带你体验Android自定义圆形刻度罗盘 仪表盘 实现指针动态改变
近期有一个自定义View的功能,类似于仪表盘的模型,可以将指针动态指定到某一个刻度上,话不多说,先上图
先说下思路
1.先获取自定义的一些属性,初始化一些资源
2.在onMeasure中测量控件的具体大小
3.然后就在onDraw中先绘制有渐变色的圆弧形色带
4.再绘制几个大的刻度和刻度值
5.再绘制两个大刻度之间的小刻度
6.再绘制处于正中间的圆和三角形指针
7.最后绘制实时值
其实这也从侧面体现了一个自定义view的流程
1.继承View,重写构造方法
2.加载自定义属性和其它资源
3.重写onMeasure方法去确定控件的大小
4.重写onDraw方法去绘制
5.如果有点击事件的话,还得重写onTouchEvent或者dispatchTouchEvent去处理点击事件
来上代码吧,具体注释已经写的很详细了
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public class NoiseboardView extends View {
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final String TAG = "NoiseboardView";
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private int mRadius; // 圆弧半径
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private int mBigSliceCount; // 大份数
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private int mScaleCountInOneBigScale; // 相邻两个大刻度之间的小刻度个数
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private int mScaleColor; // 刻度颜色
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private int mScaleTextSize; // 刻度字体大小
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private String mUnitText = ""; // 单位
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private int mUnitTextSize; // 单位字体大小
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private int mMinValue; // 最小值
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private int mMaxValue; // 最大值
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private int mRibbonWidth; // 色条宽
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private int mStartAngle; // 起始角度
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private int mSweepAngle; // 扫过角度
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private int mPointerRadius; // 三角形指针半径
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private int mCircleRadius; // 中心圆半径
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private float mRealTimeValue = 0.0f; // 实时值
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private int mBigScaleRadius; // 大刻度半径
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private int mSmallScaleRadius; // 小刻度半径
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private int mNumScaleRadius; // 数字刻度半径
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private int mViewColor_green; // 字体颜色
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private int mViewColor_yellow; // 字体颜色
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private int mViewColor_orange; // 字体颜色
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private int mViewColor_red; // 字体颜色
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private int mViewWidth; // 控件宽度
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private int mViewHeight; // 控件高度
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private float mCenterX;//中心点圆坐标x
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private float mCenterY;//中心点圆坐标y
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private Paint mPaintScale;//圆盘上大小刻度画笔
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private Paint mPaintScaleText;//圆盘上刻度值画笔
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private Paint mPaintCirclePointer;//绘制中心圆,指针
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private Paint mPaintValue;//绘制实时值
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private Paint mPaintRibbon;//绘制色带
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private RectF mRectRibbon;//存储色带的矩形数据
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private Rect mRectScaleText;//存储刻度值的矩形数据
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private Path path;//绘制指针的路径
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private int mSmallScaleCount; // 小刻度总数
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private float mBigScaleAngle; // 相邻两个大刻度之间的角度
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private float mSmallScaleAngle; // 相邻两个小刻度之间的角度
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private String[] mGraduations; // 每个大刻度的刻度值
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private float initAngle;//指针实时角度
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private SweepGradient mSweepGradient ;//设置渐变
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private int[] color = new int[7];//渐变颜色组
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public NoiseboardView(Context context) {
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this(context, null);
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}
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public NoiseboardView(Context context, AttributeSet attrs) {
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this(context, attrs, 0);
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}
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public NoiseboardView(Context context, AttributeSet attrs, int defStyleAttr) {
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super(context, attrs, defStyleAttr);
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//自定义属性
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TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.NoiseboardView, defStyleAttr, 0);
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mRadius = a.getDimensionPixelSize(R.styleable.NoiseboardView_radius, dpToPx(80));
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mBigSliceCount = a.getInteger(R.styleable.NoiseboardView_bigSliceCount, 5);
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mScaleCountInOneBigScale = a.getInteger(R.styleable.NoiseboardView_sliceCountInOneBigSlice, 5);
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mScaleColor = a.getColor(R.styleable.NoiseboardView_scaleColor, Color.WHITE);
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mScaleTextSize = a.getDimensionPixelSize(R.styleable.NoiseboardView_scaleTextSize, spToPx(12));
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mUnitText = a.getString(R.styleable.NoiseboardView_unitText);
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mUnitTextSize = a.getDimensionPixelSize(R.styleable.NoiseboardView_unitTextSize, spToPx(14));
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mMinValue = a.getInteger(R.styleable.NoiseboardView_minValue, 0);
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mMaxValue = a.getInteger(R.styleable.NoiseboardView_maxValue, 150);
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mRibbonWidth = a.getDimensionPixelSize(R.styleable.NoiseboardView_ribbonWidth, 0);
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a.recycle();
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init();
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}
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private void init() {
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//起始角度是从水平正方向即(钟表3点钟方向)开始从0算的,扫过的角度是按顺时针方向算
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mStartAngle = 175;
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mSweepAngle = 190;
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mPointerRadius = mRadius / 3 * 2;
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mCircleRadius = mRadius / 17;
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mSmallScaleRadius = mRadius - dpToPx(10);
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mBigScaleRadius = mRadius - dpToPx(18);
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mNumScaleRadius = mRadius - dpToPx(20);
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mSmallScaleCount = mBigSliceCount * 5;
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mBigScaleAngle = mSweepAngle / (float) mBigSliceCount;
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mSmallScaleAngle = mBigScaleAngle / mScaleCountInOneBigScale;
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mGraduations = getMeasureNumbers();
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//确定控件的宽度 padding值,在构造方法执行完就被赋值
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mViewWidth = getPaddingLeft() + mRadius * 2 + getPaddingRight() + dpToPx(4);
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mViewHeight = mViewWidth;
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mCenterX = mViewWidth / 2.0f;
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mCenterY = mViewHeight / 2.0f;
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mPaintScale = new Paint();
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mPaintScale.setAntiAlias(true);
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mPaintScale.setColor(mScaleColor);
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mPaintScale.setStyle(Paint.Style.STROKE);
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mPaintScale.setStrokeCap(Paint.Cap.ROUND);
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mPaintScaleText = new Paint();
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mPaintScaleText.setAntiAlias(true);
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mPaintScaleText.setColor(mScaleColor);
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mPaintScaleText.setStyle(Paint.Style.STROKE);
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mPaintCirclePointer = new Paint();
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mPaintCirclePointer.setAntiAlias(true);
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mRectScaleText = new Rect();
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path = new Path();
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mPaintValue = new Paint();
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mPaintValue.setAntiAlias(true);
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mPaintValue.setStyle(Paint.Style.STROKE);
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mPaintValue.setTextAlign(Paint.Align.CENTER);
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mPaintValue.setTextSize(mUnitTextSize);
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initAngle = getAngleFromResult(mRealTimeValue);
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mViewColor_green = getResources().getColor(R.color.green_value);
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mViewColor_yellow = getResources().getColor(R.color.yellow_value);
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mViewColor_orange = getResources().getColor(R.color.orange_value);
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mViewColor_red = getResources().getColor(R.color.red_value);
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color[0] = mViewColor_red;
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color[1] = mViewColor_red;
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color[2] = mViewColor_green;
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color[3] = mViewColor_green;
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color[4] = mViewColor_yellow;
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color[5] = mViewColor_orange;
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color[6] = mViewColor_red;
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//色带画笔
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mPaintRibbon = new Paint();
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mPaintRibbon.setAntiAlias(true);
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mPaintRibbon.setStyle(Paint.Style.STROKE);
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mPaintRibbon.setStrokeWidth(mRibbonWidth);
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mSweepGradient = new SweepGradient(mCenterX, mCenterY,color,null);
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mPaintRibbon.setShader(mSweepGradient);//设置渐变 从X轴正方向取color数组颜色开始渐变
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if (mRibbonWidth > 0) {
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int r = mRadius - mRibbonWidth / 2 + dpToPx(1) ;
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mRectRibbon = new RectF(mCenterX - r, mCenterY - r, mCenterX + r, mCenterY + r);
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}
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}
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/**
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* 确定每个大刻度的值
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* @return
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*/
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private String[] getMeasureNumbers() {
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String[] strings = new String[mBigSliceCount + 1];
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for (int i = 0; i <= mBigSliceCount; i++) {
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if (i == 0) {
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strings[i] = String.valueOf(mMinValue);
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} else if (i == mBigSliceCount) {
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strings[i] = String.valueOf(mMaxValue);
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} else {
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strings[i] = String.valueOf(((mMaxValue - mMinValue) / mBigSliceCount) * i);
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}
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}
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return strings;
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}
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/**
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* <dt>UNSPECIFIED : 0 << 30 = 0</dt>
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* <dd>
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* 父控件没有对子控件做限制,子控件可以是自己想要的尺寸
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* 其实就是子空间在布局里没有设置宽高,但布局里添加控件都要设置宽高,所以这种情况暂时没碰到
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* </dd>
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*
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* <dt>EXACTLY : 1 << 30 = 1073741824</dt>
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* <dd>
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* 父控件给子控件决定了确切大小,子控件将被限定在给定的边界里。
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* 如果是填充父窗体(match_parent),说明父控件已经明确知道子控件想要多大的尺寸了,也是这种模式
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* </dd>
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*
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* <dt>AT_MOST : 2 << 30 = -2147483648</dt>
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* <dd>
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* 在布局设置wrap_content,父控件并不知道子控件到底需要多大尺寸(具体值),
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* 需要子控件在onMeasure测量之后再让父控件给他一个尽可能大的尺寸以便让内容全部显示
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* 如果在onMeasure没有指定控件大小,默认会填充父窗体,因为在view的onMeasure源码中,
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* AT_MOST(相当于wrap_content )和EXACTLY (相当于match_parent )两种情况返回的测量宽高都是specSize,
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* 而这个specSize正是父控件剩余的宽高,所以默认onMeasure方法中wrap_content 和match_parent 的效果是一样的,都是填充剩余的空间。
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* </dd>
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*
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* @param widthMeasureSpec
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* @param heightMeasureSpec
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*/
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@Override
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protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
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int widthMode = MeasureSpec.getMode(widthMeasureSpec);//从约束规范中获取模式
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int widthSize = MeasureSpec.getSize(widthMeasureSpec);//从约束规范中获取尺寸
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int heightMode = MeasureSpec.getMode(heightMeasureSpec);
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int heightSize = MeasureSpec.getSize(heightMeasureSpec);
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//在布局中设置了具体值
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if (widthMode == MeasureSpec.EXACTLY)
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mViewWidth = widthSize;
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//在布局中设置 wrap_content,控件就取能完全展示内容的宽度(同时需要考虑屏幕的宽度)
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if (widthMode == MeasureSpec.AT_MOST)
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mViewWidth = Math.min(mViewWidth, widthSize);
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if (heightMode == MeasureSpec.EXACTLY) {
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mViewHeight = heightSize;
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} else {
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float[] point1 = getCoordinatePoint(mRadius, mStartAngle);
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float[] point2 = getCoordinatePoint(mRadius, mStartAngle + mSweepAngle);
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float maxY = Math.max(Math.abs(point1[1]) - mCenterY, Math.abs(point2[1]) - mCenterY);
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float f = mCircleRadius + dpToPx(2) + dpToPx(25) ;
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float max = Math.max(maxY, f);
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mViewHeight = (int) (max + mRadius + getPaddingTop() + getPaddingBottom() + dpToPx(2) * 2);
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if (heightMode == MeasureSpec.AT_MOST)
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mViewHeight = Math.min(mViewHeight, heightSize);
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}
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//保存测量宽度和测量高度
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setMeasuredDimension(mViewWidth, mViewHeight);
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}
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@Override
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protected void onDraw(Canvas canvas) {
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// 绘制色带
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canvas.drawArc(mRectRibbon, 170, 199, false, mPaintRibbon);
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mPaintScale.setStrokeWidth(dpToPx(2));
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for (int i = 0; i <= mBigSliceCount; i++) {
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//绘制大刻度
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float angle = i * mBigScaleAngle + mStartAngle;
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float[] point1 = getCoordinatePoint(mRadius, angle);
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float[] point2 = getCoordinatePoint(mBigScaleRadius, angle);
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canvas.drawLine(point1[0], point1[1], point2[0], point2[1], mPaintScale);
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//绘制圆盘上的数字
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mPaintScaleText.setTextSize(mScaleTextSize);
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String number = mGraduations[i];
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mPaintScaleText.getTextBounds(number, 0, number.length(), mRectScaleText);
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if (angle % 360 > 135 && angle % 360 < 215) {
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mPaintScaleText.setTextAlign(Paint.Align.LEFT);
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} else if ((angle % 360 >= 0 && angle % 360 < 45) || (angle % 360 > 325 && angle % 360 <= 360)) {
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mPaintScaleText.setTextAlign(Paint.Align.RIGHT);
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} else {
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mPaintScaleText.setTextAlign(Paint.Align.CENTER);
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}
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float[] numberPoint = getCoordinatePoint(mNumScaleRadius, angle);
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if (i == 0 || i == mBigSliceCount) {
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canvas.drawText(number, numberPoint[0], numberPoint[1] + (mRectScaleText.height() / 2), mPaintScaleText);
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} else {
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canvas.drawText(number, numberPoint[0], numberPoint[1] + mRectScaleText.height(), mPaintScaleText);
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}
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}
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//绘制小的子刻度
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mPaintScale.setStrokeWidth(dpToPx(1));
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for (int i = 0; i < mSmallScaleCount; i++) {
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if (i % mScaleCountInOneBigScale != 0) {
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float angle = i * mSmallScaleAngle + mStartAngle;
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float[] point1 = getCoordinatePoint(mRadius, angle);
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float[] point2 = getCoordinatePoint(mSmallScaleRadius, angle);
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mPaintScale.setStrokeWidth(dpToPx(1));
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canvas.drawLine(point1[0], point1[1], point2[0], point2[1], mPaintScale);
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}
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}
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if (mRealTimeValue <= 40) {
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mPaintValue.setColor(mViewColor_green);
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mPaintCirclePointer.setColor(mViewColor_green);
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} else if (mRealTimeValue > 40 && mRealTimeValue <= 90) {
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mPaintValue.setColor(mViewColor_yellow);
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mPaintCirclePointer.setColor(mViewColor_yellow);
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} else if (mRealTimeValue > 90 && mRealTimeValue <= 120) {
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mPaintValue.setColor(mViewColor_orange);
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mPaintCirclePointer.setColor(mViewColor_orange);
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} else {
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mPaintValue.setColor(mViewColor_red);
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mPaintCirclePointer.setColor(mViewColor_red);
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}
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//绘制中心点的圆
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mPaintCirclePointer.setStyle(Paint.Style.STROKE);
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mPaintCirclePointer.setStrokeWidth(dpToPx(4));
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canvas.drawCircle(mCenterX, mCenterY, mCircleRadius + dpToPx(3), mPaintCirclePointer);
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//绘制三角形指针
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path.reset();
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mPaintCirclePointer.setStyle(Paint.Style.FILL);
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float[] point1 = getCoordinatePoint(mCircleRadius / 2, initAngle + 90);
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path.moveTo(point1[0], point1[1]);
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float[] point2 = getCoordinatePoint(mCircleRadius / 2, initAngle - 90);
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path.lineTo(point2[0], point2[1]);
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float[] point3 = getCoordinatePoint(mPointerRadius, initAngle);
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path.lineTo(point3[0], point3[1]);
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path.close();
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canvas.drawPath(path, mPaintCirclePointer);
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// 绘制三角形指针底部的圆弧效果
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canvas.drawCircle((point1[0] + point2[0]) / 2, (point1[1] + point2[1]) / 2, mCircleRadius / 2, mPaintCirclePointer);
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//绘制实时值
