Android实现类似360,QQ管家那样的悬浮窗

一、前言：
我手机从来不装这些东西，不过，有次看到同事的android手机上，有个qq管家在桌面上浮着，同事拖动管家时，管家就变成一只鸟，桌面下方还有个弹弓，桌面顶部有只乌鸦，把管家也就是鸟拖动到弹弓那，然后，松手，鸟就飞出去。这个过程是动画过程，做的事，实际上是清楚内存。

二：原理：
其实，没什么原理，用到的就是windowmanager以及windowmanager.layoutparams，对这个layoutparams做文章，当设置为属性后，然后，创建一个view，将这个view添加到windowmanager中就行。

package com.chris.floats.window;
import android.os.bundle;
import android.util.displaymetrics;
import android.view.gravity;
import android.view.windowmanager;
import android.app.activity;
import android.content.context;
public class mainactivity extends activity {
private static windowmanager mwindowmgr = null;
private windowmanager.layoutparams mwindowmgrparams = null;
private static floatswindowview mfloatswindowview = null;

@override
protected void oncreate(bundle savedinstancestate) {
super.oncreate(savedinstancestate);
setcontentview(r.layout.activity_main);
}
/*
* 显示应用主界面时，去除悬浮层
*/
@override
public void onwindowfocuschanged(boolean hasfocus) {
if(hasfocus){
if(mfloatswindowview != null){
mwindowmgr.removeview(mfloatswindowview);
mfloatswindowview = null;
}
}else{
getwindowlayout();
}
}
private void initparams(){
displaymetrics dm = getresources().getdisplaymetrics();
mwindowmgrparams.x = dm.widthpixels - 136;
mwindowmgrparams.y = 300;
mwindowmgrparams.width = 136;
mwindowmgrparams.height = 136;
}
private void getwindowlayout(){
if(mfloatswindowview == null){
mwindowmgr = (windowmanager)getbasecontext().getsystemservice(context.window_service);
mwindowmgrparams = new windowmanager.layoutparams();

/*
* 2003 在指悬浮在所有界面之上
* (4.0+系统中，在下拉菜单下面，而在2.3中，在上拉菜单之上)
*/
mwindowmgrparams.type = 2003;
mwindowmgrparams.format = 1;

/*
* 代码实际是wmparams.flags |= flag_not_focusable;
* 40的由来是wmparams的默认属性（32）+ flag_not_focusable（8）
*/
mwindowmgrparams.flags = 40;
mwindowmgrparams.gravity = gravity.left | gravity.top;
initparams();

mfloatswindowview = new floatswindowview(this);
mwindowmgr.addview(mfloatswindowview, mwindowmgrparams);
}
}
}

上面代码，主要在getwindowlayout函数中，最后两行就是创建一个view，并加入到windowmanager中。
继承view的悬浮view：

package com.chris.floats.window;
import android.content.context;
import android.content.intent;
import android.graphics.drawable.animationdrawable;
import android.util.attributeset;
import android.util.displaymetrics;
import android.view.gravity;
import android.view.motionevent;
import android.view.view;
import android.view.viewtreeobserver.onpredrawlistener;
import android.view.windowmanager;
public class floatswindowview extends view {
private context mcontext = null;
private windowmanager mwindowmgr = null;
private windowmanager.layoutparams mwindowmgrparams = null;
private animationdrawable manimationdrawable = null;

private int iposx = 0;
private int iposy = 0;
private int ilastposx = 0;
private int ilastposy = 0;
private boolean bmoved = false;

public floatswindowview(context context) {
this(context, null, 0);
}
public floatswindowview(context context, attributeset attrs) {
this(context, attrs, 0);
}
public floatswindowview(context context, attributeset attrs, int defstyle) {
super(context, attrs, defstyle);

mcontext = context;
mwindowmgr = (windowmanager)getcontext().getapplicationcontext().getsystemservice("window");
mwindowmgrparams = new windowmanager.layoutparams();
initparams();

manimationdrawable = new animationdrawable();
for(int i = 0; i < 4; i++){
int id = getresources().getidentifier("a"+ i, "drawable", mcontext.getpackagename());
manimationdrawable.addframe(getresources().getdrawable(id), 100);
}
manimationdrawable.setoneshot(false);
this.setbackgrounddrawable(manimationdrawable);

onpredrawlistener listener = new onpredrawlistener(){
@override
public boolean onpredraw() {
manimationdrawable.start();
return true;
}
};
this.getviewtreeobserver().addonpredrawlistener(listener);
}

private void initparams(){
displaymetrics dm = getresources().getdisplaymetrics();
mwindowmgrparams.x = dm.widthpixels - 136;
mwindowmgrparams.y = 300;
mwindowmgrparams.width = 136;
mwindowmgrparams.height = 136;
}

@override
public boolean ontouchevent(motionevent event) {

switch(event.getaction()){
case motionevent.action_down:
iposx = (int)event.getx();
iposy = (int)event.gety();
bmoved = false;
break;

case motionevent.action_move:
bmoved = true;
ilastposx = (int)event.getx();
ilastposy = (int)event.gety();
updatepostion(ilastposx - iposx, ilastposy - iposy);
break;

case motionevent.action_up:
if(!bmoved){
intent it=new intent(mcontext, mainactivity.class);
mcontext.startactivity(it);
}
break;

default:
break;
}
return true;
}
private void updatepostion(int x, int y){
mwindowmgrparams.type = 2003;
mwindowmgrparams.format = 1;
mwindowmgrparams.flags = 40;
mwindowmgrparams.gravity = gravity.left | gravity.top;
mwindowmgrparams.x += x;
mwindowmgrparams.y += y;
mwindowmgr.updateviewlayout(this, mwindowmgrparams);
}
}

之所以将updateposition中的参数与activity中设置一样，是为了确保在move时，造成相对位置的不一样，而导致闪砾，大家要是不理解，可以实验下。

三、小结：
这篇文章实现了简单的悬浮窗口动画效果，如果要想做成像360,qq管家那样，还需要一些其它的操作：
1. 比如启动一个后台服务来监控系统信息；
2. action_down时，修改悬浮窗口上的图片；
3. action_move时窗口跟随；
4. action_up时，创建一个线程，来完成释放后，向上运动的动画过程等；