自学鸿蒙应用开发（12）- Checkbox

<?xml version="1.0" encoding="utf-8"?>
<DirectionalLayout
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:height="match_parent"
    ohos:width="match_parent"
    ohos:orientation="vertical">
    <Component
        ohos:height="0vp"
        ohos:weight="3"
        ohos:width="match_parent"
        />
    <DirectionalLayout
        xmlns:ohos="http://schemas.huawei.com/res/ohos"
        ohos:height="match_content"
        ohos:width="match_content"
        ohos:layout_alignment="center"
        ohos:orientation="vertical">
        <Image
            ohos:id="$+id:image"
            ohos:width="match_content"
            ohos:height="match_content"
            ohos:layout_alignment="center"
            ohos:image_src="$media:DevEco"
        />
        <TextField
            ohos:id="$+id:text_field"
            ohos:width="match_parent"
            ohos:height="30vp"
            ohos:text_size="20fp"
            ohos:text_alignment="center"
            ohos:hint="Please input text and press [Click me!] button."
            ohos:background_element="$graphic:background_text_field"
        />
        <Button
            ohos:id="$+id:hello_button"
            ohos:width="match_content"
            ohos:height="match_content"
            ohos:text_size="27fp"
            ohos:text="Click me!"
            ohos:layout_alignment="center"
            ohos:background_element="$graphic:background_button"
            ohos:margin="15vp"
            ohos:right_padding="8vp"
            ohos:left_padding="8vp"
            />
        <Checkbox
            ohos:id="$+id:check_box"
            ohos:height="match_content"
            ohos:width="match_content"
            ohos:layout_alignment="center"
            ohos:text="24小时制"
            ohos:text_size="20fp" />
        <TimePicker
            ohos:id="$+id:time_picker"
            ohos:24_hour_mode="false"
            ohos:height="match_content"
            ohos:width="match_parent"
            ohos:layout_alignment="horizontal_center"
            ohos:text_am="AM"
            ohos:text_pm="PM"
            ohos:normal_text_size="20fp"
            ohos:selected_text_size="25fp"/>
    </DirectionalLayout>
    <Component
        ohos:height="0vp"
        ohos:weight="5"
        ohos:width="match_parent"
        />
</DirectionalLayout>

package com.example.helloharmony.slice;
import com.example.helloharmony.ResourceTable;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.agp.components.*;
import ohos.agp.window.dialog.ToastDialog;
import java.time.LocalTime;
import java.time.temporal.ChronoUnit;

public class ComponentAbilitySlice extends AbilitySlice {
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_component);
        //获取textfield输入组件
        TextField tf = (TextField) findComponentById(ResourceTable.Id_text_field);
        //获取button组件
        Button button = (Button) findComponentById(ResourceTable.Id_hello_button);
        //获取Checkbox组件
        Checkbox check_box = (Checkbox)findComponentById(ResourceTable.Id_check_box);
        //获取TimePicker组件
        TimePicker picker = (TimePicker) findComponentById(ResourceTable.Id_time_picker);
        //根据Checkbox的状态设定TimePicker的形式。
        picker.set24Hour(check_box.isChecked());
        // 为按钮设置点击事件回调
        button.setClickedListener(new Component.ClickedListener() {
            public void onClick(Component v) {
                LocalTime rightNow = LocalTime.now();
                LocalTime pickTime = LocalTime.of(picker.getHour(), picker.getMinute(), picker.getSecond());
                String msg;
                if(pickTime.isBefore(rightNow))
                    msg = "所选时间比现在时刻早" + pickTime.until(rightNow, ChronoUnit.SECONDS) + "秒";
                else if(pickTime.isAfter(rightNow))
                    msg = "所选时间比现在时刻晚" + rightNow.until(pickTime, ChronoUnit.SECONDS) + "秒";
                else
                    msg = "所选时间和现在时刻一样";
                new ToastDialog(getContext())
                        .setText(msg)
                        .show();
            }
        });
        //为RadioContainer设置事件响应
        check_box.setCheckedStateChangedListener((view, state) -> {
            picker.set24Hour(state);
        });
        //为TimePicker设定事件响应
        picker.setTimeChangedListener(
            new TimePicker.TimeChangedListener() {
                @Override
                public void onTimeChanged(TimePicker timePicker, int hour, int minute, int second) {
                    tf.setText(hour + ":" + minute + ":" + second);
                }
            }
        );
    }
    @Override
    public void onActive() {
        super.onActive();
    }
    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }
}