版权声明:我正在参加 2016年度博客之星评选,来来来,开车咯,赶紧帮投票吧! 时间:11月28日到12月18日每天都可以为我投一票 投票地址:http://blog.csdn.net/vote/candidate.html?username=jdsjlzx
用了我一个周末的时间,个中愤懑就不说了,就这个问题,我翻遍全球网络没有一篇像样的资料,现在将实现原理简单叙述如下:
调用WindowManager,并设置WindowManager.LayoutParams的相关属性,通过WindowManager的addView方法创建View,这样产生出来的View根据WindowManager.LayoutParams属性不同,效果也就不同了。比如创建系统顶级窗口,实现悬浮窗口效果!
WindowManager的方法很简单,基本用到的就三个addView,removeView,updateViewLayout。
而WindowManager.LayoutParams的属性就多了,非常丰富,具体请查看SDK文档。这里给出Android中的WindowManager.Java源码,可以具体看一下。
下面是简单示例代码:
[java] view plain copy print ? <span style="color:#000000;FONT-WEIGHT: bold">public</span> <span style="color:#000000;FONT-WEIGHT: bold">class</span> myFloatView <span style="color:#000000;FONT-WEIGHT: bold">extends</span> Activity <span style="color:#009900;">{</span> <span style="color:#008000;FONT-STYLE: italic; FONT-WEIGHT: bold">/** Called when the activity is first created. */</span> @Override <span style="color:#000000;FONT-WEIGHT: bold">public</span> <span style="color:#000066;FONT-WEIGHT: bold">void</span> onCreate<span style="color:#009900;">(</span>Bundle savedInstanceState<span style="color:#009900;">)</span> <span style="color:#009900;">{</span> <span style="color:#000000;FONT-WEIGHT: bold">super</span>.<span style="color:#006633;">onCreate</span><span style="color:#009900;">(</span>savedInstanceState<span style="color:#009900;">)</span><span style="color:#339933;">;</span> setContentView<span style="color:#009900;">(</span>R.<span style="color:#006633;">layout</span>.<span style="color:#006633;">main</span><span style="color:#009900;">)</span><span style="color:#339933;">;</span> <span style="color:#003399;">Button</span> bb<span style="color:#339933;">=</span><span style="color:#000000;FONT-WEIGHT: bold">new</span> <span style="color:#003399;">Button</span><span style="color:#009900;">(</span>getApplicationContext<span style="color:#009900;">(</span><span style="color:#009900;">)</span><span style="color:#009900;">)</span><span style="color:#339933;">;</span> WindowManager wm<span style="color:#339933;">=</span><span style="color:#009900;">(</span>WindowManager<span style="color:#009900;">)</span>getApplicationContext<span style="color:#009900;">(</span><span style="color:#009900;">)</span>.<span style="color:#006633;">getSystemService</span><span style="color:#009900;">(</span><span style="color:#0000ff;">"window"</span><span style="color:#009900;">)</span><span style="color:#339933;">;</span> WindowManager.<span style="color:#006633;">LayoutParams</span> wmParams <span style="color:#339933;">=</span> <span style="color:#000000;FONT-WEIGHT: bold">new</span> WindowManager.<span style="color:#006633;">LayoutParams</span><span style="color:#009900;">(</span><span style="color:#009900;">)</span><span style="color:#339933;">;</span> <span style="color:#008000;FONT-STYLE: italic; FONT-WEIGHT: bold">/** *以下都是WindowManager.LayoutParams的相关属性 * 具体用途请参考SDK文档 */</span> wmParams.<span style="color:#006633;">type</span><span style="color:#339933;">=</span><span style="color:#cc66cc;">2002</span><span style="color:#339933;">;</span> <span style="color:#666666;FONT-STYLE: italic">//这里是关键,你也可以试试2003</span> wmParams.<span style="color:#006633;">format</span><span style="color:#339933;">=</span><span style="color:#cc66cc;">1</span><span style="color:#339933;">;</span> <span style="color:#008000;FONT-STYLE: italic; FONT-WEIGHT: bold">/** *这里的flags也很关键 *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) */</span> wmParams.<span style="color:#006633;">flags</span><span style="color:#339933;">=</span><span style="color:#cc66cc;">40</span><span style="color:#339933;">;</span> wmParams.