Android 无法在一行中多次选择微调器下拉菜单项

我的问题是，我可以在微调器下拉菜单中选择一个列表项，但如果不先选择另一个项，我就无法在一行中多次选择一个项。必须有一种方法来更改父类中的选择参数。知道怎么做吗

我的微调器下拉菜单中有一些项目

dropdownMenu = (Spinner) findViewById(R.id.dropdownMenu);

List<String> list = new ArrayList<>();

list.add("Filters");
list.add("list 2");
list.add("list 3");

ArrayAdapter<String> dataAdapter = new ArrayAdapter<>(this,
        android.R.layout.simple_spinner_item, list);

dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

dropdownMenu.setAdapter(dataAdapter);

以下是在

MainActivity

dropdownMenu.setOnItemSelectedListener(this);

public void onItemSelected(AdapterView<?> parent, View view,
                           int pos, long id) {
    // An item was selected. You can retrieve the selected item using
    // parent.getItemAtPosition(pos)
    Log.v(TAG,"SELECTED");

    // There must be a way to change the selected 
    // property to false here
}

public void onNothingSelected(AdapterView<?> parent) {
    // Another interface callback
}

public void未选中（AdapterView父视图、视图、，
内部位置，长id）{
//已选择一个项目。您可以使用
//父项getItemAtPosition（pos）
Log.v（标记“选定”）；
//必须有一种方法来更改所选的
//属性在此处设置为false
}
未选择公共无效（AdapterView父级）{
//另一个接口回调
}

您需要实现如下自定义微调器：

public class CustomSpinner extends Spinner {

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

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

    public CustomSpinner(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());
        }
    }
}

---

所有帖子都给出了一半答案，因此发布了完整的实现，以便于初学者更好地理解

创建一个自定义微调器类，如下所示

import android.content.Context;
import android.util.AttributeSet;

import androidx.appcompat.widget.AppCompatSpinner;

/** Spinner extension that calls onItemSelected even when the selection is the same as its previous value */
public class NDSpinner extends AppCompatSpinner {

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());
    }
}
}

现在在xml文件中，创建一个微调器。将微调器标记替换为

，例如

在java文件中，定义微调器变量，如下所示： 例如：-

NDSpinner ndSpinner = findViewById(R.id.spinnerId);

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