Develop Reference

Custom android square textview text is not centered

I am trying to create a textview that will always be squared so I have implemented this custom class.
public class SquareTextView extends TextView {
public SquareTextView(Context context) {
super(context);
}
public SquareTextView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public SquareTextView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int max = Math.max(getMeasuredWidth(), getMeasuredHeight());
setMeasuredDimension(max, max);
}
}
Here is an example layout that illustrates the problem:
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="8dp"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:paddingTop="8dp">
<com.mypackage.SquareTextView
android:layout_width="wrap_content"
android:layout_height="50dp"
android:layout_gravity="right|top"
android:background="#000"
android:gravity="center"
android:padding="4dp"
android:text="1"
android:textColor="#FFF"/>
</LinearLayout>
Here is an image of this
This works great in getting the view squared, however, it seems like the gravity gets messed up. With this, the text seems to always be in the top left corner. How can I have a TextView that will always be squared but still keep the gravity or at least be able to center the text?
EDIT: After some testing I have noticed that if you set the width or height to a specific dp size the gravity seems to be working again. So it probably has to do with the WRAP_CONTENT attribute. Will that be handled in another way in the onmeasure method that could cause my own method to not work as expected?

Hope you have already got the answer by now. If not, you can use this:
public class TextAlphaSquareTextView extends AppCompatTextView {
private int mTextAlpha = 0;
private boolean isSquare = false;
public TextAlphaSquareTextView(Context context) {
super(context);
init(null);
}
public TextAlphaSquareTextView(Context context, AttributeSet attrs) {
super(context, attrs);
init(attrs);
}
public TextAlphaSquareTextView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init(attrs);
}
private void init(AttributeSet attrs) {
if (attrs == null) {
} else {
TypedArray a = getContext().obtainStyledAttributes(attrs, R.styleable.TextAlphaSquareTextView);
mTextAlpha = a.getInteger(R.styleable.TextAlphaSquareTextView_textAlpha, 100);
isSquare = a.getBoolean(R.styleable.TextAlphaSquareTextView_squareMode, false);
a.recycle();
if(mTextAlpha < 0 || mTextAlpha > 100)
throw new IllegalArgumentException("Alpha range should be b/w 0 to 100 (in percentage)");
else {
setAlphaOnTextColor();
}
}
setText(getText());
}
void setAlphaOnTextColor() {
int alpha = ((255 * mTextAlpha) / 100);
setTextColor(getTextColors().withAlpha(alpha));
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (isSquare) {
int width = this.getMeasuredWidth();
int height = this.getMeasuredHeight();
int size = Math.max(width, height);
int widthSpec = MeasureSpec.makeMeasureSpec(size, MeasureSpec.EXACTLY);
int heightSpec = MeasureSpec.makeMeasureSpec(size, MeasureSpec.EXACTLY);
super.onMeasure(widthSpec, heightSpec);
}
}
}
you need to call super.onMeasure() again with EXACT spec and the calculated size, since setMeasureDimension() seems to be ignoring the gravity.

ImageView setMaxHeight or getWidth doesn't work

I have this code:
holder.ImageMain.setMaxHeight(holder.ImageMain.getWidth());
My intention is to have a square imageview if the image is big and horizontal. the code will set a height that is the same as the width.
But for some reason it's not working. The imageView has been long and horizontal.
Do you have any idea what's wrong with it?

You can try to use
android:adjustViewBounds= "true"
or to a more controled case, use instead a custom ImageView that in the onMeasure method adjust it size like you want. For example here are an example to create a 16/9 ImageView
public class SixteenNineImageView extends ImageView {
public SixteenNineImageView(Context context) {
super(context);
}
public SixteenNineImageView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public SixteenNineImageView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#TargetApi(Build.VERSION_CODES.LOLLIPOP)
public SixteenNineImageView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
final int width = getMeasuredWidth();
final int height = (width * 9) / 16;
setMeasuredDimension(width, height);
}
}

How can I catch that View become visible

I inflate Views on ScrollView.
And I need to get event, when on scrolling one of this Views (last, for example, or special type) becomes visible (in screen zone).

If a view changes visibility, the onlayout method is called, you could try overwriting that method and check it's state.

