自学鸿蒙应用开发(10)- Switch组件
本文介绍在鸿蒙应用中Switch组件的基本用法。
增加Switch组件
如下代码中57行~66行所示,在布局中增加Switch组件。
<DirectionalLayoutxmlns:ohos="http://schemas.huawei.com/res/ohos"ohos:height="match_parent"ohos:width="match_parent"ohos:orientation="vertical"><Componentohos:height="0vp"ohos:weight="3"ohos:width="match_parent"/><DirectionalLayoutxmlns:ohos="http://schemas.huawei.com/res/ohos"ohos:height="match_content"ohos:width="match_content"ohos:layout_alignment="center"ohos:orientation="vertical"><Imageohos:id="$+id:image"ohos:width="match_content"ohos:height="match_content"ohos:layout_alignment="center"ohos:image_src="$media:DevEco"/><TextFieldohos: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"/><Buttonohos: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"/><DirectionalLayoutohos:height="match_content"ohos:width="match_content"ohos:layout_alignment="center"ohos:orientation="horizontal"><Textohos:id="$+id:text_pick_type"ohos:height="match_content"ohos:width="match_content"ohos:text="时间类型:"ohos:text_size="20fp"/><Switchohos:id="$+id:btn_switch"ohos:text_state_off="12H"ohos:text_color="#FFFFFF"ohos:text_state_on="24H"ohos:text_size="20fp"ohos:height="match_content"ohos:width="match_content"/>DirectionalLayout><TimePickerohos: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><Componentohos:height="0vp"ohos:weight="5"ohos:width="match_parent"/>DirectionalLayout>
代码中组件id被指定为btn_switch,会在下面的响应代码中用到。
在代码中使用Switch组件
如下面代码中20行和42行~49行所示,在获取Switch组件后,在Switch响应处理中根据Switch的当前状态为TimePicker设定是否像是为24小时制。
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 {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);Switch btnSwitch = (Switch) findComponentById(ResourceTable.Id_btn_switch);//获取datepicker组件TimePicker picker = (TimePicker) findComponentById(ResourceTable.Id_time_picker);picker.set24Hour(btnSwitch.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";elsemsg = "所选时间和现在时刻一样";new ToastDialog(getContext()).setText(msg).show();}});//为Switch设置事件响应btnSwitch.setCheckedStateChangedListener(new AbsButton.CheckedStateChangedListener() {// 回调处理Switch状态改变事件public void onCheckedChanged(AbsButton button, boolean isChecked) {picker.set24Hour(isChecked);}});//为TimePicker设定事件响应picker.setTimeChangedListener(new TimePicker.TimeChangedListener() {public void onTimeChanged(TimePicker timePicker, int hour, int minute, int second) {tf.setText(hour + ":" + minute + ":" + second);}});}public void onActive() {super.onActive();}public void onForeground(Intent intent) {super.onForeground(intent);}}
画面显示如下:
参考文档
Switch组件:
https://developer.harmonyos.com/cn/docs/documentation/doc-guides/ui-java-component-switch-0000001060806006
Switch类:
https://developer.harmonyos.com/cn/docs/documentation/doc-references/switch-0000001054199994
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