自绘View(时钟)

public class ClockView extends View {

//绘制表盘的画笔

private Paint circlePaint;

//绘制表盘圆心的画笔

private Paint dotPaint;

//绘制表盘上竖线的画笔

private Paint linePaint;

//绘制表盘文本的画笔

private Paint textPaint;

private Paint hourPaint;

private Paint minPaint;

private Paint secPaint;

private Calendar calendar;

//new一个控件时调用

public ClockView(Context context) {

this(context, null);

}

//在xml文件中定义控件，则会调用这个方法

public ClockView(Context context, AttributeSet attrs) {

this(context, attrs, 0);

}

//该方法一般由系统调用，调用时给View设置了默认风格属性

public ClockView(Context context, AttributeSet attrs, int defStyleAttr) {

super(context, attrs, defStyleAttr);

circlePaint = new Paint();

//设置画笔的颜色

circlePaint.setColor(Color.GREEN);

//设置画笔风格为描边

circlePaint.setStyle(Paint.Style.STROKE);

//设置画笔宽度

circlePaint.setStrokeWidth(4);

//去锯齿

circlePaint.setAntiAlias(true);

dotPaint = new Paint();

dotPaint.setColor(Color.RED);

dotPaint.setStyle(Paint.Style.FILL);

dotPaint.setAntiAlias(true);

linePaint = new Paint();

linePaint.setColor(Color.GREEN);

linePaint.setAntiAlias(true);

linePaint.setStrokeWidth(4);

textPaint = new Paint();

textPaint.setAntiAlias(true);

textPaint.setTextSize(18);

textPaint.setColor(Color.RED);

textPaint.setTextAlign(Paint.Align.CENTER);

hourPaint = new Paint();

hourPaint.setColor(Color.BLUE);

hourPaint.setStrokeWidth(6);

hourPaint.setAntiAlias(true);

minPaint = new Paint();

minPaint.setColor(Color.GREEN);

minPaint.setStrokeWidth(3);

secPaint = new Paint();

secPaint.setColor(Color.RED);

secPaint.setStrokeWidth(1);

calendar = Calendar.getInstance();

}

//绘制控件

// super.onDraw(canvas);，自绘View中删与不删都行，继承现有控件增强其功能时不可以删除

@Override

protected void onDraw(Canvas canvas) {

//获取控件的宽高

int width = getWidth();

int height = getHeight();

int radius = width / 2;

canvas.drawCircle(width / 2, height / 2, radius - 2, circlePaint);

canvas.drawCircle(radius, radius, 20, dotPaint);

for (int i = 1; i < 13; i++) {

//画布旋转之前，先将画布上已经画好的东西保存下来

canvas.save();

//第一个参数表示旋转度数

//第二三个参数表示旋转中心点

canvas.rotate(i * 30, radius, radius);

canvas.drawLine(width / 2, 3, width / 2, 13, linePaint);

//1.要绘制的文本

//2.文本的X轴中心点，如果在画笔中没有设置setTextAlign属性，则该参数表示文本的起始位置

//3.文本的基线

//4.画笔

canvas.drawText(i + "", width / 2, 35, textPaint);

//画布旋转角度复原

canvas.restore();

}

calendar = Calendar.getInstance();

int hour = calendar.get(Calendar.HOUR);

int minute = calendar.get(Calendar.MINUTE);

canvas.save();

canvas.rotate(hour * 30 + minute / 2, radius, radius);

canvas.drawLine(width / 2, height / 2 + 40, width / 2, 100, hourPaint);

canvas.restore();

canvas.save();

canvas.rotate(minute * 6, radius, radius);

canvas.drawLine(width / 2, height / 2 + 45, width / 2, 80, minPaint);

canvas.restore();

int second = calendar.get(Calendar.SECOND);

canvas.save();

canvas.rotate(second * 6, radius, radius);

canvas.drawLine(width / 2, height / 2 + 50, width / 2, 60, secPaint);

canvas.restore();

postInvalidateDelayed(1000);

}

好了现在把它放到XML里面就可以了，大家都来试试吧

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