java - 根据选择的数字设置微调器值？

Question

我不确定这是否是正确的方法，我需要一些帮助来解决这个问题。我想从 NumberPicker 中选择一个数字。选择后，我希望 setOnValueChangedListener 能够捕获该值并运行 for 循环并将结果值存储在数组列表中。接下来，我希望循环值显示在我的 spinner 中。但我收到一条错误消息，指出“无法解析构造函数 ArrayAdapter(....)”，当我运行该应用程序时，我收到此错误消息:

"Error:(79, 58) error: no suitable constructor found for ArrayAdapter(,int,List) constructor ArrayAdapter.ArrayAdapter(Context,int,int,List) is not applicable (actual and formal argument lists differ in length) constructor ArrayAdapter.ArrayAdapter(Context,int,List) is not applicable (actual argument cannot be converted to Context by method invocation conversion) constructor ArrayAdapter.ArrayAdapter(Context,int,int,Object[]) is not applicable (actual and formal argument lists differ in length) constructor ArrayAdapter.ArrayAdapter(Context,int,Object[]) is not applicable (actual argument cannot be converted to Context by method invocation conversion) constructor ArrayAdapter.ArrayAdapter(Context,int,int) is not applicable (actual argument cannot be converted to Context by method invocation conversion) constructor ArrayAdapter.ArrayAdapter(Context,int) is not applicable (actual and formal argument lists differ in length)"

      @Override    
     protected void onCreate(Bundle savedInstanceState) {        

super.onCreate(savedInstanceState);
           setContentView(R.layout.new_item);
           final List<Integer> resultInteger = new ArrayList<Integer>(); // to store the integer value

   final Spinner hourSpinner = (Spinner) findViewById(R.id.hourSpinner);


    final NumberPicker HourPicker = (NumberPicker) findViewById(R.id.HourNumberPicker);
    HourPicker.setMinValue(9);
    HourPicker.setMaxValue(15);
    HourPicker.setWrapSelectorWheel(false);

    HourPicker.setOnValueChangedListener(new NumberPicker.OnValueChangeListener() {
        @Override
        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {

            Integer value = HourPicker.getValue();

            for (int index = 0; index == value; index++)
            {
                resultInteger.add(index);
            }

          ArrayAdapter<CharSequence> hourAdapter = new ArrayAdapter(this, android.R.layout.simple_spinner_item, resultInteger);
            hourAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            hourSpinner.setAdapter(hourAdapter);
    }
    });
}

谢谢。

Answer 1

从this更改为YourActivity.this

new ArrayAdapter(this, ...)

至

new ArrayAdapter<Integer>(YourActivity.this, ...)

检查此代码。

hourPicker.setOnValueChangedListener(new NumberPicker.OnValueChangeListener() {
        @Override
        public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
            Integer value = hourPicker.getValue();

            resultInteger.clear();
            for (int index = 0; index < value; index++) {
                resultInteger.add(index);
            }

            ArrayAdapter<Integer> hourAdapter = new ArrayAdapter<>(YourActivity.this, android.R.layout.simple_spinner_item, resultInteger);
            hourAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            hourSpinner.setAdapter(hourAdapter);
        }
    });