Develop Reference

How to make recyclerView_items unclickable, while one of them is clicked and working?

Premise
Each of my RecyclerView_items displays an image, and changes its image_resource when tapped.
One of them is the right answer which has additional function: navigation to another fragment 5-second after changing its image.
Basically, the function of clickListener of RecyclerView_items is
wrong item
click -> change image_resource
right item
click -> change image_resource -> delay(5000) -> navigate to another fragment
Problem
Then, my problem is that after the right_item is tapped, other items are clickable during delay(5000).
I don't want them to change their images during delay(5000).
How to do it?! Thanks in advance.

You can achieve this by adding a flag at time when user click right image then make that variable false. As such after the delay before moving to the next fragment make it true again.
boolean flag = true;
then in your item click method
view.setOnClickListner {
if (flag) {
if (rightimageclicked) {
flag = false;
delay {
flag = true;
// Move to other fragment
}
} else {
// change the image for wrong click
}
}
}

The simple trick you can use is make a FrameLayout or View that overlaps on the RecyclerView. Set ists visibility to GONE. Then inside activity or fragment where you can access this FrameLayout or View which is overlapping, add an empty OnClickListener on this view.
*viewId*.setOnClickListener { }
Now set its visibility to VISIBLE when you call delay. When delay finished again set its visibility to GONE

This is what I understood, you want to lock the entire screen (make all items or buttons unclickable) when you are in delay(5000).
This is what I would do, give a CLICKABLE overlay view on top of recycler view and toggle its visibility. I used the same for locking the entire screen while making an API call.
view_overlay.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/rl_progress"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/transparent"
android:clickable="true"
android:focusable="true"
android:elevation="5dp"
android:visibility="invisible">
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:background="#android:color/transparent"
android:indeterminateTint="#android:color/transparent" />
</RelativeLayout>
Obviously you can replace ProgressBar with just View to get a transaprent view.
To include it in your main view, give this at the bottom of your parent layout or below recycler view. Whichever you choose make sure you have the overlay view on top of recycler view.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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">
...
...
...
<include layout="#layout/view_overlay" />
</RelativeLayout>

How to avoid total view-hierarchy re-layout when using EditText?

Background
I have a rather complex layout being shown to the user in an activity.
One of the views is an EditText.
Since I had to make one of the views stay behind the soft-keyboard, yet the rest above it, I had to listen to view-layout changes (written about it here).
The problem
I've noticed that whenever the EditText has focus and shows its caret, the entire view-hierarchy gets re-layout.
You can see it by either looking at the log of the listener I've created, or by enabling "show surface updates" via the developers settings.
This causes bad performance on some devices, especially if the layout of the activity is complex or have fragments that have complex layouts.
The code
I'm not going to show the original code, but there is a simple way to reproduce the issue:
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
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"
tools:context="com.example.user.myapplication.MainActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="just some text"/>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="phone"
android:text="write here"
android:textSize="18dp"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="just some text 2"/>
</LinearLayout>
</FrameLayout>
MainActivity.java
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViewById(android.R.id.content).getViewTreeObserver().addOnPreDrawListener(new OnPreDrawListener() {
#Override
public boolean onPreDraw() {
Log.d("AppLog", "onPreDraw");
return true;
}
});
}
}
What I've tried
When disabling the caret (using "cursorVisible", which for some reason is called a "cursor" instead) , I can see that the problem doesn't exist.
I've tried to find an alternative to the built-in caret behavior, but I can't find. Only thing I've found is this post, but it seems to make it static and I'm not sure as to how well it performs (performance and compatibility vs normal caret).
I've tried to set the size of the EditText forcefully, so that it won't need to cause invalidation of the layout that contains it. It didn't work.
I've also noticed that on the original app, the logs can (for some reason) continue being written even when the app goes to the background.
I've reported about this issue (including sample and video) here, hoping that Google will show what's wrong or a fix for this.
The question
Is there a way to avoid the re-layout of the entire view hierarchy ? A way that will still let the EditText have the same look&feel of normal EditText?
Maybe a way to customize how the EditText behaves with the caret?

