微调的setOnItemSelectedListener不叫

问题描述

我用的 setOnItemSelectedListener 以指定哪个项目的微调选择，但我认为它不叫。它应打印它的工作原理的程序运行时。

XML code：

 ＆LT;微调
    机器人：ID =@ + ID /数量
    机器人：layout_width =94dp
    机器人：layout_height =27dp
    机器人：layout_x =11DP
    机器人：layout_y =118dp
     /＆GT;
 

Java的code：

 公共类数量扩展活动
{微调量;
    公共无效的onCreate（捆绑savedInstanceState）
    {
    量=（微调）findViewById（R.id.quantity）;    quantity.setOnItemSelectedListener（新AdapterView.OnItemSelectedListener（）
            {
                公共无效onItemSelected（适配器视图＆LT;＆GT;母公司，观景，INT POS，长I​​D）
                {
                    对象项目= parent.getItemAtPosition（POS）                    的System.out.println（它的工作......）;                }                公共无效onNothingSelected（适配器视图＆LT;＆GT;母公司）
                {                }
            }）;
    }}
 

解决方案

试试这个

  @覆盖
    保护无效的onCreate（捆绑savedInstanceState）{
        super.onCreate（savedInstanceState）;
        的setContentView（R.layout.Your_Layout）;            / *为填补你的微调* /
        清单＆LT;串GT; SpinnerArray =新的ArrayList＆LT;串GT;（）;
        SpinnerArray.add（项目1）;
        SpinnerArray.add（项目2）;
        SpinnerArray.add（项目3）;
        SpinnerArray.add（项目4）;
        SpinnerArray.add（项目5）;        ArrayAdapter＆LT;串GT;适配器=新ArrayAdapter＆LT;串GT;（这一点，
                android.R.layout.simple_spinner_item，SpinnerArray）;
        adapter.setDropDownViewResource（android.R.layout.simple_spinner_dropdown_item）;
        微调微调=（微调）findViewById（R.id.quantity）;
        spinner.setAdapter（适配器）;        spinner.setOnItemSelectedListener（新OnItemSelectedListener（）{            @覆盖
            公共无效onItemSelected（适配器视图＆LT;＆GT;为arg0，ARG1查看，
                    INT ARG2，长ARG3）{
                // TODO自动生成方法存根
                对象项目= arg0.getItemAtPosition（ARG2）;
                如果（项目！= NULL）{
                    Toast.makeText（MainActivity.this，item.toString（），
                            Toast.LENGTH_SHORT）.show（）;
                }
                Toast.makeText（MainActivity.this，入选
                        Toast.LENGTH_SHORT）.show（）;            }            @覆盖
            公共无效onNothingSelected（适配器视图＆LT;＆GT;为arg0）{
                // TODO自动生成方法存根            }
        }）;
    }
 

I used setOnItemSelectedListener to specify which item is selected in a spinner, but i think it is not called. it should print "It works" when the program runs.

XML code:

<Spinner
    android:id="@+id/quantity"
    android:layout_width="94dp"
    android:layout_height="27dp"
    android:layout_x="11dp"
    android:layout_y="118dp"
     />

Java code:

public class quantity extends Activity
{

Spinner  quantity;


    public void onCreate(Bundle savedInstanceState)
    {
    quantity=(Spinner)findViewById(R.id.quantity);

    quantity.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener()
            {
                public void onItemSelected(AdapterView<?> parent, View view, int pos, long id)
                {
                    Object item = parent.getItemAtPosition(pos);

                    System.out.println("it works...   ");

                }

                public void onNothingSelected(AdapterView<?> parent)
                {

                }
            });


    }

}

解决方案

Try this

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.Your_Layout);

            /*for fill your Spinner*/
        List<String> SpinnerArray = new ArrayList<String>();
        SpinnerArray.add("Item 1");
        SpinnerArray.add("Item 2");
        SpinnerArray.add("Item 3");
        SpinnerArray.add("Item 4");
        SpinnerArray.add("Item 5");

        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_spinner_item, SpinnerArray);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        Spinner spinner = (Spinner) findViewById(R.id.quantity);
        spinner.setAdapter(adapter);

        spinner.setOnItemSelectedListener(new OnItemSelectedListener() {

            @Override
            public void onItemSelected(AdapterView<?> arg0, View arg1,
                    int arg2, long arg3) {
                // TODO Auto-generated method stub
                Object item = arg0.getItemAtPosition(arg2);
                if (item!=null) {
                    Toast.makeText(MainActivity.this, item.toString(),
                            Toast.LENGTH_SHORT).show();
                }
                Toast.makeText(MainActivity.this, "Selected",
                        Toast.LENGTH_SHORT).show();

            }

            @Override
            public void onNothingSelected(AdapterView<?> arg0) {
                // TODO Auto-generated method stub

            }
        });
    }

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