SVG 指可伸缩矢量图形 (Scalable Vector Graphics)
自定义一个View
/**
* 自定义View展示SVG
*/
public class MapView extends View {
public static final String TAG = "MapView";
//绘制地图的颜色
private int[] colorArray = new int[]{0xFF00FFFF,0xFF239BD7, 0xFF30A9E5, 0xFF80CBF1};
// 记录下path的范围
private RectF totalRect;
// 记录下所有写item
private volatile List<MapItem> mapItemList;
// 默认值缩放比例是 1.0f
private float scale = 1.0f;
// 选中的item
private MapItem selectItem;
private Paint paint;
// 记录下宽高
private int width;
private int height;
public MapView(Context context) {
this(context, null);
}
public MapView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public MapView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
paint = new Paint();
paint.setAntiAlias(true);
new Thread(parserPath).start();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// 记录下宽高 适配显示的svg
width = MeasureSpec.getSize(widthMeasureSpec);
height = MeasureSpec.getSize(heightMeasureSpec);
Log.i(TAG,"onMeasure " + width + " " + height);
super.onMeasure(widthMeasureSpec,heightMeasureSpec);
}
/**
* 计算缩放比例，以小为准
*/
private void calculationScale() {
if (totalRect != null){
double mapWidth = totalRect.width();
double mapHeight = totalRect.height();
scale = Math.min((float) (width/mapWidth),(float) (height/mapHeight));
}
}
@Override
protected void onDraw(Canvas canvas) {
// 把所有的path都画出来
if (mapItemList != null && !mapItemList.isEmpty()){
canvas.save();
canvas.scale(scale,scale);
for (MapItem item : mapItemList){
item.drawItem(canvas, paint, item.equals(selectItem));
}
canvas.restore();
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
handlerTouch(event.getX(),event.getY());
return super.onTouchEvent(event);
}
private void handlerTouch(float x, float y) {
if (mapItemList.isEmpty()){
return;
}
// 先置空下选中的item
selectItem = null;
// 记录下选中的item
for (MapItem item : mapItemList){
if (item.isTouch(x/scale,y/scale)){
selectItem = item;
break;
}
}
// 如果选中今了item，重新绘制
if (selectItem != null){
postInvalidate();
}
}
private Runnable parserPath = new Runnable() {
@Override
public void run() {
// 读取SVG文件
InputStream inputStream = getContext().getResources().openRawResource(R.raw.china);
List<MapItem> itemList = new ArrayList<>();
try {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder documentBuilder = factory.newDocumentBuilder();
Document document = documentBuilder.parse(inputStream);
Element rootElement = document.getDocumentElement();
NodeList pathList = rootElement.getElementsByTagName("path");
//首先 定义四个点，用于记录SVG的范围
float left = -1;
float right = -1;
float top = -1;
float bottom = -1;
for (int i = 0;i < pathList.getLength();i++){
Element item = (Element) pathList.item(i);
String pathData = item.getAttribute("android:pathData");
Path path = PathParser.createPathFromPathData(pathData);
if (path == null){
break;
}
MapItem mapItem = new MapItem(path);
// 取出范围
RectF rect = new RectF();
path.computeBounds(rect,true);
mapItem.setRectF(rect);
// 设置颜色
int colorIndex = i % 4;
mapItem.setDrawColor(colorArray[colorIndex]);
itemList.add(mapItem);
//遍历取出每个path中的left取所有的最小值
left = left == -1 ? rect.left : Math.min(left, rect.left);
//遍历取出每个path中的right取所有的最大值
right = right == -1 ? rect.right : Math.max(right, rect.right);
//遍历取出每个path中的top取所有的最小值
top = top == -1 ? rect.top : Math.min(top, rect.top);
//遍历取出每个path中的bottom取所有的最大值
bottom = bottom == -1 ? rect.bottom : Math.max(bottom, rect.bottom);
}
// 根据SVG的范围计算缩放比例
totalRect = new RectF(left,top,right,bottom);
calculationScale();
Log.i(TAG,"parser path over.");
mapItemList = itemList;
// 开始绘制所有的path
postInvalidate();
} catch (Exception e){
Log.e(TAG,"parser path error. " + e.getMessage());
}
}
};
}
/**
* SVG中单个path封装
*/
public class MapItem {
// item对应的path
private Path path;
// path对应的范围
private RectF rectF;
// 绘制颜色
private int drawColor;
public MapItem(Path path) {
this.path = path;
}
public void setRectF(RectF rectF) {
this.rectF = rectF;
}
public void setDrawColor(int drawColor) {
this.drawColor = drawColor;
}
public void drawItem(Canvas canvas, Paint paint, boolean isSelect){
if(isSelect){
//选中时，绘制描边效果
paint.clearShadowLayer();
paint.setStrokeWidth(1);
paint.setStyle(Paint.Style.FILL);
paint.setColor(drawColor);
canvas.drawPath(path, paint);
paint.setStyle(Paint.Style.STROKE);
paint.setColor(Color.BLACK);
canvas.drawPath(path, paint);
}else{
//这是不选中的情况下 设置边界
paint.setStrokeWidth(2);
paint.setColor(Color.BLACK);
paint.setStyle(Paint.Style.FILL);
paint.setShadowLayer(8,0,0,0xffffff);
canvas.drawPath(path,paint);
//后面是填充
paint.clearShadowLayer();
paint.setColor(drawColor);
paint.setStyle(Paint.Style.FILL);
paint.setStrokeWidth(2);
canvas.drawPath(path, paint);
}
}
/**
* 根据点击的 x y 位置，使用区域Api Region.contains，是否检测触摸到item
*/
public boolean isTouch(float x, float y) {
Region region = new Region();
Region clip = new Region((int) rectF.left, (int) rectF.top, (int) rectF.right, (int) rectF.bottom);
region.setPath(path, clip);
return region.contains((int)x,(int)y);
}
}
使用起来比较简单，demo地址 https://github.com/liuguangsen/SvgTest
推荐矢量动画 android 官网地址 https://developer.android.google.cn/guide/topics/graphics/vector-drawable-resources
android技术深入探索开发，欢迎骚扰，liugstick@163.com
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