Spinner数据加载的自定义加载器

如果您想要自定义Spinner的数据加载器，您可以通过扩展AsyncTask类来实现。以下是一个简单的示例，演示如何使用AsyncTask来加载数据并将其设置到Spinner中：

public class CustomLoader extends AsyncTask<Void, Void, List<String>> {

    private Context mContext;
    private Spinner mSpinner;
    private ProgressDialog mProgressDialog;

    public CustomLoader(Context context, Spinner spinner) {
        mContext = context;
        mSpinner = spinner;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        mProgressDialog = new ProgressDialog(mContext);
        mProgressDialog.setMessage("Loading data...");
        mProgressDialog.show();
    }

    @Override
    protected List<String> doInBackground(Void... voids) {
        // Simulate loading data from a data source (e.g. network request, database query)
        List<String> dataList = new ArrayList<>();
        dataList.add("Item 1");
        dataList.add("Item 2");
        dataList.add("Item 3");
        
        // Simulate a delay for demonstration purposes
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        return dataList;
    }

    @Override
    protected void onPostExecute(List<String> dataList) {
        super.onPostExecute(dataList);
        mProgressDialog.dismiss();

        ArrayAdapter<String> adapter = new ArrayAdapter<>(mContext, android.R.layout.simple_spinner_item, dataList);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        mSpinner.setAdapter(adapter);
    }
}

您可以在Activity或Fragment中调用CustomLoader来加载数据并设置到Spinner中：

Spinner spinner = findViewById(R.id.spinner);
CustomLoader customLoader = new CustomLoader(this, spinner);
customLoader.execute();

请注意，上述示例仅是一个简单的演示，实际情况中您可能需要根据您的需求进行定制和扩展。您还可以添加错误处理、数据缓存、数据过滤等功能来优化您的自定义加载器。