本文介绍在鸿蒙应用中Switch组件的基本用法。
Swtich
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。
<?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" /> <DirectionalLayout ohos:height="match_content" ohos:width="match_content" ohos:layout_alignment="center" ohos:orientation="horizontal"> <Text ohos:id="$+id:text_pick_type" ohos:height="match_content" ohos:width="match_content" ohos:text="时间类型：" ohos:text_size="20fp"/> <Switch ohos:id="$+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> <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>
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 { @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); 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"; else msg = "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 @Override public void onCheckedChanged(AbsButton button, boolean isChecked) { picker.set24Hour(isChecked); } }); //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); }}
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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