Develop Reference

Android implement navigation

I am trying to learn Android development and have stumbled across the following thing I cannot solve.
I have imported Bottom Bar Navigation via Gradle to my app and have managed to set it up according to instructions. Here is what my screen looks like now.
As you can see, I have three tabs at the bottom that I am trying to use for navigation. The problem however is, that even though I know how to detect which element has been clicked via following:
mBottomBar.setItemsFromMenu(R.menu.bottombar_menu, new OnMenuTabClickListener() {
#Override
public void onMenuTabSelected(#IdRes int menuItemId) {
if (menuItemId == R.id.bb_menu_favorites) {
// The user selected item number one.
}
}
#Override
public void onMenuTabReSelected(#IdRes int menuItemId) {
if (menuItemId == R.id.bb_menu_favorites) {
// The user reselected item number one, scroll your content to top.
}
}
});
I have no idea how to actually perform the navigation request - e.g. when user moves to different tab, I want to show my other screen instead of Hello World! that you can see at the moment.
I believe that for this I need to actually change my activity_main.xml file as currently it looks like this:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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.robert.testproject.MainActivity">
<include layout="#layout/page_import"/>
</RelativeLayout>
This is where I have ended. As far as my understanding goes, I somehow need to use Intent (correct me if I am wrong) for the navigation purposes, but I am not quite sure how to handle this.
Any help in this matter - switching views, would be more than appreciated.

Use a Fragment for each bottom tab (3 Fragments for 3 views). Have a container layout(maybe a FrameLayout) in the Activity. Each Fragment will have different layouts. Replace the fragments based on what the user has tapped on the bottom bar.

Android Placing Text (bar) at bottom of Application

I want to be able to display text (a bar if you will) at the bottom of my application dynamically to indicate if the the application is online or not (an endless issue for users currently). I don't need for this to have any action, but I do need it to be able to control it displaying or not based on them toggling between online and offline mode. So the split action bar is not what I am looking for.
Not enough reputation points to post an example. Doh. Here is the link:
Ugly example, look at bottom
Something simple is fine - I am good with XML based or dynamic (though I will also need to hide and show it dynamically).
Thanks!

Dynamic solution. Define your method that the activity will use to hide / display your bottom TextView (text bar?).
In your XML:
<TextView
android:id="#+id/text_bar"
...
...
android:visibility="gone"/>
In your activity:
public MyActivity extends Activity{
private TextView mTextBar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.your_activity_xml);
...
...
mTextBar = (TextView) findViewById(R.id.text_bar);
}
public void updateVisibility(boolean visible){
int visibility = (visible) ? View.VISIBLE: View.GONE;
mTextBar.setVisibility(visibility);
}
}
Initially, the TextView (your text bar) has it's visibiity set to gone. Dynamically, when you want to show it call the updateVisibility(true) method to show it, and updateVisibility(false) to hide it.
Since I'm not sure how you are handling the check for the network status (in queries, in the onCreate, etc). I don't know what you intended to do for the TextView. If you need advice on how to position the TextView on the bottom of the screen I can provide example code for that as well.

Change from one layout view to another and going back?

want to make an Android app that starts with a main layout and when you push a button (called stateButton) that is in this layout the layout changes to a main2 layout containing another button (called boton2), and when you push this one you get back to the first main.
I want to do this in the same activity without creating or starting another one.
Here I show you part of the code:
public class NuevoshActivity extends Activity
implements SensorEventListener, OnClickListener {
private Button stateButton;
private Button boton2;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
this.stateButton = (Button) this.findViewById(R.id.boton);
this.boton2 = (Button) this.findViewById(R.id.boton2);
stateButton.setOnClickListener(this);
boton2.setOnClickListener(this);
}
#Override
public void onClick(View v) {
if(v==stateButton) {
setContentView(R.layout.main2);
}
else if(v==boton2) {
setContentView(R.layout.main);
}
}
}
The mains only have some images, text views and the buttons.
But I've some troubles. Can't it just be as simple as that or what am I missing or what is wrong?

