Question

我已经创建了3个数字选择器，计划在选中时添加/总计这些数字选择器，但现在我面临一些字符串数组问题

输入：这里是我选择数字选择器20,30,10的数字

输出：103020

但我需要它总计10 + 20 + 30 = 60并且不显示输出像103020

   NumberPicker.OnValueChangeListener onValueChanged = new NumberPicker.OnValueChangeListener() {
            @Override
            public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
                NumberPicker[] nps = new NumberPicker[3];
                nps[0] = (NumberPicker) findViewById(R.id.carbPercentage);
                nps[1] = (NumberPicker) findViewById(R.id.proteinPercentage);
                nps[2] = (NumberPicker) findViewById(R.id.fatPercentage);

                String temp = "";
                for (int i = 0; i < 3; i++) {
                    String[] values = nps[i].getDisplayedValues();
                    temp = values[nps[i].getValue()] + temp;
                }

                TextView tv = (TextView) findViewById(R.id.totalPercentage);
                tv.setText(temp);
            }
        };

        NumberPicker[] nps = new NumberPicker[3];
        nps[0] = (NumberPicker) findViewById(R.id.carbPercentage);
        nps[1] = (NumberPicker) findViewById(R.id.proteinPercentage);
        nps[2] = (NumberPicker) findViewById(R.id.fatPercentage);

        String[] values = new String[21];
        for (int i = 0; i < values.length; i++) {
            values[i] = Integer.toString(i * 5);
        }

        for (int i = 0; i < 3; i++) {
            nps[i].setMaxValue(values.length - 1);
            nps[i].setMinValue(0);
            nps[i].setDisplayedValues(values);
            nps[i].setOnValueChangedListener(onValueChanged);
        }

Answer 1

我不明白为什么你试图通过字符串连接＆＃39; temp＆＃39;来连接NumberPicker值。变量即可。而是使用它：

在数字选择器的onValueChange事件处理程序中，

long totalSum = 0L;

for(int i=0; i<3; i++)
      totalSum + = nps[i].getValue(); // getValue() method returns int

TextView tv = (TextView) findViewById(R.id.totalPercentage);
tv.setText(String.valueOf(totalSum));

如果有帮助，请告诉我。

Answer 2

请参阅下面@oathkeeper的ans是真的。让我描述一件最好的事情。

＆＃34;的 + ＆＃34;它以不同的方式工作。

(String + string) always return string concate. (String + int/long) always return string concate. (int/long + string) always return string concate. (int/long + int/long) always return int/long (Mathamatical opration).

JAVA的简单和基本概念。

Answer 3

您只需将nps[i].getDisplayedValues()更改为nps[i].getValue()即可返回int值。然后将这些int值一起添加，然后显示它。

   NumberPicker.OnValueChangeListener onValueChanged = new NumberPicker.OnValueChangeListener() {
            @Override
            public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
                NumberPicker[] nps = new NumberPicker[3];
                nps[0] = (NumberPicker) findViewById(R.id.carbPercentage);
                nps[1] = (NumberPicker) findViewById(R.id.proteinPercentage);
                nps[2] = (NumberPicker) findViewById(R.id.fatPercentage);

                // change here!
                int sum = 0;
                // String temp = "";
                for (int i = 0; i < 3; i++) {
                    String[] values = nps[i].getDisplayedValues();
                    sum += Integer.parseInt(values[nps[i].getValue()]);
                    // temp = values[nps[i].getValue()] + temp;
                }

                TextView tv = (TextView) findViewById(R.id.totalPercentage);
                tv.setText(String.valueOf(sum));
            }
        };

        NumberPicker[] nps = new NumberPicker[3];
        nps[0] = (NumberPicker) findViewById(R.id.carbPercentage);
        nps[1] = (NumberPicker) findViewById(R.id.proteinPercentage);
        nps[2] = (NumberPicker) findViewById(R.id.fatPercentage);

        String[] values = new String[21];
        for (int i = 0; i < values.length; i++) {
            values[i] = Integer.toString(i * 5);
        }

        for (int i = 0; i < 3; i++) {
            nps[i].setMaxValue(values.length - 1);
            nps[i].setMinValue(0);
            nps[i].setDisplayedValues(values);
            nps[i].setOnValueChangedListener(onValueChanged);
        }

如何获得不同的数字选择器数量和总计

3 个答案: