Question

我正在尝试实施微调器，并且在生产线上

spinner1.setAdapter(adapter1);

我收到以下错误：

java.lang.NullPointerException：尝试在空对象引用上调用虚拟方法'void android.widget.Spinner.setAdapter（android.widget.SpinnerAdapter）'

这是我的代码：

public class Temp extends Fragment implements AdapterView.OnItemSelectedListener{
    private static final String[] paths1 = {"sam1", "sam2", "sam3", "sam4"},
            paths2 = {"1", "2", "3", "4"};
    private String name,seq;
    private Spinner spinner1,spinner2;
    private TextView tv1;
    private ArrayAdapter<String> adapter1,adapter2;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container,
                             @Nullable Bundle savedInstanceState) {
        View attendFragView = inflater.inflate(R.layout.fragment_attendance, container, false);

        //Spinner 1 code
        spinner1=(Spinner)attendFragView.findViewById(R.id.regPageFacSpinner1);
        adapter1=new ArrayAdapter<String>(attendFragView.getContext(),R.layout.spinner_lay_notched,
                paths2);
        adapter1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner1.setAdapter(adapter1);
        spinner1.setOnItemSelectedListener(this);

        //Spinner 2 Code

        spinner2=(Spinner)attendFragView.findViewById(R.id.regPageFacSpinner2);
        adapter2=new ArrayAdapter<String>(attendFragView.getContext(),R.layout.spinner_lay_notched,
                paths1);
        adapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner2.setAdapter(adapter2);
        spinner2.setOnItemSelectedListener(this);


        final EditText et1 = (EditText) attendFragView.findViewById(R.id.secOtpFac);
        tv1=(TextView)attendFragView.findViewById(R.id.attendPageFac5);

        Button genOtp = (Button) attendFragView.findViewById(R.id.otpGenButFac);
        genOtp.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                String dept= et1.getText().toString();
                String name=spinner1.getSelectedItem().toString();
                String seq=spinner2.getSelectedItem().toString();
                JSONObject attendJSONSend = new JSONObject();
                try {
                    attendJSONSend.put("name", name);
                    attendJSONSend.put("seq", seq);
                    attendJSONSend.put("dept", dept);
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        });
        return attendFragView;
    }

    @Override
    public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {

    }

    @Override
    public void onNothingSelected(AdapterView<?> adapterView) {

    }
}

Answer 1

正如异常所说，spinner1为空，因为编译器尝试在空对象上使用setAdapter。

为了解决此问题的建议。（因为我经常面对）。

检查布局，并确保代码和XML布局文件中的视图ID正确。
Android Studio将保存您创建的视图ID，尽管您可能之前已将其删除。尝试清理/重建。
更具体地说，问题出在以下ID：R.id.regPageFacSpinner1上。

祝你好运。

片段中的Spinners的“ setAdapter”不起作用

1 个答案: