如何实现Android Spinner同已选选项重选的事件触发功能

Android 原生Spinner默认仅在新选中条目位置与当前已选中位置不一致时，才会触发OnItemSelectedListener的onItemSelected回调，这是你重复选中同一位置条目无法触发API调用的核心原因。

通过自定义Spinner强制同位置选中也触发回调，实现步骤如下：

1. 新建自定义Spinner类 #

import android.content.Context;
import android.util.AttributeSet;
import android.widget.AdapterView;
import android.widget.Spinner;

public class ReSelectableSpinner extends Spinner {
    public ReSelectableSpinner(Context context) {
        super(context);
    }

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

    public ReSelectableSpinner(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    public void setSelection(int position, boolean animate) {
        super.setSelection(position, animate);
        AdapterView.OnItemSelectedListener listener = getOnItemSelectedListener();
        if (listener != null && position == getSelectedItemPosition()) {
            listener.onItemSelected(this, getSelectedView(), position, getSelectedItemId());
        }
    }

    @Override
    public void setSelection(int position) {
        super.setSelection(position);
        AdapterView.OnItemSelectedListener listener = getOnItemSelectedListener();
        if (listener != null && position == getSelectedItemPosition()) {
            listener.onItemSelected(this, getSelectedView(), position, getSelectedItemId());
        }
    }
}

2. 替换布局文件中的Spinner #

将布局中原有的<Spinner>标签替换为自定义的ReSelectableSpinner，需填写你项目中该类的完整包名：

<!-- 替换为你实际的包名 -->
<com.your.package.name.ReSelectableSpinner
    android:id="@+id/your_spinner_id"
    <!-- 其余原有属性保持不变 -->
    />

3. 优化原有监听器逻辑 #

你原有逻辑基本不需要修改，仅需要补充异常分支、API请求回调中的界面状态恢复逻辑，避免请求出错后界面无法操作：

spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
        if (isNetworkAvailable()) {
            progressBar.setVisibility(View.VISIBLE);
            getWindow().setFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE,
                    WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE);
            try {
                if (position == 0) {
                    progressBar.setVisibility(View.GONE);
                    getWindow().clearFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE);
                    return;
                } else {
                    changePath(position, arrayitem.get(position));
                    // 请在changePath方法的API请求回调（成功/失败）中统一添加以下逻辑，恢复界面操作
                    // progressBar.setVisibility(View.GONE);
                    // getWindow().clearFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE);
                }
            } catch (JSONException e) {
                e.printStackTrace();
                // 异常分支恢复界面状态
                progressBar.setVisibility(View.GONE);
                getWindow().clearFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE);
            }
        }
    }

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

    }
});

内容的提问来源于stack exchange，提问作者Malhotra