「Mac畅玩鸿蒙与硬件26」UI互动应用篇3 - 倒计时和提醒功能实现 原创

// CountdownPage.ets
@Component
export struct CountdownPage {
  @State timeLeft: number = 0; // 剩余时间
  @State initialTime: number = 0; // 初始时间
  @State isRunning: boolean = false; // 倒计时状态
  private intervalId: number | null = null; // 定时器 ID

  build() {
    Column({ space: 20 }) {
      Row() {
        Text("倒计时：")
          .fontSize(25)
          .fontWeight(FontWeight.Bold);
        Text(this.formatTime(this.timeLeft))
          .fontSize(25)
          .fontColor(Color.Red);
      }

      // 输入初始时间
      TextInput({ placeholder: "设置倒计时时间（秒）" })
        .type(InputType.Number)
        .onChange((value: string) => {
          if (!this.isRunning) {
            this.initialTime = parseInt(value) || 0;
            this.timeLeft = this.initialTime; // 更新剩余时间
          }
        });

      // 按钮交互行
      Row({ space: 20 }) {
        Button(this.isRunning ? '暂停' : '开始')
          .onClick(() => {
            if (this.isRunning) {
              this.stopCountdown();
            } else {
              this.startCountdown();
            }
          });

        Button('重置')
          .onClick(() => {
            this.resetCountdown();
          });
      }
      .justifyContent(FlexAlign.Center);

      // 提示倒计时结束
      if (this.timeLeft === 0 && this.isRunning) {
        Text("时间到！")
          .fontSize(30)
          .fontColor(Color.Green)
          .fontWeight(FontWeight.Bold);
      }
    }
    .padding(20)
    .height('100%')
    .width('100%')
    .alignItems(HorizontalAlign.Center);
  }

  private startCountdown() {
    if (this.timeLeft > 0) {
      this.isRunning = true;
      this.intervalId = setInterval(() => {
        if (this.timeLeft > 1) {
          this.timeLeft -= 1;
        } else {
          this.stopCountdown();
        }
      }, 1000);
    }
  }

  private stopCountdown() {
    this.isRunning = false;
    if (this.intervalId !== null) {
      clearInterval(this.intervalId);
      this.intervalId = null;
    }
  }

  private resetCountdown() {
    this.stopCountdown();
    this.timeLeft = this.initialTime; // 将倒计时重置为初始时间
  }

  private formatTime(time: number): string {
    return `${Math.floor(time / 60).toString().padStart(2, '0')}:${(time % 60).toString().padStart(2, '0')}`;
  }
}
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// Index.ets
import { CountdownPage } from './CountdownPage'

@Entry
@Component
struct Index {
  build() {
    Column() {
      CountdownPage() // 调用自定义组件
    }
    .padding(20) // 设置页面内边距
  }
}
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