Develop Reference

CoordinatorLayout with multiple snapping points

Here I've got quite a complex animation that may be resolved (I believe) in a simple way using the CoordinatorLayout. It has 3 states:
Initial (left screen) - Header view is shown fully (orange
background): Toolbar, grey roundrect (it's actually a photo there)
plus some other views below (TextViews, RatingBar etc)
Scrolling the content up (middle
screen) - roundrect is zooming up with a changing green foreground alpha level over it, so it becomes green while scrolling (well, it is not obvious with these screens. Green background is actually a zoomed roundrect with a green foreground over it, and that is the cause the header background becomes green and not orange)
Scrolling once more (right screen) - the rest of the header should be scrolled up
Scrolling down the content should lead to the appearing of the views in a reverse way accordingly.
I had some experience working with the CoordinatorLayout, but I'm really not sure I understand how to handle 2 anchor points. I understand how the scroll flags work and that for zooming (p. 2) and for changing the foreground alpha I need a custom Behavior implementation, but for now I cannot understand how shall I handle all of this in a complex.
All I've found so far is Saúl Molinero's tutorial and also this tutorial with examples.
So please sorry for the poor description here, I'll update my question of course and will add the source code when I have some success with this issue, but for now I'd be glad to get some hints maybe or tutorials I've missed. Hope someone had something similar in the projects.
Here's my test repo with the code and here is a link to my layout.xml file.

You can get two snapping points with just setting the scroll flags as follows:
<android.support.design.widget.CollapsingToolbarLayout
...stuff...
app:layout_scrollFlags="scroll|enterAlways|snap">
So, fully expanded is one stopping point and with just the toolbar visible is the second stopping point. When the view is scrolled further, the toolbar disappears. So this is how you want things to work when scrolling up.
Now when the app bar is fully collapsed, the app bar will start showing immediately when scrolling down. That is not a surprise, since that is what enterAlways does. If the top of the content has been scrolled out of view, then you won't see it again until after the app bar is fully expanded. So, if this is the behavior you want, we'll just stop there.
However, I think that what you want is the exiting behavior outlined above but with a different entry behavior. You will get the late entry behavior if you set the scroll flags as follows:
<android.support.design.widget.CollapsingToolbarLayout
...stuff...
app:layout_scrollFlags="scroll|snap">
This just deleted the enterAlways flag. With these scroll flags, the app bar will not reappear (once collapsed) until the top of the content is visible and "pulls" the app bar into view.
So, one solution (of what is probably many) is to write a new behavior that will be attached to the AppBarLayout some code that will change the scroll flags once the app bar is fully collapsed and change them back as it opens again. That way you can change the behavior to be what you want and still use the Android machinery to figure out what the specific operations are at the view level. This can be done in a custom view or in the activity - wherever you have access to the scroll state of the app bar and the scrolling flags. It can also be done in a behavior but that is probably not the best place for it.
Oh, and as you have discovered, snapping is janky on API 26.
Here is an implementation of the concept. For simplicity, the implementation is in an activity:
ScrollingActivity.java
public class ScrollingActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_scrolling);
final AppBarLayout appBar = (AppBarLayout) findViewById(R.id.app_bar);
appBar.post(new Runnable() {
#Override
public void run() {
CollapsingToolbarLayout toolbarLayout =
(CollapsingToolbarLayout) findViewById(R.id.toolbar_layout);
setupAppBar(appBar, toolbarLayout);
}
});
}
private void setupAppBar(AppBarLayout appBar, final CollapsingToolbarLayout toolbarLayout) {
// Scroll range is positive but offsets are negative. Make signs agree for camparisons.
final int mScrollRange = -appBar.getTotalScrollRange();
appBar.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {
private boolean mAppBarCollapsed = false;
#Override
public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
if (verticalOffset == mScrollRange) { // App bar just collapsed
mAppBarCollapsed = true;
AppBarLayout.LayoutParams lp =
(AppBarLayout.LayoutParams) toolbarLayout.getLayoutParams();
int flags = lp.getScrollFlags()
& ~AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS;
lp.setScrollFlags(flags);
toolbarLayout.setLayoutParams(lp);
} else if (mAppBarCollapsed) { // App bar is opening back up
mAppBarCollapsed = false;
AppBarLayout.LayoutParams lp =
(AppBarLayout.LayoutParams) toolbarLayout.getLayoutParams();
int flags = lp.getScrollFlags()
| AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS;
lp.setScrollFlags(flags);
toolbarLayout.setLayoutParams(lp);
}
}
});
}
}

