I'm trying to develop a version of the MvxExpandableListView that would always be expanded.
The code that I wrote seems to work, but I'm pretty sure I don't do things the right way. I tried to find some info about Android Widgets lifecycle, but found only info about Activity lifecycle.
More specifically, where should the ExpandAll() method be called ?
I've tried several places and ended by putting it into the OnDraw() handler.
To prevent collapsing, I called the ExpandGroup() method in the GroupCollapse Handler. hmm not sure it's the right way to do it either.
So, here is the code :
public class MvxExpandedListView : MvxExpandableListView
{
private bool _allExpanded = false;
private void ExpandAll()
{
var nbGroups = ThisAdapter.GroupCount;
for (int i = 0; i < nbGroups; i++)
{
ExpandGroup(i);
}
}
private void Init()
{
GroupCollapse += MvxExpandableListView_GroupCollapse;
SetSelector(Android.Resource.Color.Transparent);
CacheColorHint = Color.Transparent;
SetGroupIndicator(null);
}
public MvxExpandedListView(Context context, IAttributeSet attrs)
: base(context, attrs)
{
Init();
}
public MvxExpandedListView(Context context, IAttributeSet attrs, MvxExpandableListAdapter adapter)
: base(context, attrs, adapter)
{
Init();
}
protected MvxExpandedListView(IntPtr javaReference, JniHandleOwnership transfer)
: base(javaReference, transfer)
{
Init();
}
void MvxExpandableListView_GroupCollapse(object sender, ExpandableListView.GroupCollapseEventArgs e)
{
// There must be a better way...
this.ExpandGroup(e.GroupPosition);
}
protected override void OnDraw(Canvas canvas)
{
base.OnDraw(canvas);
// Ugly !
if (!_allExpanded)
{
ExpandAll();
_allExpanded = true;
}
}
public override bool CollapseGroup(int groupPosition)
{
return false;
}
}
Thanks in advance for your help,
Kindanam
Related
I have a custom edittext control which has a clear (x) icon set on the right when it's in focus and has text. Clicking the clear icon removes the text from the textbox. Unfortunately, when you click into the textbox, the focus change event is fired infinitely, as changing the compound drawable within the focus change listener seems to fire off two more focus change events, the first with the focus off, and the second with the focus back on. Any idea how I can get this working without the infinite loop?
Here is the code:
public class CustomEditText : EditText {
private Drawable clearButton;
protected CustomEditText (IntPtr javaReference, JniHandleOwnership transfer) : base (javaReference, transfer) {
}
public CustomEditText (Context context) : base (context) {
Init ();
}
public CustomEditText (Context context, IAttributeSet attrs) : base (context, attrs) {
Init (attrs);
}
public CustomEditText (Context context, IAttributeSet attrs, int defStyle) : base (context, attrs, defStyle) {
Init (attrs);
}
protected void Init (IAttributeSet attrs = null) {
// Set up clear button
SetupClearButton ();
SetupEvents ();
}
private void SetupClearButton () {
clearButton = ContextCompat.GetDrawable (Android.App.Application.Context, Resource.Drawable.forms_edit_text_clear_gray);
clearButton.SetBounds (0, 0, clearButton.IntrinsicWidth, clearButton.IntrinsicHeight);
}
private void SetupEvents () {
// Handle clear button visibility
this.TextChanged += (sender, e) => {
if (this.HasFocus)
UpdateClearButton ();
};
this.FocusChange += (object sender, FocusChangeEventArgs e) => {
UpdateClearButton (e.HasFocus);// Gets called infinitely
};
// Handle clearing the text
this.Touch += (sender, e) => {
if (this.GetCompoundDrawables ()[2] != null &&
e.Event.Action == MotionEventActions.Up &&
e.Event.GetX () > (this.Width - this.PaddingRight - clearButton.IntrinsicWidth)) {
this.Text = "";
UpdateClearButton ();
e.Handled = true;
} else
e.Handled = false;
};
}
private void UpdateClearButton (bool hasFocus = true) {
var compoundDrawables = this.GetCompoundDrawables ();
var compoundDrawable = this.Text.Length == 0 || !hasFocus ? null : clearButton;
if (compoundDrawables[2] != compoundDrawable)
this.SetCompoundDrawables (compoundDrawables[0], compoundDrawables[1], compoundDrawable, compoundDrawables[3]);
}
}
I ported DroidParts' ClearableEditText to Xamarin.Android to use when using the Android's Support Library widgets were not appropriate.
