自学鸿蒙应用开发(10)- Switch组件
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·
2021-01-04 17:46
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。
<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 {
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
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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