Custom child view bringToFront not working as expected

I have a custom view added as a child of a LinearLayout. I need this custom view to anchor to the bottom irrespective of the parent viewgroup. Here's how I'm doing it.
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (!drawn) {
drawn = true;
Rect rect = new Rect();
((View) getParent()).getGlobalVisibleRect(rect);
setY(rect.bottom - rect.top - getContext().getResources().getDimension(R.dimen.bottom_bar_height));
setZ(UiUtils.dpToPx(8f));
forceLayout();
bringToFront();
} else {
binding.bottomBarLl.draw(canvas);
}
}
When I add the custom view to a LinearLayout parent, if the children above this child have match_parent height, this one doesn't show.
Below is a screenshot from the layout inspector where it is shown to be laid out but doesn't show.
The inspector also shows that the getZ() of the custom view is 24.
I'm building for API level 21+ but I've also tried ((View) getParent()).invalidate(); and getParent().requestLayout(); in the onDraw() to no good.
From the documentation for View.bringToFront()
bringToFront
Added in API level 1
void bringToFront ()
Change the view's z order in
the tree, so it's on top of other sibling views. This ordering change
may affect layout, if the parent container uses an order-dependent
layout scheme (e.g., LinearLayout). Prior to KITKAT this method should
be followed by calls to requestLayout() and invalidate() on the view's
parent to force the parent to redraw with the new child ordering.
this should be working, but it isn't for me. What am I doing incorrectly?

Like other questions which couldn't get it to work with a LinearLayout, I also used a coordinator layout finally where the linear layout and my custom view are siblings and things are working fine. It would be great if someone could explain the documentation though, since it is misleading otherwise.

fitSystemWindows programmatically for status bar transparency

My app has one activity that hosts different fragments for each section. I have recently made the status bar translucent by setting fitSystemWindows to true, which has set it to the background colour of the app. This is fine for fragments that have a toolbar, where the colours match, like so:
However one of my fragments has a photo and a translucent toolbar, so I'd like to have the photo occupy the space of the status bar too, rather than the background colour.
I believe the solution is to set fitSystemWindows to false for that fragment only, and manually add padding to the translucent toolbar. Doing this programmatically seems to have no effect, what could I be doing wrong?
Here is my main activity layout:
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/main_parent_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:fitsSystemWindows="true">
<!-- Container for various fragment layouts, including nav drawer and toolbar -->
</RelativeLayout>
And from within my fragment's onCreateView():
RelativeLayout daddyLayout = (RelativeLayout)getActivity().findViewById(R.id.main_parent_view);
daddyLayout.setFitsSystemWindows(false);
daddyLayout.invalidate();
This seems to have no effect, like so:
If I set fitSystemWindows to false in the main_parent_view, the status bar padding is gone and it works but obviously affects every fragment.

Well, you are in dilemma situation there, because from one hand you need to apply insets (because Toolbar should be correctly padded), and on the other hand you should not apply insets (because you want ImageView to be drawn under status bar).
Turns out there's a nice API provided by the framework for that case:
ViewCompat.setOnApplyWindowInsetsListener(toolbar, (v, insets) -> {
((ViewGroup.MarginLayoutParams) v.getLayoutParams()).topMargin =
insets.getSystemWindowInsetTop();
return insets.consumeSystemWindowInsets();
});
Assuming your root layout has android:fitsSystemWindows="true", now appropriate insets would be applied to your Toolbar only, and not the ImageView.
But, there's a problem.
The problem is that your root layout is RelativeLayout, which doesn't dispatch its children any information about insets. Neither do its sibling layouts (LinearLayout, FrameLayout).
If you had as a root layout one of "materialish" layouts (CoordinatorLayout, DrawerLayout), then children would be dispatched those window insets.
The other option is to subclass RelativeLayout and dispatch WindowInsets to
children manually.
#TargetApi(Build.VERSION_CODES.KITKAT_WATCH)
#Override
public WindowInsets onApplyWindowInsets(WindowInsets insets) {
int childCount = getChildCount();
for (int index = 0; index < childCount; index++)
getChildAt(index).dispatchApplyWindowInsets(insets); // let children know about WindowInsets
return insets;
}
You can see this answer for a detailed explanation with precisely same requirement you have.

I have resolve this question in 4.4
if(test){
Log.d(TAG, "fit true ");
relativeLayout.setFitsSystemWindows(true);
relativeLayout.requestFitSystemWindows();
getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
}else {
Log.d(TAG, "fit false");
relativeLayout.setFitsSystemWindows(false);
relativeLayout.requestFitSystemWindows();
getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
}

You can use a CoordinatorLayout as your activity root view and then setFitsSystemWindows(boolean) will work.
This is because, as explained in this blog post , DrawerLayout and CoordinatorLayout both have different rules on how fitsSystemWindows applies to them - they both use it to inset their child Views, but also call dispatchApplyWindowInsets() on each child, allowing them access to the fitsSystemWindows="true" property.
This is a difference from the default behavior with layouts such as FrameLayout where when you use fitsSystemWindows="true" is consumes all insets, blindly applying padding without informing any child views (that's the 'depth first' part of the blog post).

Saw the same issue. Solved it in my app by removing fitSystemWindows from the activity declaration and adding paddingTop to the fragment. Obviously not an ideal solution but seems to be working.

simply put
View decorView = getActivity().getWindow().getDecorView();
decorView.setSystemUiVisibility(
View.SYSTEM_UI_FLAG_LAYOUT_STABLE
| View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
and for status bar color use:
getActivity().getWindow().setBackgroundDrawableResource(R.color.green);

Dynamically Setting RelativeLayout.LayoutParams.addRule

I have this issue where I have a relative layout that has two child relative layouts (leftpanel and rightpanel). They're inside a custom layout for listview items and each item is updated from a json response from the server. So the size depends on what the server provides.
Issue: I want to have each panel's height to match each other, but it seems that setting layout_height to match_parent doesn't work (actually, if this can be resolved, then no more problems).
What I did: I programmatically set the align top and bottom of each panel to each other -- if the other's bigger, adjust the other one and vice versa. So what I did was to have a view (rightpanel) to listen to rightPanel.getViewTreeObserver().addOnScrollChangedListener(), and call the method below everytime there's a scroll change:
private void updateLayoutAlignmentParams(ViewHolder viewHolder) {
RelativeLayout.LayoutParams leftPanelLayoutParams = (RelativeLayout.LayoutParams)viewHolder.leftPanel.getLayoutParams();
RelativeLayout.LayoutParams rightPanelLayoutParams = (RelativeLayout.LayoutParams)viewHolder.rightPanel.getLayoutParams();
int leftPanelHeight = viewHolder.leftPanel.getHeight();
int rightPanelHeight = viewHolder.rightPanel.getHeight();
if(leftPanelHeight > rightPanelHeight) {
rightPanelLayoutParams.addRule(RelativeLayout.ALIGN_BOTTOM, 0);
rightPanelLayoutParams.addRule(RelativeLayout.ALIGN_TOP, 0);
leftPanelLayoutParams.addRule(RelativeLayout.ALIGN_BOTTOM, viewHolder.rightPanel.getId());
leftPanelLayoutParams.addRule(RelativeLayout.ALIGN_TOP, viewHolder.rightPanel.getId());
} else {
leftPanelLayoutParams.addRule(RelativeLayout.ALIGN_BOTTOM, 0);
leftPanelLayoutParams.addRule(RelativeLayout.ALIGN_TOP, 0);
rightPanelLayoutParams.addRule(RelativeLayout.ALIGN_BOTTOM, viewHolder.leftPanel.getId());
rightPanelLayoutParams.addRule(RelativeLayout.ALIGN_TOP, viewHolder.leftPanel.getId());
}
}
What happens: not all the views get updated while scrolling; so I get a lop-sided listview item where one is bigger than the other vertically but some do adjust well. Odd thing is, when the item gets out of view, it's lop-sided, then gets corrected consistently.
Note: I also tried
addOnDrawListener() - every item is updated but I get an ArrayList out of bounds index but doesn't point to any line in my code. Wouldn't be the best solution anyway as I need to support devices with API < 16.
setOnGlobalLayoutListener() - Nothing happens.
Please let me know if you know why or have a better solution.

Finally [kindof] fixed it! Replaced the whole method with the code below:
private void updateLayoutAlignmentParams(ViewHolder viewHolder) {
viewHolder.rightPanel.setMinimumHeight(viewHolder.leftPanel.getHeight());
viewHolder.leftPanel.setMinimumHeight(viewHolder.rightPanel.getHeight());
}
Although, I was able to achieve having the left and right panel aligned with each other using the code above. I'm now having issues where the previous view's height and width are retained when I switch views. :(
Edit:
Okay, I ended up using LinearLayout to wrap the whole listview item. Not really sure why RelativeLayout isn't complying with match_parent, though.

display view on top of action bar

Is there a way to render a view on top of the action bar? I want to create a small tip box that will point the user to an item in the action bar. I know that a Toast with a set view will be rendered above the action bar. Does anyone know how to do this with a view?
I have attempted using FrameLayout with layout_gravity="top" and inflating a view and then adding it to the running activity's layout.
I appreciate you in advance.
Edit:
Here is an image of what I was thinking:
Edit:
Perhaps some more detail is needed. I am looking for a way, or to find out if it is even possible to add a view to the view hierarchy of the activity so that it is rendered last.
Similar to CSS, I want a higher z-index order for this particular view ( the blue floating box in the image), such that it would be rendered on top of the Action Bar region in the activity. The view is in no way associated with Action Bar, it is simply drawn on top of it.

