As question title, I want to use the change values of accelerator at three axis x,y,z to test that device is standing still or is moving.
I can use titanium to get values of accelerator in 3 axis:
Ti.Accelerometer.addEventListenter('update',function(e))
{
var x=e.x;
var y=e.y;
var z=e.z;
var timestamp=e.timestamp;
}
In real device, those values change continuously. I want to calculate the change between two times update consecutive. But I need some pointers on how to do the calculation.
How about in addEventListener you keep 3 static variables or a single static structure containing the last values and calculate the abs() difference on them and the current values?
Pseudo code ( handling just one variable - expand to three ):
int f( int x )
{
static int old_x = -1;
if( x != old_x )
{
// movement detected and do something
old_x = x;
}
else
{
// no movement
}
}
}
you can use Ti.App.Properties variables to store values if you want. Instead of your pseudocode's c++ style static variable, use a property and update it at the end of your event listener.
http://developer.appcelerator.com/apidoc/mobile/1.8.2/Titanium.App.Properties-module
Related
Ok I am having an issue trying to put a square root equation in a calculator. I am trying to figure out the expression builder. I know the expression builder takes the math operations of add, subtract, multiply, divide, equals and the parenthesis. What I am doing is trying to build the square root section. I have a simple Percent code to help with the square root.
In the Square root vs the Percent you see I am using binding. So here is the code for both.
On the square root is it possible to use the expression builder? I know there is no absolute formula for square root except for a number that is multipliable with itself like the number 4.
Sqrt(4) = 2
binding.btnSqrt.setOnClickListener {
var square = (tv_equation.text.toString().toDouble() / 2)
binding.tvResult.text = square.toString()
}
So in the event you a non square equation
sqrt(23) = 4.79
How would I simulate that as one function within the button. Can I use expression or would I need to use Kotlin.math
So between the two I divide by 100 on the percent. It works great.
binding.btnPercent.setOnClickListener {
var percentage = (tv_equation.text.toString().toDouble() / 100)
binding.tvResult.text = percentage.toString()
}
All my other buttons work fine and so I am just working on the square root before I can release this to google play.
You would need to use some form of a square root function.
AS you mentioned in your question Kotlin Sqrt Function is a very suitable choice
binding.btnSqrt.setOnClickListener {
if(!tv_equation.text.isNullOrEmpty){
var number = tv_equation.text.toString().toDouble()
binding.tvResult.text = sqrt(number).toString()
}
You can create a sqrt function using the Quake's first inverse square root.
Quake's first inverse square root.
Pseudo Code:
float InvSqrt(float x){
float xhalf = 0.5f * x;
int i = *(int*)&x; // store floating-point bits in integer
i = 0x5f3759df - (i >> 1); // initial guess for Newton's method
x = *(float*)&i; // convert new bits into float
x = x*(1.5f - xhalf*x*x); // One round of Newton's method
return x;
}
So the answer i want to add is a little more suitable with the previous answer. Maybe this will help some people in the future. This solution will also limit the decimal space to 4 decimals.
binding.btnSqrt.setOnClickListener{
val df = DecimalFormat("#.####")
if(!tv_equation.text.isNullOrEmpty())
{
val number = tv_equation.text.toString().toDouble()
binding.tvResult.text = df.format(sqrt(number))
}
}
you can adjust the val df = DecimalFormat("#.####") where the # to as many decimals as you would want.
I've been having some problems using Transform.Rotate in dart/Flutter.
I have set up my code so that I can rotate an image with gestures. However once I've rotated the image once and let go and continue the rotation the image is reset back to its original position.
It's the same issue shown here: Rotation gesture produces undesired rotation
The solution here is to save the transform in a variable. Is there any way to save the transform in a variable in Dart/Flutter?
Also the ideal situation would be that I can animate the rotation a little so it's delayed slightly because right now it responds straight away to rotation. If this part is unclear please let me know!!
Any suggestions are welcome!!!
You basically want to save the state of the widget so I think you will need to wrap it in a StatefulWidget to be able to do that.
(https://www.youtube.com/watch?v=AqCMFXEmf3w)
To smooth out the animation you could maybe try and use the AnimatedContainer?
I haven't used it myself but I think it should be what you need! (https://www.youtube.com/watch?v=yI-8QHpGIP4)
EDIT
Okay, I've got it working for you.
