I am using a horizontal layout manager for my RecyclerView.
I need to make RecyclerView in the next way: when click on some item - make smoothScrool to that position and put that item in the center of RecyclerView (if it possible, for example, 10 item from 20).
So, I have no problem with smoothScrollToPosition(), but how to put item than in the center of RecyclerView???
Thanks!
Yes it's possible.
By implementing RecyclerView.SmoothScroller's method onTargetFound(View, State, Action).
/**
* Called when the target position is laid out. This is the last callback SmoothScroller
* will receive and it should update the provided {#link Action} to define the scroll
* details towards the target view.
* #param targetView The view element which render the target position.
* #param state Transient state of RecyclerView
* #param action Action instance that you should update to define final scroll action
* towards the targetView
*/
abstract protected void onTargetFound(View targetView, State state, Action action);
Specifically in LinearLayoutManager with LinearSmoothScroller:
public class CenterLayoutManager extends LinearLayoutManager {
public CenterLayoutManager(Context context) {
super(context);
}
public CenterLayoutManager(Context context, int orientation, boolean reverseLayout) {
super(context, orientation, reverseLayout);
}
public CenterLayoutManager(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
}
#Override
public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, int position) {
RecyclerView.SmoothScroller smoothScroller = new CenterSmoothScroller(recyclerView.getContext());
smoothScroller.setTargetPosition(position);
startSmoothScroll(smoothScroller);
}
private static class CenterSmoothScroller extends LinearSmoothScroller {
CenterSmoothScroller(Context context) {
super(context);
}
#Override
public int calculateDtToFit(int viewStart, int viewEnd, int boxStart, int boxEnd, int snapPreference) {
return (boxStart + (boxEnd - boxStart) / 2) - (viewStart + (viewEnd - viewStart) / 2);
}
}
}
Improvements to the answer - there is no need to override the LinearLayoutManager
From the previous answer:
public class CenterSmoothScroller extends LinearSmoothScroller {
public CenterSmoothScroller(Context context) {
super(context);
}
#Override
public int calculateDtToFit(int viewStart, int viewEnd, int boxStart, int boxEnd, int snapPreference) {
return (boxStart + (boxEnd - boxStart) / 2) - (viewStart + (viewEnd - viewStart) / 2);
}
}
Here how to use it:
RecyclerView.LayoutManager lm = new GridLayoutManager(...): // or whatever layout manager you need
...
RecyclerView.SmoothScroller smoothScroller = new CenterSmoothScroller(recyclerView.getContext());
smoothScroller.setTargetPosition(position);
lm.startSmoothScroll(smoothScroller);
Just in case someone needs the Kotlin equivalent of the class in the accepted answer.
class CenterLayoutManager : LinearLayoutManager {
constructor(context: Context) : super(context)
constructor(context: Context, orientation: Int, reverseLayout: Boolean) : super(context, orientation, reverseLayout)
constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int, defStyleRes: Int) : super(context, attrs, defStyleAttr, defStyleRes)
override fun smoothScrollToPosition(recyclerView: RecyclerView, state: RecyclerView.State, position: Int) {
val centerSmoothScroller = CenterSmoothScroller(recyclerView.context)
centerSmoothScroller.targetPosition = position
startSmoothScroll(centerSmoothScroller)
}
private class CenterSmoothScroller(context: Context) : LinearSmoothScroller(context) {
override fun calculateDtToFit(viewStart: Int, viewEnd: Int, boxStart: Int, boxEnd: Int, snapPreference: Int): Int = (boxStart + (boxEnd - boxStart) / 2) - (viewStart + (viewEnd - viewStart) / 2)
}
}
Based on #Boda's answer, if you want to control smooth scroll speed (for better animation) you can use below:
class CenterLayoutManager : LinearLayoutManager {
constructor(context: Context) : super(context)
constructor(context: Context, orientation: Int, reverseLayout: Boolean) : super(
context,
orientation,
reverseLayout
)
constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int, defStyleRes: Int) : super(
context,
attrs,
defStyleAttr,
defStyleRes
)
override fun smoothScrollToPosition(
recyclerView: RecyclerView,
state: RecyclerView.State,
position: Int
) {
val centerSmoothScroller = CenterSmoothScroller(recyclerView.context)
centerSmoothScroller.targetPosition = position
startSmoothScroll(centerSmoothScroller)
}
private class CenterSmoothScroller(context: Context) : LinearSmoothScroller(context) {
override fun calculateDtToFit(
viewStart: Int,
viewEnd: Int,
boxStart: Int,
boxEnd: Int,
snapPreference: Int
): Int = (boxStart + (boxEnd - boxStart) / 2) - (viewStart + (viewEnd - viewStart) / 2)
override fun calculateSpeedPerPixel(displayMetrics: DisplayMetrics): Float {
return MILLISECONDS_PER_INCH / displayMetrics.densityDpi
}
}
companion object {
// This number controls the speed of smooth scroll
private const val MILLISECONDS_PER_INCH = 150f
}
}
Usage:
recyclerView.layoutManager = CenterLayoutManager(requireContext(), LinearLayoutManager.HORIZONTAL, false)
recyclerView.smoothScrollToPosition(selectedPosition)
since now(Feb 2019), I could easily use this code in ListView
(ListView)word_list_view.smoothScrollToPositionFromTop(your_item_index, center_position.y);
RecyclerView not verified, I guess would be the same.
Related
Is there a way to custom checkbox to Read aloud with format : checkbox + [text] + [state of checkbox] that the screen reader, in android case the TalkBack, has to read the accessible elements ?
CODE:
class CustomRadioButton : AppCompatRadioButton {
var talkBackString: CharSequence? = null
constructor(context: Context, attrs: AttributeSet, defStyle: Int) : super(
context,
attrs,
defStyle
) {
setupView()
}
constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {
setupView()
}
constructor(context: Context) : super(context) {
setupView()
}
private fun setupView() {
accessibilityDelegate = MyAccessibilityDelegate()
}
inner class MyAccessibilityDelegate : AccessibilityDelegate() {
/**
* Override function onInitializeAccessibilityNodeInfo of AccessibilityDelegate
* #param host is [View]
* #param info is [AccessibilityNodeInfo]
*/
override fun onInitializeAccessibilityNodeInfo(host: View, info: AccessibilityNodeInfo) {
super.onInitializeAccessibilityNodeInfo(host, info)
if (talkBackString.isNullOrEmpty() && host.contentDescription.isNullOrEmpty().not()) {
talkBackString = host.contentDescription
}
info.apply {
contentDescription = ""
hintText = talkBackString.toString()
error = ""
text = ""
}
}
}
}
In my project I use a RecyclerView that I only want to scroll by calling the startSmoothScroll() method of the LayoutManager:
private fun next(){
val layoutManager = pager.layoutManager as BattlePageLayoutManager
layoutManager.startSmoothScroll(smoothScroller(layoutManager.findFirstVisibleItemPosition() + 1))
layoutManager.finishScroll()
}
I do not want the user to be able to scroll manually, e. g. by swiping.
I already tried to achieve this through overriding the method onInterceptTouchEvent() of the parent FrameLayout.
override fun onInterceptTouchEvent(ev: MotionEvent): Boolean {
if (ev.actionMasked == MotionEvent.ACTION_DOWN){
startClickTime = System.currentTimeMillis()
startX = ev.x
startY = ev.y
}
val allowEvent = (System.currentTimeMillis() - startClickTime) < 1000 && (startX-ev.x).absoluteValue < 15 && (startY-ev.y).absoluteValue < 15
return !allowEvent
}
That worked basically, but it occured that after double-tapping the View users are able to scroll by themselves.
Do you have any other ideas to approach this?