<span style="color:#006633;">width</span><span style="color:#339933;">=</span><span style="color:#cc66cc;">40</span><span style="color:#339933;">;</span> wmParams.<span style="color:#006633;">height</span><span style="color:#339933;">=</span><span style="color:#cc66cc;">40</span><span style="color:#339933;">;</span> wm.<span style="color:#006633;">addView</span><span style="color:#009900;">(</span>bb, wmParams<span style="color:#009900;">)</span><span style="color:#339933;">;</span> <span style="color:#666666;FONT-STYLE: italic">//创建View</span> <span style="color:#009900;">}</span> <span style="color:#009900;">}</span> public class myFloatView extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); Button bb=new Button(getApplicationContext()); WindowManager wm=(WindowManager)getApplicationContext().getSystemService("window"); WindowManager.LayoutParams wmParams = new WindowManager.LayoutParams(); /** *以下都是WindowManager.LayoutParams的相关属性 * 具体用途请参考SDK文档 */ wmParams.type=2002; //这里是关键,你也可以试试2003 wmParams.format=1; /** *这里的flags也很关键 *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) */ wmParams.flags=40; wmParams.width=40; wmParams.height=40; wm.addView(bb, wmParams); //创建View } }别忘了在AndroidManifest.xml中添加权限:
[java] view plain copy print ? <span style="color:#339933;"><</span>uses<span style="color:#339933;">-</span>permission android<span style="color:#339933;">:</span>name<span style="color:#339933;">=</span><span style="color:#0000ff;">"android.permission.SYSTEM_ALERT_WINDOW"</span> <span style="color:#339933;">/></span> <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />PS:这里举例说明一下type的值的意思:
[java] view plain copy print ? <span style="color:#008000;FONT-STYLE: italic; FONT-WEIGHT: bold">/** * Window type: phone. These are non-application windows providing * user interaction with the phone (in particular incoming calls). * These windows are normally placed above all applications, but behind * the status bar. */</span> <span style="color:#000000;FONT-WEIGHT: bold">public</span> <span style="color:#000000;FONT-WEIGHT: bold">static</span> <span style="color:#000000;FONT-WEIGHT: bold">final</span> <span style="color:#000066;FONT-WEIGHT: bold">int</span> TYPE_PHONE <span style="color:#339933;">=</span> FIRST_SYSTEM_WINDOW<span style="color:#339933;">+</span><span style="color:#cc66cc;">2</span><span style="color:#339933;">;</span> <span style="color:#008000;FONT-STYLE: italic; FONT-WEIGHT: bold">/** * Window type: system window, such as low power alert. These windows * are always on top of application windows. */</span> <span style="color:#000000;FONT-WEIGHT: bold">public</span> <span style="color:#000000;FONT-WEIGHT: bold">static</span> <span style="color:#000000;FONT-WEIGHT: bold">final</span> <span style="color:#000066;FONT-WEIGHT: bold">int</span> TYPE_SYSTEM_ALERT <span style="color:#339933;">=</span> FIRST_SYSTEM_WINDOW<span style="color:#339933;">+</span><span style="color:#cc66cc;">3</span><span style="color:#339933;">;</span> /** * Window type: phone. These are non-application windows providing * user interaction with the phone (in particular incoming calls). * These windows are normally placed above all applications, but behind * the status bar. */ public static final int TYPE_PHONE = FIRST_SYSTEM_WINDOW+2; /** * Window type: system window, such as low power alert. These windows * are always on top of application windows. */ public static final int TYPE_SYSTEM_ALERT = FIRST_SYSTEM_WINDOW+3;这个FIRST_SYSTEM_WINDOW的值就是2000。2003和2002的区别就在于2003类型的View比2002类型的还要top,能显示在系统下拉状态栏之上!
————————————————————————————-
已经给出可自由移动悬浮窗口的Demo,参加这里。
顶 0 踩 0 上一篇横竖屏切换时候Activity的生命周期 下一篇Android中可自由移动悬浮窗口的Demo