转载请注明出处：王亟亟的大牛之路

现在各种各样的进度条的呈现方式各种各样，我们老旧的条状条子和转圈圈的方式已经无法满足我们的业务需求，今天亟亟上的是一个水滴状循环滚动的一个自定义视图，你可以把他用在各种不同的场景下。

先上效果图：

然后又添加了真空，隐藏和显示的效果，如图。

项目结构：

主Activity

public class MainActivity extends AppCompatActivity {private MetaballView metaballView;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);metaballView = (MetaballView) this.findViewById(R.id.metaball);}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.menu_main, menu);return true;}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {// Handle action bar item clicks here. The action bar will// automatically handle clicks on the Home/Up button, so long// as you specify a parent activity in AndroidManifest.xml.int id = item.getItemId();//noinspection SimplifiableIfStatementif (id == R.id.action_fill) {metaballView.setPaintMode(1);return true;} else if (id == R.id.action_strock) {metaballView.setPaintMode(0);return true;}else if(id==R.id.action_disappear){metaballView.setVisibility(View.GONE);return  true;}else if(id==R.id.action_appear){metaballView.setVisibility(View.VISIBLE);return  true;}return super.onOptionsItemSelected(item);}
}

CustomView

public class MetaballView extends View {private Paint paint = new Paint();private float handle_len_rate = 2f;private float radius = 30;private final int ITEM_COUNT = 6;private final int ITEM_DIVIDER = 60;private final float SCALE_RATE = 0.3f;private float maxLength;private ArrayList<Circle> circlePaths = new ArrayList<>();private float mInterpolatedTime;private MoveAnimation wa;private Circle circle;public MetaballView(Context context) {super(context);init();}public MetaballView(Context context, AttributeSet attrs) {super(context, attrs);init();}public MetaballView(Context context, AttributeSet attrs, int defStyleAttr) {super(context, attrs, defStyleAttr);init();}private class Circle {float[] center;float radius;}public void setPaintMode(int mode) {paint.setStyle(mode == 0 ? Paint.Style.STROKE : Paint.Style.FILL);}private void init() {paint.setColor(Color.WHITE);paint.setStyle(Paint.Style.FILL);paint.setAntiAlias(true);Circle circlePath = new Circle();circlePath.center = new float[]{(radius + ITEM_DIVIDER), radius * 1.4f};circlePath.radius = radius / 4 * 3;circlePaths.add(circlePath);for (int i = 1; i < ITEM_COUNT; i++) {circlePath = new Circle();circlePath.center = new float[]{(radius * 2 + ITEM_DIVIDER) * i, radius * 1.4f};circlePath.radius = radius;circlePaths.add(circlePath);}maxLength = (radius * 2 + ITEM_DIVIDER) * ITEM_COUNT;}private float[] getVector(float radians, float length) {float x = (float) (Math.cos(radians) * length);float y = (float) (Math.sin(radians) * length);return new float[]{x, y};}private class MoveAnimation extends Animation {@Overrideprotected void applyTransformation(float interpolatedTime, Transformation t) {super.applyTransformation(interpolatedTime, t);mInterpolatedTime = interpolatedTime;invalidate();}}/*** @param canvas          画布* @param j* @param i* @param v               控制两个圆连接时候长度，间接控制连接线的粗细，该值为1的时候连接线为直线* @param handle_len_rate* @param maxDistance*/private void metaball(Canvas canvas, int j, int i, float v, float handle_len_rate, float maxDistance) {final Circle circle1 = circlePaths.get(i);final Circle circle2 = circlePaths.get(j);RectF ball1 = new RectF();ball1.left = circle1.center[0] - circle1.radius;ball1.top = circle1.center[1] - circle1.radius;ball1.right = ball1.left + circle1.radius * 2;ball1.bottom = ball1.top + circle1.radius * 2;RectF ball2 = new RectF();ball2.left = circle2.center[0] - circle2.radius;ball2.top = circle2.center[1] - circle2.radius;ball2.right = ball2.left + circle2.radius * 2;ball2.bottom = ball2.top + circle2.radius * 2;float[] center1 = new float[]{ball1.centerX(),ball1.centerY()};float[] center2 = new float[]{ball2.centerX(),ball2.centerY()};float d = getDistance(center1, center2);float radius1 = ball1.width() / 2;float radius2 = ball2.width() / 2;float pi2 = (float) (Math.PI / 2);float u1, u2;if (d > maxDistance) {canvas.drawCircle(ball1.centerX(), ball1.centerY(), circle1.radius, paint);canvas.drawCircle(ball2.centerX(), ball2.centerY(), circle2.radius, paint);} else {float scale2 = 1 + SCALE_RATE * (1 - d / maxDistance);float scale1 = 1 - SCALE_RATE * (1 - d / maxDistance);radius2 *= scale2;
//            radius1 *= scale1;canvas.drawCircle(ball1.centerX(), ball1.centerY(), radius1, paint);canvas.drawCircle(ball2.centerX(), ball2.centerY(), radius2, paint);}Log.d("Metaball_radius", "radius1:" + radius1 + ",radius2:" + radius2);if (radius1 == 0 || radius2 == 0) {return;}if (d > maxDistance || d <= Math.abs(radius1 - radius2)) {return;} else if (d < radius1 + radius2) {u1 = (float) Math.acos((radius1 * radius1 + d * d - radius2 * radius2) /(2 * radius1 * d));u2 = (float) Math.acos((radius2 * radius2 + d * d - radius1 * radius1) /(2 * radius2 * d));} else {u1 = 0;u2 = 0;}Log.d("Metaball", "center2:" + Arrays.toString(center2) + ",center1:" + Arrays.toString(center1));float[] centermin = new float[]{center2[0] - center1[0], center2[1] - center1[1]};float angle1 = (float) Math.atan2(centermin[1], centermin[0]);float angle2 = (float) Math.acos((radius1 - radius2) / d);float angle1a = angle1 + u1 + (angle2 - u1) * v;float angle1b = angle1 - u1 - (angle2 - u1) * v;float angle2a = (float) (angle1 + Math.PI - u2 - (Math.PI - u2 - angle2) * v);float angle2b = (float) (angle1 - Math.PI + u2 + (Math.PI - u2 - angle2) * v);Log.d("Metaball", "angle1:" + angle1 + ",angle2:" + angle2 + ",angle1a:" + angle1a + ",angle1b:" + angle1b + ",angle2a:" + angle2a + ",angle2b:" + angle2b);float[] p1a1 = getVector(angle1a, radius1);float[] p1b1 = getVector(angle1b, radius1);float[] p2a1 = getVector(angle2a, radius2);float[] p2b1 = getVector(angle2b, radius2);float[] p1a = new float[]{p1a1[0] + center1[0], p1a1[1] + center1[1]};float[] p1b = new float[]{p1b1[0] + center1[0], p1b1[1] + center1[1]};float[] p2a = new float[]{p2a1[0] + center2[0], p2a1[1] + center2[1]};float[] p2b = new float[]{p2b1[0] + center2[0], p2b1[1] + center2[1]};Log.d("Metaball", "p1a:" + Arrays.toString(p1a) + ",p1b:" + Arrays.toString(p1b) + ",p2a:" + Arrays.toString(p2a) + ",p2b:" + Arrays.toString(p2b));float[] p1_p2 = new float[]{p1a[0] - p2a[0], p1a[1] - p2a[1]};float totalRadius = (radius1 + radius2);float d2 = Math.min(v * handle_len_rate, getLength(p1_p2) / totalRadius);d2 *= Math.min(1, d * 2 / (radius1 + radius2));Log.d("Metaball", "d2:" + d2);radius1 *= d2;radius2 *= d2;float[] sp1 = getVector(angle1a - pi2, radius1);float[] sp2 = getVector(angle2a + pi2, radius2);float[] sp3 = getVector(angle2b - pi2, radius2);float[] sp4 = getVector(angle1b + pi2, radius1);Log.d("Metaball", "sp1:" + Arrays.toString(sp1) + ",sp2:" + Arrays.toString(sp2) + ",sp3:" + Arrays.toString(sp3) + ",sp4:" + Arrays.toString(sp4));Path path1 = new Path();path1.moveTo(p1a[0], p1a[1]);path1.cubicTo(p1a[0] + sp1[0], p1a[1] + sp1[1], p2a[0] + sp2[0], p2a[1] + sp2[1], p2a[0], p2a[1]);path1.lineTo(p2b[0], p2b[1]);path1.cubicTo(p2b[0] + sp3[0], p2b[1] + sp3[1], p1b[0] + sp4[0], p1b[1] + sp4[1], p1b[0], p1b[1]);path1.lineTo(p1a[0], p1a[1]);path1.close();canvas.drawPath(path1, paint);}private float getLength(float[] b) {return (float) Math.sqrt(b[0] * b[0] + b[1] * b[1]);}private float getDistance(float[] b1, float[] b2) {float x = b1[0] - b2[0];float y = b1[1] - b2[1];float d = x * x + y * y;return (float) Math.sqrt(d);}//测试用
//    @Override
//    public boolean onTouchEvent(MotionEvent event) {//        switch (event.getAction()) {//            case MotionEvent.ACTION_DOWN:
//                break;
//            case MotionEvent.ACTION_MOVE:
//                Circle circle = circlePaths.get(0);
//                circle.center[0] = event.getX();
//                circle.center[1] = event.getY();
//                invalidate();
//                break;
//            case MotionEvent.ACTION_UP:
//                break;
//        }
//
//        return true;
//    }@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);circle = circlePaths.get(0);circle.center[0] = maxLength * mInterpolatedTime;for (int i = 1, l = circlePaths.size(); i < l; i++) {metaball(canvas, i, 0, 0.6f, handle_len_rate, radius * 4f);}}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {widthMeasureSpec = MeasureSpec.makeMeasureSpec((int) (ITEM_COUNT * (radius * 2 + ITEM_DIVIDER)), MeasureSpec.EXACTLY);heightMeasureSpec = MeasureSpec.makeMeasureSpec((int) (2 * radius * 1.4f), MeasureSpec.EXACTLY);super.onMeasure(widthMeasureSpec, heightMeasureSpec);}private void stopAnimation() {this.clearAnimation();postInvalidate();}private void startAnimation() {wa = new MoveAnimation();wa.setDuration(2500);wa.setInterpolator(new AccelerateDecelerateInterpolator());wa.setRepeatCount(Animation.INFINITE);wa.setRepeatMode(Animation.REVERSE);startAnimation(wa);}@Overrideprotected void onVisibilityChanged(View changedView, int visibility) {super.onVisibilityChanged(changedView, visibility);if (visibility == GONE || visibility == INVISIBLE) {stopAnimation();} else {startAnimation();}}@Overrideprotected void onAttachedToWindow() {super.onAttachedToWindow();startAnimation();}@Overrideprotected void onDetachedFromWindow() {stopAnimation();super.onDetachedFromWindow();}}

想改变呈现的方式可以修改Style文件以及setColor这里更改自己想要的颜色，也可以改构造函数用外部传入的方式来活用该类

布局文件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"android:background="#001d30"android:clipChildren="false"android:paddingBottom="@dimen/activity_vertical_margin"android:paddingLeft="@dimen/activity_horizontal_margin"android:paddingRight="@dimen/activity_horizontal_margin"android:paddingTop="@dimen/activity_vertical_margin"tools:context=".MainActivity"><com.dodola.animview.MetaballViewandroid:id="@+id/metaball"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_centerInParent="true" />
</RelativeLayout>

源码已上传，地址：http://yunpan.cn/cddIXXQbqTf2m 访问密码 681c
有问题或者有业务QQ452270579交流，谢谢