小编Bao*_*Bao的帖子

我一直在尝试用JavaScript 编写Sieve of Eratosthenes算法.基本上我只是遵循以下步骤:

1. 创建从2到(n-1)的连续整数列表
2. 设第一个素数p等于2
3. 从p开始,以p为增量计数并删除每个数字(p和p的倍数)
4. 转到列表中的下一个数字并重复2,3,4
5. 将无意删除的素数添加回列表

这就是我想出的:

function eratosthenes(n){
var array = [];
var tmpArray = []; // for containing unintentionally deleted elements like 2,3,5,7,...
var maxPrimeFactor = 0;
var upperLimit = Math.sqrt(n);
var output = [];

// Eratosthenes algorithm to find all primes under n

// Make an array from 2 to (n - 1)
//used as a base array to delete composite number from
for(var i = 2; i < n; i++){
    array.push(i); …

我试图通过另一个微调器中的选定项更新微调器.以下代码块描述了我是如何做到的.

我可以使用onItemSelected()方法中的if语句成功更新spinner3.但我的问题是,似乎一个循环只是继续运行,它自动从spinner2中选择值"5" (所以Toast只是继续吐出"你选择了5").

加载活动后,Toast将显示所有三个微调器的每个选择.这是否意味着当适配器设置为微调器时,每个微调器的第一个选择是否完成？

将adapter3绑定到spinner3(在if语句中)是否会触发一个新的spinner2选择？

提前致谢!

public class WheelchairHelperMain extends Activity{

Spinner spinner2;
Spinner spinner3;
ArrayAdapter<CharSequence> adapter3 ;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.wheelchair_helper_main);

    Spinner spinner1 = (Spinner)findViewById(R.id.spinner1);
    ArrayAdapter<CharSequence> adapter1 = ArrayAdapter.createFromResource(this, R.array.destinations_list, android.R.layout.simple_spinner_item);
    adapter1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner1.setAdapter(adapter1);
    spinner1.setOnItemSelectedListener(new MyOnItemSelectedListener());

    spinner2 = (Spinner)findViewById(R.id.spinner2);
    ArrayAdapter<CharSequence> adapter2 = ArrayAdapter.createFromResource(this,R.array.departure_timeH_list,android.R.layout.simple_spinner_item);
    adapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner2.setAdapter(adapter2);
    spinner2.setOnItemSelectedListener(new MyOnItemSelectedListener());

    spinner3 = (Spinner)findViewById(R.id.spinner3);
    spinner3.setOnItemSelectedListener(new MyOnItemSelectedListener());



}

public class MyOnItemSelectedListener implements OnItemSelectedListener{


    public void onItemSelected(AdapterView<?> parent, View v, int pos,long id) {
        // TODO Auto-generated method …