我们都知道 Android 中使用 Spannable 可以实现 TextView 富文本的显示,但是在自定义控件中如何使用 Spannable 绘制不同样式的文字呢?
例如这种效果,标题中的 分数字61
是粗体,分
是常规字体,并且相对于 61
更小些。
第一反应可能是使用 SpannableString.setSpan()
设置 RelativeSizeSpan
, 然后在 onDraw()
中进行绘制,事实是这样实现是没有效果的,因为 onDraw()
中只能获取到 SpannableString
中的内容,拿不到 Span
.
那如何在自定义View 中使用 Spannable 呢? 答案就是系统提供的 Layout
类,
/** * 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 { }
可以看到 Layout
是一个抽象类,有三个子类,可以实现一些自动换行的显示效果。
- BoringLayout
- DynamicLayout
- StaticLayout
实现代码
1. 定义自定义属性
2. 继承 View, 在 onDraw()
中绘制
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()); } }
3. 在布局中引用
总结
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