I've noticed that whenever the EditText has focus and shows its caret,
the entire view-hierarchy gets re-layout.
This is not true. Size and position of EditText is constant - there is no re-layouting. You can check it by using code below.
findViewById(android.R.id.content).getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
Log.d("AppLog", "Layout phase");
}
});
Because of blinking caret - EditText constatly calls invalidate(). This forces the GPU to draw EditText again.
On my nexus 5 (marshmallow) I see that only EditText beeing redrawn (Show GPU view updates - enabled).

How about overriding dispatchOnPreDraw() all the vies you use in activity and having flag to check whether that specific view needs to redraw ?
As you need to disable redraw of all other views only when a text view is on focus. So when a text view is on focus have a flag to disable the redrawing of other views.
if dispatchOnPreDraw() method returns false then refreshing of view will be continues else not. I don't know how complex is your layout and how many views are used, but here a separate class should extent a view used and override that method, and also need a mechanism/variable to distinguish the object in current focus.
Hope this method helps!

Clicking on overlapping UI elements

I have a Fragment that takes up half the Activity. Behind it, a ListView.
The problem is that when the user taps anywhere on the Fragment that overlaps with a row on the ListView, the row gets clicked and it's onClick method gets called.
A workaround was giving an onClick to the LinearLayout in the Fragment layout XML file, like so :
<LinearLayout 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:orientation="vertical"
tools:context="com.example.karimnseirackground="#color/material_blue_grey_950"
android:onClick="doNothing">
Which I don't think is very elegant because I have to add a doNothing method to every Activity that uses this Fragment
If there isn't a way to stop onClicks from being called on elements BEHIND the Fragment, how can I still give it a null onClick without having a dummy method everywhere ?
Thank you

Instead of setting the android:onClick you can just set android:clickable="true". This will let the View capture the click and not pass it to the view behind.

Android: RelativeLayout background drawable disappears

I have an xml layout for a Fragment (android.support.v4.app.Fragment). When this Fragment is added for the first time, the background drawable displays fine. But when this Fragment is replaced with another Fragment, then later replaced back in again (by creating a new instance and using FragmentTransaction.replace()), the background drawable disappears (but not in all cases, see below). Here is the layout xml for the Fragment:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<include layout="#layout/footer_photos" />
<RelativeLayout
android:id="#+id/pageLayout"
android:background="#drawable/body_background2"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_above="#id/footer">
<ImageView
android:id="#+id/page"
android:layout_height="500dp"
android:layout_width="400dp"
android:layout_centerInParent="true"
android:background="#FFF" />
</RelativeLayout>
</RelativeLayout>
The background drawable in question is in the RelativeLayout with the id "pageLayout".
Possible clues:
When I remove the ImageView in there, the background drawable shows up fine.
The other Fragments have similar layout xmls (with the same background drawable), but without ImageViews inside of them, and they work fine.
One of these Fragments has a WebView and buttons inside of it, and this one's background shows up fine.
After replacing the "WebView Fragment" with the Fragment in question, the background shows up fine (!?).
EDIT: The same issue consistently occurs if an image is loaded into the ImageView then a dialog-themed activity is launched on top of it, then finished. My solution below fixes both cases.

Found a better solution than my last one. In onResume() for the Fragment, just need to do:
getView().post(new Runnable() {
#Override
public void run() {
View v = getView();
if (v != null)
v.invalidate();
}
});
It causes a flicker, but at least it seems to work consistently.

i had a similar problem. With a relativelayout, there was an imageView and a textView.
I resolved with a call to bringToFront method:
myImageView.bringToFront();
Hope this helped.

Okay, I fixed this issue while trying to fix another issue. The issue was solved by calling setLayoutParams() on the page ImageView (with whatever layout params). This caused the background of the pageLayout RelativeLayout to show up again. The cause of the issue remains unknown...

