Android自定义可拖拽的悬浮按钮DragFloatingActionButton

悬浮按钮floatingactionbutton是android 5.0系统添加的新控件,floatingactionbutton是继承至imageview，所以floatingactionbutton拥有imageview的所有属性。本文讲解的是一个实现了可拖拽的悬浮按钮，并为此添加了类似于qq的吸附边框的功能。在此之前，先了解下其简单的使用方式吧：

首先你得添加其依赖

compile 'com.android.support:design:25.3.1'

然后在布局文件中使用。

<android.support.design.widget.floatingactionbutton
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:layout_gravity="right|bottom"
   android:src="@drawable/ic_launcher"
   />

如图：

 

floatingactionbutton正常显示的情况下有个填充的颜色，有个阴影；点击的时候会有一个ripplecolor，并且阴影的范围可以增大。其中：

1、填充的颜色默认使用就是style当中的coloraccent。

2、ripplecolor默认取的是theme当中的colorcontrolhighlight。

3、elevation和pressedtranslationz，前者用户设置正常显示的阴影大小；后者是点击时显示的阴影大小。

好了，现在介绍本文的重点：可拖拽的，有吸附功能的悬浮按钮

先上代码。

import android.animation.objectanimator;
import android.content.context;
import android.support.design.widget.floatingactionbutton;
import android.util.attributeset;
import android.util.log;
import android.view.motionevent;
import android.view.animation.decelerateinterpolator;
public class dragfloatactionbutton extends floatingactionbutton {
 private int screenwidth;
 private int screenheight;
 private int screenwidthhalf;
 private int statusheight;
 private int virtualheight;
 public dragfloatactionbutton(context context) {
  super(context);
  init();
 }
 public dragfloatactionbutton(context context, attributeset attrs) {
  super(context, attrs);
  init();
 }
 public dragfloatactionbutton(context context, attributeset attrs, int defstyleattr) {
  super(context, attrs, defstyleattr);
  init();
 }
 private void init() {
  screenwidth = screenutils.getscreenwidth(getcontext());
  screenwidthhalf = screenwidth / 2;
  screenheight = screenutils.getscreenheight(getcontext());
  statusheight = screenutils.getstatusheight(getcontext());
  virtualheight=screenutils.getvirtualbarheigh(getcontext());
 }
 private int lastx;
 private int lasty;
 private boolean isdrag;
 @override
 public boolean ontouchevent(motionevent event) {
  int rawx = (int) event.getrawx();
  int rawy = (int) event.getrawy();
  switch (event.getaction() & motionevent.action_mask) {
   case motionevent.action_down:
    isdrag = false;
    getparent().requestdisallowintercepttouchevent(true);
    lastx = rawx;
    lasty = rawy;
    log.e("down---->", "getx=" + getx() + "；screenwidthhalf=" + screenwidthhalf);
    break;
   case motionevent.action_move:
    isdrag = true;
    //计算手指移动了多少
    int dx = rawx - lastx;
    int dy = rawy - lasty;
    //这里修复一些手机无法触发点击事件的问题
    int distance= (int) math.sqrt(dx*dx+dy*dy);
    log.e("distance---->",distance+"");
    if(distance<3){//给个容错范围，不然有部分手机还是无法点击
     isdrag=false;
     break;
    }
    float x = getx() + dx;
    float y = gety() + dy;
    //检测是否到达边缘 左上右下
    x = x < 0 ? 0 : x > screenwidth - getwidth() ? screenwidth - getwidth() : x;
    // y = y < statusheight ? statusheight : (y + getheight() >= screenheight ? screenheight - getheight() : y);
    if (y<0){
     y=0;
    }
    if (y>screenheight-statusheight-getheight()){
     y=screenheight-statusheight-getheight();
    }
    setx(x);
    sety(y);
    lastx = rawx;
    lasty = rawy;
    log.e("move---->", "getx=" + getx() + "；screenwidthhalf=" + screenwidthhalf + " " + isdrag+" statusheight="+statusheight+ " virtualheight"+virtualheight+ " screenheight"+ screenheight+" getheight="+getheight()+" y"+y);
    break;
   case motionevent.action_up:
    if (isdrag) {
     //恢复按压效果
     setpressed(false);
     log.e("action_up---->", "getx=" + getx() + "；screenwidthhalf=" + screenwidthhalf);
     if (rawx >= screenwidthhalf) {
      animate().setinterpolator(new decelerateinterpolator())
        .setduration(500)
        .xby(screenwidth - getwidth() - getx())
        .start();
     } else {
      objectanimator oa = objectanimator.offloat(this, "x", getx(), 0);
      oa.setinterpolator(new decelerateinterpolator());
      oa.setduration(500);
      oa.start();
     }
    }
    log.e("up---->",isdrag+"");
    break;
  }
  //如果是拖拽则消耗事件，否则正常传递即可。
  return isdrag || super.ontouchevent(event);
 }
}

