android - 用于浮点数的 android numberpicker

Question

我们应用程序的用户应该能够调整浮点数。目前，我用所有可能的值填充了一个 ArrayAdapter 并将它附加到一个微调器上。

这个解决方案并没有真正满足我们的期望，因为微调框下拉框太高了。有没有更好的办法？我在看 Numberpicker - 但这似乎只适用于整数值。

有任何想法吗？

谢谢！

score 21 · Accepted Answer

NumberPicker不只是整数..甚至你可以使用Floats String等。

看到这个并阅读它。

对于教程：

http://gafurbabu.wordpress.com/2012/03/29/android-number-picker-dialog/

我NumberPicker很久以前就这样用过，在这里发帖可能会有一些用处：

    NumberPicker np;
    String nums[]= {"Select Fraction","1/64","1/32","3/64","1/16","5/64","3/32","7/64","1/8","9/64","5/32","11/64","3/16","13/64","7/32","15/64","1/4","17/64","9/32","19/64","5/16","21/64","11/32","23/64","3/8","25/64","13/32","27/64","7/16","29/64"};

            np = (NumberPicker) findViewById(R.id.np);

            np.setMaxValue(nums.length-1);
            np.setMinValue(0);
            np.setWrapSelectorWheel(false);
            np.setDisplayedValues(nums);
            np.setDescendantFocusability(NumberPicker.FOCUS_BLOCK_DESCENDANTS);

您可以制作ArrayList任何数据类型并分配它。

score 3 · Accepted Answer

另一种解决方案是将两个数字字段组合成一个组件。请参阅货币选择器示例。它的优点是您不必为微调器初始化所有可能的双精度值。

您可能还需要使用函数附加特殊数字格式，如“00”、“0123”或其他。java.lang.String.format()例子在这里。

添加双选择器 xml 布局：

<LinearLayout
  xmlns:android = "http://schemas.android.com/apk/res/android"
  android:layout_width = "fill_parent"
  android:layout_height = "wrap_content"
  android:gravity = "center">

  <NumberPicker
    android:id = "@+id/integer_picker"
    android:layout_width = "wrap_content"
    android:layout_height = "wrap_content"
    android:layout_gravity = "center"/>

  <TextView
    android:layout_width = "wrap_content"
    android:layout_height = "wrap_content"
    android:layout_gravity = "center"
    android:padding = "5dp"
    android:text = "@string/local_separator"
    android:textSize = "20sp"/>

  <NumberPicker
    android:id = "@+id/fraction_picker"
    android:layout_width = "wrap_content"
    android:layout_height = "wrap_content"
    android:layout_gravity = "center"/>

  <TextView
    android:layout_width = "wrap_content"
    android:layout_height = "wrap_content"
    android:layout_gravity = "center"
    android:padding = "5dp"
    android:text = "@string/measure_unit_sign"
    android:textSize = "20sp"/>

</LinearLayout>

添加自定义 Double Picker 类：

import android.content.Context;
import android.view.LayoutInflater;
import android.widget.NumberPicker;

/**
 * UI component for double (floating point) values. Can be used
 * for money and other measures.
 */
public class DoublePicker
  extends NumberPicker {

  private int decimals;
  private NumberPicker integerPicker;
  private NumberPicker fractionPicker;

  public DoublePicker(
    Context context) {

    super(
      context);

      LayoutInflater
        .from(
          context)
        .inflate(
          R.layout.double_picker,
          this);

      integerPicker =
        (NumberPicker) findViewById(
          R.id.integer_picker);

      fractionPicker =
        (NumberPicker) findViewById(
          R.id.fraction_picker);
  }

  public int getDecimals() {

    return decimals;
  }

  /**
   * Sets the amount of digits after separator.
   *
   * @param decimals Anount of decimals.
   */
  public void setDecimals(final int decimals) {

    this.decimals = decimals;

    this.setFormatter(new DoublePicker.Formatter() {

      @Override
      public String format(int i) {

        return String.format(
          "%." + decimals + "f",
          i);
      }
    });
  }

  public void setValue(double value) {

    integerPicker.setValue((int) value);

    fractionPicker.setValue(
      Integer.valueOf(
        String
          .valueOf(value)
          .split(".")
          [1]));
  }
}

在活动 xml 中使用新的 Double Picker 组件：

<com.example.DoublePicker
  android:id ="@+id/double_picker"
  android:layout_width ="match_parent"
  android:layout_height ="wrap_content" />

score 1 · Accepted Answer

在Kotlin中，您可以使用这个方便NumberPicker的扩展对话框，它将您的Double值缩放到合适的Int范围内，并在调用任何回调之前将Int值转换回s。所以它基本上隐藏了只支持Double的事实。感觉真的会支持，试试看！NumberPickerIntNumberPickerDouble

这是您需要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()
}

现在您可以像这样使用它（在 a 中Fragment）：

showNumberPickerDialog(
    title = "Your Weight",
    value = 75.0, // in kilograms
    range = 10.0 .. 300.0,
    stepSize = 0.1,
    formatToString = { "$it kg" },
    valueChooseAction = { saveNewWeight(it) }
)

android - 用于浮点数的 android numberpicker

3 回答 3

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