I'm trying to determine the real dimension in pixels of some UI elements !
Those elements are inflated from a .xml file and are initialized with dip width and height so that the GUI will eventually support multiple screen size and dpi (as recommended by android specs).
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="150dip"
android:orientation="vertical">
<ImageView
android:id="@+id/TlFrame"
android:layout_width="110dip"
android:layout_height="90dip"
android:src="@drawable/timeline_nodrawing"
android:layout_margin="0dip"
android:padding="0dip"/></LinearLayout>
This previous xml represent one frame. But I do add many dynamically inside a horizontal layout describe here :
<HorizontalScrollView
android:id="@+id/TlScroller"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_margin="0dip"
android:padding="0dip"
android:scrollbars="none"
android:fillViewport="false"
android:scrollbarFadeDuration="0"
android:scrollbarDefaultDelayBeforeFade="0"
android:fadingEdgeLength="0dip"
android:scaleType="centerInside">
<!-- HorizontalScrollView can only host one direct child -->
<LinearLayout
android:id="@+id/TimelineContent"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_margin="0dip"
android:padding="0dip"
android:scaleType="centerInside"/>
</HorizontalScrollView >
The method defined to add one frame inside my java code :
private void addNewFrame()
{
LayoutInflater inflater = (LayoutInflater) _parent.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
ViewGroup root = (ViewGroup) inflater.inflate(R.layout.tl_frame, null);
TextView frameNumber = (TextView) root.findViewById(R.id.FrameNumber);
Integer val = new Integer(_nFramesDisplayed+1); //+1 to display ids starting from one on the user side
frameNumber.setText(val.toString());
++_nFramesDisplayed;
_content.addView(root);
// _content variable is initialized like this in c_tor
// _content = (LinearLayout) _parent.findViewById(R.id.TimelineContent);
}
Then inside my code, I try to get the actual real size in pixel because I need this to draw some opengl stuff over it.
LayoutInflater inflater = (LayoutInflater) _parent.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
ViewGroup root = (ViewGroup) inflater.inflate(R.layout.tl_frame, null);
ImageView frame = (ImageView) root.findViewById(R.id.TlFrame);
frame.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
frame.measure(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
final int w = frame.getMeasuredWidth();
final int h = frame.getMeasuredHeight();
Everything seems to work fine except that those values are way bigger than the actual pixel size of the ImageView.
Reported infos from getWindowManager().getDefaultDisplay().getMetrics(metrics); are the following : density = 1,5 densityDpi = 240 widthPixel = 600 heightPixel = 1024
Now, I know the rule from android is : pixel = dip * (dpi /160). But nothing makes any sense with the value returned. For that ImageView of (90dip X 110dip), the returned values of the measure() method is (270 x 218) which I assumed is in pixel !
Anyone has any idea why ? Is the value returned in pixel ?
By the way : I've been testing the same code but with a TextView instead than an ImageView and everything seems to be working fine ! Why !?!?
You're calling measure incorrectly.
measure takes MeasureSpec values which are specially packed by MeasureSpec.makeMeasureSpec. measure ignores LayoutParams. The parent doing the measuring is expected to create a MeasureSpec based on its own measurement and layout strategy and the child's LayoutParams.
If you want to measure the way that WRAP_CONTENT usually works in most layouts, call measure like this:
frame.measure(MeasureSpec.makeMeasureSpec(maxWidth, MeasureSpec.AT_MOST),
MeasureSpec.makeMeasureSpec(maxHeight, MeasureSpec.AT_MOST));
If you don't have max values (for example if you're writing something like a ScrollView that has infinite space) you can use the UNSPECIFIED mode:
frame.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
Do that:
frame.measure(0, 0);
final int w = frame.getMeasuredWidth();
final int h = frame.getMeasuredHeight();
Solved!
Ok ! Kind of Answering my own question here...But not completly
1 - It seems that on some devices, The ImageView measuring do not provide with exact values. I've seen lots of reports on this happenning on Nexus and Galaxy devices for example.
2 - A work around that I've come up with :
Set the width and height of your ImageView to "wrap_content" inside xml code.
Inflate the layout inside your code (generally in the UI initialization I suppose).
LayoutInflater inflater = (LayoutInflater)
_parent.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
ViewGroup root = (ViewGroup) inflater.inflate(R.layout.tl_frame, null);
ImageView frame = (ImageView) root.findViewById(R.id.TlFrame);
Calculate your own ratio for your image view, based on the typical Android calculation
//ScreenDpi can be acquired by getWindowManager().getDefaultDisplay().getMetrics(metrics);
pixelWidth = wantedDipSize * (ScreenDpi / 160)
Use the calculated size to set your ImageView dynamycally inside your code
frame.getLayoutParams().width = pixeWidth;
And voila ! your ImageView has now the wanted Dip size ;)
view.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
@SuppressLint("NewApi")
@SuppressWarnings("deprecation")
@Override
public void onGlobalLayout() {
//now we can retrieve the width and height
int width = view.getWidth();
int height = view.getHeight();
//this is an important step not to keep receiving callbacks:
//we should remove this listener
//I use the function to remove it based on the api level!
if(android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN){
view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
}else{
view.getViewTreeObserver().removeGlobalOnLayoutListener(this);
}
}
});
One should go with How to get width/height of a View
You have to create Custom Textview and use it in your layouts and use getActual height function to set the height at runtime
public class TextViewHeightPlus extends TextView {
private static final String TAG = "TextViewHeightPlus";
private int actualHeight=0;
public int getActualHeight() {
return actualHeight;
}
public TextViewHeightPlus(Context context) {
super(context);
}
public TextViewHeightPlus(Context context, AttributeSet attrs) {
super(context, attrs);
setCustomFont(context, attrs);
}
public TextViewHeightPlus(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
actualHeight=0;
actualHeight=(int) ((getLineCount()-1)*getTextSize());
}
}
Unfortunately, in Activity lifecycle methods such as Activity#onCreate(Bundle), a layout pass has not yet been performed, so you can't yet retrieve the size of views in your view hierarchy. However, you can explicitly ask Android to measure a view using View#measure(int, int).
As @adamp's answer points out, you have to provide View#measure(int, int) with MeasureSpec values, but it can be a bit daunting figuring out the correct MeasureSpec.
The following method tries to determine the correct MeasureSpec values and measures the passed in view:
public class ViewUtil {
public static void measure(@NonNull final View view) {
final ViewGroup.LayoutParams layoutParams = view.getLayoutParams();
final int horizontalMode;
final int horizontalSize;
switch (layoutParams.width) {
case ViewGroup.LayoutParams.MATCH_PARENT:
horizontalMode = View.MeasureSpec.EXACTLY;
if (view.getParent() instanceof LinearLayout
&& ((LinearLayout) view.getParent()).getOrientation() == LinearLayout.VERTICAL) {
ViewGroup.MarginLayoutParams lp = (ViewGroup.MarginLayoutParams) view.getLayoutParams();
horizontalSize = ((View) view.getParent()).getMeasuredWidth() - lp.leftMargin - lp.rightMargin;
} else {
horizontalSize = ((View) view.getParent()).getMeasuredWidth();
}
break;
case ViewGroup.LayoutParams.WRAP_CONTENT:
horizontalMode = View.MeasureSpec.UNSPECIFIED;
horizontalSize = 0;
break;
default:
horizontalMode = View.MeasureSpec.EXACTLY;
horizontalSize = layoutParams.width;
break;
}
final int horizontalMeasureSpec = View.MeasureSpec
.makeMeasureSpec(horizontalSize, horizontalMode);
final int verticalMode;
final int verticalSize;
switch (layoutParams.height) {
case ViewGroup.LayoutParams.MATCH_PARENT:
verticalMode = View.MeasureSpec.EXACTLY;
if (view.getParent() instanceof LinearLayout
&& ((LinearLayout) view.getParent()).getOrientation() == LinearLayout.HORIZONTAL) {
ViewGroup.MarginLayoutParams lp = (ViewGroup.MarginLayoutParams) view.getLayoutParams();
verticalSize = ((View) view.getParent()).getMeasuredHeight() - lp.topMargin - lp.bottomMargin;
} else {
verticalSize = ((View) view.getParent()).getMeasuredHeight();
}
break;
case ViewGroup.LayoutParams.WRAP_CONTENT:
verticalMode = View.MeasureSpec.UNSPECIFIED;
verticalSize = 0;
break;
default:
verticalMode = View.MeasureSpec.EXACTLY;
verticalSize = layoutParams.height;
break;
}
final int verticalMeasureSpec = View.MeasureSpec.makeMeasureSpec(verticalSize, verticalMode);
view.measure(horizontalMeasureSpec, verticalMeasureSpec);
}
}
Then you can simply call:
ViewUtil.measure(view);
int height = view.getMeasuredHeight();
int width = view.getMeasuredWidth();
Alternatively, as @Amit Yadav suggested, you can use OnGlobalLayoutListener to have a listener called after the layout pass has been performed. The following is a method that handles unregistering the listener and method naming changes across versions:
public class ViewUtil {
public static void captureGlobalLayout(@NonNull final View view,
@NonNull final ViewTreeObserver.OnGlobalLayoutListener listener) {
view.getViewTreeObserver()
.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
final ViewTreeObserver viewTreeObserver = view.getViewTreeObserver();
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
viewTreeObserver.removeOnGlobalLayoutListener(this);
} else {
//noinspection deprecation
viewTreeObserver.removeGlobalOnLayoutListener(this);
}
listener.onGlobalLayout();
}
});
}
}
Then you can:
ViewUtil.captureGlobalLayout(rootView, new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
int width = view.getMeasureWidth();
int height = view.getMeasuredHeight();
}
});
Where rootView can be the root view of your view hierarchy and view can be any view within your hierarchy that you want to know the dimensions of.
来源：https://stackoverflow.com/questions/6157652/android-getmeasuredheight-returns-wrong-values