Did you try overriding canScrollVertically() method in the LayoutManager?
mLayoutManager = new LinearLayoutManager(getActivity()) {
#Override
public boolean canScrollVertically() {
return false;
}
};
Edit:
Create your own implementation of RecyclerView which it disables the touch event while scrolling is performing. Then you have to change the RecyclerView class in the xml file and Fragment/Activity with it.
Find here an example in Kotlin
class MyRecyclerView : RecyclerView {
constructor(context: Context) : super(context) {}
constructor(context: Context, attrs: AttributeSet?) : super(context, attrs) {}
constructor(context: Context, attrs: AttributeSet?, defStyle: Int) : super(context, attrs, defStyle) {}
override fun onInterceptTouchEvent(e: MotionEvent): Boolean {
return if (scrollState != RecyclerView.SCROLL_STATE_IDLE) false else super.onInterceptTouchEvent(e)
}
}
And in Java
public class MyRecyclerView extends RecyclerView {
public MyRecyclerView(Context context) {
super(context);
}
public MyRecyclerView(Context context, #Nullable AttributeSet attrs) {
super(context, attrs);
}
public MyRecyclerView(Context context, #Nullable AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
#Override
public boolean onInterceptTouchEvent(MotionEvent e) {
if(getScrollState() != SCROLL_STATE_IDLE)
return false;
return super.onInterceptTouchEvent(e);
}
}
You might want to block the user interaction with RecyclerView, not with FrameLayout itself.
Check RecyclerView.OnItemTouchListener.
In your RecyclerView, you can implement OnItemTouchListener and override every method to do nothing.
That will block the user interaction with RecyclerView, making scroll not happen.
This question already has answers here:
All Editexts be replace by same value after pop a Fragment
(4 answers)
Closed 4 years ago.
I have a custom view with an edittext and an imageview. I use this view multiple times in the same layout. It's behaving very strange though. Whenever I rotate the device the value from the last declared view in the xml is put into all the other views in the layout and I just can't figure out where things go wrong.
My view:
class InputView(context: Context, attrs: AttributeSet?, #AttrRes defStyleAttr: Int) : ConstraintLayout(context, attrs, defStyleAttr) {
private var textInputLayout: TextInputLayout
private var textView: TextInputEditText
private var imageView: ImageView
constructor(context: Context) : this(context, null)
constructor(context: Context, attrs: AttributeSet?) : this(context, attrs, 0)
init {
val view = LayoutInflater.from(context).inflate(R.layout.custom_inputview, this, true)
textInputLayout = view.custom_inputview_text_input_layout
textView = view.custom_inputview_text_input_edit_text
imageView = view.custom_inputview_image_view
attrs.let {
context.theme.obtainStyledAttributes(
it,
R.styleable.InputView,
defStyleAttr, 0).apply {
try {
textView.textSize = getDimension(R.styleable.InputView_android_textSize, 16.0f)
textView.text = SpannableStringBuilder(getString(R.styleable.InputView_android_text) ?: "")
textInputLayout.hint = getText(R.styleable.InputView_android_hint)
if (getDrawable(R.styleable.InputView_android_src) == null) {
imageView.isVisible = false
} else {
imageView.setImageDrawable(getDrawable(R.styleable.InputView_android_src))
imageView.setColorFilter(getColorOrThrow(R.styleable.InputView_android_tint))
}
textView.maxLines = getInteger(R.styleable.InputView_android_maxLines, 1)
textView.minLines = getInteger(R.styleable.InputView_android_minLines, 0)
textView.setLines(getInteger(R.styleable.InputView_android_lines, 1))
textView.inputType = getInteger(R.styleable.InputView_android_inputType, EditorInfo.IME_NULL)
textView.setCompoundDrawablesWithIntrinsicBounds(
getDrawable(R.styleable.InputView_android_drawableStart),
getDrawable(R.styleable.InputView_android_drawableTop),
getDrawable(R.styleable.InputView_android_drawableEnd),
getDrawable(R.styleable.InputView_android_drawableBottom))
} finally {
recycle()
}
}
}
}
override fun onSaveInstanceState(): Parcelable {
// 1
val bundle = Bundle()
// 2
bundle.putString("text", textView.text.toString())
// 3
Log.d("InputView", "Saving state text: ${textView.text.toString()}")
bundle.putParcelable("superState", super.onSaveInstanceState())
return bundle
}
override fun onRestoreInstanceState(state: Parcelable) {
// 4
var viewState = state
if (viewState is Bundle) {
// 5
Log.d("InputView", "Textview text: ${viewState.getString("text")}")
textView.text = SpannableStringBuilder(viewState.getString("text"))
// 6
viewState = viewState.getParcelable("superState")
}
super.onRestoreInstanceState(viewState)
}
}
I've tried overriding onSaveIntanceState() and onRestoreInstanceState(), but it doesn't change anything.
Screenshot before rotation:
Screenshot after rotation:
Added this to my custom view and the problem was gone:
class InputView(context: Context, attrs: AttributeSet?, #AttrRes defStyleAttr: Int) : ConstraintLayout(context, attrs, defStyleAttr) {
...
#Suppress("UNCHECKED_CAST")
public override fun onSaveInstanceState(): Parcelable? {
val superState = super.onSaveInstanceState()
val ss = SavedState(superState)
ss.childrenStates = SparseArray()
for (i in 0 until childCount) {
getChildAt(i).saveHierarchyState(ss.childrenStates as SparseArray<Parcelable>)
}
return ss
}
#Suppress("UNCHECKED_CAST")
public override fun onRestoreInstanceState(state: Parcelable) {
val ss = state as SavedState
super.onRestoreInstanceState(ss.superState)
for (i in 0 until childCount) {
getChildAt(i).restoreHierarchyState(ss.childrenStates as SparseArray<Parcelable>)
}
}
override fun dispatchSaveInstanceState(container: SparseArray<Parcelable>) {
dispatchFreezeSelfOnly(container)
}
override fun dispatchRestoreInstanceState(container: SparseArray<Parcelable>) {
dispatchThawSelfOnly(container)
}
class SavedState(superState: Parcelable?) : BaseSavedState(superState) {
var childrenStates: SparseArray<Any>? = null
override fun writeToParcel(out: Parcel, flags: Int) {
super.writeToParcel(out, flags)
childrenStates?.let {
out.writeSparseArray(it)
}
}
}
}
I know how to disable fadingedge from scrollbar but what I need is to disable just the bottom fading edge without disabling the top fading edge effect, is that possible?
You can achieve the effect you want by extending the ScrollView and overriding one of those two methods:
float getTopFadingEdgeStrength()
float getBottomFadingEdgeStrength()
They'll alow you to change the size of the fading edge - just set bottom value to 0 and you are ready to go :)
Code example with bottom fading turned off:
/**
* Created by scana on 14.12.14.
*/
public class TopFadeEdgeScrollView extends ScrollView {
public TopFadeEdgeScrollView(Context context) {
super(context);
}
public TopFadeEdgeScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public TopFadeEdgeScrollView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#Override
protected float getBottomFadingEdgeStrength() {
return 0.0f;
}
}
scana's answer is correct.
Here's a Kotlin version of his answer that has methods to disable specific edges.
import android.content.Context
import android.util.AttributeSet
import android.widget.ScrollView
class FadingEdgeScrollView #JvmOverloads constructor(
context: Context,
attrs: AttributeSet? = null,
defStyle: Int = 0
) : ScrollView(context, attrs, defStyle) {
var topFadingStrength: Float? = null
var bottomFadingStrength: Float? = null
var leftFadingStrength: Float? = null
var rightFadingStrength: Float? = null
override fun getTopFadingEdgeStrength(): Float {
return topFadingStrength ?: super.getTopFadingEdgeStrength()
}
override fun getBottomFadingEdgeStrength(): Float {
return bottomFadingStrength ?: super.getBottomFadingEdgeStrength()
}
override fun getLeftFadingEdgeStrength(): Float {
return leftFadingStrength ?: super.getLeftFadingEdgeStrength()
}
override fun getRightFadingEdgeStrength(): Float {
return rightFadingStrength ?: super.getRightFadingEdgeStrength()
}
fun disableTopFade() {
topFadingStrength = 0f
}
fun disableBottomFade() {
bottomFadingStrength = 0f
}
fun disableLeftFade() {
leftFadingStrength = 0f
}
fun disableRightFade() {
rightFadingStrength = 0f
}
}
I have a WebView in a ViewPager.