Note: DroidParts is under Apache 2.0 license so I can not post my C# derivative in full to StackOverflow, but the key to avoiding the continuous focus changing is in the OnTouch and OnFocusChange methods and the fact that the listeners are added to the base EditText Widget.
Full Code # https://gist.github.com/sushihangover/01a7965aae75d8ef0589697aa8f0e750
public bool OnTouch(View v, MotionEvent e)
{
if (GetDisplayedDrawable() != null)
{
int x = (int)e.GetX();
int y = (int)e.GetY();
int left = (loc == Location.LEFT) ? 0 : Width - PaddingRight - xD.IntrinsicWidth;
int right = (loc == Location.LEFT) ? PaddingLeft + xD.IntrinsicWidth : Width;
bool tappedX = x >= left && x <= right && y >= 0 && y <= (Bottom - Top);
if (tappedX)
{
if (e.Action == MotionEventActions.Up)
{
Text = "";
if (listener != null)
{
listener.DidClearText();
}
}
return true;
}
}
if (l != null)
return l.OnTouch(v, e);
return false;
}
public void OnFocusChange(View v, bool hasFocus)
{
if (hasFocus)
SetClearIconVisible(!string.IsNullOrEmpty(Text));
else
SetClearIconVisible(false);
if (f != null)
f.OnFocusChange(v, hasFocus);
}
Original StackOverflow Q/A: How to create EditText with cross(x) button at end of it?
In my opinion, the easiest implementation I have is this :
public class ClearableEditext : EditText
{
Context mContext;
Drawable imgX;
public ClearableEditext(Context context) : base(context)
{
init(context, null);
}
public ClearableEditext(Context context, Android.Util.IAttributeSet attrs) : base(context, attrs)
{
init(context, attrs);
}
public ClearableEditext(Context context, Android.Util.IAttributeSet attrs, int defStyleAttr) : base(context, attrs, defStyleAttr)
{
init(context, attrs);
}
public ClearableEditext(Context context, Android.Util.IAttributeSet attrs, int defStyleAttr, int defStyleRes) : base(context, attrs, defStyleAttr, defStyleRes)
{
init(context, attrs);
}
public void init(Context ctx, Android.Util.IAttributeSet attrs)
{
mContext = ctx;
imgX = ContextCompat.GetDrawable(ctx, Android.Resource.Drawable.PresenceOffline);
imgX.SetBounds(0, 0, imgX.IntrinsicWidth, imgX.IntrinsicHeight);
manageClearButton();
this.SetOnTouchListener(new TouchHelper(this, imgX));
this.AddTextChangedListener(new TextListener(this));
}
public void manageClearButton()
{
if (this.Text.ToString().Equals(""))
removeClearButton();
else
addClearButton();
}
public void addClearButton()
{
this.SetCompoundDrawables(this.GetCompoundDrawables()[0],
this.GetCompoundDrawables()[1],
imgX,
this.GetCompoundDrawables()[3]);
}
public void removeClearButton()
{
this.SetCompoundDrawables(this.GetCompoundDrawables()[0],
this.GetCompoundDrawables()[1],
null,
this.GetCompoundDrawables()[3]);
}
}
public class TouchHelper : Java.Lang.Object, View.IOnTouchListener
{
ClearableEditext Editext;
public ClearableEditext objClearable { get; set; }
Drawable imgX;
public TouchHelper(ClearableEditext editext, Drawable imgx)
{
Editext = editext;
objClearable = objClearable;
imgX = imgx;
}
public bool OnTouch(View v, MotionEvent e)
{
ClearableEditext et = Editext;
if (et.GetCompoundDrawables()[2] == null)
return false;
// Only do this for up touches
if (e.Action != MotionEventActions.Up)
return false;
// Is touch on our clear button?
if (e.GetX() > et.Width - et.PaddingRight - imgX.IntrinsicWidth)
{
Editext.Text = string.Empty;
if (objClearable != null)
objClearable.removeClearButton();
}
return false;
}
}
public class TextListener : Java.Lang.Object, ITextWatcher
{
public ClearableEditext objClearable { get; set; }
public TextListener(ClearableEditext objRef)
{
objClearable = objRef;
}
public void AfterTextChanged(IEditable s)
{
}
public void BeforeTextChanged(ICharSequence s, int start, int count, int after)
{
}
public void OnTextChanged(ICharSequence s, int start, int before, int count)
{
if (objClearable != null)
objClearable.manageClearButton();
}
}
Probably Sushi has a better answer but i would suggest you to try this one out.
To change the x icon as your custom one change the image in init()
I'm pretty new in the android world.
I try to create in my app a custom control like the following description:
- Objects appears one by one (timer) at the right of that custom controls and are translated (with animation) to the left of the screen.
The rendering is the following right now:
And the code is like:
public abstract class SheetBase : SurfaceView
{
protected override void OnDraw(Canvas canvas)
{
base.OnDraw(canvas);
this.Update(canvas);
}
}
public class MusicSheet : SheetBase, ISurfaceHolderCallback
{
public MusicSheet(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer)
{
}
public MusicSheet(Context context) : base(context)
{
}
public MusicSheet(Context context, IAttributeSet attrs) : base(context, attrs)
{
}
public MusicSheet(Context context, IAttributeSet attrs, int defStyleAttr) : base(context, attrs, defStyleAttr)
{
}
public MusicSheet(Context context, IAttributeSet attrs, int defStyleAttr, int defStyleRes) : base(context, attrs, defStyleAttr, defStyleRes)
{
}
protected override void Update(Canvas canvas)
{
// Logic to draw staf on Canvas
}
public void SurfaceChanged(ISurfaceHolder holder, Format format, int width, int height)
{
this.Invalidate();
}
public void SurfaceCreated(ISurfaceHolder holder)
{
this._thread = new Thread(this.Loop);
this._thread.Start();
}
public void SurfaceDestroyed(ISurfaceHolder holder)
{
this._thread?.Abort();
}
private void Loop()
{
while (true)
{
Canvas c = null;
try
{
c = this.Holder.LockCanvas();
c.DrawColor(Color.Transparent, PorterDuff.Mode.Clear);
// Draw content at the new position
}
finally
{
if (c != null)
this.Holder.UnlockCanvasAndPost(c);
}
Thread.Sleep(10);
}
}
}
What do you think about the solution / performances ?
You can use ViewPropertyAnimator to translate a View.
For example,
view.animate()
.translationX(100) // horizontal translation
.translationY(100) // vertical translation
To animate from right to left:
view.animate()
.translationX( - screenWidth )
Refer the doc for more info.
I recently used TextInputLayout and it's setError() method. The problem I'm getting is, when I clear the error by calling setError(null) it leaves so much of empty space at the bottom.
Normal:
With error:
After clearing error:
After looking at the source, I found that they are making the view INVISIBLE instead of GONE
.setListener(new ViewPropertyAnimatorListenerAdapter() {
#Override
public void onAnimationEnd(View view) {
view.setVisibility(INVISIBLE); // here it is
updateLabelVisibility(true);
} }).start();
I'm wondering why is it so? How to resolve this to avoid the empty space?
Check out the docs for
public void setErrorEnabled (boolean enabled)
It says
Whether the error functionality is enabled or not in this layout.
Enabling this functionality before setting an error message via
setError(CharSequence), will mean that this layout will not change
size when an error is displayed.
Well based on this, try setting setErrorEnabled(true) before setError(), and, set setErrorEnabled(false) after setError(null).
Method setErrorEnabled(false) will clear the extra space, so call it after setError(null).
Dont use setErrorEnabled(boolean), it just doesnt show up the error from the second time.
public class MyTextInputLayout extends android.support.design.widget.TextInputLayout {
public MyTextInputLayout(Context context) {
super(context);
}
public MyTextInputLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyTextInputLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#Override
public void setError(#Nullable CharSequence error) {
super.setError(error);
View layout = getChildAt(1);
if (layout != null) {
if (error != null && !"".equals(error.toString().trim())) {
layout.setVisibility(VISIBLE);
} else {
layout.setVisibility(GONE);
}
}
}
}
Then just setError(errorMessage); or setError(null);
See this page. Google will release the fix in future support library version. It says,
If you want to fix it now you can extends the TextInputLayout and
override the setErrorEnabled() method, but I cant guarantee the
backward compatibility. Because its some danger to change state in
TextInputLayout.
public class TextInputLayout extends android.support.design.widget.TextInputLayout{
public TextInputLayout(Context context) {
super(context);
}
public TextInputLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
public TextInputLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#Override
public void setErrorEnabled(boolean enabled) {
super.setErrorEnabled(enabled);
if (enabled) {
return;
}
if (getChildCount() > 1) {
View view = getChildAt(1);
if (view != null) {
view.setVisibility(View.GONE);
}
}
}
}
I create a custom view for avoiding repeated code and override setError method.
public class UserInputView extends TextInputLayout {
public UserInputView(Context context) {
this(context, null);
}
public UserInputView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public UserInputView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#Override
public void setError(#Nullable CharSequence error) {
boolean isErrorEnabled = error != null;
setErrorEnabled(isErrorEnabled);
super.setError(error);
}
}
The source code of TextInputLayout show the following:
If you need to clear the error, just use
til.setErrorEnabled(false);
This will hide the error text and stretch the bottom space to its standard size.
In case you need to set the error again, just use
til.setError("Your text");
which automatically calls til.setErrorEnabled(true) as it assumes you need the error functionality.
This is extension in kotlin solving problem:
fun TextInputLayout.clearError() {
error = null
isErrorEnabled = false
}
The following code works fine
textInputLatout.getEditText().addTextChangedListener(new TextWatcher() {
#Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
#Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
if (s.length() < 1) {
textInputLayout.setErrorEnabled(true);
textInputLayout.setError("Please enter a value");
}
if (s.length() > 0) {
textInputLayout.setError(null);
textInputLayout.setErrorEnabled(false);
}
}
#Override
public void afterTextChanged(Editable s) {
}
});
By using mTextInputLayout.setErrorEnabled(false); i have solved this problem
Then you should override it like so:
#Override
public void onAnimationEnd(View view)
{
view.setVisibility(GONE); // <-- this is where you make it GONE
updateLabelVisibility(true);
}
Or try this i.e. on a button or whatever you are using:
final Button btn = (Button) findViewById(R.id.btn);
btn.setVisibility(View.GONE); //<--- makes the button gone
In this example the contentScrim attribute is set with a color, but I can't figure out how to control when it starts. I woud like to start the color transition sooner.
Can you give me a hint? Thanks in advance.
You'd have to create a class that extends CollapsingToolbarLayout. Something like this (you might need to adjust that so it exactly fits your needs):
public class CustomCollapsingToolbarLayout extends CollapsingToolbarLayout {
public static interface Listener {
public void onContentScrimAnimationStarted(boolean showing);
}
private Listener mListener;
public CustomCollapsingToolbarLayout(Context context) {
super(context);
}
public CustomCollapsingToolbarLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
public CustomCollapsingToolbarLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#Override
public void setScrimsShown(boolean shown, boolean animate) {
super.setScrimsShown(shown, animate);
if (animate && mListener != null) {
mListener.onContentScrimAnimationStarted(shown);
}
}
public void setListener(Listener listener) {
mListener = listener;
}
}
And just call setListener on your CustomCollapsingToolbarLayout instance.
CustomCollapsingToolbarLayout mToolbarLayout =
(CustomCollapsingToolbarLayout) findViewById(R.id.toolbar_layout);
mToolbarLayout.setListener(new Listener() {
#Override
public void onContentScrimAnimationStarted(boolean showing) {
//do what you want
}
});
EDIT (actually answering the question):
Modify the scrimVisibleHeightTrigger value (with the setScrimVisibleHeightTrigger method of the CollapsingToolbarLayout) to change the starting point of the animation.
I've overridden ScrollView to pass MotionEvents to a GestureDetector to detect fling events on the ScrollView. I need to be able to detect when the scrolling stops. This doesn't coincide with the MotionEvent.ACTION_UP event because this usually happens at the start of a fling gesture, which is followed by a flurry of onScrollChanged() calls on the ScrollView.
So basically what we are dealing with here is the following events:
onFling
onScrollChanged, onScrollChanged, onScrollChanged, ... , onScrollChanged
There's no callback for when the onScrollChanged events are done firing. I was thinking of posting a message to the event queue using a Handler during onFling and waiting for the Runnable to execute to signal the end of the fling, unfortunately it fires after the first onScrollChanged call.
Any other ideas?
I've combined a few of the answers from here to construct a working listener that resembles the way AbsListView does it. It's essentially what you describe, and it works well in my testing.
Note: you can simply override ScrollView.fling(int velocityY) rather than use your own GestureDetector.
import android.content.Context;
import android.util.AttributeSet;
import android.widget.ScrollView;
public class CustomScrollView extends ScrollView {
private static final int DELAY_MILLIS = 100;
public interface OnFlingListener {
public void onFlingStarted();
public void onFlingStopped();
}
private OnFlingListener mFlingListener;
private Runnable mScrollChecker;
private int mPreviousPosition;
public CustomScrollView(Context context) {
this(context, null, 0);
}
public CustomScrollView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public CustomScrollView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
mScrollChecker = new Runnable() {
#Override
public void run() {
int position = getScrollY();
if (mPreviousPosition - position == 0) {
mFlingListener.onFlingStopped();
removeCallbacks(mScrollChecker);
} else {
mPreviousPosition = getScrollY();
postDelayed(mScrollChecker, DELAY_MILLIS);
}
}
};
}
#Override
public void fling(int velocityY) {
super.fling(velocityY);
if (mFlingListener != null) {
mFlingListener.onFlingStarted();
post(mScrollChecker);
}
}
public OnFlingListener getOnFlingListener() {
return mFlingListener;
}
public void setOnFlingListener(OnFlingListener mOnFlingListener) {
this.mFlingListener = mOnFlingListener;
}
}
Thank you #PaulBurke +1
Xamarin Solution
using Android.Content;
using Android.Runtime;
using Android.Util;
using Android.Widget;
using System;
public class CustomScrollView : ScrollView
{
public event EventHandler FlingEnded;
public event EventHandler FlingStarted;
private Action ScrollChecker;
private int PreviousPosition;
private const int DELAY_MILLIS = 100;
public CustomScrollView(Context context) : base(context) => Init();
public CustomScrollView(Context context, IAttributeSet attrs) : base(context, attrs) => Init();
public CustomScrollView(Context context, IAttributeSet attrs, int defStyleAttr) : base(context, attrs, defStyleAttr) => Init();
public CustomScrollView(Context context, IAttributeSet attrs, int defStyleAttr, int defStyleRes) : base(context, attrs, defStyleAttr, defStyleRes) => Init();
public CustomScrollView(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer) { }
private void Init()
{
ScrollChecker = () =>
{
int position = ScrollY;
if (PreviousPosition - position == 0)
{
FlingEnded?.Invoke(this, new EventArgs());
RemoveCallbacks(ScrollChecker);
}
else
{
PreviousPosition = ScrollY;
PostDelayed(ScrollChecker, DELAY_MILLIS);
}
};
}
public override void Fling(int velocityY)
{
base.Fling(velocityY);
FlingStarted?.Invoke(this, new EventArgs());
Post(ScrollChecker);
}
}
Usage:
myCustomScrollView.FlingEnded += myCustomScrollView_FlingEnded;
protected void myCustomScrollView_FlingEnded(object sender, EventArgs e) =>
{
//Do onFlingEnded code here
};