How to make picture in a Canvas onTouch, like a button. Just to be press and nothing else. I can insert picture in Canvas, now how can I make her onTouch? Can somebody pls give me easy exsample? Dont be mad, cuz this is probably stupid and easy question
Thank you
public boolean handleTouch(MotionEvent event)
{
float newX = event.getX();
float newY = event.getY();
switch (event.getAction())
{
case MotionEvent.ACTION_DOWN:
if (isInRect((int) newX, (int) newY))
{
refreshView();
}
//....
}
}
You cannot add an onClick or onTouch listener to something you've drawn with the canvas. These listeners can only be applied to views.
Another method will be to apply the onTouchListener to the view, and find the touch position to find whether the touch was on the pictures position.
Related
I've spent some time researching this and still haven't found a great answer.
What I would like is to drag an ImageView around the screen. Not a drag and drop, but just an actual drag.
This tutorial has been helpful:
http://code.tutsplus.com/tutorials/android-gesture--mobile-2239
It works perfect, but it's designed to drag a bitmap, not an ImageView. I've tried replacing the Bitmap with an ImageView, but I'm not sure how the Canvas and ImageView interact in the onDraw method. I've tried imageView.draw(canvas); and that doesn't seem to work - the ImageView doesn't show up at all.
Bitmaps are not idea, because you can't add borders to them like you can with an ImageView.
I'd also like to be able to fling the ImageView off the screen.
Any suggestions?
Thanks in advance.
You can create RelativeLayout that match all your screen. In the layout create ImageView.
Set OnTouchListener listener to your relative layout to handle your finger coordinate.
After that you can write something like this :
public boolean onTouch(View v, MotionEvent event)
{
if (event.getAction() == MotionEvent.ACTION_MOVE)
{
move(event);
}
}
public void move(MotionEvent event)
{
RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) mImageView.getLayoutParams();
layoutParams.topMargin = event.getY();
layoutParams.leftMargin = event.getX();
mImageView.setLayoutParams(layoutParams);
}
Like using method move(MotionEvent event) you can drag your imageView where you want.
I hope this help you!
I'm working on an app that plots nodes on a map, and each node has edges that are represented by a line between them. I've drawn the edges using Canvas and drawLine(), but it would be useful if the lines themselves could be clickable. By that I mean a method of allowing the user to touch the line or think they're touching the line and an event can trigger. (like display edge info, etc...)
I can't rightly attach a touch event to a line I've drawn with Canvas, so I was thinking of placing ImageViews inbetween the ends of each edge line that's drawn. The ImageView could be a dot so it's clear where the touch event triggers.
Does anyone have any other suggestions? I'm mainly looking for ideas that I've missed. Maybe there's something in the Android API that can help with this that I'm unaware of.
Thanks in advance for any tips!
Use a path to draw the line:
Path linePath;
Paint p;
RectF rectF;
float point1X, point1Y, point2X, point2Y;
// initialize components
// draw the line
linePath.moveTo(point1X, point1Y);
linePath.lineTo(point2X, point2Y);
canvas.drawPath(linePath, p);
linePath.computeBounds(rectF, true);
Override onTouchEvent(MotionEvent):
#Override
public boolean onTouchEvent(MotionEvent event) {
float touchX = event.getX();
float touchY = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
if (rectF.contains(touchX, touchY)) {
// line has been clicked
}
break;
}
return true;
}
I have a view, and I want to move it with finger. I wanted to get the xDelta and yDelta and just translate the matrix of the view (not image view, any view, RelativeLayout for example).
I am wondering how to do that:
Overriding RelativeLayout's onDraw and apply translation matrix there. Is that possible?
I am currently doing it with applying animation on each onTouch event. The animation is with duration 0 and the start/end of x/y is the same (setFillAfter = true). It just puts the view where I want. But isn't that too expensive?
Can't I manipulate the matrix of any view directly through onDraw? I tried something like this:
#Override
protected void onDraw(Canvas canvas) {
if (getDx() != 0 && getDy() != 0) {
m = canvas.getMatrix();
m.postTranslate(dx, dy);
canvas.setMatrix(m);
}
super.onDraw(canvas);
}
But it seems that I am doing it wrong.
If you want to implement drag gesture then you can use onTouchListener and in its MotionEvent.ACTION_MOVE set padding using setPadding to that view.
Here is the sample code:
case MotionEvent.ACTION_MOVE:
yourView.setPadding((int)event.getRawX(), (int)event.getRawY(), 0, 0);
Sample for onTouchListener :-
OnTouchListener drag= new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction() & MotionEvent.ACTION_MASK){
case MotionEvent.ACTION_DOWN:
break;
case MotionEvent.ACTION_POINTER_DOWN:
break;
case MotionEvent.ACTION_MOVE:
img.setPadding((int)event.getRawX(), (int)event.getRawY(), 0, 0);
break;
case MotionEvent.ACTION_UP:
break;
case MotionEvent.ACTION_POINTER_UP:
break;
} return true;
}
};
You need to create the dragging image at run time and have to adjust its position. In this sample code I have not adjusted the position so the dragged image is not created at the position of touch. You also need to consider the height and width of the image to be dragged.
Hope it helps !
I hate to be the one to tell you that your problem is even easier than you thought, but here's what it looks like:
#Override
protected void onDraw(Canvas canvas) {
if (getDx() != 0 && getDy() != 0) {
canvas.translate(getDx(), getDy());
}
super.onDraw(canvas);
}
Hope this helps!
If you want to Move your layout permanently (In case of temporary, we can use animation ) then Use Drag And Drop API from android Official Page . Hope this will help you
Couple of things that would help in achieving it:
Make sure that your view originally has enough space in the direction you want to use. Like 'match_parent' etc
Use GestureDetector.onSimpleGestureListener and override onDraw ( return true;) , onScroll -- connect it using onTouchEvent and you will directly get the distance , or you can calculate yourself by using the event1 and event2
Store this information in variable(s) and call invalidate()
in your onDraw method - use this information by canvas.translate(..use those variables..); super.onDraw(canvas);
and your will achieve the result
PS: The drawing starts by taking left-top as 0,0
I'm working on an Android app and I want to add some eyecandy to the UI. I have an activity (let's call it MainActivity) which has some text fields, buttons and a gallery on it.
What I would like to achieve is: When the user touches somewhere on this activity, there should be some visual effect at the point where he touched (e.g. something like sparkles etc.).
So the essential parts of my question are:
a) How can I determine where the user touched
b) how can I draw my effects on to the screen (as an 'overlay' to the activity).
Thanks in advance for every helpful answer.
(I've checked out this answer but it doesn't seem to be applicable to my situation. )
First, you have to add onTouchListener to your root Layout, then you can get coordinates, where the user has touched the screen.
example :
float x,y;
rl = (RelativeLayout) findViewById(R.id.root_layout);
rl.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
float x = event.getX();
float y = event.getY();
return super.onTouchEvent();
}
});
You should override the onTouchEvent method of your activity. You can then obtain the coordinates of the touch event:
#Override
public boolean onTouchEvent(MotionEvent event) {
float touchX = event.getX();
float touchY = event.getY();
switch(event.getAction()) {
case MotionEvent.ACTION_DOWN:
// touch down
break;
case MotionEvent.ACTION_MOVE:
// movement
break;
case MotionEvent.ACTION_UP:
// touch up
break;
default:
// default
}
return super.onTouchEvent(event);
}
To answer further on your question, to have a overlay, look at the APIDemos -> Graphics -> OpenGL ES -> Translucent GLSurfaceView. This will help you to create overlay on your activity. There may be some other example in API demos which will get you some help. Android's API Demos are good set of examples to address some known issues.
If you are working on ICS then I recommend you to look at the Developer Options in Settings application. If you are not working with ICS, I believe you can look at the APIDEMOS for touchevents. They draw lines on touches. The code in that, can get you started.
i am developing game.i am displaying gun object center bottom of the screen.when user tap on screen i need to rotate gun that direction.i done rotating image.but when user tap on screen i need to rotate image that direction.can you please help me
Thanks in advance
Aswan
is your image a bitmap? could you convert it to one? Would an onClick listener not work and when the user clicks do something like.. http://www.anddev.org/resize_and_rotate_image_-_example-t621.html
Seeing some code as to what you've attempting would be nice also. The following will help you with checking if the bitmap has been clicked in case you're stuck on that also http://developer.android.com/reference/android/view/View.html .
I've never attemped this myself but I think that would work. Try redrawing the bitmap when you have resized it.
Just use onTouchListener for your View and use this code for that
#Override
public boolean onTouch(View v, MotionEvent event) {
float currentX = event.getX();
float currentY = event.getY();
Log.i(TAG, "action type is"+event.getAction());
switch (event.getAction()) {
case MotionEvent.ACTION_MOVE: {
Log.i(TAG, "Entering in onTouch");
double rotationAngleRadians = Math.atan2(currentX - dialer.centerX, dialer.centerY - currentY);
dialer.rotationAngle = (int) Math.toDegrees(rotationAngleRadians);
Log.i(TAG, "rotaion angle"+dialer.rotationAngle);
dialer.invalidate();
return true;
}
}
return true;
}