Question

我有一个大小为20的数组，但是当我运行我的代码时，它只输出3个值。如何在数组中输入20个值？

 public class LoopsMaybe
{
  public static void main(String [] args)
  {

    int[] lott = new int[20];
  for( int i=5; i<lott.length;i=i+7)
  {


      System.out.println(i);


      }

  }

 }

输出：五 12 19

我希望它打印出5,12,19,26,33,40,47 .....并停在序列中的第20个数字

Answer 1

对于那些对Java 8细节感兴趣的人来说，完成这项工作的一种非常简单明了的方法是：

int seed = 5, inc = 7, many = 20;
IntStream is = IntStream.iterate(seed, n -> n + inc);
is.limit(many).forEach(x -> System.out.print(x + " "));

产出：5 12 19 26 33 40 47 54 61 68 75 82 89 96 103 110 117 124 131 138

Answer 2

如果你必须使用数组，那么你需要其他东西来执行增量7。这样你可以保证20次迭代。

public class LoopsMaybe
{
    public static void main(String [] args)
    {

        int[] lott = new int[20];
        int inc=5;
        for( int i=0; i<lott.length;i++)
        {
            System.out.println(inc);
            inc += 7;
        }
    }
}

Answer 3

public class ProductListAdapter extends BaseAdapter implements Filterable {
    List<ProductModel> mStringFilterList;
    ValueFilter valueFilter;
    int item_number = 0;
    TextWatcher tt = null;
    private Activity activity;
    private LayoutInflater inflater;
    private List<ProductModel> modelItems;
    private OnAddRemoveListener myaddInterface;
    TextView tvTitle;
    Button minusIcon, addIcon;

    public ProductListAdapter(Activity activity, List<ProductModel> modelItems, OnAddRemoveListener myaddInterface) {
        this.activity = activity;
        this.modelItems = modelItems;
        mStringFilterList = modelItems;
        this.myaddInterface = myaddInterface;
    }

    @Override
    public int getCount() {
        return modelItems.size();
    }

    @Override
    public Object getItem(int location) {
        return modelItems.get(location);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }/*
    @Override
    public boolean isEnabled(int position) {
        return false;
    }*/

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {

        if (inflater == null)
            inflater = (LayoutInflater) activity
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        if (convertView == null)
            convertView = inflater.inflate(R.layout.product_item_row, null);

        final ProductModel m = modelItems.get(position);

        tvTitle = (TextView) convertView.findViewById(R.id.tv2);
        TextView tprice = (TextView) convertView.findViewById(R.id.tv3);
        boolean ignoreNextTextChange = true;
        final EditText tvItems = (EditText) convertView.findViewById(R.id.num);
        tvItems.setText("0");
        minusIcon = (Button) convertView.findViewById(R.id.minus);
        addIcon = (Button) convertView.findViewById(R.id.add);

        //add items
        addIcon.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.d("add button", "clicked");
                int new_item_number = 1 + Integer.parseInt(tvItems.getText().toString());
                tvItems.setText("" + new_item_number);
                (myaddInterface).onItemadded(String.valueOf(m.getPrice()), new_item_number, position);
            }
        });

        minusIcon.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.d("minus button", "clicked");

                int new_item_number = Integer.parseInt(tvItems.getText().toString());
                if (new_item_number > 0) {
                    (myaddInterface).onItemremoved(String.valueOf(m.getPrice()), position);
                    tvItems.setText("" + (new_item_number - 1));
                } else if (tvItems.getText().toString().equals("0")) {

                    tvItems.setText("0");
                }

            }
        });

        tvTitle.setText(m.getname());
        tprice.setText("(" + m.getPrice() + ")");

    public void afterTextChanged(Editable s) {
        if (tvItems.getText().toString().trim().length() == 1) { 
 
            //to check if input is greater than 0 so we can proceed 
            if (Integer.valueOf(tvItems.getText().toString().trim()) > 0) {
               //displays toast 
               Toast.makeText(activity, s, Toast.LENGTH_SHORT).show();    
            } 
         } 
    } 
 
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
    } 
 
    public void onTextChanged(CharSequence s, int start, int before, int count) {
    } 
}; 
        tvItems.addTextChangedListener(tt);
        return convertView;
    }

    //code for search filter, not associated with the question
    
    @Override
    public Filter getFilter() {
        if (valueFilter == null) {
            valueFilter = new ValueFilter();
        }
        return valueFilter;
    }

    private class ValueFilter extends Filter {
        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            FilterResults results = new FilterResults();
            if (constraint != null && constraint.length() > 0) {
                ArrayList<ProductModel> filterList = new ArrayList<>();
                for (int i = 0; i < mStringFilterList.size(); i++)
                    if ((mStringFilterList.get(i).getname().toUpperCase())
                            .contains(constraint.toString().toUpperCase()) || (mStringFilterList.get(i).getproductDesc().toUpperCase())
                            .contains(constraint.toString().toUpperCase())) {


                        ProductModel m = new ProductModel(mStringFilterList.get(i)
                                .getProduct_id(), mStringFilterList.get(i)
                                .getname(), mStringFilterList.get(i)
                                .getPrice(), mStringFilterList.get(i)
                                .getimage_url(), mStringFilterList.get(i)
                                .getproductDesc());

                        filterList.add(m);
                    }
                results.count = filterList.size();
                results.values = filterList;
            } else {
                results.count = mStringFilterList.size();
                results.values = mStringFilterList;
                //show no results
            }

           /* }else if((mStringFilterList.get(i).getproductDesc().toUpperCase())
                    .contains(constraint.toString().toUpperCase())){}*/

            return results;

        }

        @Override
        protected void publishResults(CharSequence constraint,
                                      FilterResults results) {
            modelItems = (List<ProductModel>) results.values;
            notifyDataSetChanged();
        }

    }

}

我想输出20个数字？

3 个答案: