Android自定义View中使用Spannable的实例详解

/**
 * A base class that manages text layout in visual elements on
 * the screen.
 * 
For text that will be edited, use a {@link DynamicLayout},
 * which will be updated as the text changes.
 * For text that will not change, use a {@link StaticLayout}.
 */
public abstract class Layout {
 
}

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public class ArcProgressView extends View {
 private int arcBackgroundColor; // 圆弧背景颜色
 private int arcProgressColor;  // 圆弧进度颜色
 private int arcSubTitleColor;  // 副标题颜色
 private float arcStrokeWidth;  // 圆弧线的厚度
 private float arcTitleTextSize; // 标题文字大小
 private float arcSubTitleTextSize; // 副标题文字大小
 private float arcProgress; // 进度
 private int arcTitleNumber; // 值
 private Paint paint;
 private float centerX;
 private float centerY;
 private float radius; // 半径
 private RectF rectF;
 private int startAngle = 135;
 private int sweepAngle = 270;
 private String subTitle = "1月份";
 private SpannableString spannableString;
 private TextPaint textPaint;
 private RelativeSizeSpan relativeSizeSpan;
 private DynamicLayout dynamicLayout;
 private String text = "11分";
 private StyleSpan styleSpan;
 private float curProgress; // 当前进度
 private int curNumber;
 public ArcProgressView(Context context) {
  this(context, null);
 }
 public ArcProgressView(Context context, @Nullable AttributeSet attrs) {
  this(context, attrs, 0);
 }
 public ArcProgressView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  readAttrs(context, attrs);
  init(context);
 }
 private void readAttrs(Context context, AttributeSet attributeSet) {
  TypedArray typedArray = context.obtainStyledAttributes(attributeSet, R.styleable.ArcProgressView);
  arcBackgroundColor = typedArray.getColor(R.styleable.ArcProgressView_arcBackgroundColor, 0x1c979797);
  arcProgressColor = typedArray.getColor(R.styleable.ArcProgressView_arcProgressColor, 0xff3372FF);
  arcSubTitleColor = typedArray.getColor(R.styleable.ArcProgressView_arcSubTitleColor, 0x66000000);
  arcStrokeWidth = typedArray.getDimensionPixelSize(R.styleable.ArcProgressView_arcStrokeWidth, dp2px(5));
  arcTitleTextSize = typedArray.getDimensionPixelSize(R.styleable.ArcProgressView_arcTitleTextSize, dp2px(30));
  arcSubTitleTextSize = typedArray.getDimensionPixelSize(R.styleable.ArcProgressView_arcSubTitleTextSize, dp2px(14));
  arcProgress = typedArray.getFloat(R.styleable.ArcProgressView_arcProgress, 1.0f);
  arcTitleNumber = typedArray.getInt(R.styleable.ArcProgressView_arcTitleNumber, 100);
  typedArray.recycle();
 }
 private void init(Context context) {
  paint = new Paint(Paint.ANTI_ALIAS_FLAG);
  paint.setStrokeCap(Paint.Cap.ROUND);
  relativeSizeSpan = new RelativeSizeSpan(0.6f);
  styleSpan = new StyleSpan(android.graphics.Typeface.BOLD);
  textPaint = new TextPaint(TextPaint.ANTI_ALIAS_FLAG);
  textPaint.setColor(arcProgressColor);
//  textPaint.setTextAlign(Paint.Align.CENTER); // 设置该属性导致文字间有间隔
  textPaint.setTextSize(sp2px(22));
 }
 @Override
 protected void onSizeChanged(int w, int h, int oldw, int oldh) {
  super.onSizeChanged(w, h, oldw, oldh);
  centerX = w / 2f;
  centerY = h / 2f;
  radius = (Math.min(w, h) - arcStrokeWidth) / 2f;
  rectF = new RectF(-radius, -radius, radius, radius);
 }
 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  super.onMeasure(widthMeasureSpec, heightMeasureSpec);
  int width = getMeasuredSize(widthMeasureSpec, dp2px(100));
  int height = getMeasuredSize(heightMeasureSpec, dp2px(100));
  setMeasuredDimension(width, height);
 }
 @Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  // 绘制圆弧和进度
  drawArc(canvas);
  // 绘制文字 title
  drawTitleText(canvas);
  // 绘制文字副标题
  drawSubTitle(canvas);
 }
 @Override
 protected void onAttachedToWindow() {
  super.onAttachedToWindow();
  startAnimation();
 }
 private void startAnimation() {
  ValueAnimator progressAnimator = ValueAnimator.ofFloat(0f, arcProgress);
  ValueAnimator numberAnimator = ValueAnimator.ofInt(0, arcTitleNumber);
  progressAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
   @Override
   public void onAnimationUpdate(ValueAnimator animation) {
    curProgress = (float) animation.getAnimatedValue();
    invalidate();
   }
  });
  numberAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
   @Override
   public void onAnimationUpdate(ValueAnimator animation) {
    curNumber = (int) animation.getAnimatedValue();
    text = curNumber + "分";
   }
  });
  AnimatorSet animatorSet = new AnimatorSet();
  animatorSet.playTogether(progressAnimator, numberAnimator);
  animatorSet.setDuration(700);
  animatorSet.setInterpolator(new LinearInterpolator());
  animatorSet.start();
 }
 private void drawSubTitle(Canvas canvas) {
  canvas.save();
  canvas.translate(centerX, centerY);
  paint.setTextSize(arcSubTitleTextSize);
  paint.setTextAlign(Paint.Align.CENTER);
  paint.setColor(arcSubTitleColor);
  paint.setStyle(Paint.Style.FILL);
  paint.setStrokeWidth(0);
  canvas.drawText(subTitle, 0, 60, paint);
  canvas.restore();
 }
 private void drawArc(Canvas canvas) {
  canvas.save();
  canvas.translate(centerX, centerY);
  paint.setColor(arcBackgroundColor);
  paint.setStrokeWidth(arcStrokeWidth);
  paint.setStyle(Paint.Style.STROKE);
  canvas.drawArc(rectF, startAngle, sweepAngle, false, paint);
  paint.setColor(arcProgressColor);
  canvas.drawArc(rectF, startAngle, sweepAngle * curProgress, false, paint);
  canvas.restore();
 }
 private void drawTitleText(Canvas canvas) {
  canvas.save();
  textPaint.setTextSize(arcTitleTextSize);
  float textWidth = textPaint.measureText(text); // 文字宽度
  float textHeight = -textPaint.ascent() + textPaint.descent(); // 文字高度
  // 由于 StaticLayout 绘制文字时，默认画在Canvas的(0,0)点位置，所以居中绘制居中位置，需要将画布 translate到中间位置。
  canvas.translate(centerX - textWidth * 2 / 5f, centerY - textHeight * 2 / 3f);
  spannableString = SpannableString.valueOf(text);
  spannableString.setSpan(styleSpan, 0, text.length() - 1, Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
  spannableString.setSpan(relativeSizeSpan, text.length() - 1, text.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
  dynamicLayout = new DynamicLayout(spannableString, textPaint, getWidth(), Layout.Alignment.ALIGN_NORMAL, 0, 0, false);
  dynamicLayout.draw(canvas);
  canvas.restore();
 }
 /**
  * 对外提供方法，设置进度
  *
  * @param percent
  */
 public void setArcProgress(float percent) {
  this.curProgress = percent;
  invalidate();
 }
 private int getMeasuredSize(int measureSpec, int defvalue) {
  int mode = MeasureSpec.getMode(measureSpec);
  int size = MeasureSpec.getSize(measureSpec);
  if (mode == MeasureSpec.EXACTLY) {
   return size;
  }
  return Math.min(size, defvalue);
 }
 private int dp2px(int dp) {
  return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, getResources().getDisplayMetrics());
 }
 private int sp2px(int sp) {
  return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, sp, getResources().getDisplayMetrics());
 }
}