Android实现炫酷SVG动画效果 _svg动画

知识为进步之母,而进步又为富强之源泉。这篇文章主要讲述Android实现炫酷SVG动画效果相关的知识，希望能为你提供帮助。
svg是眼下十分流行的图像文件格式了,svg严格来说应该是一种开放标准的矢量图形语言，使用svg格式我们能够直接用代码来描画图像，能够用不论什么文字处理工具打开svg图像。通过改变部分代码来使图像具有交互功能，并能够随时插入到html中通过浏览器(如火狐浏览器)来观看。使用svg格式可让你设计激动人心的、高分辨率的Web图形页面。

svg格式具备眼下网络流行的jpg和png等格式无法具备的优势：能够随意放大图形显示，但绝不会以牺牲图像质量为代价; 可在svg图像中保留可编辑和可搜寻的状态; 平均来讲，svg文件比其他格式的图像文件要小非常多，因而下载也非常快。

我们先来看几张android上使用SVG的效果图：

文章图片

文章图片

从上面的图片看到，假设我们自己来实现这种特效，很的麻烦，只是接下来给大家介绍一个开源控件，就能够配合SVG实现这些效果。

首先我们来了解SVG文件的格式，举个样例：

< svg xmlns=" http://www.w3.org/2000/svg" id=" svg" class=" svg" viewBox=" 0 0 960 480" preserveAspectRatio=" xMinYMin meet" > < path fill=" #B4BEC8" stroke=" #B4BEC8" stroke-width=" 2px" stroke-miterlimit=" 10" d=" M570.14 440.2l-29.165-28.99c-7.103-8.5-6.152-36.718-6.02-40.665H425.048c.133 3.947 1.082 32.164-6.018 40.666l-29.166 28.99c-1.237 1.404-1.712 2.505-1.623 3.37h-.054c.76 7.727 6.664 6.332 13.607 6.332H558.01c6.696 0 12.412 1.27 13.493-5.56.58-.953.274-2.282-1.364-4.14z" style=" fill-opacity: 1; stroke-opacity: 0; -webkit-transition: fill-opacity 1s ease-in-out, stroke-opacity 1s ease-in-out; transition: fill-opacity 1s ease-in-out, stroke-opacity 1s ease-in-out; stroke-dasharray: 474.095184326172px, 474.095184326172px; stroke-dashoffset: 0px; " > < /path> < path fill=" #C8D2DC" stroke=" #C8D2DC" stroke-width=" 2px" stroke-miterlimit=" 10" d=" M727.488 355.125c0 8.514-6.597 15.42-14.738 15.42h-465.5c-8.14 0-14.74-6.906-14.74-15.42V45.42c0-8.517 6.6-15.42 14.74-15.42h465.5c8.142 0 14.738 6.903 14.738 15.42v309.705z" style=" fill-opacity: 1; stroke-opacity: 0; -webkit-transition: fill-opacity 1s ease-in-out, stroke-opacity 1s ease-in-out; transition: fill-opacity 1s ease-in-out, stroke-opacity 1s ease-in-out; stroke-dasharray: 1645.18310546875px, 1645.18310546875px; stroke-dashoffset: 0px; " > < /path> < path fill=" #fff" stroke=" #C8D2DC" stroke-width=" 2px" stroke-miterlimit=" 10" d=" M489.01 343.713c-.042-4.223 3.447-6.254 3.605-6.352-1.963-2.866-5.018-3.263-6.102-3.31-2.602-.26-5.074 1.53-6.39 1.53s-3.356-1.49-5.506-1.448c-2.836.04-5.445 1.645-6.907 4.182-2.942 5.11-.75 12.672 2.116 16.814 1.4 2.02 3.072 4.305 5.268 4.22 2.114-.08 2.913-1.362 5.467-1.362 2.556 0 3.274 1.363 5.51 1.322 2.273-.04 3.716-2.064 5.105-4.098 1.61-2.35 2.273-4.63 2.313-4.748-.05-.02-4.434-1.7-4.48-6.75M484.807 331.31c1.168-1.41 1.953-3.37 1.738-5.327-1.68.068-3.713 1.12-4.916 2.53-1.08 1.247-2.027 3.245-1.77 5.16 1.87.143 3.784-.95 4.947-2.362" style=" fill-opacity: 1; stroke-opacity: 0; -webkit-transition: fill-opacity 1s ease-in-out, stroke-opacity 1s ease-in-out; transition: fill-opacity 1s ease-in-out, stroke-opacity 1s ease-in-out; stroke-dasharray: 115.244583129883px, 115.244583129883px; stroke-dashoffset: 0px; " > < /path> < path fill=" #3C4650" stroke=" #3C4650" stroke-width=" 2px" stroke-miterlimit=" 10" d=" M727.488 315.527V45.982c0-8.828-6.597-15.982-14.738-15.982h-465.5c-8.14 0-14.74 7.155-14.74 15.982v269.545H727.49z" style=" fill-opacity: 1; stroke-opacity: 0; -webkit-transition: fill-opacity 1s ease-in-out, stroke-opacity 1s ease-in-out; transition: fill-opacity 1s ease-in-out, stroke-opacity 1s ease-in-out; stroke-dasharray: 1547.85571289063px, 1547.85571289063px; stroke-dashoffset: 0px; " > < /path> < path fill=" #141E28" stroke=" #141E28" stroke-width=" 2px" stroke-miterlimit=" 10" d=" M251.2 48.887h457.205v245.52H251.2z" style=" fill-opacity: 1; stroke-opacity: 0; -webkit-transition: fill-opacity 1s ease-in-out, stroke-opacity 1s ease-in-out; transition: fill-opacity 1s ease-in-out, stroke-opacity 1s ease-in-out; stroke-dasharray: 1405.44995117188px, 1405.44995117188px; stroke-dashoffset: 0px; " > < /path> < /svg>

上面的代码非常复杂，假设说它们是代码的话，可是我们能够注意到，这样的书写方式。有点类似于html。都是使用标签
使用最多的标签是path，也就是路径

有的人也会想到，要实现照片上的动态效果。我们能够使用Android自带的画图类和函数，复杂的曲线路径，我们能够使用path这个类来制定
那会不会SVG里面的path，事实上也是这样，那么我们就能够将SVG中的path，相应到android，然后绘制出来就好了。

SVG里面还有各种标签：
包含line直线，circle圆。rect矩形，eliipse椭圆。polygon多边形，等等

这些仅仅要我们又一个SVG文件，都能够将其转换成java代码
作为一个程序猿，我们当然不能手动去做这个工作，那就涉及两个问题，一个是SVG的解析，一个是解析后的绘制

幸运的是，已经有人完毕了这个工作。而且在Github上开源 https://github.com/geftimov/android-pathview

这篇文章将作为一个简单的样例，来使用上面的开源控件
为了解析SVG,我们须要将一个androidsvg.jar包括进我们的lib

以下我们来看这个控件的简单使用。作为一个自己定义控件，我们仅仅须要在布局文件中面加入

< ?xml version=" 1.0" encoding=" utf-8" ?> < LinearLayout xmlns:android=" http://schemas.android.com/apk/res/android" android:orientation=" vertical" android:background=" #ff0000" android:layout_width=" fill_parent" android:layout_height=" fill_parent" > < com.example.kaiyicky.myapplication.PathView xmlns:app=" http://schemas.android.com/apk/res-auto" android:id=" @+id/pathView" android:layout_width=" match_parent" android:layout_height=" match_parent" app:pathColor=" @android:color/white" app:svg=" @raw/ironman_white" app:pathWidth=" 5" /> < /LinearLayout>

事实上app:svg指定了一个SVG文件，我们能够把这个文章放在raw文件夹以下

文章图片

然后来看Activity里面：

public class MainActivity extends FragmentActivity {@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); final PathView pathView = (PathView) findViewById(R.id.pathView); //final Path path = makeConvexArrow(50, 100); //pathView.setPath(path); pathView.setFillAfter(true); pathView.useNaturalColors(); pathView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { pathView.getPathAnimator(). delay(100). duration(1500). interpolator(new AccelerateDecelerateInterpolator()). start(); } }); }private Path makeConvexArrow(float length, float height) { final Path path = new Path(); path.moveTo(0.0f, 0.0f); path.lineTo(length / 4f, 0.0f); path.lineTo(length, height / 2.0f); path.lineTo(length / 4f, height); path.lineTo(0.0f, height); path.lineTo(length * 3f / 4f, height / 2f); path.lineTo(0.0f, 0.0f); path.close(); return path; }}

看到凝视的部分，调用了makeConvexArraw()方法，假设我们没有在xml文件中面指定svg文件。我们也能够在代码中手动指定绘制的路径
让代码跑起来，点击屏幕。于是就实现了下面效果：

文章图片

就是这么简单。至于这么制作SVG文件，大家能够找美工帮忙，使用ps和ai,能够将图片转换成SVG

最后是源代码下载地址：http://download.csdn.net/detail/kangaroo835127729/9016349

整个过程有两个类，一个是SVG解析工具类：

/** * Util class to init and get paths from svg. */ public class SvgUtils { /** * It is for logging purposes. */ private static final String LOG_TAG = " SVGUtils" ; /** * All the paths with their attributes from the svg. */ private final List< SvgPath> mPaths = new ArrayList< SvgPath> (); /** * The paint provided from the view. */ private final Paint mSourcePaint; /** * The init svg. */ private SVG mSvg; /** * Init the SVGUtils with a paint for coloring. * * @param sourcePaint - the paint for the coloring. */ public SvgUtils(final Paint sourcePaint) { mSourcePaint = sourcePaint; }/** * Loading the svg from the resources. * * @param contextContext object to get the resources. * @param svgResource int resource id of the svg. */ public void load(Context context, int svgResource) { if (mSvg != null) return; try { mSvg = SVG.getFromResource(context, svgResource); mSvg.setDocumentPreserveAspectRatio(PreserveAspectRatio.UNSCALED); } catch (SVGParseException e) { Log.e(LOG_TAG, " Could not load specified SVG resource" , e); } }/** * Draw the svg to the canvas. * * @param canvas The canvas to be drawn. * @param widthThe width of the canvas. * @param height The height of the canvas. */ public void drawSvgAfter(final Canvas canvas, final int width, final int height) { final float strokeWidth = mSourcePaint.getStrokeWidth(); rescaleCanvas(width, height, strokeWidth, canvas); }/** * Render the svg to canvas and catch all the paths while rendering. * * @param width- the width to scale down the view to, * @param height - the height to scale down the view to, * @return All the paths from the svg. */ public List< SvgPath> getPathsForViewport(final int width, final int height) { final float strokeWidth = mSourcePaint.getStrokeWidth(); Canvas canvas = new Canvas() { private final Matrix mMatrix = new Matrix(); @Override public int getWidth() { return width; }@Override public int getHeight() { return height; }@Override public void drawPath(Path path, Paint paint) { Path dst = new Path(); //noinspection deprecation getMatrix(mMatrix); path.transform(mMatrix, dst); paint.setAntiAlias(true); paint.setStyle(Paint.Style.STROKE); paint.setStrokeWidth(strokeWidth); mPaths.add(new SvgPath(dst, paint)); } }; rescaleCanvas(width, height, strokeWidth, canvas); return mPaths; }/** * Rescale the canvas with specific width and height. * * @param widthThe width of the canvas. * @param heightThe height of the canvas. * @param strokeWidth Width of the path to add to scaling. * @param canvasThe canvas to be drawn. */ private void rescaleCanvas(int width, int height, float strokeWidth, Canvas canvas) { final RectF viewBox = mSvg.getDocumentViewBox(); final float scale = Math.min(width / (viewBox.width() + strokeWidth), height / (viewBox.height() + strokeWidth)); canvas.translate((width - viewBox.width() * scale) / 2.0f, (height - viewBox.height() * scale) / 2.0f); canvas.scale(scale, scale); mSvg.renderToCanvas(canvas); }/** * Path with bounds for scalling , length and paint. */ public static class SvgPath { /** * Region of the path. */ private static final Region REGION = new Region(); /** * This is done for clipping the bounds of the path. */ private static final Region MAX_CLIP = new Region(Integer.MIN_VALUE, Integer.MIN_VALUE, Integer.MAX_VALUE, Integer.MAX_VALUE); /** * The path itself. */ final Path path; /** * The paint to be drawn later. */ final Paint paint; /** * The length of the path. */ final float length; /** * The bounds of the path. */ final Rect bounds; /** * The measure of the path, we can use it later to get segment of it. */ final PathMeasure measure; /** * Constructor to add the path and the paint. * * @param pathThe path that comes from the rendered svg. * @param paint The result paint. */ SvgPath(Path path, Paint paint) { this.path = path; this.paint = paint; measure = new PathMeasure(path, false); this.length = measure.getLength(); REGION.setPath(path, MAX_CLIP); bounds = REGION.getBounds(); } } }

一个是SVG控件类：

/** * PathView is an View that animate paths. */ public class PathView extends View { /** * Logging tag. */ public static final String LOG_TAG = " PathView" ; /** * The paint for the path. */ private Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); /** * Utils to catch the paths from the svg. */ private final SvgUtils svgUtils = new SvgUtils(paint); /** * All the paths provided to the view. Both from Path and Svg. */ private List< SvgUtils.SvgPath> paths = new ArrayList< SvgUtils.SvgPath> (0); /** * This is a lock before the view is redrawn * or resided it must be synchronized with this object. */ private final Object mSvgLock = new Object(); /** * Thread for working with the object above. */ private Thread mLoader; /** * The svg image from the raw directory. */ private int svgResourceId; /** * Object that build the animation for the path. */ private AnimatorBuilder animatorBuilder; /** * The progress of the drawing. */ private float progress = 0f; /** * If the used colors are from the svg or from the set color. */ private boolean naturalColors; /** * If the view is filled with its natural colors after path drawing. */ private boolean fillAfter; /** * The width of the view. */ private int width; /** * The height of the view. */ private int height; /** * Default constructor. * * @param context The Context of the application. */ public PathView(Context context) { this(context, null); }/** * Default constructor. * * @param context The Context of the application. * @param attrsattributes provided from the resources. */ public PathView(Context context, AttributeSet attrs) { this(context, attrs, 0); }/** * Default constructor. * * @param contextThe Context of the application. * @param attrsattributes provided from the resources. * @param defStyle Default style. */ public PathView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); paint.setStyle(Paint.Style.STROKE); getFromAttributes(context, attrs); }/** * Get all the fields from the attributes . * * @param context The Context of the application. * @param attrsattributes provided from the resources. */ private void getFromAttributes(Context context, AttributeSet attrs) { final TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.PathView); try { if (a != null) { paint.setColor(a.getColor(R.styleable.PathView_pathColor, 0xff00ff00)); paint.setStrokeWidth(a.getFloat(R.styleable.PathView_pathWidth, 8.0f)); svgResourceId = a.getResourceId(R.styleable.PathView_svg, 0); } } finally { if (a != null) { a.recycle(); } } }/** * Set paths to be drawn and animated. * * @param paths - Paths that can be drawn. */ public void setPaths(final List< Path> paths) { for (Path path : paths) { this.paths.add(new SvgUtils.SvgPath(path, paint)); } synchronized (mSvgLock) { updatePathsPhaseLocked(); } }/** * Set path to be drawn and animated. * * @param path - Paths that can be drawn. */ public void setPath(final Path path) { paths.add(new SvgUtils.SvgPath(path, paint)); synchronized (mSvgLock) { updatePathsPhaseLocked(); } }/** * Animate this property. It is the percentage of the path that is drawn. * It must be [0,1]. * * @param percentage float the percentage of the path. */ public void setPercentage(float percentage) { if (percentage < 0.0f || percentage > 1.0f) { throw new IllegalArgumentException(" setPercentage not between 0.0f and 1.0f" ); } progress = percentage; synchronized (mSvgLock) { updatePathsPhaseLocked(); } invalidate(); }/** * This refreshes the paths before draw and resize. */ private void updatePathsPhaseLocked() { final int count = paths.size(); for (int i = 0; i < count; i++) { SvgUtils.SvgPath svgPath = paths.get(i); svgPath.path.reset(); svgPath.measure.getSegment(0.0f, svgPath.length * progress, svgPath.path, true); // Required only for Android 4.4 and earlier svgPath.path.rLineTo(0.0f, 0.0f); } }@Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); synchronized (mSvgLock) { canvas.save(); canvas.translate(getPaddingLeft(), getPaddingTop()); final int count = paths.size(); for (int i = 0; i < count; i++) { final SvgUtils.SvgPath svgPath = paths.get(i); final Path path = svgPath.path; final Paint paint1 = naturalColors ?
svgPath.paint : paint; canvas.drawPath(path, paint1); } fillAfter(canvas); canvas.restore(); } }/** * If there is svg , the user called setFillAfter(true) and the progress is finished. * * @param canvas Draw to this canvas. */ private void fillAfter(final Canvas canvas) { if (svgResourceId != 0 & & fillAfter & & progress == 1f) { svgUtils.drawSvgAfter(canvas, width, height); } }@Override protected void onSizeChanged(final int w, final int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); if (mLoader != null) { try { mLoader.join(); } catch (InterruptedException e) { Log.e(LOG_TAG, " Unexpected error" , e); } } if (svgResourceId != 0) { mLoader = new Thread(new Runnable() { @Override public void run() {svgUtils.load(getContext(), svgResourceId); synchronized (mSvgLock) { width = w - getPaddingLeft() - getPaddingRight(); height = h - getPaddingTop() - getPaddingBottom(); paths = svgUtils.getPathsForViewport(width, height); updatePathsPhaseLocked(); } } }, " SVG Loader" ); mLoader.start(); } }@Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); if (svgResourceId != 0) { int widthSize = MeasureSpec.getSize(widthMeasureSpec); int heightSize = MeasureSpec.getSize(heightMeasureSpec); setMeasuredDimension(widthSize, heightSize); return; }int desiredWidth = 0; int desiredHeight = 0; final float strokeWidth = paint.getStrokeWidth() / 2; for (SvgUtils.SvgPath path : paths) { desiredWidth += path.bounds.left + path.bounds.width() + strokeWidth; desiredHeight += path.bounds.top + path.bounds.height() + strokeWidth; } int widthSize = MeasureSpec.getSize(widthMeasureSpec); int heightSize = MeasureSpec.getSize(heightMeasureSpec); int widthMode = MeasureSpec.getMode(widthMeasureSpec); int heightMode = MeasureSpec.getMode(widthMeasureSpec); int measuredWidth, measuredHeight; if (widthMode == MeasureSpec.AT_MOST) { measuredWidth = desiredWidth; } else { measuredWidth = widthSize; }if (heightMode == MeasureSpec.AT_MOST) { measuredHeight = desiredHeight; } else { measuredHeight = heightSize; }setMeasuredDimension(measuredWidth, measuredHeight); }/** * If the real svg need to be drawn after the path animation. * * @param fillAfter - boolean if the view needs to be filled after path animation. */ public void setFillAfter(final boolean fillAfter) { this.fillAfter = fillAfter; }/** * If you want to use the colors from the svg. */ public void useNaturalColors() { naturalColors = true; }/** * Animator for the paths of the view. * * @return The AnimatorBuilder to build the animation. */ public AnimatorBuilder getPathAnimator() { if (animatorBuilder == null) { animatorBuilder = new AnimatorBuilder(this); } return animatorBuilder; }/** * Get the path color. * * @return The color of the paint. */ public int getPathColor() { return paint.getColor(); }/** * Set the path color. * * @param color -The color to set to the paint. */ public void setPathColor(final int color) { paint.setColor(color); }/** * Get the path width. * * @return The width of the paint. */ public float getPathWidth() { return paint.getStrokeWidth(); }/** * Set the path width. * * @param width - The width of the