《HarmonyOS Next 开发进阶：打造功能完备的 Todo 应用华章》

@Entry@Componentstruct DatePickerDemo {  @State selectedDate: Date = new Date();  @State showDatePicker: boolean = false;
  formatDate(date: Date): string {    return `${date.getFullYear()}-${(date.getMonth() + 1).toString().padStart(2, '0')}-${date.getDate().toString().padStart(2, '0')}`;  }
  build() {    Column() {      Text('选择日期: ' + this.formatDate(this.selectedDate))        .margin({ bottom: 16 })
      Button('选择日期')        .onClick(() => { this.showDatePicker = true; })
      if (this.showDatePicker) {        DatePicker({          start: new Date('2020-01-01'),          end: new Date('2030-12-31'),          selected: this.selectedDate,        })          .onChange((value: DatePickerInfo) => {            this.selectedDate = new Date(value.year, value.month - 1, value.day);          })          .margin({ bottom: 16 })      }    }  }}

@Entry@Componentstruct TaskStatistics {  @State todoList: TodoItem[] = [    new TodoItem('任务1', Priority.HIGH),    new TodoItem('任务2', Priority.MEDIUM),    new TodoItem('任务3', Priority.LOW)  ];
  getCompletionPercentage(): number {    if (this.todoList.length === 0) return 0;    const completedCount = this.todoList.filter(item => item.isCompleted).length;    return Math.round((completedCount / this.todoList.length) * 100);  }
  getPriorityStats(): PriorityStatItem[] {    const highStat: PriorityStatItem = { priority: Priority.HIGH, count: 0, color: '#FF3B30' };    const mediumStat: PriorityStatItem = { priority: Priority.MEDIUM, count: 0, color: '#FF9500' };    const lowStat: PriorityStatItem = { priority: Priority.LOW, count: 0, color: '#34C759' };
    this.todoList.forEach(item => {      switch (item.priority) {        case Priority.HIGH: highStat.count++; break;        case Priority.MEDIUM: mediumStat.count++; break;        case Priority.LOW: lowStat.count++; break;      }    });
    return [highStat, mediumStat, lowStat];  }
  build() {    Column() {      Text('任务统计')        .fontSize(24)        .fontWeight(FontWeight.Bold)        .margin({ bottom: 16 })
      Text(`完成率: ${this.getCompletionPercentage()}%`)        .margin({ bottom: 16 })
      ForEach(this.getPriorityStats(), (stat: PriorityStatItem) => {        Row() {          Circle()            .fill(stat.color)            .width(12)            .height(12)            .margin({ right: 8 })          Text(`${stat.priority}: ${stat.count} 个`)        }        .margin({ bottom: 8 })      })    }  }}

import vibrator from '@ohos.vibrator';
@Entry@Componentstruct VibrationDemo {  vibrateShort() {    try {      vibrator.vibrate(10);    } catch (error) {      console.error('Failed to vibrate:', error);    }  }
  build() {    Column() {      Text('点击按钮体验振动反馈')        .margin({ bottom: 16 })
      Button('短振动')        .onClick(() => this.vibrateShort())    }  }}

import promptAction from '@ohos.promptAction';
@Entry@Componentstruct DialogDemo {  async showConfirmationDialog() {    try {      const dialogButtons: Array<DialogButton> = [        { text: '取消', color: '#8E8E93' },        { text: '确定', color: '#FF3B30' }      ];
      const options: promptAction.ShowDialogOptions = {        title: '确认删除',        message: '确定要删除此任务吗？',        buttons: dialogButtons      };
      const result = await promptAction.showDialog(options);      if (result && result.index === 1) {        console.log('用户确认删除');      }    } catch (error) {      console.error('对话框显示失败:', error);    }  }
  build() {    Column() {      Text('点击按钮显示对话框')        .margin({ bottom: 16 })
      Button('删除任务')        .onClick(() => this.showConfirmationDialog())    }  }}