And the ViewPager seems to consume all the horizontal scrolling, so that I can't scroll in the WebView (vertical works).
How can I achieve that the WebView has got priority consuming the horizontal scrolling?
don't ask me why this code gets formatted like this,
1. implement a custom ViewPager Instance like this:
import android.content.Context;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
public class CustomViewPager extends ViewPager {
private MagazineWebView_WithoutFlipWebView mCurrentPageWebView_; //custom webview
public CustomViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
}
#Override
public boolean onInterceptTouchEvent(MotionEvent event) {
if (Constants.LOGGING) {
Log.v(Constants.LOG_OEAMTC_APP, "CustomViewPager - onInterceptTouchEvent");
}
// if view zoomed out (view starts at 33.12... scale level) ... allow
// zoom within webview, otherwise disallow (allow viewpager to change
// view)
if (mCurrentPageWebView_ != null && (mCurrentPageWebView_.getScale() * 100) > 34) {
Log.v(Constants.LOG_OEAMTC_APP, "CustomViewPager - intrcepted: " + String.valueOf((mCurrentPageWebView_.getScale() * > 100)));
this.requestDisallowInterceptTouchEvent(true);
}
else {
if (mCurrentPageWebView_ != null) {
Log.v(Constants.LOG_OEAMTC_APP,
"CustomViewPager - not intrcepted: " + String.valueOf(mCurrentPageWebView_.getScale() * 100));
}
this.requestDisallowInterceptTouchEvent(false);
}
return super.onInterceptTouchEvent(event);
}
public MagazineWebView_WithoutFlipWebView getCurrentPageWebView() {
return mCurrentPageWebView_;
}
public void setCurrentPageWebView(MagazineWebView_WithoutFlipWebView currentPageWebView) {
mCurrentPageWebView_ = currentPageWebView;
}
}
2. in your main (ViewPager) Activity add the following lines to the view pager
mViewPager_ = new AwesomePagerAdapter();
viewpapgerInLayout = (CustomViewPager) findViewById(R.id.awesomepager);
viewpapgerInLayout.setAdapter(mViewPager_);
viewpapgerInLayout.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageSelected(int position) {
viewpapgerInLayout.setCurrentPageWebView(mLstPagesWebviews_.get(position));
}
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
3. finally, run it :=) if the zoom level is at initial zoom,
changes pages is allowed, all the other time you can navigate your web view
Ps.: *Don't forget* to change your ViewPager in your *.xml file with the CustomViewPager Class you just created
good luck :)
Try this
WebView mWebView = (WebView) findViewById(R.id.MyWebview);
mWebView.getSettings().setLoadWithOverviewMode(true);
mWebView.getSettings().setUseWideViewPort(true);
mWebView.getSettings().setSupportZoom(true);
mWebView.getSettings().setBuiltInZoomControls(true);
mWebView.getSettings().setUserAgentString("Mozilla/5.0 (iPhone; U; CPU like Mac OS X; en) AppleWebKit/420+ (KHTML, like Gecko) Version/3.0 Mobile/1A543a Safari/419.3");
Late to this question and I come up with a different approach to fix this issue by override the WebView onTouchEvent method. It works on both ViewPager and ViewPager2. Hope this would help the future SO.
