Develop Reference

Animate newly created View of unknown size

I want to animate View right after it was added to parent (something like DrawerLayout). The problem is that View has varying size, and animation target position depends on that size. Simplified sample code:
AnimatingView extends View {
public int offsetX;
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
final int screenWidth = MeasureSpec.getSize(widthMeasureSpec);
final int screenHeight = MeasureSpec.getSize(heightMeasureSpec);
offsetX = calculateOffset(screenWidth);
...
}
}
Code similar to this triggers the animation:
#Override
public void onClick(View v) {
AnimatingView animatingView = new AnimatingView(getContext());
parentLayout.addView(animatingView);
animatingView.animate().x(animatingView.offsetX).setDuration(500).start();
}
In this case onMeasure() happens after animate(), so animation fails. What is the correct way of doing stuff which depends on view measuring?
The simple & stupid way would be something like animateOnceAfterMeasuring() based on isInitialized flag, but I don't think it the correct way of doing this.

this should work:
AnimatingView animatingView = new AnimatingView(getContext());
parentLayout.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
#Override
public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) {
v.removeOnLayoutChangeListener(this);
animatingView.animate().x(animatingView.offsetX).setDuration(500).start();
}
});

You can use the ViewTreeObserver for this
#Override
public void onClick(View v) {
final AnimatingView animatingView = new AnimatingView(getContext());
parentLayout.addView(animatingView);
animatingView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
if (Build.VERSION.SDK_INT < 16) {
animatingView.getViewTreeObserver().removeGlobalOnLayoutL‌​istener(this);
} else {
animatingView.getViewTreeObserver().removeOnGlobalLayoutList‌​ener(this);
}
animatingView.animate().x(animatingView.offsetX).setDuration(500).start();
}
});
}

How to invalidate view after it changed?

Please see this example img below first.
Sorry, my reputation is not enough, click below to see gif please
example img
Just as you see, i am using horizontalscrollview in bottom area. I can not scroll it to border when it become bigger. I can not figure out why, hope someone can help me solve this problem.
public class Rebound extends HorizontalScrollView implements View.OnClickListener {
private LinearLayout container;
private HorizontalScrollViewAdapter adapter;
private int childWidth, childHeight;
private CurrentImageChangeListener listener;
private OnItemClickListener onClickListener;
public Rebound(Context context, AttributeSet attrs) {
super(context);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
container = (LinearLayout) getChildAt(0);
}
#Override
public void invalidate() {
super.invalidate();
}
public void initDatas(HorizontalScrollViewAdapter adapter) {
this.adapter = adapter;
container = (LinearLayout) getChildAt(0);
final View view = adapter.getView(0, null, container);
container.addView(view);
calculateChildView(view);
}
private void calculateChildView(View view) {
if (childWidth == 0 && childHeight == 0) {
int w = View.MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
int h = View.MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
view.measure(w, h);
childHeight = view.getMeasuredHeight();
childWidth = view.getMeasuredWidth();
}
initChild();
}
private void initChild() {
container = (LinearLayout) getChildAt(0);
container.removeAllViews();
for (int i = 0; i < adapter.getCount(); i++) {
View view = adapter.getView(i, null, container);
view.setOnClickListener(this);
container.addView(view);
}
}
#Override
public void onClick(View v) {
}
public interface CurrentImageChangeListener {
void onCurrentImgChanged(int position, View viewIndicator);
}
public interface OnItemClickListener {
void onClick(View view, int pos);
}
public void setOnItemClickListener(OnItemClickListener onClickListener) {
this.onClickListener = onClickListener;
}
public void setCurrentImageChangeListener(CurrentImageChangeListener listener) {
this.listener = listener;
}
}

