从 NumberPicker 获取浮点数/双精度数

Question

我正在尝试https://github.com/SimonVT/android-numberpicker 库，参考是https://developer.android.com/reference/android/widget/NumberPicker.html#getValue%28%29 现在，API 级别 11 NumberPicker 在 getValue 方法中返回 int 值，SimonVT numberpicker 也返回 int 值。

但我使用以下代码在数字选择器中设置了双值：

String[] nums = {"1","1.5","2","2.5","3","3.5","4","4.5","5","5.5","6","6.5","7","7.5","8","8.5","9"};

final NumberPicker listeningScorenp = (NumberPicker) findViewById(R.id.listeningScore);
listeningScorenp.setMaxValue(nums.length-1);
listeningScorenp.setMinValue(0);
listeningScorenp.setWrapSelectorWheel(false);
listeningScorenp.setDisplayedValues(nums);

现在我不知道如何从 NUMberPicker 检索浮点/双精度值。

Answer 1

我刚刚使用您的代码进行了测试。 getValue() 实际上返回所选项目的索引（仅当您设置显示值时）。你需要做的就是解析字符串，你就会得到你想要的。

String[] nums = {"1","1.5","2","2.5","3","3.5","4","4.5","5","5.5","6","6.5","7","7.5","8","8.5","9"};
int index = listeningScorenp.getValue();
String val = nums[index];
float selectedFloat = Float.parseFloat(val);

Answer 2

在 Kotlin 中，您可以使用这个方便的 NumberPicker 扩展，它会显示一个对话框 - 在包装之下，它会将您的 Double 值缩放到合适的 Int 范围并转换 Int在调用任何回调之前将值返回到Doubles。所以它基本上隐藏了NumberPicker只支持Int的事实。感觉NumberPicker居然会支持Double，试试看！

这是您可以复制和粘贴的片段扩展：

fun Fragment.showNumberPickerDialog(
    title: String,
    value: Double,
    range: ClosedRange<Double>,
    stepSize: Double,
    formatToString: (Double) -> String,
    valueChooseAction: (Double) -> Unit
) {
    val numberPicker = NumberPicker(context).apply {
        setFormatter { formatToString(it.toDouble() * stepSize) }
        wrapSelectorWheel = false

        minValue = (range.start / stepSize).toInt()
        maxValue = (range.endInclusive / stepSize).toInt()
        this.value = (value.toDouble() / stepSize).toInt()

        // NOTE: workaround for a bug that rendered the selected value wrong until user scrolled, see also: https://stackoverflow.com/q/27343772/3451975
        (NumberPicker::class.java.getDeclaredField("mInputText").apply { isAccessible = true }.get(this) as EditText).filters = emptyArray()
    }

    MaterialAlertDialogBuilder(context)
        .setTitle(title)
        .setView(numberPicker)
        .setPositiveButton("OK") { _, _ -> valueChooseAction(numberPicker.value.toDouble() * stepSize) }
        .setNeutralButton("Cancel") { _, _ -> /* do nothing, closes dialog automatically */ }
        .show()
}

那么你可以像这样使用它：

showNumberPickerDialog(
    title = "Your Weight",
    value = 75.0, // in kilograms
    range = 10.0 .. 300.0,
    formatToString = { "$it kg" },
    valueChooseAction = { saveNewWeight(it) }
)