相关疑难解决方法(0)

嘿伙计我一直在用动态列表实现numpicker,即在某些事件上有所改变,比如它可能是一个按钮点击或者其他.问题是每当我将列表从较长的长度切换到较小的长度时它起作用,较小的长度到较大的长度它不会改变,而我总是将第一个项目设置为所选项目.它崩溃了.PLS.帮助.我是Android的新手.

码:

public class MainActivity extends Activity {
    NumberPicker numPicker = null;
    String values1[]    =   null;

    String values2[]    =   null;

    String values3[]    =   null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        values1 =new String []{
                "Yello",
                "Red",
                "White",
                "Green",
                "Black"
        };
        values2 =new String []{
                "Mango",
                "Orange"
        };
        values3 =new String []{
                "Class",
                "Pointer",
                "Function",
                "Interafce",
                "Constructor"
        };



        numPicker = (NumberPicker)findViewById(R.id.numberPicker1);
        numPicker.setDisplayedValues(values1);

        if(values1.length>1)
        {
            numPicker.setMaxValue(values1.length-1);
        }
        else
        {
            numPicker.setMaxValue(values1.length);          
        }
        numPicker.setMinValue(0);   
        numPicker.setValue(0);
        numPicker.setBackgroundColor(1);
        numPicker.setWrapSelectorWheel(false);
        numPicker.setDescendantFocusability(NumberPicker.FOCUS_BLOCK_DESCENDANTS);


        //On value change listner …