screenutils.java

package com.example.cmos.retrofitdemo;
import android.app.activity;
import android.content.context;
import android.graphics.rect;
import android.util.displaymetrics;
import android.view.display;
import android.view.window;
import android.view.windowmanager;
import java.lang.reflect.method;
/**
 * created by gongwq on 2017/6/14 0014.
 */
public class screenutils {
 private screenutils() {
  /* cannot be instantiated */
  throw new unsupportedoperationexception("cannot be instantiated");
 }
 /**
  * 获得屏幕高度
  *
  * @param context
  * @return
  */
 public static int getscreenwidth(context context) {
  windowmanager wm = (windowmanager) context
    .getsystemservice(context.window_service);
  displaymetrics outmetrics = new displaymetrics();
  wm.getdefaultdisplay().getmetrics(outmetrics);
  return outmetrics.widthpixels;
 }
 /**
  * 获得屏幕宽度
  *
  * @param context
  * @return
  */
 public static int getscreenheight(context context) {
  windowmanager wm = (windowmanager) context
    .getsystemservice(context.window_service);
  displaymetrics outmetrics = new displaymetrics();
  wm.getdefaultdisplay().getmetrics(outmetrics);
  return outmetrics.heightpixels;
 }
 /**
  * 获得状态栏的高度
  *
  * @param context
  * @return
  */
 public static int getstatusheight(context context) {
  int statusheight = -1;
  try {
   class<?> clazz = class.forname("com.android.internal.r$dimen");
   object object = clazz.newinstance();
   int height = integer.parseint(clazz.getfield("status_bar_height")
     .get(object).tostring());
   statusheight = context.getresources().getdimensionpixelsize(height);
  } catch (exception e) {
   e.printstacktrace();
  }
  return statusheight;
 }
 /**
  * 获取虚拟功能键高度
  */
 public static int getvirtualbarheigh(context context) {
  int vh = 0;
  windowmanager windowmanager = (windowmanager) context.getsystemservice(context.window_service);
  display display = windowmanager.getdefaultdisplay();
  displaymetrics dm = new displaymetrics();
  try {
   @suppresswarnings("rawtypes")
   class c = class.forname("android.view.display");
   @suppresswarnings("unchecked")
   method method = c.getmethod("getrealmetrics", displaymetrics.class);
   method.invoke(display, dm);
   vh = dm.heightpixels - windowmanager.getdefaultdisplay().getheight();
  } catch (exception e) {
   e.printstacktrace();
  }
  return vh;
 }
 public static int getvirtualbarheigh(activity activity) {
  int titleheight = 0;
  rect frame = new rect();
  activity.getwindow().getdecorview().getwindowvisibledisplayframe(frame);
  int statusheight = frame.top;
  titleheight = activity.getwindow().findviewbyid(window.id_android_content).gettop() - statusheight;
  return titleheight;
 }
}

上面的代码也很简单，相信看代码中的注释就可以看的明白了。但是这里还是讲下其实现原理：这个自定义的悬浮按钮，我们主要是重写了其ontouch事件，捕捉触摸事件，然后利用setx(),sety()方法将其移动。而吸附效果，主要是利用的属性动画，最后，不要忘了return 是否还在拖拽的结果，免得无法触发点击事件。

ps

最后贴一个弹出框。推荐用popmenu,相比于popwindow，这个会自动调整显示的位置，这在拖拽的悬浮按钮中很有用，因为如果用后者，你将按钮移到屏幕上方，而当你的弹出框也是设置在显示的悬浮按钮的上方，那么就有可能会遮挡弹出框的内容。

dragfloatactionbutton= (dragfloatactionbutton) findviewbyid(r.id.floatbtn);
  dragfloatactionbutton.setonclicklistener(this);
....
 @override
 public void onclick(view view) {
  switch (view.getid()) {
   case r.id.floatbtn:
    popupmenu popupmenu=new popupmenu(this,view);
    getmenuinflater().inflate(r.menu.pop_item,popupmenu.getmenu());
    popupmenu.setonmenuitemclicklistener(new popupmenu.onmenuitemclicklistener() {
     @override
     public boolean onmenuitemclick(menuitem menuitem) {
      switch (menuitem.getitemid()){
       case r.id.action_last:
        toast.maketext(testactivity.this,""+menuitem.getitemid(),toast.length_short).show();
        break;
       case r.id.action_next:
        toast.maketext(testactivity.this,""+menuitem.getitemid(),toast.length_short).show();
        break;
      }
      return false;
     }
    });
    popupmenu.show();
    log.e("****--->","float");
    // toast.maketext(this,"flaot---",toast.length_short).show();
    break;
  }
 }

     新建menu文件夹，在里面添加pop_item.xml文件

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto">
 <item
  android:id="@+id/action_delete"
  android:orderincategory="100"
  android:title="删除"
  app:showasaction="never" />
 <item
  android:id="@+id/action_save"
  android:orderincategory="200"
  android:title="保存"
  app:showasaction="never" />
 <item
  android:id="@+id/action_last"
  android:orderincategory="300"
  android:title="上一步"
  app:showasaction="never" />
 <item
  android:id="@+id/action_next"
  android:icon="@null"
  android:orderincategory="400"
  android:title="下一步"
  app:showasaction="never" />
</menu>

以上所述是小编给大家介绍的android自定义可拖拽的悬浮按钮dragfloatingactionbutton，希望对大家有所帮助