Offset vector;
double startingAngle;
double deltaAngle = 0.0;
double finalAngle = 0.0;
// store the final angle of the object
double finalObjectAngle = 0.0;
void _onPanStart(DragStartDetails details) {
_polarCoordFromGlobalOffset(details.globalPosition);
startingAngle = vector.direction;
print('START = $startingAngle ===================================');
}
void _onPanUpdate(DragUpdateDetails details) {
_polarCoordFromGlobalOffset(details.globalPosition);
setState(() {
// HERE you should use the finalObjectAngle
deltaAngle = vector.direction - startingAngle + finalObjectAngle;
finalAngle = deltaAngle;
});
}
void _onPanEnd(DragEndDetails details) {
finalAngle = deltaAngle;
// Save the finalAngle of the object
finalObjectAngle = finalAngle;
print('End = $finalAngle ===================================');
}
I want to avoid the repeated values and the -0 values in Y-Axis, avoiding the image situation.
I have these ideas to solve this, but any solution:
Limit the zoom before having repeated values in YAxis, therefore stop the infinite zoom-in on the chart
Get the YAxis values and remove the duplicate values.
Though this is an older question I'd like to add to it for future reference. Newer versions of the library have a little known feature that resolves the duplicated labels, called granularity. This is way simpler to use than the older solutions (though to be fair, this wasn't available at the time those were posted).
You can always check the latest AxisBase Javadocs (3.0.0-beta1) for a more detailed explanation. Here are the relevant methods:
setGranularity(float granularity):
Set a minimum interval for the axis when zooming in. The axis is not
allowed to go below that limit. This can be used to avoid label
duplicating when zooming in.
setGranularityEnabled(boolean enabled):
Enabled/disable granularity control on axis value intervals. If
enabled, the axis interval is not allowed to go below a certain
granularity.
So in your case you'd need to set the granularity to 0.1f since you have one decimal point. The following snippet of code should avoid the repeated values on the axis:
YAxis yAxis = mChart.getAxisLeft();
yAxis.setGranularityEnabled(true);
yAxis.setGranularity(0.1f);
tl;dr You can do this by changing the label count in onChartScale.
First, you want your listener set up:
chart.setOnChartGestureListener(this); // set a listener ;)
You try to get the top/bottom drawn values and check what gets drawn on the screen. Apply some basic calculations, and you're set.
The following code will draw 2 labels if the zoom level gets (too) high and up to 9 otherwise:
#Override
public void onChartScale(MotionEvent me, float scaleX, float scaleY) {
final YAxis yAxis = mChart.getAxisLeft();
final Transformer transformer = mChart.getTransformer(YAxis.AxisDependency.LEFT);
// ...minor dirty hack
final PointD top = transformer.getValuesByTouchPoint(0, 0);
final PointD bottom = transformer.getValuesByTouchPoint(0, mChart.getHeight());
final int diff = (int)(top.y - bottom.y);
// draw 2-9 axis labels
final int count = Math.min(9, Math.max(diff, 2));
Log.d("scale", String.format("scale %f: diff %d and count %d", scaleY, diff, count));
// "force" the count, for there are drawing issues where none get drawn on high zoom levels (just try it out)
yAxis.setLabelCount(count, true);
}
// todo implement other interface methods
The value formatter and everything else stays the same.
And some ugly screenshot to show that it works :D
code like this:
mchart.setAutoScaleMinMaxEnabled(false);
mchart.getAxisLeft().setAxisMaxValue(10);
mchart.getAxisLeft().setAxisMinValue(5);
mchart.getAxisRight().setAxisMaxValue(10);
mchart.getAxisRight().setAxisMinValue(5);
or:
boolean a = isReady;
mchart.getAxisLeft().setFormater(new format(float b){ return "" ;})
When u get data :
mchart.setAutoScaleMinMaxEnabled(true);
mchart.getAxisLeft().resetAxisMaxValue();
mchart.getAxisLeft().resetAxisMinValue();
mchart.getAxisRight().resetAxisMaxValue();
mchart.getAxisRight().resetAxisMinValue(5);
I have no code by my hand.
You can set granularity to your required value to prevent the repetition when zoomed.
mBarChart.getAxisLeft().setGranularity(1f); // y-axis scale will be 0,1,2,3,4....
mBarChart.getAxisLeft().setGranularityEnabled(true);
If you want to set granularity dynamically, then implement IAxisValueFormatter and compare the return value to get the difference and set Granularity to that difference.
private float yAxisScaleDifference = -1;
private boolean granularitySet = false;
//say the values returned by IAxisFormatter is in hundreds: 100, 200, 300...
mBarChart.getAxisLeft.setValueFormatter(new IAxisValueFormatter() {
#Override
public String getFormattedValue(float v, AxisBase axisBase) {
if(!granularitySet) {
if(yAxisScaleDifference == -1) {
yAxisScaleDifference = v; //10
}
else {
float diff = v - yAxisScaleDifference; //200 - 100 = 100
if(diff >= 1000) {
yAxisLeft.setGranularity(1000f);
}
else if(diff >= 100) {
yAxisLeft.setGranularity(100f); //set to 100
}
else if(diff >= 1f) {
yAxisLeft.setGranularity(1f);
}
granularitySet =true;
}
}
return val;
}
});
Another Example:
say Y-Axis returns [1200,3400,8000,9000....]
first time: 1200
second time: 3400 - 1200 = 2200
granularity set to 1000
If the difference is not uniform you have to use array to store the differences and take the average to get the right granularity.
If you are using IAxisValueFormatter the problem might be in the conversion of float to Int when trying to access the values array.
For me the solution was to
IAxisValueFormatter numAppointmentsXAxisFormatter = new IAxisValueFormatter() {
#Override
public String getFormattedValue(float value, AxisBase axis) {
int index = (int)Math.ceil(value);
if(index < 0){
index = 0;
}else if(index >= numAppointmentsLabels.size()){
index = numAppointmentsLabels.size()-1;
}
return numAppointmentsLabels.get(index);
}
};
I also added +1 to the label count
chart.getXAxis().setLabelCount(numValue+1, true);
Hope it helps
I have never used MPAndroidCharts before, but just a little search here and there got me this method which I think would be useful.
public void setLabelCount(int count, boolean force) {
if (count > 25)
count = 25;
if (count < 2)
count = 2;
mLabelCount = count;
mForceLabels = force;
}
The description says that "exact specified count of labels will be drawn and evenly distributed alongside the axis". If you can make it work in your favor, you might be able to limit the zoom.
Also, there is another method-
public int getLabelCount() {
return mLabelCount;
}
This returns the number of labels on the axis. Hope this helps.
https://github.com/PhilJay/MPAndroidChart/blob/5a15715b25991e3d61d27d552f9eba45975d65e7/MPChartLib/src/com/github/mikephil/charting/components/YAxis.java
I am trying to make the following camera panning js script, to work as it should, meaning panning the camera left and right. What I have accomplished till now, is to move camera only left and back to its starting position. I can't get it move left and right on a gui.button being clicked/touched.
Here is the js script:
#pragma strict
var target : GameObject;
var xpositionLeft = 10;
var xpositionRight = -10;
//var smooth : float = 5; // Don't know where should I put this var to make it pan smooth?
private static var isPanning = false;
function Update()
{
if(isPanning == true)
{
transform.position.x = target.transform.position.x;
transform.position.x = xpositionLeft;
}
else
{
transform.position.x = target.transform.position.x; // It only pan the camera left, not right!
transform.position.x = xpositionRight;
}
}
static function doPanning ()
{
isPanning = !isPanning;
}
Can someone give a clue on how to make this script work? I'm new to Unity and programming, so any help is more than welcomed.
Thank you all in advance for your time, and your answers.
There are several problems with your code. First, the lines transform.position.x = target.transform.position.x; don't have any effect, because you're immediately overwriting it in the next line. Your code basically only flips transform.position.x between -10 and 10.
Second, the behavior you expect doesn't match the logic in your code. You have only two states, isPanning true and false, but you need three states: pan left, pan right and do nothing.
// how far the camera should move witch each click
var xPositionOffset = 10;
// -1 = left, 0 = do dothing, 1 = right
var panDirection = 0;
function Update()
{
if (panDirection != 0) // pan left/right
{
transform.position.x = transform.position.x + (panDirection * xPositionOffset);
panDirection = 0;
}
}
Now you only need to set the variable panDirection to -1 or 1 if one your buttons is pressed and the camera will move farther to that side.
If you're having trouble with the vector arithmetic, have a look at the chapter 'Understanding Vector Arithmetic' from the Unity manual.
The above code will move the camera not very smooth, but it's easier to understand the basic concept this way. You can use the function Vector3.MoveTowards to get a smoother movement and the example showed in the linked reference should help you to implement it.
Hey guys so I've been trying to solve this for awhile I have looked on many forums and tried to understand what they were trying to convey with the code using ActionScript 3 but i still get nothing. My main goal is to have a character on stage named "mainPlayer" now i want to set up touch events so that when the user drages his finger up down or side to side i want to the mainPlayer to follow the users path or if the user touches a point on the screen and holds his finger there the mainPlayer will be attracted to the touch and move to the point where the finger is currently at on the screen.
Ive seen lots of stuff with Phase and ID implemented but dont really understand whats going on
so far this is what i have set up:
public class realmEngine extends MovieClip
{
//MultiTouch gestures
Multitouch.inputMode = MultitouchInputMode.TOUCH_POINT;
Multitouch.inputMode = MultitouchInputMode.GESTURE;
public var mainPlayer:mcPlayer;
//PlayerControls
private var speed:Number = 8.0;
public var vx:Number = 0;
public var vy:Number = 0;
private var friction:Number = 0.85;
private var maxSpeed:Number = 15;
public function realmEngine()
{
//Add Player to Stage
mainPlayer = new mcPlayer();
stage.addChild(mainPlayer);
mainPlayer.x = (stage.stageWidth / 2) - 300;
mainPlayer.y = (stage.stageHeight / 2 );
//trace("this works");
//Setup Touch Event listeners
mainPlayer.addEventListener(TouchEvent.TOUCH_BEGIN, onTouchBegin);
stage.addEventListener(TouchEvent.TOUCH_MOVE, onTouchMove);
stage.addEventListener(TouchEvent.TOUCH_END, onTouchEnd);
//Game Loop Event Listener
stage.addEventListener(Event.ENTER_FRAME, gameLoop);
}
private function gameLoop(e:Event):void
{
mainPlayerControls();
}
private function mainPlayerControls():void
{
}
private function onTouchEnd(e:TouchEvent):void
{
}
private function onTouchMove(e:TouchEvent):void
{
}
private function onTouchBegin(e:TouchEvent):void
{
}
}
I'm not sure what to do inside the onTouch Functions in order for the object that i add to stage by Code to follow the users touch on the screen.
Can anyone lead my in the right direction or give me any advice? I woudld really appreciate it thanks guys
Yes I happen to know how to do this, I just wasn't sure if I had grasped fully what you wanted to achieve.
Note that I won't be taking into account the speed and maxSpeed variables for moving the player. It's beyond this scope and beyond the scope of the top of my head. A little bit of internet searching will get you far on that subject however!
First of all, in order to make the object follow a path drawn by the user, we need a way to store the path. For this, I suggest a Vector with Point as its datatype. It's fast and easy to work with when adding and removing elements without having to worry about its length.
We also need a way to tell wether the player sprite should move or not, in other words wether the user is pressing the finger on the screen or not.
private var _pathPoints : Vector.<Point>;
private var _isMoving : Boolean = false;
Easy-cakes. Now for the fun part!
First, we need to change the scope of the onTouchBegin event, from mainPlayer to the stage. If we don't, the user won't be able to touch an abstract point on the stage and get the player sprite to move there. Simply done with a change to
mainPlayer.addEventListener(TouchEvent.TOUCH_BEGIN, onTouchBegin);
Then we take care of when the user moves his or her finger. Nothing fancy going on here.
We're just simply storing the coordinates in our vector and storing the current state of wether the user is pressing the screen or not.
private function onTouchBegin ( e:TouchEvent ) : void
{
_pathPoints.push( new Point( e.stageX, e.stageY ) );
_isMoving = true;
}
private function onTouchMove ( e:TouchEvent ) : void
{
_pathPoints.push( new Point( e.stageX, e.stageY ) );
}
private function onTouchEnd ( e:TouchEvent ) : void
{
// Dirty but quick way of clearing the vector
_pathPoints.splice(0);
_isMoving = false;
}
Finally, for the even funnier part; the main game loop! Or "Where the Magic Happens".
private function mainPlayerControls () : void
{
// Update player position and forces
vx *= friction;
vy *= friction;
mainPlayer.x += vx;
mainPlayer.y += vy;
// Check if the player should be moving to a new point
if( _isMoving )
{
// Get a reference to the current target coordinate
var target : Point = _pathPoints[0];
// Check if the player position has reached the current target point
// We use a bounding box with dimensions equal to max speed to ensure
// that the player doesn't move across the point, move back towards it
// and start jojo-ing back and forth
if(mainPlayer.x >= target.x - maxSpeed && mainPlayer.x <= target.x + maxSpeed &&
mainPlayer.y >= target.y - maxSpeed && mainPlayer.y <= target.y)
{
// The player has reached its target
//so we remove the first element of the vector
_pathPoints.shift();
// and update the target reference
target = _pathPoints[0];
}
// Calculate velocities to the first element of the vector
vx = mainPlayer.x - target.x;
vy = mainPlayer.y - target.y;
}
}