Note: Replace your WebView with NestedScrollWebView
import android.content.Context
import android.util.AttributeSet
import android.view.MotionEvent
import android.webkit.WebView
import androidx.core.view.NestedScrollingChild
import androidx.core.view.NestedScrollingChildHelper
import androidx.core.view.ViewCompat
class NestedScrollWebView : WebView, NestedScrollingChild {
companion object {
val TAG: String = NestedScrollWebView::class.java.simpleName
}
private var lastMotionX: Int = 0
private var lastMotionY: Int = 0
private val scrollOffset = IntArray(2)
private val scrollConsumed = IntArray(2)
private var nestedOffsetY: Int = 0
private var childHelper = NestedScrollingChildHelper(this)
constructor(context: Context) : super(context) {
init()
}
constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {
init()
}
constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
init()
}
private fun init() {
isNestedScrollingEnabled = true
}
override fun onTouchEvent(event: MotionEvent): Boolean {
var result = false
val trackedEvent = MotionEvent.obtain(event)
val action = event.actionMasked
if (action == MotionEvent.ACTION_DOWN) {
nestedOffsetY = 0
}
val x = event.x.toInt()
val y = event.y.toInt()
event.offsetLocation(0f, nestedOffsetY.toFloat())
when (action) {
MotionEvent.ACTION_DOWN -> {
lastMotionX = x
lastMotionY = y
startNestedScroll(ViewCompat.SCROLL_AXIS_VERTICAL)
result = super.onTouchEvent(event)
}
MotionEvent.ACTION_MOVE -> {
var deltaY = lastMotionY - y
if (kotlin.math.abs(deltaY) > kotlin.math.abs(lastMotionX - x) &&
(canScrollVertically(1) || canScrollVertically(-1))
) {
requestDisallowInterceptTouchEvent(true)
}
if (dispatchNestedPreScroll(0, deltaY, scrollConsumed, scrollOffset)) {
deltaY -= scrollConsumed[1]
trackedEvent.offsetLocation(0f, scrollOffset[1].toFloat())
nestedOffsetY += scrollOffset[1]
}
lastMotionY = y - scrollOffset[1]
val oldY = scrollY
val newScrollY = Math.max(0, oldY + deltaY)
val dyConsumed = newScrollY - oldY
val dyUnconsumed = deltaY - dyConsumed
if (dispatchNestedScroll(0, dyConsumed, 0, dyUnconsumed, scrollOffset)) {
lastMotionY -= scrollOffset[1]
trackedEvent.offsetLocation(0f, scrollOffset[1].toFloat())
nestedOffsetY += scrollOffset[1]
}
result = super.onTouchEvent(trackedEvent)
trackedEvent.recycle()
}
MotionEvent.ACTION_POINTER_DOWN, MotionEvent.ACTION_UP, MotionEvent.ACTION_CANCEL -> {
stopNestedScroll()
requestDisallowInterceptTouchEvent(false)
result = super.onTouchEvent(event)
}
}
return result
}
// NestedScrollingChild
override fun setNestedScrollingEnabled(enabled: Boolean) {
childHelper.isNestedScrollingEnabled = enabled
}
override fun stopNestedScroll() {
childHelper.stopNestedScroll()
}
override fun isNestedScrollingEnabled() =
childHelper.isNestedScrollingEnabled
override fun startNestedScroll(axes: Int) =
childHelper.startNestedScroll(axes)
override fun hasNestedScrollingParent() =
childHelper.hasNestedScrollingParent()
override fun dispatchNestedScroll(dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, offsetInWindow: IntArray?) =
childHelper.dispatchNestedScroll(dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed, offsetInWindow)
override fun dispatchNestedPreScroll(dx: Int, dy: Int, consumed: IntArray?, offsetInWindow: IntArray?) =
childHelper.dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow)
override fun dispatchNestedFling(velocityX: Float, velocityY: Float, consumed: Boolean) =
childHelper.dispatchNestedFling(velocityX, velocityY, consumed)
override fun dispatchNestedPreFling(velocityX: Float, velocityY: Float) =
childHelper.dispatchNestedPreFling(velocityX, velocityY)
}