Flutter的模拟时钟

Flutter的模拟时钟可以为你的应用程序增添一丝时尚和技术感。这篇文章将会为你介绍如何创建和自定义Flutter的模拟时钟。

创建Flutter的模拟时钟

创建Flutter的模拟时钟需要使用Flutter的绘画功能。我们需要在Flutter的canvas画板上绘制表盘和指针。

步骤一：创建画板

class ClockView extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      width: MediaQuery.of(context).size.width,
      height: MediaQuery.of(context).size.height,
      child: CustomPaint(
        painter: ClockPainter(),
      ),
    );
  }
}

步骤二：绘制表盘

class ClockPainter extends CustomPainter {
  @override
  void paint(Canvas canvas, Size size) {
    var centerX = size.width / 2;
    var centerY = size.height / 2;
    var radius = min(centerX, centerY);
    
    // 绘制表盘
    var dialPaint = Paint();
    dialPaint.color = Colors.white;
    dialPaint.strokeWidth = 20;
    dialPaint.strokeCap = StrokeCap.round;
    dialPaint.style = PaintingStyle.stroke;
    
    var dashBrush = Paint();
    dashBrush.color = Colors.grey;
    dashBrush.strokeWidth = 1;
    dashBrush.style = PaintingStyle.stroke;

    canvas.drawCircle(Offset(centerX, centerY), radius, dialPaint);
    
    var hourMarkLength = 10.0;
    var minuteMarkLength = 5.0;
    
    for (double i = 0; i < 360; i += 30) {
      var x1 = centerX + (radius - 28) * cos(radians(i));
      var y1 = centerY + (radius - 28) * sin(radians(i));
      var x2 = centerX + (radius - hourMarkLength) * cos(radians(i));
      var y2 = centerY + (radius - hourMarkLength) * sin(radians(i));

      canvas.drawLine(Offset(x1, y1), Offset(x2, y2), dashBrush);
    }
}

步骤三：绘制指针

class ClockPainter extends CustomPainter {
  @override
  void paint(Canvas canvas, Size size) {
    var centerX = size.width / 2;
    var centerY = size.height / 2;
    var radius = min(centerX, centerY);
    
    // 绘制表盘
    var dialPaint = Paint();
    dialPaint.color = Colors.white;
    dialPaint.strokeWidth = 20;
    dialPaint.strokeCap = StrokeCap.round;
    dialPaint.style = PaintingStyle.stroke;
    
    var dashBrush = Paint();
    dashBrush.color = Colors.grey;
    dashBrush.strokeWidth = 1;
    dashBrush.style = PaintingStyle.stroke;

    canvas.drawCircle(Offset(centerX, centerY), radius, dialPaint);
    
    var hourMarkLength = 10.0;
    var minuteMarkLength = 5.0;
    
    for (double i = 0; i < 360; i += 30) {
      var x1 = centerX + (radius - 28) * cos(radians(i));
      var y1 = centerY + (radius - 28) * sin(radians(i));
      var x2 = centerX + (radius - hourMarkLength) * cos(radians(i));
      var y2 = centerY + (radius - hourMarkLength) * sin(radians(i));

      canvas.drawLine(Offset(x1, y1), Offset(x2, y2), dashBrush);
    }
    
    // 绘制指针
    var hourHandPaint = Paint();
    hourHandPaint.color = Colors.black;
    hourHandPaint.style = PaintingStyle.stroke;
    hourHandPaint.strokeCap = StrokeCap.round;
    hourHandPaint.strokeWidth = 6;
    
    var minuteHandPaint = Paint();
    minuteHandPaint.color = Colors.black;
    minuteHandPaint.style = PaintingStyle.stroke;
    minuteHandPaint.strokeCap = StrokeCap.round;
    minuteHandPaint.strokeWidth = 4;

    var secondHandPaint = Paint();
    secondHandPaint.color = Colors.redAccent;
    secondHandPaint.style = PaintingStyle.stroke;
    secondHandPaint.strokeCap = StrokeCap.round;
    secondHandPaint.strokeWidth = 2;
    
    var dateTime = DateTime.now();
    var hourHandX = centerX + 50 * cos(radians(dateTime.hour * 30 + dateTime.minute * 0.5));
    var hourHandY = centerY + 50 * sin(radians(dateTime.hour * 30 + dateTime.minute * 0.5));
    canvas.drawLine(Offset(centerX, centerY), Offset(hourHandX, hourHandY), hourHandPaint);

    var minuteHandX = centerX + 75 * cos(radians(dateTime.minute * 6));
    var minuteHandY = centerY + 75 * sin(radians(dateTime.minute * 6));
    canvas.drawLine(Offset(centerX, centerY), Offset(minuteHandX, minuteHandY), minuteHandPaint);

    var secondHandX = centerX + 75 * cos(radians(dateTime.second * 6));
    var secondHandY = centerY + 75 * sin(radians(dateTime.second * 6));
    canvas.drawLine(Offset(centerX, centerY), Offset(secondHandX, secondHandY), secondHandPaint);
  }
}

现在我们的Flutter模拟时钟已经完成，你可以把它添加到你的应用程序中！

自定义Flutter的模拟时钟

你可以自由地自定义Flutter的模拟时钟，例如，你可以更改表盘和指针的颜色和样式。下面是一些示例代码：

更改表盘颜色和样式

// 更改表盘颜色和样式
var dialPaint = Paint();
dialPaint.color = Colors.white;
dialPaint.strokeWidth = 20;
dialPaint.strokeCap = StrokeCap.round;
dialPaint.style = PaintingStyle.stroke;

更改指针颜色和样式

// 更改指针颜色和样式
var hourHandPaint = Paint();
hourHandPaint.color = Colors.black;
hourHandPaint.style = PaintingStyle.stroke;
hourHandPaint.strokeCap = StrokeCap.round;
hourHandPaint.strokeWidth = 6;

var minuteHandPaint = Paint();
minuteHandPaint.color = Colors.black;
minuteHandPaint.style = PaintingStyle.stroke;
minuteHandPaint.strokeCap = StrokeCap.round;
minuteHandPaint.strokeWidth = 4;

var secondHandPaint = Paint();
secondHandPaint.color = Colors.redAccent;
secondHandPaint.style = PaintingStyle.stroke;
secondHandPaint.strokeCap = StrokeCap.round;
secondHandPaint.strokeWidth = 2;

更改指针的位置和长度

// 更改指针的位置和长度
var hourHandX = centerX + 50 * cos(radians(dateTime.hour * 30 + dateTime.minute * 0.5));
var hourHandY = centerY + 50 * sin(radians(dateTime.hour * 30 + dateTime.minute * 0.5));
canvas.drawLine(Offset(centerX, centerY), Offset(hourHandX, hourHandY), hourHandPaint);

var minuteHandX = centerX + 75 * cos(radians(dateTime.minute * 6));
var minuteHandY = centerY + 75 * sin(radians(dateTime.minute * 6));
canvas.drawLine(Offset(centerX, centerY), Offset(minuteHandX, minuteHandY), minuteHandPaint);

var secondHandX = centerX + 75 * cos(radians(dateTime.second * 6));
var secondHandY = centerY + 75 * sin(radians(dateTime.second * 6));
canvas.drawLine(Offset(centerX, centerY), Offset(secondHandX, secondHandY), secondHandPaint);

现在你已经知道如何创建和自定义Flutter的模拟时钟了。祝你好运！