When you use findViewById, you are actually trying to find a view inside the layout you specified by the setContentView. So using setContentView again and again might bring problems when you are trying to check for buttons.
Instead of using a setContentView, I would add the 2 layouts for the screen as child's for a view-flipper which only shows one child at a time. And you can specify the index of which child to show. The benefit of using a view flipper is that you can easily specify a 'in' and 'out' animation for the view if you need an animation when you switch between views. This is a lot cleaner method then recalling setContentView again and again.

The FrameLayout handles this wonderfully... Use this with the <include... contstruct to load multiple other layouts, then you can switch back and forth between them by using setvisibility(View.VISIBLE); and setVisibility(View.INVISIBLE); on the individual layouts.
For example:
Main XML including two other layouts:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout android:id="#+id/frameLayout1" android:layout_width="fill_parent" android:layout_height="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android">
<include android:id="#+id/buildinvoice_step1_layout" layout="#layout/buildinvoice_step1" android:layout_width="fill_parent" android:layout_height="fill_parent"></include>
<include android:id="#+id/buildinvoice_step2_layout" android:layout_width="fill_parent" layout="#layout/buildinvoice_step2" android:layout_height="fill_parent"></include>
</FrameLayout>
Code to switch between layouts:
findViewById(R.id.buildinvoice_step1_layout).setVisibility(View.VISIBLE);
findViewById(R.id.buildinvoice_step2_layout).setVisibility(View.INVISIBLE);
You will also need to set the visibility of the individual layouts when the activity starts (or in XML) otherwise you will see them both - one on top of the other.

Your boton2 button will be NULL because the definition of the button is in main2.xml.
The only views you will be able to find are the views which are defined in main.xml.

Thanks!!! All the info was usefull to understand a lot of things and as C0deAttack commented I've got troubles with the button on the main2. What I've done is to set View.VISIBLE and View.GONE to the TextViews and Buttons that I wanted in each layout. Thank you very much.

sliding drawer appear in all activities

I am developing an application that contains many activities
and i created my own menu (i don't want to use the built in menu button) with the Sliding Drawer
as the sliding drawer is at the bottom of the screen and contains my menu buttons
what i need is to make that sliding drawer to appear in all my activities
i tried to create an activity and set it's content view to the xml file that includes the drawer and then extends that activity in all other activities but this solution doesn't work
so any suggestions ?

Extending is the right way. Just override setContentView in the right way.
Here's the working example, but instead of drawer, I use a created a custom tabbar:
Define a layout with your drawer like this:
this is act_layout.xml
<LinearLayout
...
android:orientation="vertical"
>
<YourDrawer
...
/>
<FrameLayout
android:id="#+id/act_content"
...
>
// Here will be all activity content placed
</FrameLayout>
</LinearLayout>
This will be your base layout to contain all other layouts in the act_content frame.
Next, create a base activity class, and do the following:
public abstract class DrawerActivity extends Activity {
protected LinearLayout fullLayout;
protected FrameLayout actContent;
#Override
public void setContentView(final int layoutResID) {
// Your base layout here
fullLayout= (LinearLayout) getLayoutInflater().inflate(R.layout.act_layout, null);
actContent= (FrameLayout) fullLayout.findViewById(R.id.act_content);
// Setting the content of layout your provided to the act_content frame
getLayoutInflater().inflate(layoutResID, actContent, true);
super.setContentView(fullLayout);
// here you can get your drawer buttons and define how they
// should behave and what must they do, so you won't be
// needing to repeat it in every activity class
}
}
What we do, is basically intercept all calls to setContentView(int resId), inflate our layout for drawer from xml, inflate our layout for activity (by reId provided in method call), combine them as we need, and set as the contentView of the activity.
EDIT:
After you've created the stuff above, just proceed to write an app as usual, create layouts (without any mention of a drawer) create activities, but instead of extending simple activity, extend DrawerActivity, like so:
public abstract class SomeActivity extends DrawerActivity {
protected void onCreate(Bundle bundle) {
setContentView(R.layout.some_layout);
}
}
What happens, is that setContentView(R.layout.some_layout) is intercepted. Your DrawerActivity loads the layout you provided from xml, loads a standart layout for your drawer, combines them and then sets it as contentView for the activity.

Finally after 3 years, here's the complete solution to this important question for whom may have not been completely guided by Mr. Orlov's answer.
His method for making a hierarchy view was completely OK but there was some small mistakes that may mislead beginner developers.
As Gabe also mentioned, you can get rid of abstract in declaration.
There's no need to wrap both child with a FrameLayout. The parent could be anything RelativeLayout, LinearLayout, etc. But the most important part is that you must declare the FrameLayout before the Slider.
So the 100% working soloution would be like this :
activity_drawer.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<FrameLayout
android:id="#+id/drawer_frame"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<YourDrawer
android:id="#+id/drawer_drawer"
android:layout_width="match_parent"
android:layout_height="fill_parent" >
</YourDrawer>
</RelativeLayout>
DrawerActivity.java
public class DrawerActivity extends Activity {
protected RelativeLayout fullLayout;
protected FrameLayout frameLayout;
#Override
public void setContentView(int layoutResID) {
fullLayout = (RelativeLayout) getLayoutInflater().inflate(R.layout.activity_drawer, null);
frameLayout = (FrameLayout) fullLayout.findViewById(R.id.drawer_frame);
getLayoutInflater().inflate(layoutResID, frameLayout, true);
super.setContentView(fullLayout);
//Your drawer content...
}
}
MainActivity.java
public class MainActivity extends DrawerActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}
Don't forget to declare DrawerActivity in manifest.
Hope it helped.

I know this is two years late but for those who would like an answer here it is. Mr Orlov had an appropriate response, just a few adjustments needed.
delete the abstract after public. (this is what causes an error)
wrap BOTH your sliding drawer and FrameLayout with another FrameLayout and set the width and height to match_parent. (This allows BOTH layouts to appear).
ALSO: If you want your sliding drawer to appear on top of your layout (duh!) then place the frameLayout that is after the slidingDrawer before the slidingDrawer.

2 layouts 1 activity android

I have a navigation bar in my app, the thing is that I want the navbar to be available in all activities. I suppose that I have to set contentView two times, but that doesn't work, of course.
I've been looking at and but I dont get it to work. I have a super class, can I set this second layout from my super class?

You should include the nav bar via <include> tag from the other layouts. Setting the content layout twice will not work, as Android is in the callbacks basically always using what the user has told last. So
setContentLayout(R.layout.nav);
setContentLayout(R.layout.main);
will result in only the main layout being used.
Have a look at this article which gives an example of using the include tag.

You can extend standard activities (Activity, ListActivity, etc.. if you use any others) and use them as a base for including a nav_bar.
For example:
Define a layout with nabar like this
<LinearLayout
...
android:orientation="vertical"
>
<YourNavBarComponent
...
/>
<FrameLayout
android:id="#+id/nav_content"
...
>
// Leave this empty for activity content
</FrameLayout>
</LinearLayout>
This will be your base layout to contain all other layouts in the nav_content frame.
Next, in create a base activity class, and do the following:
public abstract class NavActivity extends Activity {
protected LinearLayout fullLayout;
protected FrameLayout navContent;
#Override
public void setContentView(final int layoutResID) {
fullLayout= (LinearLayout) getLayoutInflater().inflate(R.layout.nav_layout, null); // Your base layout here
navContent= (FrameLayout) fullLayout.findViewById(R.id.nav_content);
getLayoutInflater().inflate(layoutResID, navContent, true); // Setting the content of layout your provided in the nav_content frame
setContentView(fullLayout);
// here you can get your navigation buttons and define how they should behave and what must they do, so you won't be needing to repeat it in every activity class
}
}
And now, when you create a new activity, where you need a nav bar, just extend NavActivity instead. And your nav bar will be placed where you need it, without repeating it in every layout over and over again, and polluting the layouts (not to mention repeating a code to control navigation in every activity class).

Try merging layouts, as described on Android Developers Blog.