Develop Reference

Align reclyerview childers from bottom

I'm trying to make chart with reclyerview. The issue that i'm having is i can't seem to make child items align from bottom, instead of the top of the reclyerview.
I have tried, reverseLayout and stackFromEnd
I have searched left and right. Still have no idea why does this happen.
Can anyone please help me.
Any helpfull ideas would be appreciated.

Layout managers align items to top-start by default because it's the most stable in case RecyclerView has height of wrap_content which could cause some layout issues.
If your RecyclerView has fixed size you can try to extend layout manager you're using to force it to lay out items on bottom:
// inside your activity or fragment where you're initializing RecyclerView
recyclerView.setLayoutManager(new LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false) {
#Override
public void layoutDecoratedWithMargins(#NonNull View child, int left, int top, int right, int bottom) {
// calculate available space in recyclerView
int offset = getHeight() - getPaddingTop() - getPaddingBottom();
// subtract height of item being laid out
offset -= bottom - top;
// lay out item lower than usual
super.layoutDecoratedWithMargins(child, left, top + offset, right, bottom + offset);
}
});

I kinda figured it out.
As i have static height, i created another wrapper around child, that was alligned to bottom, and the parrent set as specific height.
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="80dp"
android:layout_height="200dp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
android:layout_marginRight="8dp"
>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent">
<TextView
android:id="#+id/tv_time"
style="#style/BoldWhiteText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="7.5"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

Problem with inflating xml-Layout on custom layout class

I have a custom ConstraintLayout class (Card.java) which overrides the onDraw() method to draw a hexagon in his background. On the foreground i try to have three TextViews to display three numbers.
For this I inflate a card.xml in the constructor of Card. The TextViews are displayed, but not at the right position. They should match the width and height of the Card and then position itself to the top-left and top-right corner and one to the bottom of the Card. But they do something like shrink itself and go to the top-left corner.
I have tried to change the root element of card.xml to "merge" instead of "...ConstraintLayout" but this doesn't change anything.
I also tried to use Guidelines to position the TextViews relative to its width. I try to prevent the use of fixed margins, so the Text is always at the right place, also when the size of the Card changes.
Card.java:
public class Card extends ConstraintLayout {
private int mSize;
private Path mHexagon;
private Paint mPaintHexagon;
private TextView mT1, mT2, mT3;
public Card(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
inflate(context, R.layout.card, this);
// Numbers
mT1 = findViewById(R.id.num1);
mT2 = findViewById(R.id.num2);
mT3 = findViewById(R.id.num3);
// Hexagon
mSize = Field.getHexSize(); // Size is used to calculate the
setPath();
mPaintHexagon = new Paint(Paint.ANTI_ALIAS_FLAG);
mPaintHexagon.setColor(0x50888888);
mPaintHexagon.setStyle(Paint.Style.FILL);
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawPath(mHexagon, mPaintHexagon);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int width = 2 * mSize;
int height = (int) (Math.sqrt(3) * mSize);
Log.d(TAG, "Measure w:" + width + " h:" + height);
setMeasuredDimension(width, height);
}
}
card.xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/num2"
android:textAppearance="#style/TextAppearance.AppCompat.Large"
android:text="2"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginTop="8dp"
app:layout_constraintStart_toStartOf="parent"
android:layout_marginStart="8dp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/num1"
android:textAppearance="#style/TextAppearance.AppCompat.Large"
android:text="1"
app:layout_constraintStart_toEndOf="#+id/num2"
app:layout_constraintEnd_toStartOf="#+id/num3"
app:layout_constraintBottom_toBottomOf="parent"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/num3"
android:textAppearance="#style/TextAppearance.AppCompat.Large"
android:text="3"
app:layout_constraintEnd_toEndOf="parent"
android:layout_marginEnd="8dp"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginTop="8dp"/>
</android.support.constraint.ConstraintLayout>
activity_main.xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
android:background="#color/colorAccentDark"
android:padding="5dp">
<de.portugall.markus.takeiteasy.Card
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
android:id="#+id/card"/>
</android.support.constraint.ConstraintLayout>
Screenshot Card in Layout-Debug mode

'onMeasure()` has some rules that you are not strictly following. I have seen these rules broken with impunity, but I think that you are being caught, but we will push on.
In onMeasure() you are setting the height and width of the custom layout but ConstraintLayout still understands the layout as wrap_content. You will need to set the layout params to the new height and width. Add the following code to the end of onMeasure():
// Although we have measured the layout, we need to tell ConstraintLayout in the
// LayoutParams that the size is not longer "wrap_content".
ViewGroup.LayoutParams lp = getLayoutParams();
lp.width = width;
lp.height = height;
setLayoutParams(lp);
The second issue that you have is that you are adding a ConstraintLayout (card.xml) to a ConstraintLayout (your custom layout), but you are not setting the constraints. In the constructor for Card.java, add the following to set the constraints:
ConstraintLayout layout = (ConstraintLayout) inflate(context, R.layout.card, this);
// We have added R.layout.card to a ConstraintLayout (this custom layout), so we need
// to make sure that it is constrained properly.
ConstraintSet cs = new ConstraintSet();
cs.clone(layout);
cs.connect(R.id.layout, ConstraintSet.START, ConstraintSet.PARENT_ID, ConstraintSet.START);
cs.connect(R.id.layout, ConstraintSet.TOP, ConstraintSet.PARENT_ID, ConstraintSet.TOP);
cs.connect(R.id.layout, ConstraintSet.END, ConstraintSet.PARENT_ID, ConstraintSet.END);
cs.connect(R.id.layout, ConstraintSet.BOTTOM, ConstraintSet.PARENT_ID, ConstraintSet.BOTTOM);
cs.applyTo(layout);
You will need to change the height and width of the layout in card.xml to 0dp. match_parent is never appropriate in ConstraintLayout.
This is a pictorial description of what is happening:
On a related note, you should consider using the merge facility to avoid nested ConstraintLayouts as other have mentioned.

Set width and height based on dimentions of parent's parent Android Studio

I'm dynamicly adding ImageViews in a LinearLayout witch is inside a HorizontalScrollView.
Now I want to set the width and height of these ImageViews based on the parent LinearLayout of this HorizontalScrollView.
This is my xml (information_imagescrollview_item.xml):
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/parentlayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingTop="5dp"
android:paddingBottom="5dp">
<HorizontalScrollView
android:id="#+id/horizontal_scroll"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<LinearLayout
android:id="#+id/linear"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:orientation="horizontal" >
</LinearLayout>
</HorizontalScrollView>
</LinearLayout>
and this is my code:
View contentView = inflater.inflate(R.layout.information_imagescrollview_item, container, false);
LinearLayout scrollViewLayout = (LinearLayout) contentView.findViewById(R.id.linear);
for(Object intObj : page.content) {
ImageView imageView = new ImageView(this.getContext());
Drawable myDrawable = getResources().getDrawable((int) intObj);
imageView.setImageDrawable(myDrawable);
scrollViewLayout.addView(imageView);
}
page.addView(contentView);
How can I set each imageView to have the same width and height as the parentlayout in the xml?

It is possible to change a dynamic view's dimensions by code. So I would bet you should change the ImageView's layout parameters in the for loop before adding it to your LinearLayout like this:
for(Object intObj : page.content) {
ImageView imageView = new ImageView(this.getContext());
Drawable myDrawable = getResources().getDrawable((int) intObj);
imageView.setImageDrawable(myDrawable);
//Changing height...
imageView.getLayoutParams().height = ViewGroup.LayoutParams.MATCH_PARENT;
//...and width
imageView.getLayoutParams().width = ViewGroup.LayoutParams.MATCH_PARENT;
scrollViewLayout.addView(imageView);
}
This will set the ImageView's width and height to the containing (parent) LinearLayout's width and height.

Views are invisible after they was added into ViewGroup

I'm adding views programatically into FrameLayout:
public class PixelGridView extends FrameLayout {
...
public void addViewWithoutCoords(TableView view, int column, int row) {
float x = column * mCellSideSize;
float y = row * mCellSideSize;
FrameLayout.LayoutParams lp = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
view.setLayoutParams(lp);
view.setLeft(0);
view.setTop(0);
view.setX(x);
view.setY(y);
view.setVisibility(VISIBLE);
addView(view);
}
...
}
However, all they are somehow invisible. getChildCount() returns count with all of them. getVisibility() for each added view also returns VISIBLE.
I can drag'n'drop such views from another ViewGroup into my Framelayout and when I do this, all earlier added views become visible.
view layout file:
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent">
<ImageView
android:id="#+id/ivTable"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"/>
<EditText
android:id="#+id/ivTableName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:background="#color/style_table_grey"
android:textColor="#android:color/white"/>
</RelativeLayout>
Even If I add new view without drag everything become visible.

The item view of the FrameLayout and RelativeLayout can be overlapping. If two item views are in the same positions of FrameLayout, the first loaded item will be covered by the later item.

Try turn on the show layout bounds in developer option of your android devices,and find the position of your item.

Cannot center view in RelativeLayout

I am trying to center a view within a parent RelativeLayout:
private void addLoadingAnimation() {
RelativeLayout mainView = (RelativeLayout) findViewById(R.id.medical_supply_tile_activity);
mainView.removeAllViews();
GifView gifView = new GifView(this);
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
layoutParams.addRule(RelativeLayout.CENTER_IN_PARENT);
gifView.setId(R.id.loading_gif);
mainView.setBackgroundColor(getResources().getColor(android.R.color.background_light));
mainView.addView(gifView,layoutParams);
}
I have also tried adding layoutParams.addRule(RelativeLayout.ALIGN_PARENT_RIGHT, 0); before the CENTER_IN_PARENT line. Nothing seems to be working. It is always aligned to the bottom right.
Here is my parent view:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/background_light"
tools:context=".MedecineTileActivity"
android:id="#id/medical_supply_tile_activity"
android:layout_gravity="left">
</RelativeLayout>
The gravity=left is because when the loading animation is removed, I insert fragments and want them to go to the left.

I have achieved this with TextViews and ImageViews by aligning the child View's right to the parent's right and also aligning the child View's left to the parent's left.
<TextView
style="#style/NewTextM2"
android:id="#+id/soft_dialog_info_item_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/<Parent>"
android:layout_alignLeft="#+id/<Parent>"
android:layout_alignRight="#+id/<Parent>"
android:gravity="center"
android:tag="item_text"
android:text="#string/text"
android:maxLines="1" />
This will align the view to the bottom center of the parent.