I am trying to scale and rotate an image. And as the method Bitmap.createScaledBitmap() demands to specify the desired width and height, I want to set the desired width and the desired height to be exactly the same as my imageView's width and height.
Now, How can I get the width and height of any given imageView?
given that the imageView initially is empty, but just defined with findViewById()
You must wait until the view is laid out to have dimensions. You can achieve this with a ViewTreeObserver:
final ImageView view = ...;
view.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener()
{
#Override
#SuppressLint("NewApi")
#SuppressWarnings("deprecation")
public void onGlobalLayout()
{
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN)
getViewTreeObserver().removeOnGlobalLayoutListener(this);
else
getViewTreeObserver().removeGlobalOnLayoutListener(this);
// width and height are available here.
}
});
Another option is to have your own class derived from ImageView and override onLayout()
Related
Im trying to find a way to measure an ImageView after an image has been loaded into it using Glide or Picasso (or anything really). Basically, im trying to layout other views on top of the image in certain positions, but need the final ImageViews dimensions to do so accurately.
Im not sure what the best layout to use to try and do this would be, but im currently using this:
<FrameLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/viewingImageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</FrameLayout>
and loading the image into viewingImageView. These are both inside a root FrameLayout as well but I dont think that matters.
This is my latest attempt, but as commented, using .getWidth() and .getHeight() on the ImageView return 0. The width/height of the resource returns the size of the original image.
Glide
.with(this)
.load(entry.getImageUrl())
.asBitmap()
.into(new SimpleTarget<Bitmap>() {
#Override
public void onResourceReady(Bitmap resource, GlideAnimation<? super Bitmap> glideAnimation) {
mImageView.setImageBitmap(resource);
int width = mImageView.getMaxWidth(); //prints 0
int height = mImageView.getMaxHeight(); //prints 0
int resw = resource.getWidth(); //returns original image width
}
});
So how can I get the image loaded and then measure the ImageView (or its wrapping FrameLayout) after the image has been loaded? Or if possible, measuring the dimensions of the finally laid out image would be better, as I know the image doesnt always fill the entire ImageView depending on scale types. I'm open to any solutions, the above is only what ive tried so far.
You should wait for the view to be drawn, you can use OnGlobalLayoutListener like this
ViewTreeObserver vto = mImageView.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
this.mImageView.getViewTreeObserver().removeGlobalOnLayoutListener(this);
// Get the width and height
int width = mImageView.getMeasuredWidth();
int height = mImageView.getMeasuredHeight();
}
});
Create a custom class with image view.
Use this onMeasure in the image view we can get the height and width
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (mNeedsInitialScale) { // Set by setImage when a new image is set
// The measured width and height were set by super.onMeasure above
setInitialScale(getMeasuredWidth(), getMeasuredHeight());
mNeedsInitialScale = false;
}
}
I have an ImageView which has layout_width of fill_parent. I want to get the width of this ImageView in order to calculate the size of the thumbnail. The problem is that imageView.getWidth() and imageView.getHeight() both return 0 because the layout hasn't been sat yet.
My question is, does the ImageView has some kind of SizeChanged event or something of the kind? How do I react as soon as the ImageView width has been established?
Update:
I solved my problem this way. As I actually only needed the width of the ImageView which is set to fill_parent, what I actually needed was the device window size:
DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
int targetW = metrics.widthPixels;
You can hook into a number of View tree events using a ViewTreeObserver. Specifically, either an OnGlobalLayoutListener or an OnPreDrawListener should work for you depending on what you are doing with the size.
Here's an example of using a ViewTreeObserverto get a View's width once everything has been laid out:
final ImageView myImageView = (ImageView) findViewById(R.id.image);
final ViewTreeObserver observer = myImageView.getViewTreeObserver();
observer.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
int height = myImageView.getHeight();
// Do something with the height
// Remove the layout listener so we don't waste time on future passes
observer.removeOnGlobalLayoutListener(this);
}
});
According to this post's answer:
ImageView.getWidth() returns 0
You will need to call it from the following function:
public void onWindowFocusChanged(boolean hasFocus)
This is because the window has not yet been attached and as you have noticed your imageview will have no dimensions yet.
I have the a LinearLayout with width set in xml as fill_parent , now i need its width at runtime programatically. So i did this:
LinearLayout layoutGet=(LinearLayout) findViewById(R.id.GameField1);
LayoutParams layParamsGet= layoutGet.getLayoutParams();
int width=layParamsGet.width;
But width value on debugging was found to be -1, anybody with idea why can't i get the exact width at runtime for LinearLayout with fill_parent set in layout xml.
I got a simple approach working.
myLayout = (RelativeLayout) findViewById(R.id.my_layout);
myLayout.post(new Runnable()
{
#Override
public void run()
{
Log.i("TEST", "Layout width : "+ myLayout.getWidth());
}
});
Jens Vossnack's approach mentioned below works fine. However, I found that the onGlobalLayout() method of GlobalLayoutListener is called repeatedly, which may not be appropriate in certain cases.
You can try to listen to the globalLayout event, and get the width in there. You probably get the -1 because you are trying to get the width before the views are layed-out.
vto.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
//Do it here
LinearLayout layoutGet=(LinearLayout) findViewById(R.id.GameField1);
LayoutParams layParamsGet= layoutGet.getLayoutParams();
int width=layParamsGet.width;
removeOnGlobalLayoutListener(layoutGet, this); // Assuming layoutGet is the View which you got the ViewTreeObserver from
}
});
#SuppressLint("NewApi")
public static void removeOnGlobalLayoutListener(View v, ViewTreeObserver.OnGlobalLayoutListener listener){
if (Build.VERSION.SDK_INT < 16) v.getViewTreeObserver().removeGlobalOnLayoutListener(listener);
else v.getViewTreeObserver().removeOnGlobalLayoutListener(listener);
}
(vto is the view you want to get the width of)
If you look at the value for FILL_PARENT (you should be using MATCH_PARENT since FILL_PARENT is now deprecated) you will notice the value for it is -1. LayoutParams are simply attributes for how your view should look. Once the view is inflated and looks the way the params specify, the view does not go back and change those Params to reflect the actual values of the view (width/height/etc).
If you wanted to get the actual width of your view you would have to call getWidth() on your view once the layout has been inflated and displayed. Calling getWidth() before your layout has been displayed will result in 0.
LinearLayout layoutGet=(LinearLayout) findViewById(R.id.GameField1);
int width = layoutGet.getWidth();
First of all, you should use match_parent instead of fill_parent (deprecated).
When you do int width=layParamsGet.width;, you take the right result which is -1 corresponding at fill_parent.
If you wan't to get the real width, you need to wait onMesure() call and use
LinearLayout layoutGet=(LinearLayout) findViewById(R.id.GameField1);
int width = layoutGet. getMeasuredHeight();
layoutGet.getWidth() should work out
How can I determine the dimensions of my Scaled ImageView? I tried using getWidth() & getHeight it always returns 0. My xml layout for the ImageView is as follows:
<ImageView
android:id="#+id/imgView"
android:layout_width="300dp"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:scaleType="fitXY"
android:src="#drawable/my_image" />
Please suggest something.
You are probably calling getWidth() method too early. The width and height of your ImageView will not be available until the View has been rendered on the screen. Try getting them within onWindowFocusChanged:
#Override
public void onWindowFocusChanged(boolean hasFocus) {
super.onWindowFocusChanged(hasFocus);
int width = iv.getWidth();
int height = iv.getHeight();
// ...
}
You won't get those dimensions in onCreate. The view isn't measured yet and the hierarchy is not set. Those will work but you need to use them somewhere after the app has drawn the screen or the alternative is to set a ViewTreeObserver to notify you when the layout is set.ViewTreeObserver
Here is how its done:
call getVieeTreeObserver() to get a reference to the viewTreeObserver in your activity.
then add a onGlobalLayoutListener:
observer.addOnGlobalLayoutListener(new OnGlobalLayoutListener()
{
#Override
public void onGlobalLayout()
{
ViewTreeObserver obs = MyActivity.this.getViewTreeObserver();
obs.removeGlobalOnLayoutListener(this);
}
});
Inside this onGlobalLayout method you can use your view and get its width and height and do whatever with them.
How do I compute the width and height of an inflated View if the parent is a PopupWindow, not a ViewGroup? I cannot use LayoutInflator.inflate(int resId, ViewGroup parent, attachToRoot boolean) because PopupWindow is not a ViewGroup, so I use LayoutInflator.inflate(int resId) instead, but after that I getWidth() and getHeight() return zero :(
I need to resize the PopupWindow to fit the View, but cannot do so until the View has a parent. Do I have a chicken-and-egg problem?
By the way the View is a subclass of RelativeView so calculating it manually is essentially out of the question.
Thanks in advance,
Barry
Actually popupWindow supports "wrap content" constans, so if you want popup be exact as your view - use this:
popup = new PopupWindow(context);
popup.setWidth(ViewGroup.LayoutParams.WRAP_CONTENT);
popup.setHeight(ViewGroup.LayoutParams.WRAP_CONTENT);
--other options--
getWidth() and getHeight() returns zero, because view have size only after drawing on the screen. You can try to get values from LayoutParams of inflated view.
If there is fill_parent value - you are in egg-chicken situation.
If there is values in px or dp you can manually calculate size in pixels:
Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dpSize, context.getResources().getDisplayMetrics()));
If there is wrap_content value - you can use view.measure() method - all children and view itself will be measured, and you can get view.getMeasuredHeight() and view.getMeasuredWidth().
As Jin35 said, your problem was that the view's width and height haven't been calculated yet...the dimensions aren't calculated until after the layout pass.
Using a fixed width and height from dimension resources (e.g. from a values/dimens.xml file) is one workaround, since then you don't need to wait for the view's onMeasure to occur -- you can get the value of the same dimension resource you used for the view you're interested in, and use that.
A better solution is to just delay your calculations until after the onMeasure happens. You can do that by overriding onMeasure, but a more elegant solution is to use a temporary OnGlobalLayoutListener like this:
View popup = LayoutInflator.inflate(int resId);
if(popup != null) {
// set up an observer that will be called once the listView's layout is ready
android.view.ViewTreeObserver viewTreeObserver = listView.getViewTreeObserver();
if (viewTreeObserver.isAlive()) {
viewTreeObserver.addOnGlobalLayoutListener(new android.view.ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
// This will be called once the layout is finished, prior to displaying.
View popup = findViewById(resId);
if(popup != null) {
int width = popup.getMeasuredWidth();
int height = popup.getMeasuredHeight();
// don't need the listener any more
popup.getViewTreeObserver().removeGlobalOnLayoutListener(this);
}
}
});
}
}
Please try this:
Display display = getWindowManager().getDefaultDisplay();
Log.e("", "" + display.getHeight() + " " + display.getWidth());