After few hours of trying I'm looking for some hints on how to add snap-scroll mechanism to MPAndroid. Basically I want the 5 visible bars to align so they are fully visible and centered. I now imported the library source code because it looks like there's no other way to change the code in computeScroll (BarLineChartTouchListener).
Edit:
To clarify - I'm showing around 20 bars but chart is zoomed so user can scroll horizontally. What bothers me it is not getting aligned automatically so first visible bar might be clipped in half. I'm looking for snapping effect where it will round the position to the nearest multiplication of the bar width, leaving 5 fully visible bars.
I ended up adding the following function in BarLineChartBase.java. I know it's far from elegant, but seems to do the job. It's limited to targetApi > 11, because of the ValueAnimator. For lower API (which I don't cater for) you might need to have a look at nineoldandroids or some other animation loop technique.
#TargetApi(Build.VERSION_CODES.HONEYCOMB)
public void alignX() {
int count = this.getValueCount();
int xIndex = this.getLowestVisibleXIndex() + Math.round( (this.getHighestVisibleXIndex() - this.getLowestVisibleXIndex()) / 2.0f );
float xsInView = this.getXAxis().getValues().size() / this.getViewPortHandler().getScaleX();
Transformer mTrans = this.getTransformer(YAxis.AxisDependency.LEFT);
float[] pts = new float[] { xIndex - xsInView / 2f, 0 };
mTrans.pointValuesToPixel(pts);
final Matrix save = new Matrix();
save.set(this.getViewPortHandler().getMatrixTouch());
final float x = pts[0] - this.getViewPortHandler().offsetLeft();
final int frames = 20;
ValueAnimator valueAnimator = new ValueAnimator().ofInt(0, frames);
valueAnimator.setDuration(500);
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
int prev = -1;
#Override
public void onAnimationUpdate(ValueAnimator animation) {
if( (int) animation.getAnimatedValue() > prev ) {
save.postTranslate( -x / (float)frames, 0);
BarLineChartBase.this.getViewPortHandler().refresh(save, BarLineChartBase.this, true);
}
prev = (int) animation.getAnimatedValue();
}
});
valueAnimator.start();
}
I trigger it at the end of computeScroll function in BarLineChartTouchListener.
I kept names of variables as I copied code from functions like MoveViewJob, ViewPortHandler etc. Since it's only aligning in x axis - I removed Y axis calculations and used zeros instead. Any optimizations welcome, especially from the author #PhilippJahoda.
Related
Background
I'm developing an app for Android that plots data as a line graph using AndroidPlot. Because of the nature of the data, it's important that it be pannable and zoomable. I'm using AndroidPlot's sample code on bitbucket for panning and zooming, modified to allow panning and zooming in both X and Y directions.
Everything works as desired except that there are no X and Y axis lines. It is very disorienting to look at the data without them. The grid helps, but there's no guarantee that grid lines will actually fall on the axis.
To remedy this I have tried adding two series, one that falls on just the X axis and the other on the Y. The problem with this is that if one zooms out too far the axis simply end, and it becomes apparent that I have applied a 'hack'.
Question
Is it possible to add X and Y axis lines to AndroidPlot? Or will my sad hack have to do?
EDIT
Added tags
I figured it out. It wasn't trivial, took a joint effort with a collaborator, and sucked up many hours of our time.
Starting with the sample mentioned in my question, I had to extend XYPlot (which I called GraphView) and override the onPreInit method. Note that I have two PointF's, minXY and maxXY, that are defined in my overridden XYPlot and manipulated when I zoom or scroll.
#Override
protected void onPreInit() {
super.onPreInit();
final Paint axisPaint = new Paint();
axisPaint.setColor(getResources().getColor(R.color.MY_AXIS_COLOR));
axisPaint.setStrokeWidth(3); //or whatever stroke width you want
XYGraphWidget oldWidget = getGraphWidget();
XYGraphWidget widget = new XYGraphWidget(getLayoutManager(),
this,
new SizeMetrics(
oldWidget.getHeightMetric(),
oldWidget.getWidthMetric())) {
//We now override XYGraphWidget methods
RectF mGridRect;
#Override
protected void doOnDraw(Canvas canvas, RectF widgetRect)
throws PlotRenderException {
//In order to draw the x axis, we must obtain gridRect. I believe this is the only
//way to do so as the more convenient routes have private rather than protected access.
mGridRect = new RectF(widgetRect.left + ((isRangeAxisLeft())?getRangeLabelWidth():1),
widgetRect.top + ((isDomainAxisBottom())?1:getDomainLabelWidth()),
widgetRect.right - ((isRangeAxisLeft())?1:getRangeLabelWidth()),
widgetRect.bottom - ((isDomainAxisBottom())?getDomainLabelWidth():1));
super.doOnDraw(canvas, widgetRect);
}
#Override
protected void drawGrid(Canvas canvas) {
super.drawGrid(canvas);
if(mGridRect == null) return;
//minXY and maxXY are PointF's defined elsewhere. See my comment in the answer.
if(minXY.y <= 0 && maxXY.y >= 0) { //Draw the x axis
RectF paddedGridRect = getGridRect();
//Note: GraphView.this is the extended XYPlot instance.
XYStep rangeStep = XYStepCalculator.getStep(GraphView.this, XYAxisType.RANGE,
paddedGridRect, getCalculatedMinY().doubleValue(),
getCalculatedMaxY().doubleValue());
double rangeOriginF = paddedGridRect.bottom;
float yPix = (float) (rangeOriginF + getRangeOrigin().doubleValue() * rangeStep.getStepPix() /
rangeStep.getStepVal());
//Keep things consistent with drawing y axis even though drawRangeTick is public
//drawRangeTick(canvas, yPix, 0, getRangeLabelPaint(), axisPaint, true);
canvas.drawLine(mGridRect.left, yPix, mGridRect.right, yPix, axisPaint);
}
if(minXY.x <= 0 && maxXY.x >= 0) { //Draw the y axis
RectF paddedGridRect = getGridRect();
XYStep domianStep = XYStepCalculator.getStep(GraphView.this, XYAxisType.DOMAIN,
paddedGridRect, getCalculatedMinX().doubleValue(),
getCalculatedMaxX().doubleValue());
double domainOriginF = paddedGridRect.left;
float xPix = (float) (domainOriginF - getDomainOrigin().doubleValue() * domianStep.getStepPix() /
domianStep.getStepVal());
//Unfortunately, drawDomainTick has private access in XYGraphWidget
canvas.drawLine(xPix, mGridRect.top, xPix, mGridRect.bottom, axisPaint);
}
}
};
widget.setBackgroundPaint(oldWidget.getBackgroundPaint());
widget.setMarginTop(oldWidget.getMarginTop());
widget.setMarginRight(oldWidget.getMarginRight());
widget.setPositionMetrics(oldWidget.getPositionMetrics());
getLayoutManager().remove(oldWidget);
getLayoutManager().addToTop(widget);
setGraphWidget(widget);
//More customizations can go here
}
And that was that. I sure wish this was built into AndroidPlot; it'll be nasty trying to fix this when it breaks in an AndroidPlot update...
In short I want a preview similar to Google Plays, where you can slide up and the top image/video preview fades back and the rest of the view is moved up.
I've got a view that I want to be hiden like the video in this example, the action bar can remain stationary at all times, but I need the bottom part to be dragable.
I can't seem to find out which layout that is, or how it is done, all I managed to find were unrelated such as ViewPager. My current min sdk version is 18, the compile version is 21.
The following is the code I used in the app I am working
You will have to use the OnScrollChanged function in your ScrollView. ActionBar doesn't let you set the opacity , so set a background drawable on the actionbar and you can change its opacity based on the amount of scroll in the scrollview. I have given an example workflow
The function sets gives the appropriate alpha for the view locationImage based on its position WRT window .
this.getScrollY() gives you how much the scrollView has scrolled
public void OnScrollChanged(int l, int t, int oldl, int oldt) {
// Code ...
locationImage.setAlpha(getAlphaForView(locationImageInitialLocation- this.getScrollY()));
}
private float getAlphaForView(int position) {
int diff = 0;
float minAlpha = 0.4f, maxAlpha = 1.f;
float alpha = minAlpha; // min alpha
if (position > screenHeight)
alpha = minAlpha;
else if (position + locationImageHeight < screenHeight)
alpha = maxAlpha;
else {
diff = screenHeight - position;
alpha += ((diff * 1f) / locationImageHeight)* (maxAlpha - minAlpha); // 1f and 0.4f are maximum and min
// alpha
// this will return a number betn 0f and 0.6f
}
// System.out.println(alpha+" "+screenHeight +" "+locationImageInitialLocation+" "+position+" "+diff);
return alpha;
}
You can download an example working sample at https://github.com/ramanadv/fadingActionBar
Credit: CommandSpace
I've got a Custom ViewGroup class and an image I've added to it. When the screen is tapped I want to animate the added image to travel across the screen in a wavelike pattern. What I have now is below but though the image moves in a wavelike pattern it jumps around too quickly and is a blur. How can I slow it down to move in a steady wave?
ValueAnimator animator = ValueAnimator.ofFloat(0, 1); // values from 0 to 1
if(animateImage) {
incrementalValue = 0f;
animator.setDuration(4000);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(ValueAnimator animation) {
float value = ((Float) (animation.getAnimatedValue()))
.floatValue();
float amplitude = 100f;
mImage.setTranslationX(incrementalValue);
mImage.setTranslationY((float) (amplitude * Math.sin((incrementalValue) * Math.PI)));
incrementalValue += 5f;
}
});
animator.setTarget(mImage);
animator.start();
}
You declare a float value in onAnimationUpdate and never use it again. The calcualtion for the image translation is mImage.setTranslationY((float) (amplitude * Math.sin((incrementalValue) * Math.PI)));. If you insert the values and incrementalValue ( = 0) doesn't change, this calculation will always return 0 because sin(0) = 0 and one 0 in a multiplication makes the product 0. You should insert animator.getAnimatedValue for incrementalValue. Besides, i suggest you change the calculation to sin(animator.getAnimatedValue()*PI*2) this makes the wavelength of the sine 1 and the image will move up and down once per repetition of the animation and it won't jump when the aimation restarts.
Note you can still multiply with amplitude to make the image move a certain distance.
I have implemented the MuPDf in android to open,view,search,setting bookmarks etc for a PDF. Now i want the animation effect of horizontal flip i.e. similar to be like used in the FlipBoard Application in horizontal manner.
I also need to know that how can i highlight the Search Text. I am using Librelio's code
I have gone through the links Like:
Link 1
Please help.
I also need to know that how can i highlight the Search Text.
PageView.java of MuPDF:
private static final int HIGHLIGHT_COLOR = 0x802572AC; //adjust the color
...//some code of PageView.java
public void setPage(int page, PointF size) {
...//code of PageView.setPage(int page, PointF size)
// this is the part where the hightlighting happens
if (!mIsBlank && mSearchBoxes != null) {
paint.setColor(HIGHLIGHT_COLOR);
for (RectF rect : mSearchBoxes)
canvas.drawRect(rect.left*scale, rect.top*scale,
rect.right*scale, rect.bottom*scale, paint);
// you can customize it, e.g.
// int margin = 5
//canvas.drawRect((rect.left - margin) * scale, (rect.top - margin) * scale,
//(rect.right + margin) * scale, (rect.bottom + margin) * scale, paint);
}
}
to start a search, just invoke:
new SearchTask(context, mupdfCore).go("searchText", 1, 0, -1);
There are 4 types of animations in android - rotate, alpha,scale and translate.
I want to prepare curved translate animation.
Is it possible.?
What Android version do you use? Since API level 11 you can use custom Animators which can easily implement your curve translation.
If you use a version below that there is afaik only the possibility to manually concatenate multiple linear translations using the translate animation and setting animation listeners
EDIT:
Example:
View view;
animator = ValueAnimator.ofFloat(0, 1); // values from 0 to 1
animator.setDuration(5000); // 5 seconds duration from 0 to 1
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener()
{
#Override
public void onAnimationUpdate(ValueAnimator animation) {
float value = ((Float) (animation.getAnimatedValue()))
.floatValue();
// Set translation of your view here. Position can be calculated
// out of value. This code should move the view in a half circle.
view.setTranslationX((float)(200.0 * Math.sin(value*Math.PI)));
view.setTranslationY((float)(200.0 * Math.cos(value*Math.PI)));
}
});
I hope it works. Just copied & pasted (and shortened and changed) the code from one of my apps.
Here are the animators I use:
Purpose: Move View "view" along Path "path"
Android v21+:
// Animates view changing x, y along path co-ordinates
ValueAnimator pathAnimator = ObjectAnimator.ofFloat(view, "x", "y", path)
Android v11+:
// Animates a float value from 0 to 1
ValueAnimator pathAnimator = ValueAnimator.ofFloat(0.0f, 1.0f);
// This listener onAnimationUpdate will be called during every step in the animation
// Gets called every millisecond in my observation
pathAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
float[] point = new float[2];
#Override
public void onAnimationUpdate(ValueAnimator animation) {
// Gets the animated float fraction
float val = animation.getAnimatedFraction();
// Gets the point at the fractional path length
PathMeasure pathMeasure = new PathMeasure(path, true);
pathMeasure.getPosTan(pathMeasure.getLength() * val, point, null);
// Sets view location to the above point
view.setX(point[0]);
view.setY(point[1]);
}
});
Similar to: Android, move bitmap along a path?
Consider the following web link. It is a game in C. You need to isolate the projectile() function and try to understand the variables defined within it. Once you get that try implementing it in your own code.
http://www.daniweb.com/software-development/c/code/216266