本篇文章教大家如何在状态栏中加入网速实时监控，效果如下图所示
上图就是要实现的效果，我们可以通过自定义一个View,让它继承TextView，然后在该View内部添加获取实时网络并显示出来的逻辑，废话不多说，看一下代码
首先，在frameworks\base\packages\SystemUI\src\com\android\systemui\statusbar\phone下新建一个NetShowView，让它继承TextView
private long lastTotalRxBytes = 0;//上一次获取的总消耗流量 private long lastTimeStamp = 0;//记录上一次时间private String mSpeed="";private Paint mPaint;private Rect mBound;private Context mContext;private SettingsValueChangeContentObserver mContentOb;//监控数据库，是否打开网速显示private NetworkConnectReceiver mNetReceiver;private boolean mIsConn;//判断当前是否有网络连接public NetShowView(Context context, AttributeSet attrs) {super(context, attrs);setPaint(context);}private void setPaint(Context context){mContext=context;mPaint=new Paint();mPaint.setAntiAlias(true);mPaint.setColor(this.getCurrentTextColor());mPaint.setTextSize(getTextSize());mBound = new Rect();checkNetConnInit();}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);mPaint.getTextBounds(mSpeed, 0, mSpeed.length(), mBound);canvas.drawText(mSpeed, getWidth() - mBound.width()-10, getHeight() / 2 + mBound.height() / 2, mPaint);}
首先在该类里定义一些变量，在构造方法中初始化一些Paint的属性，并在onDraw方法中将网速mSpeed显示上去，以上内容比较简单，不再详述，我们看到在setPaint方法中有一个checkNetConnInit()方法，我们来看一下它的具体实现
private void checkNetConnInit(){if(mContentOb==null){mContentOb = new SettingsValueChangeContentObserver();mContext.getContentResolver().registerContentObserver(Settings.Global.getUriFor(WORK_SPEED),true, mContentOb);}if(mNetReceiver==null){mNetReceiver= new NetworkConnectReceiver();IntentFilter filter = new IntentFilter();filter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);filter.addAction(NetSpeedService.SEND_ACTION);mContext.registerReceiver(mNetReceiver, filter);}
该类分别作了两个操作，初始化SettingsValueChangeContentObserver为其注册监听，然后初始化NetworkConnectReceiver为其注册事件，为其添加了两个action，分别为ConnectivityManager.CONNECTIVITY_ACTION和NetSpeedService.SEND_ACTION，ConnectivityManager.CONNECTIVITY_ACTION这个action是用来监听网络是否连接的，NetSpeedService.SEND_ACTION这个暂时先不看，稍后分析，我们来看一下SettingsValueChangeContentObserver和NetworkConnectReceiver的具体实现
class SettingsValueChangeContentObserver extends ContentObserver {public SettingsValueChangeContentObserver() {super( new Handler());}@Overridepublic void onChange(boolean selfChange) {super.onChange(selfChange);if(mIsConn){int state=Settings.Global.getInt(mContext.getContentResolver(), WORK_SPEED,0);if(state==1){start();//开始显示网速}else{stop();//停止显示网速}}} }
class NetworkConnectReceiver extends BroadcastReceiver {@Overridepublic void onReceive(Context context, Intent intent) {if (ConnectivityManager.CONNECTIVITY_ACTION.equals(intent.getAction())) {NetworkInfo info = intent.getParcelableExtra(ConnectivityManager.EXTRA_NETWORK_INFO);if (info != null) {if (NetworkInfo.State.CONNECTED == info.getState()) {mIsConn = true;boolean isOpen = Settings.Global.getInt(context.getContentResolver(),WORK_SPEED, 0) == 1;if (isOpen) {start();} else {stop();}} else {mIsConn = false;stop();}}}if (intent.getAction().equals(NetSpeedService.SEND_ACTION)) {showNetSpeed();}}}
SettingsValueChangeContentObserver这个内容观察者监听WORK_SPEED的值变化，这个是我们在SettingProvider中自定义的一个全局变量，我们用它来为网速显示提供一个控制开关，当WORK_SPEED值为1显示网速，为0则关闭网速显示，默认关闭
NetworkConnectReceiver中定义了两个action，我们首先来看一下ConnectivityManager.CONNECTIVITY_ACTION这个action，当NetworkConnectReceiver接收到这个事件后，代表当前打开了数据流量或者连上了WiFi，然后经过一系列判断后，我们根据网络状态和WORK_SPEED的值调用start()方法和stop()方法，下面我们来看一下这两个方法做了什么操作
private void start(){lastTotalRxBytes = TrafficStats.getTotalRxBytes(); lastTimeStamp = System.currentTimeMillis();mContext.startService(new Intent(mContext, NetSpeedService.class));setVisibility(View.VISIBLE);}
private void stop(){mContext.stopService(new Intent(mContext, NetSpeedService.class));setVisibility(View.GONE);}
start()方法中通过TrafficStats.getTotalRxBytes()获取了总接收流量，并赋予lastTotalRxBytes，开启了服务NetSpeedService，设置当前Visble为可见，stop方法调用了NetSpeedService的停止方法以及设置当前Visble为不可见，两个方法都比较简单，回过头来我们看一下NetworkConnectReceiver的另一个事件NetSpeedService.SEND_ACTION，这里调用了showNetSpeed()方法，这个方法就是计算显示网速的方法，我们来看一下具体实现
private void showNetSpeed() { long nowTotalRxBytes = TrafficStats.getTotalRxBytes(); long nowTimeStamp = System.currentTimeMillis();//modify by wxc on 0111long difTime=nowTimeStamp - lastTimeStamp;if(difTime<=0){mSpeed="0B/s";}else{String endTotal;long speedTotal=(nowTotalRxBytes-lastTotalRxBytes)*1000/difTime; if(speedTotal<1000){mSpeed=speedTotal+"B/s";}else if(speedTotal<1000*1024){endTotal=String.valueOf(speedTotal % 1024);speedTotal=speedTotal/1024;if(endTotal.length()>1){endTotal=endTotal.substring(0, 1);}mSpeed=speedTotal+"."+endTotal+"K/s";}else{endTotal=String.valueOf(speedTotal% (1024*1024));speedTotal=speedTotal/1024/1024;if(endTotal.length()>1){endTotal=endTotal.substring(0, 1);}mSpeed=speedTotal+"."+endTotal+"M/s";}}lastTimeStamp = nowTimeStamp;lastTotalRxBytes = nowTotalRxBytes;invalidate();}
以上就是showNetSpeed方法，该方法主要计算了当前网速，并将网速赋值给mSpeed，通过invalidate()方法刷新当前view显示，过程不难，不再详述，这里我们回过头来看一下NetSpeedService这个服务，该服务主要通过scheduledExecutor.scheduleWithFixedDelay方法进行一个周期任务，每隔一秒发送一个NetSpeedService.SEND_ACTION广播，当NetworkConnectReceiver接收到该广播就调用showNetSpeed()方法来刷新网速显示，以下是NetSpeedService的全部代码
public class NetSpeedService extends Service{public static final String SEND_ACTION="SEND_ACTION";private ScheduledExecutorService scheduledExecutor;@Overridepublic void onCreate() {super.onCreate();}@Overridepublic int onStartCommand(Intent intent, int flags, int startId) {stopAddOrSubtract();updateAddOrSubtract();return START_STICKY;}@Overridepublic IBinder onBind(Intent intent) {return null;}@Overridepublic void onDestroy() {super.onDestroy();stopAddOrSubtract();}private void updateAddOrSubtract() {if(scheduledExecutor==null){scheduledExecutor = Executors.newSingleThreadScheduledExecutor();scheduledExecutor.scheduleWithFixedDelay(new Runnable() {@Overridepublic void run() {Intent sendIntent = new Intent(SEND_ACTION);getApplicationContext().sendBroadcast(sendIntent);}}, 0, 1, TimeUnit.SECONDS);}}private void stopAddOrSubtract() {if (scheduledExecutor != null) {scheduledExecutor.shutdownNow();scheduledExecutor = null;}}}
以上内容完成后自定义的NetShowView就完成了，这时候我们需要将其添加到如图所示的StatusBar上，打开frameworks\base\packages\SystemUI\res\layout\system_icons.xml文件，在此文件中添加该view，大小位置可以自己调节，同时我们可以在Setting中添加一个网速显示的switch开关，通过设置WORK_SPEED的值来实现功能
<com.android.systemui.ShowViewandroid:id="@+id/net_show_text"android:layout_width="56dp"android:layout_height="match_parent"android:textColor="#ffffff"android:visibility="gone"android:textSize="12dip"/>
OK,通过以上的步骤就可以在状态栏添加实时网速监控了，感兴趣的可以自己试试