You need to override the view's onVisibilityChanged(). This is also called when one of the view's ancestors changes visibility.

This I inflated my GridView and get what you want
public class MyGrideView extends GridView {
boolean expanded = false;
public MyGrideView(Context context) {
super(context);
}
public MyGrideView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyGrideView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public boolean isExpanded() {
return expanded;
}
#Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// HACK! TAKE THAT ANDROID!
if (isExpanded()) {
// Calculate entire height by providing a very large height hint.
// But do not use the highest 2 bits of this integer; those are
// reserved for the MeasureSpec mode.
int expandSpec = MeasureSpec.makeMeasureSpec(
Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
ViewGroup.LayoutParams params = getLayoutParams();
params.height = getMeasuredHeight();
} else {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
}
public void setExpanded(boolean expanded) {
this.expanded = expanded;
}
}

Android: Custom View

I am trying to make a custom view that is square, using the width as the height. I am also using a pre-defined layout which I inflate as it's UI. As soon as I overrode onMeasure, the custom view no longer appears. Here is my code:
public class MyView extends RelativeLayout{
public MyView(Context context) {
super(context);
addView(setupLayout(context));
}
public MyView(Context context, AttributeSet attrs) {
super(context, attrs);
addView(setupLayout(context));
}
public MyView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
addView(setupLayout(context));
}
private View setupLayout(Context context) {
LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View myView = inflater.inflate(R.layout.view_layout, null);
return myView;
}
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec), MeasureSpec.getSize(widthMeasureSpec));
}
}
I have 2 questions:
How do I override onMeasure so that it draws my view the way I am expecting it to?
Is there any way I can make this more efficient in terms of the view hierarchy (i.e. not be putting a RelativeLayout inside a RelativeLayout)

You can use this code from Jan Němec's answer to a similar question :
import android.content.Context;
import android.util.AttributeSet;
import android.widget.LinearLayout;
public class SquareLayout extends LinearLayout {
public SquareLayout(Context context) {
super(context);
}
public SquareLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int width = MeasureSpec.getSize(widthMeasureSpec);
int height = MeasureSpec.getSize(heightMeasureSpec);
if (width > (int)(mScale * height + 0.5)) {
width = (int)(mScale * height + 0.5);
} else {
height = (int)(width / mScale + 0.5);
}
super.onMeasure(
MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY),
MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY)
);
}
}
Or try to use this library project.

Gridview height gets cut

I'm trying to display 8 items inside a gridview. Sadly, the gridview height is always too little, so that it only shows the first row, and a little part of the second.
Setting android:layout_height="300dp" makes it work. wrap_content and fill_parent apparently not.
My grid view:
<GridView
android:id="#+id/myId"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:horizontalSpacing="2dp"
android:isScrollContainer="false"
android:numColumns="4"
android:stretchMode="columnWidth"
android:verticalSpacing="20dp" />
My items resource:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:minHeight="?android:attr/listPreferredItemHeight" >
<ImageView
android:id="#+id/appItemIcon"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:src="#android:drawable/ic_dialog_info"
android:scaleType="center" />
<TextView
android:id="#+id/appItemText"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="My long application name"
android:gravity="center_horizontal"
android:textAppearance="?android:attr/textAppearanceSmall" />
</LinearLayout>
The issue does not seem related to a lack of vertical space.
What can I do ?

After (too much) research, I stumbled on the excellent answer of Neil Traft.
Adapting his work for the GridView has been dead easy.
ExpandableHeightGridView.java:
package com.example;
public class ExpandableHeightGridView extends GridView
{
boolean expanded = false;
public ExpandableHeightGridView(Context context)
{
super(context);
}
public ExpandableHeightGridView(Context context, AttributeSet attrs)
{
super(context, attrs);
}
public ExpandableHeightGridView(Context context, AttributeSet attrs,
int defStyle)
{
super(context, attrs, defStyle);
}
public boolean isExpanded()
{
return expanded;
}
#Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
// HACK! TAKE THAT ANDROID!
if (isExpanded())
{
// Calculate entire height by providing a very large height hint.
// View.MEASURED_SIZE_MASK represents the largest height possible.
int expandSpec = MeasureSpec.makeMeasureSpec(MEASURED_SIZE_MASK,
MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
ViewGroup.LayoutParams params = getLayoutParams();
params.height = getMeasuredHeight();
}
else
{
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
}
public void setExpanded(boolean expanded)
{
this.expanded = expanded;
}
}
Include it in your layout like this:
<com.example.ExpandableHeightGridView
android:id="#+id/myId"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:horizontalSpacing="2dp"
android:isScrollContainer="false"
android:numColumns="4"
android:stretchMode="columnWidth"
android:verticalSpacing="20dp" />
Lastly you just need to ask it to expand:
mAppsGrid = (ExpandableHeightGridView) findViewById(R.id.myId);
mAppsGrid.setExpanded(true);

After using the answer from #tacone and making sure it worked, I decided to try shorting down the code. This is my result. PS: It is the equivalent of having the boolean "expanded" in tacones answer always set to true.
public class StaticGridView extends GridView {
public StaticGridView(Context context) {
super(context);
}
public StaticGridView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public StaticGridView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
#Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(MEASURED_SIZE_MASK, MeasureSpec.AT_MOST));
getLayoutParams().height = getMeasuredHeight();
}
}

Another similar approach that worked for me, is to calculate the height for one row and then with static data (you may adapt it to paginate) you can calculate how many rows you have and resize the GridView height easily.
private void resizeGridView(GridView gridView, int items, int columns) {
ViewGroup.LayoutParams params = gridView.getLayoutParams();
int oneRowHeight = gridView.getHeight();
int rows = (int) (items / columns);
params.height = oneRowHeight * rows;
gridView.setLayoutParams(params);
}
Use this code after setting the adapter and when the GridView is drawn or you will get height = 0.
gridView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
if (!gridViewResized) {
gridViewResized = true;
resizeGridView(gridView, numItems, numColumns);
}
}
});

Found tacones answer helpfull... so i ported it to C# (Xamarin)
public class ExpandableHeightGridView: GridView
{
bool _isExpanded = false;
public ExpandableHeightGridView(Context context) : base(context)
{
}
public ExpandableHeightGridView(Context context, IAttributeSet attrs) : base(context, attrs)
{
}
public ExpandableHeightGridView(Context context, IAttributeSet attrs, int defStyle) : base(context, attrs, defStyle)
{
}
public bool IsExpanded
{
get { return _isExpanded; }
set { _isExpanded = value; }
}
protected override void OnMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
// HACK! TAKE THAT ANDROID!
if (IsExpanded)
{
// Calculate entire height by providing a very large height hint.
// View.MEASURED_SIZE_MASK represents the largest height possible.
int expandSpec = MeasureSpec.MakeMeasureSpec( View.MeasuredSizeMask, MeasureSpecMode.AtMost);
base.OnMeasure(widthMeasureSpec,expandSpec);
var layoutParameters = this.LayoutParameters;
layoutParameters.Height = this.MeasuredHeight;
}
else
{
base.OnMeasure(widthMeasureSpec,heightMeasureSpec);
}
}
}

Jacob R solution in Kotlin:
class ExpandableHeightGridView #JvmOverloads constructor(
context: Context,
attrs: AttributeSet? = null,
defStyleAttr: Int = 0
) : GridView(context, attrs, defStyleAttr) {
override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
val expandSpec = MeasureSpec.makeMeasureSpec(MEASURED_SIZE_MASK,
MeasureSpec.AT_MOST)
super.onMeasure(widthMeasureSpec, expandSpec)
layoutParams.height = measuredHeight
}
}
After adding GridView to RecyclerView I got a full-size GridView (all rows are visible), as expected.

Just calculate the height for AT_MOST and set to on measure. Here GridView Scroll will not work so. Need to use Vertical Scroll View explicitly.
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int heightSpec;
if (getLayoutParams().height == LayoutParams.WRAP_CONTENT) {
heightSpec = MeasureSpec.makeMeasureSpec(
Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
}
else {
// Any other height should be respected as is.
heightSpec = heightMeasureSpec;
}
super.onMeasure(widthMeasureSpec, heightSpec);
}