Android API 21 - 时间选择器小部件

Question

在API 21上，TimePicker小部件存在问题。在API 19之前，TimePicker是一个像iOS那样的上/下列表，但在21+中，它是圆形的，就像日历应用程序中的那个。

如果使用新的小部件，它会破坏我的设计，我该如何在21+上使用旧的小部件呢？

- mars3142

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我推荐这个stackoverflow链接，提供一个编程和XML的答案：https://dev59.com/WWAf5IYBdhLWcg3woj3N - Zhang

Answer 1

您可以通过将timePickerMode属性设置为"spinner"来指定微调器式时间选择器。在Material上，默认值为"clock"。

<TimePicker
    ...
    android:timePickerMode="spinner" />

- alanv

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在创建时间选择器时，您可以传递defStyleAttr或defStyleRes。 - alanv

有没有办法让最终用户禁用新的时间选择器？一些用户发现它很难使用。 - mindplay.dk

不过作为开发者，你可以使用任何你喜欢的样式，并将其作为用户的首选项公开（但我不建议这样做）。 - alanv

为什么这个属性在文档中（http://developer.android.com/reference/android/widget/TimePicker.html）没有列出来？你是怎么知道这个属性的来源的？ - oky_sabeni

它需要在类文档中进行记录（并且在下一个版本中将会有记录），但也已经在android.R.styleable中进行了记录（请参见http://developer.android.com/reference/android/R.styleable.html#TimePicker_timePickerMode）。我知道它在那里，因为我写过它。;) - alanv

Answer 2

您可以使用自定义类编程方式来使用微调模式。对于早期版本，从Lolipop开始，它将把时间选择器模式从时钟更改为微调，并且还允许您设置在特定时间之后禁用时间选择（使用setmax()和setmin()）。在下面的代码中，我使用了setmax()来限制最大时间。

public class RangeTimePickerDialog extends TimePickerDialog {

    private int minHour = -1;
    private int minMinute = -1;

    private int maxHour = 25;
    private int maxMinute = 25;

    private int currentHour = 0;
    private int currentMinute = 0;

    private Calendar calendar = Calendar.getInstance();
    private DateFormat dateFormat;


    public RangeTimePickerDialog(Context context, int dialogTheme, OnTimeSetListener callBack, int hourOfDay, int minute, boolean is24HourView) {
        super(context, callBack, hourOfDay, minute, is24HourView);
        currentHour = hourOfDay;
        currentMinute = minute;
        dateFormat = DateFormat.getTimeInstance(DateFormat.SHORT);
        fixSpinner(context, hourOfDay, minute, is24HourView);

        try {
            Class<?> superclass = getClass().getSuperclass();
            Field mTimePickerField = superclass.getDeclaredField("mTimePicker");
            mTimePickerField.setAccessible(true);
            TimePicker mTimePicker = (TimePicker) mTimePickerField.get(this);
            mTimePicker.setOnTimeChangedListener(this);
        } catch (NoSuchFieldException e) {
        } catch (IllegalArgumentException e) {
        } catch (IllegalAccessException e) {
        }
    }

    public void setMin(int hour, int minute) {
        minHour = hour;
        minMinute = minute;
    }

    public void setMax(int hour, int minute) {
        maxHour = hour;
        maxMinute = minute;
    }

    @Override
    public void onTimeChanged(TimePicker view, int hourOfDay, int minute) {

        boolean validTime = true;
        if (hourOfDay < minHour || (hourOfDay == minHour && minute < minMinute)){
            validTime = false;
        }

        if (hourOfDay  > maxHour || (hourOfDay == maxHour && minute > maxMinute)){
            validTime = false;
        }

        if (validTime) {
            currentHour = hourOfDay;
            currentMinute = minute;
        }

        updateTime(currentHour, currentMinute);
        updateDialogTitle(view, currentHour, currentMinute);
    }

    private void updateDialogTitle(TimePicker timePicker, int hourOfDay, int minute) {
        calendar.set(Calendar.HOUR_OF_DAY, hourOfDay);
        calendar.set(Calendar.MINUTE, minute);
        String title = dateFormat.format(calendar.getTime());
        setTitle(title);
    }


    private void fixSpinner(Context context, int hourOfDay, int minute, boolean is24HourView) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) { // android:timePickerMode spinner and clock began in Lollipop
            try {
                // Get the theme's android:timePickerMode
                //two modes are available clock mode and spinner mode ... selecting spinner mode for latest versions
                final int MODE_SPINNER = 2;
                Class<?> styleableClass = Class.forName("com.android.internal.R$styleable");
                Field timePickerStyleableField = styleableClass.getField("TimePicker");
                int[] timePickerStyleable = (int[]) timePickerStyleableField.get(null);
                final TypedArray a = context.obtainStyledAttributes(null, timePickerStyleable, android.R.attr.timePickerStyle, 0);
                Field timePickerModeStyleableField = styleableClass.getField("TimePicker_timePickerMode");
                int timePickerModeStyleable = timePickerModeStyleableField.getInt(null);
                final int mode = a.getInt(timePickerModeStyleable, MODE_SPINNER);
                a.recycle();
                if (mode == MODE_SPINNER) {
                    TimePicker timePicker = (TimePicker) findField(TimePickerDialog.class, TimePicker.class, "mTimePicker").get(this);
                    Class<?> delegateClass = Class.forName("android.widget.TimePicker$TimePickerDelegate");
                    Field delegateField = findField(TimePicker.class, delegateClass, "mDelegate");
                    Object delegate = delegateField.get(timePicker);
                    Class<?> spinnerDelegateClass;
                    if (Build.VERSION.SDK_INT != Build.VERSION_CODES.LOLLIPOP) {
                        spinnerDelegateClass = Class.forName("android.widget.TimePickerSpinnerDelegate");
                    } else {

                        spinnerDelegateClass = Class.forName("android.widget.TimePickerClockDelegate");
                    }
                    if (delegate.getClass() != spinnerDelegateClass) {
                        delegateField.set(timePicker, null); // throw out the TimePickerClockDelegate!
                        timePicker.removeAllViews(); // remove the TimePickerClockDelegate views
                        Constructor spinnerDelegateConstructor = spinnerDelegateClass.getConstructor(TimePicker.class, Context.class, AttributeSet.class, int.class, int.class);
                        spinnerDelegateConstructor.setAccessible(true);
                        // Instantiate a TimePickerSpinnerDelegate
                        delegate = spinnerDelegateConstructor.newInstance(timePicker, context, null, android.R.attr.timePickerStyle, 0);
                        delegateField.set(timePicker, delegate); // set the TimePicker.mDelegate to the spinner delegate
                        // Set up the TimePicker again, with the TimePickerSpinnerDelegate
                        timePicker.setIs24HourView(is24HourView);
                        timePicker.setCurrentHour(hourOfDay);
                        timePicker.setCurrentMinute(minute);
                        timePicker.setOnTimeChangedListener(this);
                    }
                }
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
    }
    private static Field findField(Class objectClass, Class fieldClass, String expectedName) {
        try {
            Field field = objectClass.getDeclaredField(expectedName);
            field.setAccessible(true);
            return field;
        } catch (NoSuchFieldException e) {} // ignore
        // search for it if it wasn't found under the expected ivar name
        for (Field searchField : objectClass.getDeclaredFields()) {
            if (searchField.getType() == fieldClass) {
                searchField.setAccessible(true);
                return searchField;
            }
        }
        return null;
    }
}

- MarGin

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使用反射不是未来的保障。我不会使用它。 - mars3142