e想行空

public class ArcMenu extends ViewGroup {
    public ArcMenu(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
	@Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
	  int cent_x = getWidth() / 2; //viewgroup中心坐标
      int cent_y = getHeight() / 2; //viewgroup中心坐标
	  for (int i = 0; i < getChildCount(); i++) {
	  
         View childView = getChildAt(i);  //遍历子控件
         int childWidth = childView.getMeasuredWidth();  //获得子控件的宽度，需要先测量
         int childHeight = childView.getMeasuredHeight();
		 
			int cl = 0, ct = 0, cr = 0, cb = 0;		
		}
		 
		  childView.layout(cl, ct, cr, cb); //见下图
	}
	@Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        //测量所有子View的宽高
        measureChildren(widthMeasureSpec, heightMeasureSpec);
    }
}

Observable alive=Observable.just(temp_send).delay(4000,TimeUnit.MILLISECONDS).repeat(); //心跳数据（每隔4s重复发一次）
Observable send=  Observable.create(new Observable.OnSubscribe<byte[]>() {
     @Override
     public void call(Subscriber<? super byte[]> subscriber) {
         subscriberSend=subscriber;   //负责数据的发送
     }
 });
 //合并，订阅
send_subscribe= Observable.mergeDelayError(alive,send).subscribe(new Action1<byte[]>() {
     @Override
     public void call(byte[] bs) {
         send(bs);  //数据出口
     }
 });

public Observable<String> xuanSend(final String str){
    return Observable.create(new Observable.OnSubscribe<String>() {
        @Override
        public void call(Subscriber<? super String> subscriber) {
            Log.d("TASK_SHOW","任务："+str+"，状态：开始执行，发送数据：空");
            strTask=str;
            subscriber.onNext(str+"中......");
            subscriberTask=subscriber;   //执行结果的入口

        }
    }).distinct().timeout(5000,TimeUnit.MILLISECONDS).retryWhen(new Func1<Observable<? extends Throwable>, Observable<?>>() {
        @Override
        public Observable<?> call(final Observable<? extends Throwable> observable) {
            return observable.zipWith(Observable.range(1, 5), new Func2<Throwable, Integer, Object>() {
                @Override
                public Object call(Throwable throwable, Integer integer) {
                    if(throwable.getMessage()==null)
                        Log.d("TASK_SHOW","任务："+str+"，状态：异常结束，异常："+"第"+integer+"次,执行超时");
                    else
                        Log.d("TASK_SHOW","任务："+str+"，状态：异常结束，异常："+throwable.getMessage());
                    return 0;
                }
            }).delay(10000,TimeUnit.MILLISECONDS);
        }
    });
}

//任务流
  Observable<String> task=Observable.concat(mBle.connet(bleDevicesList.getmBleDevicesList_test()),mBle.enableRX(),mBle.xuanSend(sendData.setStart(false),Ble.START),mBle.xuanSend(sendData.setsafe(false,false),Ble.CANCELSAFE),mBle.disConnet());
                
	task.repeat().subscribeOn(Schedulers.computation()).observeOn(AndroidSchedulers.mainThread()).subscribe(new Subscriber<String>() {
                    @Override
                    public void onCompleted() {
						//所有任务完成，但是如果reapt（）,始终是不会完成的
					   }
                    @Override
                    public void onError(Throwable e) {
                       //发生错误时
                    }
                    @Override
                    public void onNext(String result) {
                       //任务完成
                    }

                });

int sum=0;                //（一次）
for(int i=1;i<=n;i++)    //（n+1次）
    for(int j=1;j<=n;j++)    //（n²次）
      sum++;                 //（n²次）

public class Singleton {
 
    private static Singleton instance = null;
 
    private Singleton(){
    }
 
    public static Singleton getInstance() {
        synchronized (Singleton.class) {
            if (instance == null) {
                instance = new Singleton();
            }
        }
 
        return instance;
    }
}

public class Singleton {
 
    private static volatile Singleton instance = null;
 
    private Singleton(){
    }
 
    public static Singleton getInstance() {
        // if already inited, no need to get lock everytime
        if (instance == null) {
            synchronized (Singleton.class) {
                if (instance == null) {
                    instance = new Singleton();
                }
            }
        }
 
        return instance;
    }
}

public static void main(String[] args){
   Singleton singleton = Singleton.instance;
   singleton.doSomething();
}

public class RxBus {
    private static volatile RxBus instance;
    private final Subject<Object, Object> BUS;

    // PublishSubject只会把在订阅发生的时间点之后来自原始Observable的数据发射给观察者
    public RxBus() {
        BUS = new SerializedSubject<>(PublishSubject.create());
    }

    // 单例RxBus
    public static RxBus getDefault() {
        if (instance == null) {
            synchronized (RxBus.class) {
                if (instance == null) {
                    instance = new RxBus();
                }
            }
        }
        return instance;
    }

    // 发送一个新的事件
    public void post(Object o) {
        BUS.onNext(o);
    }

    // 根据传递的 eventType 类型返回特定类型(eventType)的 被观察者
    public <T> Observable<T> toObservable(Class<T> eventType) {
        return BUS.ofType(eventType);
//        这里感谢小鄧子的提醒: ofType = filter + cast
//        return bus.filter(new Func1<Object, Boolean>() {
//            @Override
//            public Boolean call(Object o) {
//                return eventType.isInstance(o);
//            }
//        }) .cast(eventType);
    }
}

RxBus.getDefault().toObservable(String.class).subscribe(new Action1<String>() {
          @Override
          public void call(String s) {
              Toast.makeText(BleActivity.this,s,Toast.LENGTH_SHORT).show();
          }
      });