尝试在空对象引用上调用虚拟方法'void android.widget.EditText.setText [duplicate]

Question

此问题已经在这里有了答案：

What is a NullPointerException, and how do I fix it?（12个答案）

[4天前关闭。

---

我有此错误

---

尝试在空对象引用上调用虚拟方法'void android.widget.EditText.setText（java.lang.CharSequence，android.widget.TextView $ BufferType）'

---

[当我尝试使用setText方法将一些数据设置到EditText时，但它指向null并使应用程序关闭，下面的照片显示即使我设置了数据，编辑文本也为null：

---

---

请告诉我。谢谢！

更新我的代码：

---

enter code here : public class AddUserDialog extends DialogFragment {


public interface OnInputUserTypeListener {

    void sendInputAdd(UserInfoModel userInfoModel);

    void sendInputUpdate(int position, UserInfoModel userInfo);

}

public OnInputUserTypeListener onInputUserTypeListener;

private int PICK_IMAGE_REQUEST = 1;
public Button add;
public EditText editTextName, editTextEmail, editTextPhone;
public CircleImageView imageViewaddPhoto;
public TextView cancel;
public Bitmap bitmap;
String emailPattern = "[a-zA-Z0-9._-]+@[a-z]+\\.+[a-z]+";
UserInfoModel userInfo;
int position=-1;
String type;
Uri uri;


public AddUserDialog(String type) {
    this.type = type;

}

public AddUserDialog(int position,UserInfoModel userInfo ,String type) {
    this.userInfo = userInfo;
    this.type = type;
    this.position = position;


    loadUserData();

}

public AddUserDialog(int addposition,String addtype) {

    this.type = addtype;
    this.position = addposition;




}

public void loadUserData() {
    String phone = userInfo.getPhone();
    String name = userInfo.getName();
    String email = userInfo.getEmail();
   // Bitmap photo = userInfo.getPhoto();

    editTextName.setText(name,TextView.BufferType.EDITABLE);
    editTextPhone.setText(phone,TextView.BufferType.EDITABLE);
    editTextEmail.setText(email,TextView.BufferType.EDITABLE);
   // imageViewaddPhoto.setImageBitmap(photo);

}

@NonNull
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    View v = inflater.inflate(R.layout.add_user_dialog, container, false);
    initialize(v);

    listeners();


    return v;

}

public void initialize(View v) {
    add = v.findViewById(R.id.button);
    cancel = v.findViewById(R.id.cancel_dialog);
    editTextName = v.findViewById(R.id.name);
    editTextEmail = v.findViewById(R.id.email);
    editTextPhone = v.findViewById(R.id.phone);
    imageViewaddPhoto = v.findViewById(R.id.imageView);

}

public void listeners() {

    cancel.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            getDialog().dismiss();
        }
    });


    imageViewaddPhoto.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            chooseImage();
        }
    });

    add.setOnClickListener(new View.OnClickListener() {
        @RequiresApi(api = Build.VERSION_CODES.KITKAT)
        @Override
        public void onClick(View v) {


            if (TextUtils.isEmpty(editTextName.getText())) {

                editTextName.setError(getResources().getString(R.string.required));
                editTextName.requestFocus();

                return;
            }

            if (TextUtils.isEmpty(editTextPhone.getText())) {

                editTextPhone.setError(getResources().getString(R.string.required));
                editTextPhone.requestFocus();

                return;
            }

            if (TextUtils.isEmpty(editTextEmail.getText())) {

                editTextEmail.setError(getResources().getString(R.string.required));
                editTextEmail.requestFocus();

                return;
            }


            if (editTextEmail.getText().toString().trim().matches(emailPattern)) {

                editTextEmail.requestFocus();
            } else {
                editTextEmail.setError(getResources().getString(R.string.invalid));
                editTextEmail.requestFocus();
                return;
            }


            String name = editTextName.getText().toString();
            String email = editTextEmail.getText().toString();
            String phone = editTextPhone.getText().toString();

            imageViewaddPhoto.setDrawingCacheEnabled(true);


            if (!name.isEmpty() || (!phone.isEmpty() || !email.isEmpty())) {
                if (type.equals("new")) {
                    UserInfoModel u1 = new UserInfoModel(name, email, phone, bitmap);
                    onInputUserTypeListener.sendInputAdd(u1);

                    Snackbar.make(v, "User added", Snackbar.LENGTH_LONG)
                            .setAction("Action", null).show();

                    Objects.requireNonNull(getDialog()).dismiss();
                }


                if (type.equals("update")) {

                    UserInfoModel u1 = new UserInfoModel(name, email, phone, bitmap);
                    onInputUserTypeListener.sendInputUpdate(position, u1);

                    Snackbar.make(v, "User updated", Snackbar.LENGTH_LONG)
                            .setAction("Action", null).show();

                    Objects.requireNonNull(getDialog()).dismiss();

                }
            }

        }
    });


}


public void chooseImage() {
    Intent intent = new Intent();
    intent.setType("image/*");
    intent.setAction(Intent.ACTION_GET_CONTENT);
    startActivityForResult(Intent.createChooser(intent, "Select Picture"), PICK_IMAGE_REQUEST);

}

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

    if (requestCode == PICK_IMAGE_REQUEST && resultCode == RESULT_OK && data != null && data.getData() != null) {

        uri   = data.getData();

        try {
            bitmap = MediaStore.Images.Media.getBitmap(getActivity().getApplicationContext().getContentResolver(), uri);


            imageViewaddPhoto.setImageBitmap(bitmap);


        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}


@Override
public void onAttach(@NonNull Context context) {
    super.onAttach(context);

    try {
        onInputUserTypeListener = (OnInputUserTypeListener) getActivity();
    } catch (ClassCastException e) {

    }
}

}

Answer 1

您正在位于AddUserDialog类构造函数内的loadUserData（）方法内的EditTexts上调用setText（）方法。但是findViewById（）方法位于initialize（）方法内的onCreateView（）回调方法内。

由于构造函数方法在onCreateView（）回调方法之前被调用，loadUserData（）方法在initialize（）之前被调用，这意味着setText（）方法在EditText通过findViewById（）方法与UI绑定之前被调用。

您可以尝试在onCreateView（）回调中或在单独的onCreate（）回调中替换editTextName.setText（）方法。因此，EditText首先与UI绑定，然后在EditText对象上调用setText（）方法。