自学鸿蒙应用开发（8）- DatePicker组件

<?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"
            />
        <DatePicker
            ohos:id="$+id:date_pick"
            ohos:height="match_content"
            ohos:width="300vp"
            ohos:text_size="20fp"
            ohos:selected_text_size="40fp">
        </DatePicker>
    </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.Button;
import ohos.agp.components.Component;
import ohos.agp.components.DatePicker;
import ohos.agp.components.TextField;
import ohos.agp.window.dialog.ToastDialog;
import java.time.LocalDate;

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datepicker组件
        DatePicker picker = (DatePicker) findComponentById(ResourceTable.Id_date_pick);
        // 为按钮设置点击事件回调
        button.setClickedListener(new Component.ClickedListener() {
            public void onClick(Component v) {
                LocalDate rightNow = LocalDate.now();
                LocalDate pickDate = LocalDate.of(picker.getYear(), picker.getMonth(), picker.getDayOfMonth());
                String msg;
                if(pickDate.isBefore(rightNow))
                    msg = "所选日期比今天早" + pickDate.until(LocalDate.now()).getDays() + "天";
                else if(pickDate.isAfter(rightNow))
                    msg = "所选日期比今天晚" + LocalDate.now().until(pickDate).getDays() + "天";
                else
                    msg = "所选日期和今天是同一天";

                new ToastDialog(getContext())
                        .setText(msg)
                        .show();
            }
        });
        //设定事件响应
        picker.setValueChangedListener(
            new DatePicker.ValueChangedListener() {
                @Override
                public void onValueChanged(DatePicker datePicker, int year, int monthOfYear, int dayOfMonth) {
                    tf.setText(year+"/"+monthOfYear+"/"+dayOfMonth);
                }
            }
        );
    }
    @Override
    public void onActive() {
        super.onActive();
    }
    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }
}