/**
 * 氣泡布局
 */
public class BubbleRelativeLayout extends RelativeLayout {

 /**
  * 氣泡尖角方向
  */
 public enum BubbleLegOrientation {
  TOP, LEFT, RIGHT, BOTTOM, NONE
 }

 public static int PADDING = 30;
 public static int LEG_HALF_BASE = 30;
 public static float STROKE_WIDTH = 2.0f;
 public static float CORNER_RADIUS = 8.0f;
 public static int SHADOW_COLOR = Color.argb(100, 0, 0, 0);
 public static float MIN_LEG_DISTANCE = PADDING + LEG_HALF_BASE;

 private Paint mFillPaint = null;
 private final Path mPath = new Path();
 private final Path mBubbleLegPrototype = new Path();
 private final Paint mPaint = new Paint(Paint.DITHER_FLAG);

 private float mBubbleLegOffset = 0.75f;
 private BubbleLegOrientation mBubbleOrientation = BubbleLegOrientation.LEFT;

 public BubbleRelativeLayout(Context context) {
  this(context, null);
 }

 public BubbleRelativeLayout(Context context, AttributeSet attrs) {
  this(context, attrs, 0);
 }

 public BubbleRelativeLayout(Context context, AttributeSet attrs, int defStyle) {
  super(context, attrs, defStyle);
  init(context, attrs);
 }

 private void init(final Context context, final AttributeSet attrs) {

  //setGravity(Gravity.CENTER);

  ViewGroup.LayoutParams params = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
  setLayoutParams(params);

  if (attrs != null) {
   TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.bubble);

   try {
    PADDING = a.getDimensionPixelSize(R.styleable.bubble_padding, PADDING);
    SHADOW_COLOR = a.getInt(R.styleable.bubble_shadowColor, SHADOW_COLOR);
    LEG_HALF_BASE = a.getDimensionPixelSize(R.styleable.bubble_halfBaseOfLeg, LEG_HALF_BASE);
    MIN_LEG_DISTANCE = PADDING + LEG_HALF_BASE;
    STROKE_WIDTH = a.getFloat(R.styleable.bubble_strokeWidth, STROKE_WIDTH);
    CORNER_RADIUS = a.getFloat(R.styleable.bubble_cornerRadius, CORNER_RADIUS);
   } finally {
    if (a != null) {
     a.recycle();
    }
   }
  }

  mPaint.setColor(SHADOW_COLOR);
  mPaint.setStyle(Style.FILL);
  mPaint.setStrokeCap(Cap.BUTT);
  mPaint.setAntiAlias(true);
  mPaint.setStrokeWidth(STROKE_WIDTH);
  mPaint.setStrokeJoin(Paint.Join.MITER);
  mPaint.setPathEffect(new CornerPathEffect(CORNER_RADIUS));

  if (Build.VERSION.SDK_INT >= 11) {
   setLayerType(LAYER_TYPE_SOFTWARE, mPaint);
  }

  mFillPaint = new Paint(mPaint);
  mFillPaint.setColor(Color.WHITE);
  mFillPaint.setShader(new LinearGradient(100f, 0f, 100f, 200f, Color.WHITE, Color.WHITE, TileMode.CLAMP));

  if (Build.VERSION.SDK_INT >= 11) {
   setLayerType(LAYER_TYPE_SOFTWARE, mFillPaint);
  }
  mPaint.setShadowLayer(2f, 2F, 5F, SHADOW_COLOR);

  renderBubbleLegPrototype();

  setPadding(PADDING, PADDING, PADDING, PADDING);

 }

 @Override
 protected void onConfigurationChanged(Configuration newConfig) {
  super.onConfigurationChanged(newConfig);
 }

 /**
  * 尖角path
  */
 private void renderBubbleLegPrototype() {
  mBubbleLegPrototype.moveTo(0, 0);
  mBubbleLegPrototype.lineTo(PADDING * 1.5f, -PADDING / 1.5f);
  mBubbleLegPrototype.lineTo(PADDING * 1.5f, PADDING / 1.5f);
  mBubbleLegPrototype.close();
 }

 public void setBubbleParams(final BubbleLegOrientation bubbleOrientation, final float bubbleOffset) {
  mBubbleLegOffset = bubbleOffset;
  mBubbleOrientation = bubbleOrientation;
 }

 /**
  * 根據(jù)顯示方向，獲取尖角位置矩陣
  * @param width
  * @param height
  * @return
  */
 private Matrix renderBubbleLegMatrix(final float width, final float height) {

  final float offset = Math.max(mBubbleLegOffset, MIN_LEG_DISTANCE);

  float dstX = 0;
  float dstY = Math.min(offset, height - MIN_LEG_DISTANCE);
  final Matrix matrix = new Matrix();

  switch (mBubbleOrientation) {

   case TOP:
    dstX = Math.min(offset, width - MIN_LEG_DISTANCE);
    dstY = 0;
    matrix.postRotate(90);
    break;

   case RIGHT:
    dstX = width;
    dstY = Math.min(offset, height - MIN_LEG_DISTANCE);
    matrix.postRotate(180);
    break;

   case BOTTOM:
    dstX = Math.min(offset, width - MIN_LEG_DISTANCE);
    dstY = height;
    matrix.postRotate(270);
    break;

  }

  matrix.postTranslate(dstX, dstY);
  return matrix;
 }

 @Override
 protected void onDraw(Canvas canvas) {

  final float width = canvas.getWidth();
  final float height = canvas.getHeight();

  mPath.rewind();
  mPath.addRoundRect(new RectF(PADDING, PADDING, width - PADDING, height - PADDING), CORNER_RADIUS, CORNER_RADIUS, Direction.CW);
  mPath.addPath(mBubbleLegPrototype, renderBubbleLegMatrix(width, height));

  canvas.drawPath(mPath, mPaint);
  canvas.scale((width - STROKE_WIDTH) / width, (height - STROKE_WIDTH) / height, width / 2f, height / 2f);

  canvas.drawPath(mPath, mFillPaint);
 }
}

<?xml version="1.0" encoding="utf-8"?>
<resources>

 <declare-styleable name="bubble">
  <attr name="shadowColor" format="color" />
  <attr name="padding" format="dimension" />
  <attr name="strokeWidth" format="float" />
  <attr name="cornerRadius" format="float" />
  <attr name="halfBaseOfLeg" format="dimension" />
 </declare-styleable>

</resources>

public class BubblePopupWindow extends PopupWindow {

 private BubbleRelativeLayout bubbleView;
 private Context context;

 public BubblePopupWindow(Context context) {
  this.context = context;
  setWidth(ViewGroup.LayoutParams.WRAP_CONTENT);
  setHeight(ViewGroup.LayoutParams.WRAP_CONTENT);

  setFocusable(true);
  setOutsideTouchable(false);
  setClippingEnabled(false);

  ColorDrawable dw = new ColorDrawable(0);
  setBackgroundDrawable(dw);
 }

 public void setBubbleView(View view) {
  bubbleView = new BubbleRelativeLayout(context);
  bubbleView.setBackgroundColor(Color.TRANSPARENT);
  bubbleView.addView(view);
  setContentView(bubbleView);
 }

 public void setParam(int width, int height) {
  setWidth(width);
  setHeight(height);
 }

 public void show(View parent) {
  show(parent, Gravity.TOP, getMeasuredWidth() / 2);
 }

 public void show(View parent, int gravity) {
  show(parent, gravity, getMeasuredWidth() / 2);
 }

 /**
  * 顯示彈窗
  *
  * @param parent
  * @param gravity
  * @param bubbleOffset 氣泡尖角位置偏移量。默認(rèn)位于中間
  */
 public void show(View parent, int gravity, float bubbleOffset) {
  BubbleRelativeLayout.BubbleLegOrientation orientation = BubbleRelativeLayout.BubbleLegOrientation.LEFT;
  if (!this.isShowing()) {
   switch (gravity) {
    case Gravity.BOTTOM:
     orientation = BubbleRelativeLayout.BubbleLegOrientation.TOP;
     break;
    case Gravity.TOP:
     orientation = BubbleRelativeLayout.BubbleLegOrientation.BOTTOM;
     break;
    case Gravity.RIGHT:
     orientation = BubbleRelativeLayout.BubbleLegOrientation.LEFT;
     break;
    case Gravity.LEFT:
     orientation = BubbleRelativeLayout.BubbleLegOrientation.RIGHT;
     break;
    default:
     break;
   }
   bubbleView.setBubbleParams(orientation, bubbleOffset); // 設(shè)置氣泡布局方向及尖角偏移

   int[] location = new int[2];
   parent.getLocationOnScreen(location);

   switch (gravity) {
    case Gravity.BOTTOM:
     showAsDropDown(parent);
     break;
    case Gravity.TOP:
     showAtLocation(parent, Gravity.NO_GRAVITY, location[0], location[1] - getMeasureHeight());
     break;
    case Gravity.RIGHT:
     showAtLocation(parent, Gravity.NO_GRAVITY, location[0] + parent.getWidth(), location[1] - (parent.getHeight() / 2));
     break;
    case Gravity.LEFT:
     showAtLocation(parent, Gravity.NO_GRAVITY, location[0] - getMeasuredWidth(), location[1] - (parent.getHeight() / 2));
     break;
    default:
     break;
   }
  } else {
   this.dismiss();
  }
 }

 /**
  * 測(cè)量高度
  * 
  * @return
  */
 public int getMeasureHeight() {
  getContentView().measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
  int popHeight = getContentView().getMeasuredHeight();
  return popHeight;
 }

 /**
  * 測(cè)量寬度
  * 
  * @return
  */
 public int getMeasuredWidth() {
  getContentView().measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
  int popWidth = getContentView().getMeasuredWidth();
  return popWidth;
 }
}

<?xml version="1.0" encoding="utf-8"?>
<com.yuyh.library.BubbleRelativeLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 android:id="@+id/brlBackground"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:background="@android:color/transparent"
 app:cornerRadius="10"
 app:halfBaseOfLeg="18dp"
 app:padding="18dp"
 app:shadowColor="#64000000"
 app:strokeWidth="5">

</com.yuyh.library.BubbleRelativeLayout>

BubblePopupWindow leftTopWindow = new BubblePopupWindow(MainActivity.this);
View bubbleView = inflater.inflate(R.layout.layout_popup_view, null);
TextView tvContent = (TextView) bubbleView.findViewById(R.id.tvContent);
tvContent.setText("HelloWorld");
leftTopWindow.setBubbleView(bubbleView); // 設(shè)置氣泡內(nèi)容
leftTopWindow.show(view, Gravity.BOTTOM, 0); // 顯示彈窗

dependencies {
 compile 'com.yuyh.bubble:library:1.0.0'
}