I was trying to achieve something else but I needed a solution similar to this. I needed to draw an opaque layer covering the whole screen, even the action bar--sort of like a dialog. I did so this way:
ViewGroup vg = (ViewGroup)(getWindow().getDecorView().getRootView());
vg.addView(myNewView, params);
this can be used to draw anything anywhere on the screen.
UPDATE: You really shouldn't be using ActionBar anymore, you wouldn't have this issue in the first place if you were using Toolbar like Android recommends. Toolbar would go inside your activity xml like a regular view and you can can do whatever you want to it. And its fully backwards compatible.
https://developer.android.com/training/appbar/setting-up

After struggling with it myself quite some time, here's the solution (tested it - working good):
The general steps are:
Create a wrapper view
Detach the screen view children, place the wrapper, and attach the children
Inflate the content to the children
Controling the wrapper will help you control exactly the action bar and the content below it all together.
Now, using the wrapper, you can add "brothers" to the actionbar/main area. That brother is exactly what you described in your image.
Let's see some code.
First, create a method to help create a wrapper view. the wrapper will be placed between the entire screen and the content of your app. being a ViewGroup you can later on fully control it's content.
private ViewGroup setContentViewWithWrapper(int resContent) {
ViewGroup decorView = (ViewGroup) this.getWindow().getDecorView();
ViewGroup decorChild = (ViewGroup) decorView.getChildAt(0);
// Removing decorChild, we'll add it back soon
decorView.removeAllViews();
ViewGroup wrapperView = new FrameLayout(this);
// You should set some ID, if you'll want to reference this wrapper in that manner later
//
// The ID, such as "R.id.ACTIVITY_LAYOUT_WRAPPER" can be set at a resource file, such as:
// <resources xmlns:android="http://schemas.android.com/apk/res/android">
// <item type="id" name="ACTIVITY_LAYOUT_WRAPPER"/>
// </resources>
//
wrapperView.setId(R.id.ACTIVITY_LAYOUT_WRAPPER);
// Now we are rebuilding the DecorView, but this time we
// have our wrapper view to stand between the real content and the decor
decorView.addView(wrapperView, LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
wrapperView.addView(decorChild, decorChild.getLayoutParams());
LayoutInflater.from(this).inflate(getActivityLayout(),
(ViewGroup)((LinearLayout)wrapperView.getChildAt(0)).getChildAt(1), true);
return wrapperView;
}
Now, interfere with the regular Activity creation, and instead of using setContentView, use the method we've created.
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// DON'T CALL `setContentView`,
// we are replacing that line with this code:
ViewGroup wrapperView = setContentViewWithWrapper(R.layout.activity_layout);
// Now, because the wrapper view contains the entire screen (including the notification bar
// which is above the ActionBar) I think you'll find it useful to know the exact Y where the
// action bar is located.
// You can use something like that:
ViewGroup actionBar = (ViewGroup)((LinearLayout)wrapperView.getChildAt(0)).getChildAt(0);
int topOffset = actionBar.getTop();
// Now, if you'll want to add a view:
// 1. Create new view
// 2. Set padding top - use "topOffset"
// 3. Add the view to "wrapperView"
// 4. The view should be set at front. if not - try calling to "bringToFront()"
}
That's about it.
Notes
I've used Android's hierarchy-viewer to understand what's the right hierarchy. (didn't guess those 0 and 1 indexes)
If you are using some kind of a menu drawer in your activity, you might have to configure it a little bit different since drawers are already creating that wrapper for you
I've learned a lot by looking at this great library
EDIT: Refer to #CristopherOyarzúnAltamirano Answer for further support on newer Android versions
Good luck!