Android: custom views get drawn at wrong x,y coordinates

I'm trying to create a custom view, inherit from view group, and layout custom sub-views inside this view group in a customized way. Basically I'm trying to create a calendar view similar to the one in outlook, where each event takes up screen height relative to its length.
I initialize an ArrayList of View in the ViewGroup's constructor, override onMeasure, onLayout and onDraw, and everything works well, except... the rendered views all render starting at (0,0), even though I set their left and right properties to other values. Their width and height come out ok, only their top and left are wrong.
This is the code, which I abbreviated for clarity and simplicity:
public class CalendarDayViewGroup extends ViewGroup {
private Context mContext;
private int mScreenWidth = 0;
private ArrayList<Event> mEvents;
private ArrayList<View> mEventViews;
// CalendarGridPainter is a class that draws the background grid.
// this one works fine so I didn't write its actual code here.
// it just takes a Canvas and draws lines on it.
// I also tried commenting out this class and got the same result,
// so this is DEFINITELY not the problem.
private CalendarGridPainter mCalendarGridPainter;
public CalendarDayViewGroup(Context context, Date date) {
super(context);
init(date, context);
}
//... other viewGroup constructors go here...
private void init(Date date, Context context) {
mContext = context;
// the following line loads events from a database
mEvents = AppointmentsRepository.getByDateRange(date, date);
// inflate all event views
mEventViews = new ArrayList<>();
LayoutInflater inflater = LayoutInflater.from(mContext);
for (int i = 0; i < mEvents.size(); i++) {
View view = getSingleEventView(mEvents.get(i), inflater);
mEventViews.add(view);
}
// set this flag so that the onDraw event is called
this.setWillNotDraw(false);
}
private View getSingleEventView(Event event, LayoutInflater inflater) {
View view = inflater.inflate(R.layout.single_event_view, null);
// [set some properties in the view's sub-views]
return view;
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
setMeasuredDimension(MeasureSpec.getSize(widthMeasureSpec), MeasureSpec.getSize(heightMeasureSpec));
// get screen width and create a new GridPainter if needed
int screenWidth = MeasureSpec.getSize(widthMeasureSpec);
if (mScreenWidth != screenWidth)
{
mScreenWidth = screenWidth;
mCalendarGridPainter = new CalendarGridPainter(screenWidth);
}
int numChildren = mEvents.size();
for (int i = 0; i < numChildren; i++) {
View child = mEventViews.get(i);
Event event = mEvents.get(i);
// event width is the same as screen width
int specWidth = MeasureSpec.makeMeasureSpec(mScreenWidth, MeasureSpec.EXACTLY);
// event height is calculated by its length, the calculation was ommited here for simplicity
int eventHeight = 350; // actual calculation goes here...
int specHeight = MeasureSpec.makeMeasureSpec(eventHeight, MeasureSpec.EXACTLY);
child.measure(specWidth, specHeight);
}
}
#Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
int numChildren = mEvents.size();
for (int i = 0; i < numChildren; i++) {
View child = mEventViews.get(i);
Event event = mEvents.get(i);
int eventLeft = 0;
int eventTop = (i + 1) * 200; // test code, make each event start 200 pixels after the previous one
int eventWidth = eventLeft + child.getMeasuredWidth();
int eventHeight = eventTop + child.getMeasuredHeight();
child.layout(eventLeft, eventTop, eventWidth, eventHeight);
}
}
#Override
protected void onDraw(Canvas canvas) {
// draw background grid
mCalendarGridPainter.paint(canvas);
// draw events
for (View view : mEventViews) {
view.draw(canvas);
}
super.onDraw(canvas);
}
}

For some reason, it seems like the way children are drawn with ViewGroups is that the ViewGroup translates the canvas to child's position then draws the child at 0,0.
But as it turns out, ViewGroup will handle all the drawing of children for you. I think if you simplify your onDraw() method you should be all set:
#Override
protected void onDraw(Canvas canvas) {
// draw background grid
mCalendarGridPainter.paint(canvas);
// draw events
super.onDraw(canvas);
}
Now that I'm looking at your code further, I noticed you are inflating your child views within the code for your ViewGroup. It would be best to do all that outside your ViewGroup, add those views using addView(), then use getChildCount() and getChildAt() to access the child views during onLayout().

Android transfer animation of view in custom viewgroup

I want animation like expanding of the photos when I click folder of photos at gallery, like in this video about Android gallery.
i have two views in same custom viewgroup
view1 is in 0,0
view2 is in 100,100
since click "start" view1 will move to 100,0 and view2 will move to 0,100
My solution so far:
I use timer for refresh layout with new position by requestlayout.
the views' position will refresh by onLayout:
It works but it's not a native function and it is very slow with 100 views moving at same time.
Full code:
private class MyViewGroup extends ViewGroup{
View view1,view2;
Button btn;
public MyViewGroup(Context context) {
super(context);
view1=new View(context);
view1.setBackgroundColor(Color.RED);
this.addView(view1);
view2=new View(context);
view2.setBackgroundColor(Color.BLUE);
this.addView(view2);
btn=new Button(context);
btn.setText("start");
btn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
xLayout=0;
handler.sendEmptyMessage(0);
}
});
this.addView(btn);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int w = MeasureSpec.getSize(widthMeasureSpec);
int h= MeasureSpec.getSize(heightMeasureSpec);
int widthSpec = MeasureSpec.makeMeasureSpec(50, MeasureSpec.EXACTLY);
int heightSpec = MeasureSpec.makeMeasureSpec(50, MeasureSpec.EXACTLY);
view1.measure(widthSpec,heightSpec);
view2.measure(widthSpec,heightSpec);
btn.measure(widthSpec,heightSpec);
this.setMeasuredDimension(w, h);
}
private int xLayout=0;
#Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
view1.layout(xLayout,0,xLayout+50,50);
view2.layout(100-xLayout,100,150-xLayout,150);
btn.layout(0,200,50,250);
}
private void startAnimation(){
Timer timer = new Timer() ;
timer.schedule(new TimerTask(){
#Override
public void run() {
if(xLayout<100){
handler.sendEmptyMessage(0);
}
this.cancel();
}
},5);
}
private Handler handler=new Handler(){
#Override
public void handleMessage(Message msg) {
xLayout=xLayout+20;
view1.requestLayout();
startAnimation();
}
} ;
}

http://android-developers.blogspot.fr/2011/05/introducing-viewpropertyanimator.html
myView.animate().x(500).y(500);

we can use "LayoutTransition" as
final LayoutTransition transitioner = new LayoutTransition();
myViewGroup.setLayoutTransition(transitioner);
and when we click "start" addview
full code
private class MyViewGroup extends ViewGroup{
View view1,view2;
Button btn;
public MyViewGroup(final Context context) {
super(context);
view1=new View(context);
view1.setBackgroundColor(Color.RED);
this.addView(view1);
view2=new View(context);
view2.setBackgroundColor(Color.BLUE);
this.addView(view2);
btn=new Button(context);
btn.setText("start");
btn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
xLayout+=100;
MyViewGroup.this.addView(new View(context));
}
});
this.addView(btn);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int w = MeasureSpec.getSize(widthMeasureSpec);
int h= MeasureSpec.getSize(heightMeasureSpec);
int widthSpec = MeasureSpec.makeMeasureSpec(50, MeasureSpec.EXACTLY);
int heightSpec = MeasureSpec.makeMeasureSpec(50, MeasureSpec.EXACTLY);
view1.measure(widthSpec,heightSpec);
view2.measure(widthSpec,heightSpec);
btn.measure(widthSpec,heightSpec);
this.setMeasuredDimension(w, h);
}
private int xLayout=0;
#Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
view1.layout(xLayout,0,xLayout+50,50);
view2.layout(100-xLayout,100,150-xLayout,150);
btn.layout(0,200,50,250);
}
}

onMeasure not getting called in my custom viewgroup android

Im having two custom viewgroups, superViewGroup and subViewGroup. The subviewgroup contains views. Im adding my superviewgroup to a linearLayout and the subViewGroups to my superviewgroup.
The superviewgroup onMeasure() is getting called but not in the subviewgroup. but in both cases onLayout() method is getting called.
The code as follows
public class SuperViewGroup extends ViewGroup{
public SuperViewGroup(Context context) {
super(context);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
Log.i("boxchart","INSIDE ON MEASURE SUPER VIEWGROUP");
}
#Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
final int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() != View.GONE) {
child.layout(0, 0, getWidth(), getHeight());
}
}
}
}
public class SubViewGroup extends ViewGroup{
public SubViewGroup(Context context) {
super(context);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
Log.i("boxchart","INSIDE ON MEASURE SUB VIEWGROUP");
}
#Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
final int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() != View.GONE) {
child.layout(0, 0, getWidth(), getHeight());
}
}
}
}
Comments are appreciated. thanks in advance.

Because you have to actually pass the measure to the children views:
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
Log.i("boxchart","INSIDE ON MEASURE SUPER VIEWGROUP");
final int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() != View.GONE) {
//Make or work out measurements for children here (MeasureSpec.make...)
measureChild (child, widthMeasureSpec, heightMeasureSpec);
}
}
}
Otherwise you never actually measure your children. It is up to you to decide how to do this. Just because your SuperViewGroup is in a linear layout, your SuperViewGroup takes on responsibility to measure its children.