Retrieve the X & Y of FAB

Question

I have a RelativeLayout and inside this layout i have fab button:

<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_alignParentRight="true"
    android:layout_margin="8dp"/>

Now , in java I want to now, where is the fab position on the screen.I used this method according this post : enter link description here

private Point getPointOfView(View view) {
    int[] location = new int[2];
    view.getLocationInWindow(location);
    return new Point(location[0], location[1]);
}

and using this method like this:

fab = findViewById(R.id.fab);
for (int i = 0; i < pv.length; i++) {
    pv[i] = new Point(getPointOfView(fab).x ,getPointOfView(fab).y);
}

but getPointOfView(fab).x and getPointOfView(fab).y return 0.how could i retrieve the X & Y fab button?

Why down Vote? some people just know down vote instead of helping. — Cyrus the Great, Mar 11 '18 at 04:55

score 1 · Accepted Answer · answered Mar 10 '18 at 17:16

1

You can make use of View#post() API, then your code would be replaced with this one:

FloatingActionButton fab = findViewById(R.id.fab);
fab.post(new Runnable() {
    @Override
    public void run() {
        // this callback will be executed after view is laid out
        for (int i = 0; i < pv.length; ++i) {
            pv[i] = new Point(getPointOfView(fab).x ,getPointOfView(fab).y);
        }
    }
})

answered Mar 10 '18 at 17:16

azizbekian

60,783
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dude,`fab.post`execute command into ui thread.What is difference between execute this command in oncreate and without post?@azizbekian – Cyrus the Great Mar 11 '18 at 04:58
In `onCreate()` your view hierarchy hasn't yet been laid out, thus it will return zeros. – azizbekian Mar 11 '18 at 05:52
Ok,but `fab.post` is waiting to view is created? like `addOnGlobalLayoutListener` – Cyrus the Great Mar 11 '18 at 07:56
1

Yes, `View#post()` will defer an action to be performed after view is laid out some time later. – azizbekian Mar 11 '18 at 08:27

Nouman Ch · Answer 2 · 2018-03-10T14:39:12.280

0

use

View.getLocationOnScreen()

method to get values. Note: try to use this method in handler

new Handler ().post(...... v.getLocationOnScreen(location); .....);

onCreate method is to early to get location we should have to try this in onWindowFocusChanged() method of activity when application end all the view related tasks.

reference

edited Mar 10 '18 at 14:39

answered Mar 10 '18 at 14:11

Nouman Ch

4,023
4
29
42

I have changed my method to `view.getLocationOnScreen(location);` but returned 0 for x and y again – Cyrus the Great Mar 10 '18 at 14:21
I have changed my method: `private Point getPointOfView(final View view) { final int[] location = new int[2]; new Handler().post(new Runnable() { @Override public void run() { view.getLocationOnScreen(location); } }); return new Point(location[0], location[1]); }` I got 0 – Cyrus the Great Mar 10 '18 at 14:34
activity also have this paste this code inside your activity. @Override public void onWindowFocusChanged(boolean hasFocus) { if(!hasFocus) { //do anything you want here Toast.makeText(MainActivity.this,"Activity changed",Toast.LENGTH_SHORT).show(); } } – Nouman Ch Mar 10 '18 at 14:49
dude, when activity is up this method not called but i want to get fab position at first time when activity is up.this method not called first.I have just one activity – Cyrus the Great Mar 10 '18 at 14:52

score 0 · Answer 3 · answered Mar 10 '18 at 16:08

I found, how could i get fab position:

fab.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {
        for (int i = 0; i < pv.length; i++) {
            pv[i] = new Point(getPointOfView(fab).x, getPointOfView(fab).y);
        }
        fab.getViewTreeObserver().removeOnGlobalLayoutListener(this);
    }
});

but if i have mistake in removing GloabalLayout place please tel me.

Retrieve the X & Y of FAB

3 Answers3