How to get height in pixels of LinearLayout with layout_weight

Question

this is my first post. I am learning to code in java for android apps. I am using a LinearLayout "variable named: ll" with a predefined layout_weight (which I want to change whenever I want in the future) and height and width set to MATCH_PARENT. I want to get the height of this LinearLayout in pixels. I fill this using java (ll.addView(variableForAnObject);). I am trying to get its height using ll.getLayoutParams().height; but I am getting -1. Because I believe this is the constant for MATCH_PARENT. Setting the height to 0dp makes the ll invisible and gives height as 0.

Please tell me if there's a way to get its height. I think I can do this by getting screen height using DisplayMetrics and making nearly impossible calculations (for me, at least) but this will be too complex.

Unni

ll.getLayoutParams().height returns one of MATCH_PARENT or WRAP_CONTENT. the former is -1 the latter is -2 – Dornick

Answer 1

try with ll.getHeight() should work

if not, it's because android has not yet calculed its bounds, then:

//inside of onCreate method should work
ll.post(new Runnable() {
    @Override
    public void run() {
        //maybe also works height = ll.getLayoutParams().height;

        height  = ll.getHeight();

    }
});

Alewife

//maybe also works height = ll.getLayoutParams().height; no it does not – Dornick

Thanks a lot! one problem that's still there is that I get a 0 on the first run. I fill the layout and do much more stuff using a custom method and call this method in OnCreate. But on the first run, I get 0, then if I refill this layout using the same method again, the height then gets a value. I use ll.removeAllViews(); before filling the layout. – Unni

@javi I tried putting directly in onCreate as well as inside my method (which is inside onCreate) but always get a 0. I will search on this matter. – Unni

can you write the layout file, please? I will test on my computer – Alewife

Answer 2

It is -1 because its dimensions have not yet been set, whenever you set layout it takes some time to compute the actual values including height, width etc.

Use OnLayoutListener to listen when it has finished with the layout.

layout.onLayoutChange (View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
    //Extract values here
    height = view.getHeight();
    width = view.getWidth()
}

See this for more about the OnLayoutListener

Northwest

Answer 3

Define your LinearLayout in your class and use getHeight() and getWidth(). Example:

LinearLayout yourLayout = (LinearLayout) findViewById (R.id.yourLL);
double height = yourLayout.getHeight();
double width = yourLayout.getWidth();

Hope it helps! :)

Teen

Answer 4

Give the id field in your layout xml file:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" 
    android:id="@+id/<ID>>

Use this id to get reference in java class and find height and width:

LinearLayout linearLayout= (LinearLayout) findViewById (R.id.<ID>);
double height = linearLayout.getHeight();
double width = linearLayout.getWidth();

Delorasdelorenzo