Question

如何在微调器中添加默认值，如selectone？我想在spinner中添加一个在spinne上可见的值，但是当我点击微调器时，适配器的所有值都显示在我面前，而不是selectone，这是默认值。

try {

        json = new JSONObject(Status);

        // nameArray = json.names();

        valArray = json.getJSONArray("Machines");



    } catch (JSONException e) {



        e.printStackTrace();

    }



    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,

            android.R.layout.simple_spinner_item);

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



    for (int i = 0; i < valArray.length(); i++) {

        try {

            String machineName = valArray.getJSONObject(i)

                    .getString("MachineName").toString();

            // Integer machineID = Integer.parseInt(valArray.getJSONObject(

            // 0).getString("MachineID"));

            // Entities.machineID = machineID;

            adapter.add(machineName);

        } catch (JSONException e) {



            e.printStackTrace();

        }

    }



    sp_Machine.setAdapter(adapter);

提前致谢。

Answer 1

如果要动态获取微调器的值，那么这是在微调器值的第一个处添加select的方法：

try{
    HttpClient httpclient = new DefaultHttpClient();
    HttpPost httppost = new HttpPost("http://10.0.2.2/android/classname_spinner.php");
    try{
        ResponseHandler<String> responseHandler = new BasicResponseHandler();
        String responseBody = httpclient.execute(httppost,responseHandler);
        JSONObject json = new JSONObject(responseBody);

        JSONArray jArray = json.getJSONArray("output");
        arr = new String[jArray.length()+1];
        arr[0] = "-select-";
        for(int i=0;i<jArray.length();i++){
            JSONObject json_data = jArray.getJSONObject(i);
            String sclass = json_data.getString("spinner");
            arr[i+1] = sclass;
        }
    }catch (Exception e) {
        Log.e("log_tag","Error parsing classname data"+e.toString());
    }
}catch (Exception e) {
    Log.e("log_tag","Request failed"+e.toString());
}

现在将您获得的值添加到微调器中，如下所示：

classSpinner = (Spinner) findViewById(R.id.editClass);
    ArrayAdapter<String> classNameAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item,arr);
    classNameAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    classSpinner.setAdapter(classNameAdapter);

现在，当想要微调器在单击事件时返回其默认值时，只需在on click事件中写入：

reset.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                classSpinner.setSelection(0);
            }
        });

希望这会对你有所帮助。

Answer 2

这是我想出的一个解决方案。只需使用此适配器而不是常规适配器：

package perelman.yuval.carsapp;
import java.util.ArrayList;
import java.util.List;
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
public class SpinnerDualAdapter<T> extends ArrayAdapter<T> {
private ArrayAdapter<String> myAdapter;
private boolean isPromptAdapter;
private SpinnerDualAdapter(Context context, int textViewResourceId,
        List<T> objects) {
    super(context, textViewResourceId, objects);
    // TODO Auto-generated constructor stub
}

public SpinnerDualAdapter(Context context,
        int textViewResourceIdForDropdownView,
        int textViewResourceIdForDefaultView, List<T> objects,
        String defaultValue) {
    this(context, textViewResourceIdForDropdownView, objects);
    ArrayList<String> myArrayList = new ArrayList<String>();
    myArrayList.add(defaultValue);
    myAdapter = new ArrayAdapter<String>(context,
            textViewResourceIdForDefaultView, myArrayList);
    isPromptAdapter=true;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
        if(isPromptAdapter){
            isPromptAdapter=false;
            return myAdapter.getView(position, convertView, parent);
        }
        TextView tv=new TextView(getContext());
        tv.setText(this.getItem(position).toString());
    return tv;
}
@Override
public View getDropDownView(int position, View convertView, ViewGroup parent){
    isPromptAdapter=false;
    return(super.getDropDownView(position, convertView, parent));
}
}

如何在android中的spinner中添加默认值？

2 个答案: