This is what I want to achieve:
In the below image there is a white dot on the screen and i want to move the white dot to the RIGHT when right part of the screen is touched and to the LEFT when left part of the screen is touched.
This is my code:
protected void onDraw(Canvas canvas)
{
final Bitmap mball = ball;
if (pressed){
if (touch_x>canvas.getWidth()/2)
left += 2;
else left -= 2;
}
canvas.drawBitmap(mball, left, canvas.getHeight()*0.7f, null);
invalidate();
}
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
final int action = event.getAction();
int pointerIndex;
switch (action ){
case MotionEvent.ACTION_DOWN:
touch_x = event.getX();
pressed = true;
break;
case MotionEvent.ACTION_POINTER_DOWN:
touch_x = event.getX(event.getActionIndex());
pressed = true;
break;
case MotionEvent.ACTION_UP:
mActivePointerId = -1;
pressed = false;
break;
case MotionEvent.ACTION_CANCEL: {
mActivePointerId = -1;
break;
}
}
return pressed;
}
It is not working the way I want it to work. When the user touches the right part the white ball should move towards right and if LEFT part is touched without lifting off the RIGHT finger the ball should move towards left and vice-versa.
What is happening is if RIGHT part of screen is touched ball keeps moving towards right and when left part is touched without removing the right finger the ball continues to move towards right.
I have also tried using pointer Index for primary and non-primary pointers but still no luck.
Any help would be appreciated.
Related
I have created my own component which extends RelativeLayout, inside it I have a field of View type which is being positioned with margins:
Blue quad represents my parent view, and a red circle is a child.
Now I want to allow user to move this red circle while moving a finger on a screen.
This is my onTouchEvent() method:
#Override
public boolean onTouchEvent(MotionEvent event) {
int eventAction = event.getAction();
switch (eventAction) {
case MotionEvent.ACTION_DOWN:
// finger touches the screen
break;
case MotionEvent.ACTION_MOVE:
marginX = (int)event.getX();
marginY = (int)event.getY();
RelativeLayout.LayoutParams lp = (RelativeLayout.LayoutParams)pointer.getLayoutParams(); // pointer is this red circle
lp.setMargins(marginX, marginY, 0, 0);
break;
case MotionEvent.ACTION_UP:
// finger leaves the screen
break;
}
return true;
}
But I quickly found out that it doesn't refresh it's position while user is moving his finger on a screen, but instead it does it only when user releases his finger from the screen. So basically, when I move my finger, circle stays in a same position, but when I stop moving, circle is drawn in new position. I tried using invalidate() method on both, parent and child views, but it didn't help. I assume that it may have something to do with UI thread, but I don't have access to runOnUiThread()' method as it's not anActivity`.
EDIT:
I passed an activity to my class, so that I can use runOnUiThread(). My case: ACTION_MOVE now looks like this:
case MotionEvent.ACTION_MOVE:
marginX = (int)event.getX();
marginY = (int)event.getY();
activity.runOnUiThread(new Runnable() {
public void run() {
RelativeLayout.LayoutParams lp = (RelativeLayout.LayoutParams)pointer.getLayoutParams();
lp.setMargins(marginX, marginY, 0, 0);
pointer.invalidate();
}
});
break;
If it's simple pointer you can draw it on Canvas as Drawable:
#Override
protected void onDraw(Canvas canvas) {
pointer.setBounds(marginX, marginY, marginX + pointerWidth, marginY + pointerHeight);
pointer.draw(canvas);
super.onDraw(canvas);
}
And then call invalidate() on pointer in onTouchEvent() method.
I think you need drag and drop function
Refer http://www.vogella.com/articles/AndroidDragAndDrop/article.html
I have an Android applciation which I want it to draw circles around
I used OnTouchListener.
The problem is, when the users "holds" the circle in place, it doesn't update the action.
How can I know if the user's finger is on,when he doesn't move it, with the OnTouchListener
You'll have to check if what kind of event is triggering onTouchEvent.
#Override
public boolean onTouchEvent(MotionEvent event) {
float eventX = event.getX();
float eventY = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
//Do Nothing
return true;
case MotionEvent.ACTION_MOVE:
//Do Something
path.lineTo(eventX, eventY);
break;
case MotionEvent.ACTION_UP:
//Do Nothing
break;
default:
return false;
}
// Schedules a repaint.
invalidate();
return true;
}
More Information about MotionEvents can be found here.
You can know that by using
MotionEvents:
Reed more here: MotionEvents
ACTION_DOWN is for the first finger that touches the screen. This starts the gesture. The pointer data for this finger is always at index 0 in the MotionEvent.
ACTION_POINTER_DOWN is for extra fingers that enter the screen beyond the first. The pointer data for this finger is at the index returned by getActionIndex().
ACTION_POINTER_UP is sent when a finger leaves the screen but at least one finger is still touching it. The last data sample about the finger that went up is at the index returned by getActionIndex().
ACTION_UP is sent when the last finger leaves the screen. The last data sample about the finger that went up is at index 0. This ends the gesture.
ACTION_CANCEL means the entire gesture was aborted for some reason. This ends the gesture.
here is a good answer to read StackOverFlow
Filter touches by what kind they are:
boolean onScreen = false;
#Override
public boolean onTouchEvent(MotionEvent event) {
float eventX = event.getX(); //X coord of the touch
float eventY = event.getY(); //Y coord of the touch
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
// User has touched the screen
onScreen = true;
return true;
case MotionEvent.ACTION_MOVE:
// Finger is being dragged on the screen
onScreen = true; //Not required, just for clarity purposes.
break;
case MotionEvent.ACTION_UP:
// User has lifter finger
onScreen = false;
break;
default:
return false;
}
if(onScreen) {
//Finger is on the screen
}
return true;
}
Ok, so I am making a simple app on a surfaceView where I have a bitmap of a ball that goes from the top of the screen to the bottom. Once it gets to the bottom it appears at the top again where it starts to fall back down again.
Next I tried to make it so that when I clicked the ball when it was falling down it would go back to the top of the screen. However, I am having a problem with this because I can't click it (because its only one pixel, I think). I set an onTouchListener to the getX() and getY() coordinates of the click, and if the x and y coordinatesof the click are equal to the x and y of the current position of the ball then the ball goes back to the top of the screen.
This doesnt work though. Because in order for me to be able to click the ball I would have to click the exact center pixle that the ball was on at that time. So my question is how do I say: If the click is close to, or approximately equal to the current position of the ball then go back to the top. I am a noob with this so if I am asking dumb questions I apologize, I'm trying my best to learn. And thank you very much for the help. I appreciate it.
It should work for you. Just override the onTouch method.
#Override
public boolean onTouch(View v, MotionEvent me)
{
try
{
Thread.sleep(50);
} catch (InterruptedException e)
{
e.printStackTrace();
}
switch (me.getAction())
{
case MotionEvent.ACTION_DOWN:
x = me.getX();
y = me.getY();
break;
case MotionEvent.ACTION_UP:
x = me.getX();
y = me.getY();
break;
case MotionEvent.ACTION_MOVE:
x = me.getX();
y = me.getY();
break;
case MotionEvent.ACTION_OUTSIDE:
x = 100;
y = 200;
break;
}
return true;
}
Here is my scenerio. Wherever you touch my screen, an circle is drawn, and when you lift your finger/stylus of the screen, the circle disappears. This is fine, but the problem now is if you touch, then move, the circle will not update to the new position of your finger/stylus. It will just stay at the original touch position regardless of movement until you lift your finger/stylus off the screen.
How am I able to get the circle(cursor) to redraw or move itself to the new position of your finger/stylus? Here is my code:
rLO.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
cursor.x = (int)event.getX() - (cursor.radius / 2);
cursor.y = (int)event.getY() - (cursor.radius / 2);
cursor.onDraw(cursor.e);
rLO.addView(cursor);
break;
case MotionEvent.ACTION_UP:
rLO.removeView(cursor);
break;
case MotionEvent.ACTION_MOVE:
}// end switch
return true;
}
});
Thanks in advance!
Now I have an ImageView and its a circle which is at the slightly below than center position (But this should not matter).
I have written code onTouch of ImageView for ACTION_DOWN,ACTION_UP ,now consider as user have put finger on circle and move and move.... I want to active some code when user move finger and exceed the region of CIRCLE image(As soon as user exceed the region the code should be ececuted onlly once)
Here is my code
ImageView view1 = (ImageView) findViewById(R.id.fccircledetectionarea);
view1.setOnTouchListener(new OnTouchListener()
{
#Override
public boolean onTouch(View v, MotionEvent event)
{
ImageView imageView=(ImageView) findViewById(R.id.fccircledetectionarea);
switch(event.getAction())
{
case MotionEvent.ACTION_DOWN:
final float x=imageView.getTop();
Toast.makeText(PlayScreen.this, "Top Position:"+x, Toast.LENGTH_SHORT).show();
break;
case MotionEvent.ACTION_UP:
Toast.makeText(PlayScreen.this, "Over", Toast.LENGTH_SHORT).show();
break;
case MotionEvent.ACTION_MOVE:
Toast.makeText(PlayScreen.this, "Over", Toast.LENGTH_SHORT).show();
break;
}
return true;
}
});
I cannot archive my goal through ACTION_MOVE: as it start to work if user move finger within the circle
And my second query is that How to set alpha of this imageview I have used
view1.setAlpha(0);
But is not working and I have also made this imageview invisible but than my onTouch code is not working
Within your onTouch method record a boolean to check if the user is touching within the bounds of the circle.
boolean inCircle = java.lang.Math.sqrt(x*x + y*y) <= circleRadius
Where x is taken from event.getX() - circleCenterX and y is taken from event.getY() - circleCenterY (touch position's offset from center of the circle)