当再次选择当前选定的项目时，如何在Android Spinner中获得事件？

Question

我已经为旋转器编写了一个setOnItemSelectedListener，以在旋转器项目更改时做出响应。我的要求是，当我再次单击当前选择的项目时，应显示一个祝酒词。如何获得此活动？再次单击当前选择的项目时，微调器没有响应。`    StorageSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener(){        @Override        public void onItemSelected(AdapterView adapter, View v, int i, long lng) {                          Toast.makeText(getApplicationContext(), (CharSequence) StorageSpinner.getSelectedItem(), Toast.LENGTH_SHORT).show();        }        @Override        public void onNothingSelected(AdapterView arg0) {            Toast.makeText(getApplicationContext(), "Nothing selected", Toast.LENGTH_SHORT).show();        }    });  

Answer 1

当您再次单击当前选定的项目时，它将无法触发任何事件。因此，您无法捕获setOnItemSelectedListener以便微调器响应。

Answer 2

我花了好几个小时试图找到解决这个问题的方法。我得出以下结论。我不确定它是否在所有情况下都有效，但它似乎对我有用。它只是Spinner类的扩展，该类检查选择内容并在选择内容设置为相同值时调用侦听器。

import android.content.Context;

import android.util.AttributeSet;

import android.widget.Spinner;

/** Spinner extension that calls onItemSelected even when the selection is the same as its previous value */

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());

        }

    }

}

Answer 3

尝试这个

public class MySpinner extends Spinner{

OnItemSelectedListener listener;

    public MySpinner(Context context, AttributeSet attrs)

    {

        super(context, attrs);

    }

    @Override

    public void setSelection(int position)

    {

        super.setSelection(position);

        if (position == getSelectedItemPosition())

        {

            listener.onItemSelected(null, null, position, 0);

        }       

    }

    public void setOnItemSelectedListener(OnItemSelectedListener listener)

    {

        this.listener = listener;

    }

}