WindowManager wm = (WindowManager) activity.getSystemService(Context.WINDOW_SERVICE);    DisplayMetrics dm = new DisplayMetrics();    activity.getWindowManager().getDefaultDisplay().getMetrics(dm);    //通過像素密度來設置按鈕的大小    dpi = dpi(dm.densityDpi);    //屏寬    screenWidth = wm.getDefaultDisplay().getWidth();    //屏高    screenHeight = wm.getDefaultDisplay().getHeight();    //布局設置    wmParams = new WindowManager.LayoutParams();    // 設置window type    wmParams.type = WindowManager.LayoutParams.TYPE_APPLICATION;    wmParams.format = PixelFormat.RGBA_8888; // 設置圖片格式，效果為背景透明    wmParams.gravity = Gravity.LEFT | Gravity.TOP;    // 設置Window flag    wmParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;    wmParams.width = dpi;    wmParams.height = dpi;    wmParams.y = (screenHeight - dpi) >> 1;    wm.addView(this, wmParams);

  /**   * 根據密度選擇控件大小   *   */  private int dpi(int densityDpi) {    if (densityDpi <= 120) {      return 36;    } else if (densityDpi <= 160) {      return 48;    } else if (densityDpi <= 240) {      return 72;    } else if (densityDpi <= 320) {      return 96;    }    return 108;  }

import android.app.Activity;import android.content.Context;import android.graphics.PixelFormat;import android.util.DisplayMetrics;import android.view.Gravity;import android.view.LayoutInflater;import android.view.MotionEvent;import android.view.View;import android.view.WindowManager;import android.widget.RelativeLayout;import android.widget.TextView;/** * Created by xiang on 2016/12/28. * * im懸浮窗視圖 */public class ChatView extends RelativeLayout{  // 懸浮欄位置  private final static int LEFT = 0;  private final static int RIGHT = 1;  private final static int TOP = 3;  private final static int BUTTOM = 4;  private int dpi;  private int screenHeight;  private int screenWidth;  private WindowManager.LayoutParams wmParams;  private WindowManager wm;  private float x, y;  private float mTouchStartX;  private float mTouchStartY;  private boolean isScroll;  public ChatView(Activity activity) {    super(activity);    LayoutInflater.from(activity).inflate(R.layout.view_chat, this);    setBackgroundResource(R.drawable.chat_btn);    wm = (WindowManager) activity.getSystemService(Context.WINDOW_SERVICE);    DisplayMetrics dm = new DisplayMetrics();    activity.getWindowManager().getDefaultDisplay().getMetrics(dm);    //通過像素密度來設置按鈕的大小    dpi = dpi(dm.densityDpi);    //屏寬    screenWidth = wm.getDefaultDisplay().getWidth();    //屏高    screenHeight = wm.getDefaultDisplay().getHeight();    //布局設置    wmParams = new WindowManager.LayoutParams();    // 設置window type    wmParams.type = WindowManager.LayoutParams.TYPE_APPLICATION;    wmParams.format = PixelFormat.RGBA_8888; // 設置圖片格式，效果為背景透明    wmParams.gravity = Gravity.LEFT | Gravity.TOP;    // 設置Window flag    wmParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;    wmParams.width = dpi;    wmParams.height = dpi;    wmParams.y = (screenHeight - dpi) >> 1;    wm.addView(this, wmParams);    hide();  }  /**   * 根據密度選擇控件大小   *   */  private int dpi(int densityDpi) {    if (densityDpi <= 120) {      return 36;    } else if (densityDpi <= 160) {      return 48;    } else if (densityDpi <= 240) {      return 72;    } else if (densityDpi <= 320) {      return 96;    }    return 108;  }  public void show() {    if (isShown()) {      return;    }    setVisibility(View.VISIBLE);  }  public void hide() {    setVisibility(View.GONE);  }  public void destory() {    hide();    wm.removeViewImmediate(this);  }  @Override  public boolean onTouchEvent(MotionEvent event) {    // 獲取相對屏幕的坐標， 以屏幕左上角為原點    x = event.getRawX();    y = event.getRawY();    switch (event.getAction()) {      case MotionEvent.ACTION_DOWN:        // setBackgroundDrawable(openDrawable);        // invalidate();        // 獲取相對View的坐標，即以此View左上角為原點        mTouchStartX = event.getX();        mTouchStartY = event.getY();        break;      case MotionEvent.ACTION_MOVE:        if (isScroll) {          updateViewPosition();        } else {          // 當前不處于連續滑動狀態 則滑動小于圖標1/3則不滑動          if (Math.abs(mTouchStartX - event.getX()) > dpi / 3              || Math.abs(mTouchStartY - event.getY()) > dpi / 3) {            updateViewPosition();          } else {            break;          }        }        isScroll = true;        break;      case MotionEvent.ACTION_UP:        // 拖動        if (isScroll) {          autoView();          // setBackgroundDrawable(closeDrawable);          // invalidate();        } else {          // 當前顯示功能區，則隱藏          // setBackgroundDrawable(openDrawable);          // invalidate();        }        isScroll = false;        mTouchStartX = mTouchStartY = 0;        break;    }    return true;  }  /**   * 自動移動位置   */  private void autoView() {    // 得到view在屏幕中的位置    int[] location = new int[2];    getLocationOnScreen(location);    //左側    if (location[0] < screenWidth / 2 - getWidth() / 2) {      updateViewPosition(LEFT);    } else {      updateViewPosition(RIGHT);    }  }  /**   * 手指釋放更新懸浮窗位置   *   */  private void updateViewPosition(int l) {    switch (l) {      case LEFT:        wmParams.x = 0;        break;      case RIGHT:        int x = screenWidth - dpi;        wmParams.x = x;        break;      case TOP:        wmParams.y = 0;        break;      case BUTTOM:        wmParams.y = screenHeight - dpi;        break;    }    wm.updateViewLayout(this, wmParams);  }  // 更新浮動窗口位置參數  private void updateViewPosition() {    wmParams.x = (int) (x - mTouchStartX);    //是否存在狀態欄（提升滑動效果）    // 不設置為全屏（狀態欄存在） 標題欄是屏幕的1/25    wmParams.y = (int) (y - mTouchStartY - screenHeight / 25);    wm.updateViewLayout(this, wmParams);  }}

//傳入上下文ActivityChatView chatView = new ChatView(this);chatView.show();