android 如何画刻度圆
时间: 2024-02-27 22:56:40 浏览: 26
要在 Android 上画刻度圆,可以使用 Canvas 和 Paint 类。以下是一个简单的示例代码,可以画一个刻度圆:
```
public class GaugeView extends View {
private Paint mPaint;
private RectF mRectF;
private int mWidth, mHeight;
private int mRadius;
private int mStrokeWidth = 20;
private int mPadding = 50;
private int mTickCount = 20;
private int mTickLength = 50;
private int mStartAngle = 135;
private int mEndAngle = 405;
private int mIntervalAngle = (mEndAngle - mStartAngle) / (mTickCount - 1);
public GaugeView(Context context) {
super(context);
init();
}
public GaugeView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public GaugeView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeWidth(mStrokeWidth);
mRectF = new RectF();
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
mWidth = w;
mHeight = h;
mRadius = Math.min(mWidth, mHeight) / 2 - mPadding;
mRectF.set(mWidth / 2 - mRadius, mHeight / 2 - mRadius, mWidth / 2 + mRadius, mHeight / 2 + mRadius);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawArc(mRectF, mStartAngle, mEndAngle - mStartAngle, false, mPaint);
for (int i = 0; i < mTickCount; i++) {
int angle = mStartAngle + i * mIntervalAngle;
float startX = mWidth / 2 + (mRadius - mStrokeWidth / 2) * (float) Math.cos(angle * Math.PI / 180);
float startY = mHeight / 2 + (mRadius - mStrokeWidth / 2) * (float) Math.sin(angle * Math.PI / 180);
float stopX = mWidth / 2 + (mRadius - mStrokeWidth / 2 - mTickLength) * (float) Math.cos(angle * Math.PI / 180);
float stopY = mHeight / 2 + (mRadius - mStrokeWidth / 2 - mTickLength) * (float) Math.sin(angle * Math.PI / 180);
canvas.drawLine(startX, startY, stopX, stopY, mPaint);
}
}
}
```
在这个示例代码中,我们使用了一个自定义 View,重写了 onDraw 方法,使用 Canvas 和 Paint 绘制了刻度圆。具体来说,我们使用 drawArc 方法画了一个圆弧,然后使用 drawLine 方法画了刻度线。刻度线的位置和数量可以通过一些参数进行调整。最后,我们将这个自定义 View 添加到布局中即可。
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