There is a much simpler way to achieve this. ActionBar holds its layout in the class ActionBarContainer which simply inherits from FrameLayout. So in order to display something over the ActionBar you need to grab a reference to the ActionBarContainer and add your own custom View into it. Here is the code
int abContainerViewID = getResources().getIdentifier("action_bar_container", "id", "android");
FrameLayout actionBarContainer = (FrameLayout)findViewById(abContainerViewID);
LayoutInflater myinflater = getLayoutInflater();
View customView = myinflater.inflate(R.layout.yourCustomeViewLayout, null);
actionBarContainer.addView(customView);

I found this workaround based on #Sean answer:
//This is for Jelly, ICS, Honeycomb
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB && Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN_MR2){
LayoutInflater.from(this).inflate(resContent, (ViewGroup)((LinearLayout)wrapperView.getChildAt(0)).getChildAt(1), true);}
//This is for KitKat and Jelly 4.3
else if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2){
LayoutInflater.from(this).inflate(resContent, (ViewGroup) (((ViewGroup) wrapperView.getChildAt(0)).getChildAt(0)), true);}
//This is for Ginger
else{
LayoutInflater.from(this).inflate(resContent, (ViewGroup) ((LinearLayout)((FrameLayout) wrapperView.getChildAt(0)).getChildAt(0)).getChildAt(1), true);}

I found a much simpler way to do this.
I just applied android:translationZ="10dp" to the view which I need to be covering the action bar.
I chose 10dp but it can actually be anything you want as long as it is superior to the actionbar's elevation
<ImageView
android:layout_width="100dp"
android:layout_height="100dp"
android:translationZ="10dp"
android:src="#drawable/potatoe" />
Also, don't worry about Android studio's following warning :
"translationZ can't be used with API<21".
It will be ignored, but you don't really care because the toolbar shouldn't cover your view with APIs inferior to 21.

Try using ActionBar.setCustomView(). That's the only way to change the appearance of that area of the screen. You can't stick a View into the area "above" the ActionBar, because that area is basically controlled by the system. On the other hand, you can provide your own layout for it.
If you explain in more detail what you're trying to do, respondents might have some better design ideas.

https://github.com/michaelye/EasyDialogDemo
see the demo above,it may help you
dialog.setLocation(new location[])//point in screen
you could set the location[] yourself.

Use the android:actionLayout in your menu.xml file.
<?xml version="1.0" encoding="utf-8"?><menu xmlns:android="http://schemas.android.com/apk/res/android">
<item android:id="#+id/menu_id"
android:title="#string/menu_string_to_show"
android:icon="#drawable/ic_menu_icon_name"
android:showAsAction="always"
android:actionLayout="#layout/action_button_foo" /></menu>
Then create your action_button_foo.xml layout:
<?xml version="1.0" encoding="utf-8"?><TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:text="#string/menu_string_to_show"
android:drawableLeft="#drawable/ic_menu_icon_name"
android:background="#drawable/bg_btn_action_bar"
android:clickable="true" />
To handle click do the following:
#Overridepublic boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.my_menu, menu);
final MenuItem item = menu.findItem(R.id.menu_id);
item.getActionView().setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
onOptionsItemSelected(item);
}
});
return super.onCreateOptionsMenu(menu);}
That's if :)

(Reference: http://www.vogella.com/articles/AndroidActionBar/article.html)Custom Views in the ActionBar
You can also add a custom View to the ActionBar. For this you use the setCustomView method for the ActionView class. You also have to enable the display of custom views via the setDisplayOptions() method by passing in the ActionBar.DISPLAY_SHOW_CUSTOM flag.
For example you can define a layout file which contains a EditText element.
<?xml version="1.0" encoding="utf-8"?>
<EditText xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/searchfield"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:inputType="textFilter" >
This layout can be assigned to the ActionBar via the following code. The example code allow attaches a listener to the custom view.
package com.vogella.android.actionbar.customviews;
import android.app.ActionBar;
import android.app.Activity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.TextView.OnEditorActionListener;
import android.widget.Toast;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ActionBar actionBar = getActionBar();
// add the custom view to the action bar
actionBar.setCustomView(R.layout.actionbar_view);
EditText search = (EditText) actionBar.getCustomView().findViewById(R.id.searchfield);
search.setOnEditorActionListener(new OnEditorActionListener() {
#Override
public boolean onEditorAction(TextView v, int actionId,
KeyEvent event) {
Toast.makeText(MainActivity.this, "Search triggered",
Toast.LENGTH_LONG).show();
return false;
}
});
actionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM
| ActionBar.DISPLAY_SHOW_HOME);
}
}

The explanations here are all too long:
Wrap your main layout file into a top level ViewGroup (e.g. wrap a CoordinatorLayout into a FrameLayout), then inject or declare the view in the new top level layout out. The view will appear above the action bar.