The fragments are replaced , along with their background, which means that
when a fragment A is replaced by fragment B, the background changes to the background of fragment B.
If you don't give any background to fragment B, then you can see fragment B over fragment A.

Android -- Hiding Views

Okay, so I've done some looking around and I see how you are SUPPOSED to do it, but for me, it is just not working.
I need to be able to set the alpha of a RelativeLayout both in XML and in code. For my XML, I have the following
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/player_controls"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:alpha="0.0">
<RelativeLayout
android:layout_height="match_parent"
android:layout_width="match_parent"
android:id="#+id/player_controls_touch_me"
>
</RelativeLayout>
</RelativeLayout>
I get the error: no resource identifier found for attribute 'alpha' in package 'android'
Also, based on the Android documentation, I should be able to call setAlpha(double) on any View object, but when I try to make that call on a RelativeLayout it tells me that this method is not defined for this object.
Why am I not able to control the alpha transparency for a RelativeLayout object in Android? Am i missing something? Thanks!
Update
Although using the visibility property works, it prevents me from be able to click on the ViewGroup. This is important for me because I am utilizing the OnTouchListener of the ViewGroup.
What I am trying to do is to have a layer with media controls, initially hidden. when the user taps anywere on the screen, I want the controls to fade in and when they tap the screen again I want the controls to fade out. I have this part already working. I am using a viewgroup that sits over-top my entire application with an OnTouchListener attached that can determine if it has or hasn't been touched. My problem is that after the animation runs to fade out the controls, they re-appear. If I use #Hydrangea suggestion, I can have it fade out and immediately made invisible. This gives me the desired effect, but then the ViewGroup is unclickable and the user cannot get the controls to come back (or go away, depending on what we decide to do first).
I hope this makes sense.

You'll want to use a alpha animation to fade things in and out. This will maintain your touch events for your layouts. Here's an example
public class Main extends Activity {
/** Called when the activity is first created. */
private boolean mShowing = false;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
findViewById(R.id.textview).setOnClickListener(new OnClickListener(){
#Override
public void onClick(View arg0) {
if(mShowing){
Animation animation = new AlphaAnimation(1.0f, 0.0f);
animation.setFillAfter(true);
arg0.startAnimation(animation);
} else {
Animation animation = new AlphaAnimation(0.0f, 1.0f);
animation.setFillAfter(true);
arg0.startAnimation(animation);
}
mShowing = !mShowing;
}
});
}
}
Here's the accompanying xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:id="#+id/textview"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="#string/hello"
android:clickable="true"
/>
</LinearLayout>

Unless you need levels of alpha between 0 and 1, I'd suggest, if you truly want to make this item invisible, to use setVisibility();
android:visibility="invisible"
I checked out the android:alpha line, and my ide doesn't find it either. I can't guess why, though... the documentation seems pretty clear.

The alpha property is new in Android 3.0, and it's not the most efficient way to hide a view. Use View.setVisibility() or android:visibility to achieve what you want.

You can set alpha by setting the (background) color i guess. Color values can be in the format of #aarrggbb (alpha, red, green, blue).

You can add to the right answer the following option:
animation.setDuration(xxx);
To each animation instance. In this way your animation will look better.

Based on your discription, you should be able to create a view that contains only the relative layout and have the onClickListener set to it. This way you can set the visibility of the relative layout to invisible, but still register a click.
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/clickable_layout"
android:layout_height="match_parent"
android:layout_width="match_parent" >
<RelativeLayout
android:id="#+id/player_controls"
android:layout_height="match_parent"
android:layout_width="match_parent" >
<RelativeLayout
android:layout_height="match_parent"
android:layout_width="match_parent"
android:id="#+id/player_controls_touch_me"
>
</RelativeLayout>
</RelativeLayout>
</FrameLayout>

Use onTouchEvent in Activity, and then you could get touch event to control to your RelativeLayout even if it is "invisible".