path. */ public void setPathWidth(final float width) { paint.setStrokeWidth(width); }/** * Get the svg resource id. * * @return The svg raw resource id. */ public int getSvgResource() { return svgResourceId; }/** * Set the svg resource id. * * @param svgResource - The resource id of the raw svg. */ public void setSvgResource(int svgResource) { svgResourceId = svgResource; }/** * Object for building the animation of the path of this view. */ public static class AnimatorBuilder { /** * Duration of the animation. */ private int duration = 350; /** * Interpolator for the time of the animation. */ private Interpolator interpolator; /** * The delay before the animation. */ private int delay = 0; /** * ObjectAnimator that constructs the animation. */ private final ObjectAnimator anim; /** * Listener called before the animation. */ private ListenerStart listenerStart; /** * Listener after the animation. */ private ListenerEnd animationEnd; /** * Animation listener. */ private PathViewAnimatorListener pathViewAnimatorListener; /** * Default constructor. * * @param pathView The view that must be animated. */ public AnimatorBuilder(final PathView pathView) { anim = ObjectAnimator.ofFloat(pathView, " percentage" , 0.0f, 1.0f); }/** * Set the duration of the animation. * * @param duration - The duration of the animation. * @return AnimatorBuilder. */ public AnimatorBuilder duration(final int duration) { this.duration = duration; return this; }/** * Set the Interpolator. * * @param interpolator - Interpolator. * @return AnimatorBuilder. */ public AnimatorBuilder interpolator(final Interpolator interpolator) { this.interpolator = interpolator; return this; }/** * The delay before the animation. * * @param delay - int the delay * @return AnimatorBuilder. */ public AnimatorBuilder delay(final int delay) { this.delay = delay; return this; }/** * Set a listener before the start of the animation. * * @param listenerStart an interface called before the animation * @return AnimatorBuilder. */ public AnimatorBuilder listenerStart(final ListenerStart listenerStart) { this.listenerStart = listenerStart; if (pathViewAnimatorListener == null) { pathViewAnimatorListener = new PathViewAnimatorListener(); anim.addListener(pathViewAnimatorListener); } return this; }/** * Set a listener after of the animation. * * @param animationEnd an interface called after the animation * @return AnimatorBuilder. */ public AnimatorBuilder listenerEnd(final ListenerEnd animationEnd) { this.animationEnd = animationEnd; if (pathViewAnimatorListener == null) { pathViewAnimatorListener = new PathViewAnimatorListener(); anim.addListener(pathViewAnimatorListener); } return this; }/** * Starts the animation. */ public void start() { anim.setDuration(duration); anim.setInterpolator(interpolator); anim.setStartDelay(delay); anim.start(); }/** * Animation listener to be able to provide callbacks for the caller. */ private class PathViewAnimatorListener implements Animator.AnimatorListener {@Override public void onAnimationStart(Animator animation) { if (listenerStart != null) listenerStart.onAnimationStart(); }@Override public void onAnimationEnd(Animator animation) { if (animationEnd != null) animationEnd.onAnimationEnd(); }@Override public void onAnimationCancel(Animator animation) {}@Override public void onAnimationRepeat(Animator animation) {} }/** * Called when the animation start. */ public interface ListenerStart { /** * Called when the path animation start. */ void onAnimationStart(); }/** * Called when the animation end. */ public interface ListenerEnd { /** * Called when the path animation end. */ void onAnimationEnd(); } } }