velocitytracker求助，怎么用android实现控件的3D立体旋转效果

velocity profile是什么意思

velocity profile 英 [vi?l?siti ?pr?ufail] 美 [v??lɑs?ti ?pro?fa?l] 速度剖面（图），速度分布图，速度变化图 速度剖面；速度分布图；速度场；速度剖面图 双语例句 1. What then is the ideal velocity profile for a missile? 什么是导弹理想的速度分布图 呢 ? 2. The viscosity of the fluid has no direct effect on the velocity profile. 流体的粘度对速度场没有直接影响. 3. A semitheoretical modeling to calculate pressure drop and exponent of vortex velocity profile is deduced. 建立了计算旋风分离器压降及速度分布指数的通用计算式. 4. Microtremor measurement has been increasingly adopted to assess site amplification and S - wave velocity profile at sites. 微地动量测正逐渐地被应用在场址放大效应的评估,以及剪力波速剖面之推求上. 5. The velocity profile and residence time distribution in cold model of Texacogasifier were measured. 测定了德士古气化炉的冷态速度分布和停留时间分布.

velocity 和speed的区别

speed指运动的速度,既可指快速,也可指慢速; velocity表示沿一定路线运动的速度,通常指直线、弧线或圆周运动的速度,这个词可与speed通用,但多用于科学技术方面。

一、velocity词汇分析 音标：英 [v??l?s?ti] ? 美 [v??lɑ:s?ti] ? 释义：速率，速度;周转率;高速，快速 拓展资料 1、To remove the ambiguity, these laws should refer to the velocity and the eleration of the center of mass.? 要避免含糊，这些定律所指的应当是质心的速度和加速度。

2、Gazelles can move with astonishing velocity.? 羚羊跑起来有时速度惊人。

3、A liquid drop removed from a sheet or jet may be exposed to the aerodynamic pressure effect of a high relative gas velocity.? 离开液膜或射流的液滴，可能会受到高的相对速度气体的气动压力影响。

4、The current velocity of the flood stood at3.6 metres per second.? 洪水流速为每秒三点六米。

二、speed词汇分析 音标：英 [spi:d] ? 美 [spid]? 释义：速度;快速;昌盛;（汽车的）变速器，排挡 拓展资料 1、This course is designed so that students can progress at their own speed. 这门课的设计思路是让学生自己掌握进度。

2、We aim to increase the speed of delivery (= how quickly goods are sent) . 我们力争提高送货速度。

3、Are you up to speed yet on the latest developments? 你了解最新的进展情况吗？ 4、He put on an impressive turn of speed in the last lap. 他在最后一圈猛然加速。

VelocityEngine 是什么包

org.apache.velocity.app.Velocity.类是一个初始化单例的velocity实例的类。

单例模式是一种简单的设计模式，用最简单的话来说，就是让多个类共享一个实例，让他们能够访问到同样的数据。

对比发现： Velocity类中使用init方法里是使用了RuntimeSingleton.init(); 在RuntimeSingleton类中，使用到的运行实例是静态new出来的。

private static RuntimeInstance ri = new RuntimeInstance(); 而.apache.velocity.app.VelocityEngine类中，并没有一个单例类来初始化，每次都会使用 private RuntimeInstance ri = new RuntimeInstance() 来创建一个新的运行实例，这样就使得每个velocity引擎都会拥有各自的实例，互不干扰。

从RuntimeSingleton类的注释来看： /** * This is the Runtime system for Velocity. It is the * single ess point for all functionality in Velocity. * It adheres to the mediator pattern and is the only * structure that developers need to be familiar with * in order to get Velocity to perform. * * The Runtime will also cooperate with external * systems like Turbine. Runtime properties can * set and then the Runtime is initialized. * * Turbine for example knows where the templates * are to be loaded from, and where the velocity * log file should be placed. */ velocity和外部合作的项目，例如turbine，就使用的这个类来实例化velocity引擎。

ANSYS中Velocity streamline的7.974e+002是什么意思

要看绘制彩色streamline的物理量是什么，如果是速度，那就是速度为7.974e+002m/s, 或者是自定义的单位。

7.974e+002是科学计数法，等于 797.4

求助，怎么用android实现控件的3D立体旋转效果

实现水平滑动，所以可在手势抬起的时候进行判断并处理，是滑动显得流畅，代码如下： .example.rotation3dview;?? import?android.content.Context;?? import?android.graphics.Camera;?? import?android.graphics.Canvas;?? import?android.graphics.Matrix;?? import?android.util.AttributeSet;?? import?android.view.MotionEvent;?? import?android.view.VelocityTracker;?? import?android.view.View;?? import?android.view.ViewDebug.HierarchyTraceType;?? import?android.view.ViewGroup;?? import?android.widget.ImageView;?? import?android.widget.Scroller;?? public?class?Rote3DView?extends?ViewGroup{?? ????private?int?mCurScreen?=?1;?? ????//?滑动的速度?? ????private?static?final?int?SNAP_VELOCITY?=?500;?? ????private?VelocityTracker?mVelocityTracker;?? ????private?int?mWidth;?? ????private?Scroller?mScroller;?? ????private?Camera?mCamera;?? ????private?Matrix?mMatrix;?? ????//?旋转的角度，可以进行修改来观察效果?? ????private?float?angle?=?90;?? ????public?Rote3DView(Context?context,?AttributeSet?attrs)?{?? ????????super(context,?attrs);?? ????????mScroller?=?new?Scroller(context);?? ????????mCamera?=?new?Camera();?? ????????mMatrix?=?new?Matrix();?? ????????initScreens();?? ????}?? ????public?void?initScreens(){?? ????????ViewGroup.LayoutParams?p?=?new?ViewGroup.LayoutParams(?? ????????????????ViewGroup.LayoutParams.MATCH_PARENT,ViewGroup.LayoutParams.MATCH_PARENT);????? ?????????for?(int?i?=?0;?i?<?3;?i++)?{??? ?????????????this.addView(new?ImageView(this.getContext()),?i,?p);??? ?????????}??? ?????????((ImageView)this.getChildAt(0)).setImageResource(R.drawable.page1);??? ?????????((ImageView)this.getChildAt(1)).setImageResource(R.drawable.page2);??? ?????????((ImageView)this.getChildAt(2)).setImageResource(R.drawable.page3);??? ????}?? ????@Override?? ????protected?void?onLayout(boolean?changed,?int?l,?int?t,?int?r,?int?b)?{?? ????????int?childLeft?=?0;?? ????????final?int?childCount?=?getChildCount();?? ????????for(int?i?=?0;?i<?childCount;?i++){?? ????????????final?View?childView?=?getChildAt(i);?? ????????????if(childView.getVisibility()?!=?View.GONE){?? ????????????????final?int?childWidth?=?childView.getMeasuredWidth();?? ????????????????childView.layout(childLeft,?0,?childLeft?+?childWidth,?childView.getMeasuredHeight());?? ????????????????childLeft?+=?childWidth;?? ????????????}?? ????????}?? ????}?? ????@Override?? ????protected?void?onMeasure(int?widthMeasureSpec,?int?heightMeasureSpec)?{?? ????????super.onMeasure(widthMeasureSpec,?heightMeasureSpec);?? ????????final?int?width?=?MeasureSpec.getSize(widthMeasureSpec);?? ????????final?int?widthMode?=?MeasureSpec.getMode(widthMeasureSpec);?? ????????if(widthMode?!=?MeasureSpec.EXACTLY){?? ????????????throw?new?IllegalStateException("仅支持精确尺寸");?? ????????}?? ????????final?int?heightMode?=?MeasureSpec.getMode(heightMeasureSpec);?? ????????if(heightMode?!=?MeasureSpec.EXACTLY){?? ????????????throw?new?IllegalStateException("仅支持精确尺寸");?? ????????}?? ????????final?int?count?=?getChildCount();?? ????????for(int?i?=?0;?i?<?count;?i++){?? ????????????getChildAt(i).measure(widthMeasureSpec,?heightMeasureSpec);?? ????????}?? ????????scrollTo(mCurScreen?*?width,?0);?? ????}?? ????private?float?mDownX;?? ????@Override?? ????public?boolean?onTouchEvent(MotionEvent?event)?{?? ????????if(mVelocityTracker?==?null){?? ????????????mVelocityTracker?=?VelocityTracker.obtain();?? ????????}?? ????????//将当前的触摸事件传递给VelocityTracker对象?? ????????mVelocityTracker.addMovement(event);?? ????????float?x?=?event.getX();?? ????????switch?(event.getAction())?{?? ????????case?MotionEvent.ACTION_DOWN:?? ????????????if(!mScroller.isFinished()){?? ????????????????mScroller.abortAnimation();?? ????????????}?? ????????????mDownX?=?x;?? ????????????break;?? ????????case?MotionEvent.ACTION_MOVE:?? ????????????int?disX?=?(int)(mDownX?-?x);?? ????????????mDownX?=?x;?? ????????????scrollBy(disX,?0);?? ????????????break;?? ????????case?MotionEvent.ACTION_UP:?? ????????????final?VelocityTracker?velocityTracker?=?mVelocityTracker;?? ????????????puteCurrentVelocity(1000);?? ????????????int?velocityX?=?(int)?velocityTracker.getXVelocity();?? ????????????if(velocityX?>?SNAP_VELOCITY?&&?mCurScreen?>?0){?? ????????????????snapToScreen(mCurScreen?-?1);?? ????????????}else?if(velocityX?<?-SNAP_VELOCITY?&&?mCurScreen?<?getChildCount()?-?1){?? ????????????????snapToScreen(mCurScreen?+?1);?? ????????????}else{?? ????????????????snapToDestination();?? ????????????}?? ????????????if(mVelocityTracker?!=?null){?? ????????????????mVelocityTracker.recycle();?? ????????????????mVelocityTracker?=?null;?? ????????????}?? ????????????break;?? ????????}?? ????????return?true;?? ????}?? ????@Override?? ????public?puteScroll()?{?? ????????if?(puteScrollOffset())?{?? ????????????scrollTo(mScroller.getCurrX(),?mScroller.getCurrY());?? ????????????postInvalidate();?? ????????}?? ????}?? ????public?void?snapToDestination(){?? ????????setMWidth();?? ????????final?int?destScreen?=?(getScrollX()?+?mWidth?/?2)?/?mWidth;?? ????????snapToScreen(destScreen);?? ????}?? ????public?void?snapToScreen(int?whichScreen){?? ????????whichScreen?=?Math.max(0,?Math.min(whichScreen,?getChildCount()?-?1));?? ????????setMWidth();?? ????????int?scrollX?=?getScrollX();?? ????????int?startWidth?=?whichScreen?*?mWidth;?? ????????if(scrollX?!=?startWidth){?? ????????????int?delta?=?0;?? ????????????int?startX?=?0;?? ????????????if(whichScreen?>?mCurScreen){?? ????????????????setPre();?? ????????????????delta?=?startWidth?-?scrollX;?? ????????????????startX?=?mWidth?-?startWidth?+?scrollX;?? ????????????}else?if(whichScreen?<?mCurScreen){?? ????????????????setNext();?? ????????????????delta?=?-scrollX;?? ????????????????startX?=?scrollX?+?mWidth;?? ????????????}else{?? ????????????????startX?=?scrollX;?? ????????????????delta?=?startWidth?-?scrollX;?? ????????????}?? ????????????mScroller.startScroll(startX,?0,?delta,?0,?Math.abs(delta)?*?2);?? ????????????invalidate();?? ????????}?? ????}?? ????private?void?setNext(){?? ????????int?count?=?this.getChildCount();?? ????????View?view?=?getChildAt(count?-?1);?? ????????removeViewAt(count?-?1);?? ????????addView(view,?0);?? ????}?? ????private?void?setPre(){?? ????????int?count?=?this.getChildCount();?? ????????View?view?=?getChildAt(0);?? ????????removeViewAt(0);?? ????????addView(view,?count?-?1);?? ????}?? ????private?void?setMWidth(){?? ????????if(mWidth?==?0){?? ????????????mWidth?=?getWidth();?? ????????}?? ????}?? }

实现立体效果，添加如下代码： /*? ?*?当进行View滑动时，会导致当前的View无效，该函数的作用是对View进行重新绘制?调用drawScreen函数? ?*/?? @Override?? protected?void?dispatchDraw(Canvas?canvas)?{?? ????final?long?drawingTime?=?getDrawingTime();?? ????final?int?count?=?getChildCount();?? ????for?(int?i?=?0;?i?<?count;?i++)?{?? ????????drawScreen(canvas,?i,?drawingTime);?? ????}?? }?? public?void?drawScreen(Canvas?canvas,?int?screen,?long?drawingTime)?{?? ????//?得到当前子View的宽度?? ????final?int?width?=?getWidth();?? ????final?int?scrollWidth?=?screen?*?width;?? ????final?int?scrollX?=?this.getScrollX();?? ????//?偏移量不足的时?? ????if?(scrollWidth?>?scrollX?+?width?||?scrollWidth?+?width?<?scrollX)?{?? ????????return;?? ????}?? ????final?View?child?=?getChildAt(screen);?? ????final?int?faceIndex?=?screen;?? ????final?float?currentDegree?=?getScrollX()?*?(angle?/?getMeasuredWidth());?? ????final?float?faceDegree?=?currentDegree?-?faceIndex?*?angle;?? ????if?(faceDegree?>?90?||?faceDegree?<?-90)?{?? ????????return;?? ????}?? ????final?float?centerX?=?(scrollWidth?<?scrollX)???scrollWidth?+?width?? ????????????:?scrollWidth;?? ????final?float?centerY?=?getHeight()?/?2;?? ????final?Camera?camera?=?mCamera;?? ????final?Matrix?matrix?=?mMatrix;?? ????canvas.save();?? ????camera.save();?? ????camera.rotateY(-faceDegree);?? ????camera.getMatrix(matrix);?? ????camera.restore();?? ????matrix.preTranslate(-centerX,?-centerY);?? ????matrix.postTranslate(centerX,?centerY);?? ????canvas.concat(matrix);?? ????drawChild(canvas,?child,?drawingTime);?? ????canvas.restore();?? }