Question

首先，我知道这次被问了好几次，但是对于较新的Android版本，看起来建议的解决方案不起作用。即使用户选择了两次相同的项目，我也需要我的微调器调用OnItemSelected。我发现这个课应该可以解决这个问题：

    public class NDSpinner extends Spinner {

    private int lastSelected = 0;
    private static Method s_pSelectionChangedMethod = null;


    static {        
        try {
            Class noparams[] = {};
            Class targetClass = AdapterView.class;

            s_pSelectionChangedMethod = targetClass.getDeclaredMethod("selectionChanged", noparams);            
            if (s_pSelectionChangedMethod != null) {
                s_pSelectionChangedMethod.setAccessible(true);              
            }

        } catch( Exception e ) {
            Log.e("Custom spinner, reflection bug:", e.getMessage());
            throw new RuntimeException(e);
        }
    }

    public NDSpinner(Context context) {
        super(context);
    }

    public NDSpinner(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public NDSpinner(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }







@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
    if(this.lastSelected == this.getSelectedItemPosition())
        testReflectionForSelectionChanged();
    if(!changed)
        lastSelected = this.getSelectedItemPosition();

    super.onLayout(changed, l, t, r, b);
} 



    public void testReflectionForSelectionChanged() {
        try {
            Class noparams[] = {};          
            s_pSelectionChangedMethod.invoke(this, noparams);
        } catch (Exception e) {
            Log.e("Custom spinner, reflection bug: ", e.getMessage());
            e.printStackTrace();                
        }
    } 




    @Override
   public void onClick(DialogInterface dialog, int which) {    
        super.onClick(dialog, which);
    }
}

这实际上有效，但它有一个错误：它第一次调用两次项目:( 谁能告诉我怎么解决这个问题？

感谢队友。

Answer 1

我已经解决了使用这个课程的问题：

public class NDSpinner extends Spinner {

      public NDSpinner(Context context)
      { super(context); }

      public NDSpinner(Context context, AttributeSet attrs)
      { super(context, attrs); }

      public NDSpinner(Context context, AttributeSet attrs, int defStyle)
      { super(context, attrs, defStyle); }

      @Override public void
      setSelection(int position, boolean animate)
      {
        boolean sameSelected = position == getSelectedItemPosition();
        super.setSelection(position, animate);
        if (sameSelected) {
          // Spinner does not call the OnItemSelectedListener if the same item is selected, so do it manually now
          getOnItemSelectedListener().onItemSelected(this, getSelectedView(), position, getSelectedItemId());
        }
      }

      @Override public void
      setSelection(int position)
      {
        boolean sameSelected = position == getSelectedItemPosition();
        super.setSelection(position);
        if (sameSelected) {
          // Spinner does not call the OnItemSelectedListener if the same item is selected, so do it manually now
          getOnItemSelectedListener().onItemSelected(this, getSelectedView(), position, getSelectedItemId());
        }
      }
    }

非常感谢：）

Answer 2

对我来说，我扩展了AppCompatSpinner。

如果你的Spinneris用XML进行布局，请记得改变你的

<Spinner...

到

<com.example.util.NDSpinner...

没有使用相同项目调用Android Spinner OnItemSelected

2 个答案: