Develop Reference

How to change GridView image item resource using OnItemClickListener?

I am having trouble changing the GridView image item resource when clicked using OnItemClickListener and not OnTouchListener. The main reason why I want to use OnItemClickListeneris that I can get the position of the item clicked. Once I have the position, I use it to determine which image to change. When I press an item I want to change its image resource to image2, and when unpressed change it back to image1.
This is easy using OnTouchListener however I can't get the position of the selected GridView item.

Try this:
gridView.setOnTouchListener(new OnTouchListener() {
public boolean onTouch(View v, MotionEvent me) {
int action = me.getActionMasked(); // MotionEvent types such as ACTION_UP, ACTION_DOWN
float currentXPosition = me.getX();
float currentYPosition = me.getY();
int position = gridView.pointToPosition((int) currentXPosition, (int) currentYPosition);
// Access text in the cell, or the object itself
String s = (String) gridView.getItemAtPosition(position);
TextView tv = (TextView) gridView.getChildAt(position);
}
}

SemiClosedSlidingDrawer onClick not dispatched when semi-collapsed

i'm using a SemiClosedSlidingDrawer (http://pastebin.com/FtVyrcEb) and i've added on content part some buttons on the top of slider which are always visibles.
The problems is that they are clickable (or click event is dispatched) only when slider is fully opened... When slider is "semi-opened" click event not seems dispached to button... I have inspected with debugger into onInterceptTouchEvent() and in both cases (opened/semi-collapsed) the following code
#Override
public boolean onInterceptTouchEvent(MotionEvent event) {
if (mLocked) {
return false;
}
final int action = event.getAction();
float x = event.getX();
float y = event.getY();
final Rect frame = mFrame;
final View handle = mHandle;
handle.getHitRect(frame);
//FOLLOWING THE CRITICAL CODE
if (!mTracking && !frame.contains((int) x, (int) y)) {
return false;
}
return false but only when slider is opened event was dispached...
It checks if a (x,y) relative to the click are contained in a rectangle created starting from the HandleButton view of sliding drawer...
final Rect frame = mFrame;
final View handle = mHandle;
handle.getHitRect(frame);
and this is obviously false because i'm clicking on a button contained inside the content part of slidingdrawer and that's ok...
As i said above the problem is that in semi-collapsed state, buttons contained in content part are not receiving the event...
Have you any idea how can i solve this issue?
Can be some state of slidingdrawer that avoid to click childs when collapsed?
Thanks in advance...

Right, I think I've figured out a way to do this.
First you need to modify onInterceptTouchEvent() to return true whenever the user presses the visible content during the semi-opened state. So, for instance, if your SemiClosedSlidingDrawer view is located at the very bottom of the screen, you can use a simple detection algorithm, like this:
public boolean onInterceptTouchEvent(MotionEvent event) {
...
handle.getHitRect(frame);
// NEW: Check if the user pressed on the "semi-open" content (below the handle):
if(!mTracking && (y >= frame.bottom) && action == MotionEvent.ACTION_DOWN) {
return true;
}
if (!mTracking && !frame.contains((int) x, (int) y)) {
...
}
Now the touch events during the user's interaction with the semi-opened content will be dispatched to onTouchEvent(). Now we just need to intercept these events and "manually" redirect them to the right view (note that we also need to offset the coordinates for the child view):
public boolean onTouchEvent(MotionEvent event) {
...
if (mTracking) {
...
}
else
{
// NEW: Dispatch events to the "semi-open" view:
final Rect frame = mFrame;
final View handle = mHandle;
handle.getHitRect(frame);
float x = event.getX();
float y = event.getY() - frame.bottom;
MotionEvent newEvent = MotionEvent.obtain(event);
newEvent.setLocation(x, y);
return mContent.dispatchTouchEvent(newEvent);
}
return mTracking || mAnimating || super.onTouchEvent(event);
}
It's a bit of a messy implementation, but I think the basic concept is right. Let me know how it works for you!

Display image in area touch with finger on the screen

When I touch a region on my screen, I want an ImageView to be visible at the touch area. An example of imageview is as follows.
ImageView image = (ImageView)findViewById(R.id.image);
How can I set the image at region touch on the screen using the method below. Also when I tap on a new region the previous image become invisible.
#Override
public boolean onTouchEvent(MotionEvent event, view) {
final int action = event.getAction();
final int x = (int) event.getX();
final int y = (int) event.getY();
boolean result = false;
}

Use Canvas you will get the xy coordinates and you can easily get Imageview at that coordinates

ImageView click best practice

I am a newbie in Andoird.
In my case, I have a scenario that when click certain part of an image it will trigger onclick events. I tried to detecte the position when the onTouch is fired, it works, but I think it's not a standard implementation, so what is the best practice for such case?
thanks.
here is codes like:
imgView.setOnTouchListener((OnTouchListener) new OnTouchListener(){
public boolean onTouch(View v, MotionEvent event) {
if(isIn(event.getX(), event.getY(), 124,3,221,36)){
ShowMemberInfo(R.string.app_m01);
} else if(isIn(event.getX(), event.getY(), 8,155,72,181)){
..
}
return true;
}
private boolean isIn(float x, float y, int fx, int fy, int tx, int ty) {
return x<tx && x > fx && y<ty && y>fy;
}

Try to use ImageButton

Simply implement onClickListener() for your ImageView.
Easiest way to implement onClick event is to include android:onClickMe="methodName" inside your <ImageView> in XML layout and define that method inside your activity file.
For example:
public void methodName(View v)
{
....
....
// do whatever you want for click even ton imageview
}

If you want to detect the position where user touched(Relative to the ImageView user touched), you can get the touch point from MotionEvent object.
Try to register a touch event listener for the ImageView and get the touched point position from MotionEvent object's getX() and getY() methods when touch event is triggered. And then define a rectangular area and using contains() to check whether the touch point is inside the area or not.
ImageView img = new ImageView(this);
img.setOnTouchListener(new OnTouchListener(){
#Override
public boolean onTouch(View v, MotionEvent event) {
Log.w("Hit test", "is hit? "+isIn(event.getX(),event.getY(),0,0,120,120));
return false;
}
});
private boolean isIn(float x, float y, int fx, int fy, int tx, int ty){
return new Rect(fx,fy,tx,ty).contains((int)x,(int)y);
}
Hope this will be helpful to you. :)

Android touch in predefined position

I have an android code which starts vibrating for a random amount of time when the user touch a screen. Now I want to change it a bit. I want to ask the user to touch a predefined position, for example in the middle of screen. what should I do that only in some special coordinates touching become effective?

You can use a onTouchListener. The Listener gets a MotionEvent from which you can get th coordinates and check the position:
something.setOnTouchListener(new OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
// get coordinates from touch event
int x = (int) event.getX();
int y = (int) event.getY();
// check if the coordinates are in a specific area
return true;
}
});
To get the width and height you can use the following code:
Display d = getWindowManager().getDefaultDisplay();
width = d.getWidth();
height = d.getHeight();

onTouch(View v, MotionEvent event)
onTouch give you a MotionEvent, with this, you can simply do
event.getX();
event.getY();
for getting coordinates and do something with it (or not :))