
//Log.d("ImageUpload",response.body().toString());
}
else
{
//AlertPopup.alertDialogShow(UploadArt.this, response.body().getMessage(), "");
//Log.d("ImageUpload","error occurred");
imageresonse[0] =false;
//Toast.makeText(UploadArt.this,response.body().toString(),Toast.LENGTH_SHORT).show();
}
}
@Override
public void onFailure(@NonNull Call<ProfilePicUploadResponse> call, @NonNull Throwable t) {
imageresonse[0] =true;
//Toast.makeText(UploadArt.this,response.body().getMessage(),Toast.LENGTH_SHORT).show();
//AlertPopup.alertDialogShow(UploadArt.this, t.getMessage(), "");
Intent intent = new Intent();
intent.putExtra("message","message");
setResult(12);
finish();
//                    progressDialog.dismiss();
//                    Log.d("ImageUpload",t.getMessage());
//                    //AlertPopup.alertDialogShow(UploadArt.this, t.getMessage(), "");
//                    imageresonse[0] =false;
}
});
return imageresonse[0];
}
else {
return false;
}
}

我在UI中有一个开关，当它打开时询问价格。当它关闭时，它不会询问任何其他信息。

更新： 我已经解决了这个问题。 我发布的参数之一是空的。

Answer 1

在将任务 id 和 userid 转换为字符串之前，对其进行空检查。

if(uploadArtImage(response.body().getTaskId().toString().trim(),response.body().getUserId().toString().trim()))

Answer 2

response.body()只能使用一次。

if(uploadArtImage(response.body().getTaskId().toString().trim(),response.body().getUserId().toString().trim())) {...}

第二次调用 response.body(( 时将为 null。您应该像这样存储它：

String body = response.body();
if(uploadArtImage(body.getTaskId().toString().trim(),body.getUserId().toString().trim())) {...}