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canvas.drawText(trimFloat(mRealTimeValue)+" "+ mUnitText, mCenterX, mCenterY - mRadius / 3 , mPaintValue);
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}
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private int dpToPx(int dp) {
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return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, getResources().getDisplayMetrics());
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}
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private int spToPx(int sp) {
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return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, sp, getResources().getDisplayMetrics());
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}
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/**
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* 依圆心坐标,半径,扇形角度,计算出扇形终射线与圆弧交叉点的xy坐标
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*/
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public float[] getCoordinatePoint(int radius, float cirAngle) {
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float[] point = new float[2];
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double arcAngle = Math.toRadians(cirAngle); //将角度转换为弧度
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if (cirAngle < 90) {
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point[0] = (float) (mCenterX + Math.cos(arcAngle) * radius);
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point[1] = (float) (mCenterY + Math.sin(arcAngle) * radius);
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} else if (cirAngle == 90) {
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point[0] = mCenterX;
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point[1] = mCenterY + radius;
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} else if (cirAngle > 90 && cirAngle < 180) {
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arcAngle = Math.PI * (180 - cirAngle) / 180.0;
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point[0] = (float) (mCenterX - Math.cos(arcAngle) * radius);
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point[1] = (float) (mCenterY + Math.sin(arcAngle) * radius);
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} else if (cirAngle == 180) {
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point[0] = mCenterX - radius;
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point[1] = mCenterY;
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} else if (cirAngle > 180 && cirAngle < 270) {
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arcAngle = Math.PI * (cirAngle - 180) / 180.0;
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point[0] = (float) (mCenterX - Math.cos(arcAngle) * radius);
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point[1] = (float) (mCenterY - Math.sin(arcAngle) * radius);
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} else if (cirAngle == 270) {
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point[0] = mCenterX;
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point[1] = mCenterY - radius;
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} else {
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arcAngle = Math.PI * (360 - cirAngle) / 180.0;
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point[0] = (float) (mCenterX + Math.cos(arcAngle) * radius);
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point[1] = (float) (mCenterY - Math.sin(arcAngle) * radius);
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}
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Log.e("getCoordinatePoint","radius="+radius+",cirAngle="+cirAngle+",point[0]="+point[0]+",point[1]="+point[1]);
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return point;
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}
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/**
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* 通过实时数值得到指针角度
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*/
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private float getAngleFromResult(float result) {
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if (result > mMaxValue)
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return 360.0f;
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return mSweepAngle * (result - mMinValue) / (mMaxValue - mMinValue) + mStartAngle;
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}
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/**
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* float类型如果小数点后为零则显示整数否则保留
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*/
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public static String trimFloat(float value) {
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if (Math.round(value) - value == 0) {
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return String.valueOf((long) value);
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}
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return String.valueOf(value);
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}
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public float getRealTimeValue() {
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return mRealTimeValue;
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}
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/**
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* 实时设置读数值
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* @param realTimeValue
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*/
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public void setRealTimeValue(float realTimeValue) {
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if (realTimeValue > mMaxValue) return;
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mRealTimeValue = realTimeValue;
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initAngle = getAngleFromResult(mRealTimeValue);
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invalidate();
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}
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}
具体代码请看Github
没有梯子请点击这里下载