Consider an Activity MainActivity with a fragment MainFragment. The fragment has some complex layout hierarchy and a view group Frame which comes from a library com.framer:frame_me:1.1.
If I have 2 flavours foo and bar, and I want this Frame to be there only in bar flavour and not in foo, the XML element java code and dependency. How should I do this?
I can compile the dependency using
barCompile 'com.framer:frame_me:1.1'
But what about the fragment and its XML. I don't want to write 2 variations the fragment in both flavours because I don't want to maintain the same code in 2 places.
One possible idea (probably a bad one) in my mind is that this:
Move the XML element in a separate file in bar source set. Add ViewStub element in the foo source set with the same name. Now include this XML file using include in the fragment XML
Add an interface to handle Frame view in main source set. Add an empty implementation in foo source set and one in bar source set. This way all logic can remain in bar while all common logic remains in main source set.
This all sounds an awfully lot of work just to write flavour specific code and xml.
How about replacing the Frame tag in your XML with a FrameLayout container?
Then in the bar flavor's source code you can instantiate the Frame and say container.addView(frame). While the foo flavor will have no reference to the Frame class and will ignore the container.
This is similar to your first approach, but without having to maintain separate resource sets. And it seems reasonable, that you will have some flavor-specific java code anyway.
You just need abstraction. Since resources are identified using an integer index into the R class, you can use int variables as placeholders for the layout files, and given the fact a layout element ID is searched within the active layout, you can recycle the common elements. First, create a common fragment class, with all the common elements:
public abstract class BaseFlavorFragment extends Fragment {
/*Define an interface for whatever code the fragment may need from the outside and a member for keeping reference of that. You can also use the host activity, this is just for flexibility*/
public interface whateverThisDoes{
void do();
}
/*All the common fragment members go here, as protected so you can reach them from every subclass*/
protected TextView title;
protected Button mainButton;
protected whateverThisDoes listener;
public void setWhateverThisDoes(whateverThisDoes listener){
this.listener = listener;
}
/*Finally, create a int variable that will hold the reference to the layout file you need to use. you will set this in every flavor using the setContainer method.*/
protected int layout = 0;
/*this will allow you to select which XML to use
layout = R.layout.flavorlayout*/
public abstract setContainer();
/*Use this method to inflate any flavor members, like the Frame you mentioned*/
public abstract void inflateComponents();
/*Use this to set listeners, data, or anything the flavor controls do*/
public abstract void setBehaviors();
/*Set here anything the common controls do*/
protected void setCommonBehaviors(){
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//whatever
}
});
setBehaviors();
}
#Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContainer();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
View view = inflater.inflate(layout, container, false);
/*Inflate common components*/
title = (TextView) root.findViewById(R.id.title);
button = (Button) root.findViewById(R.id.button);
/*inflate flavor components, if there's any*/
inflateComponents();
/*assign data, listeners, whatever the flavor controls do*/
setBehaviors();
return view;
}
}
Now, you can just create an implementation for Foo and Bar. if the only difference is the layout file, put everything into the base class, and set the layout file using setContainer(). If you have more differences you just need to deal with them into each abstract method. The base class can live into the the common code, the implementations, into each flavor. If you don't need to set any behavioral code from the outside, you can drop the interface.
what's about build.gradle sourceSets option ?
You could put Fragment and XML in bar folders and then set:
android {
productFlavors {
...
}
sourceSets {
bar.java.srcDirs = ['src/bar/java']
bar.res.srcDirs = ['src/bar/res']
}
}
Related
I'm working on a Material design app. One feature I want to implement is some kind of a poll. When a user clicks an element of a list, the persistent bottom sheet dialog, which looks like this should show up:
Then, when user clicks any button, this dialog should go away and the modal bottom sheet dialog should show up, providing a user with more information about the list item which was clicked at the beginning. It looks like this:
I can't find any clear explanations about BottomSheetDialog and BottomSheetDialogFragment, and how to use them correctly, even after reading some information about AppCompat dialogs. So, my questions are:
In what way are they different and which one should I use for each
case?
How to get data in the activity about which button was pressed in the dialog?
Any links to the code of implementations or tutorials about using them?
Finally, I've found the solution and it works. Tell me if I'm doing something wrong. It basically works like DialogFragment from this guide, but I've done it a bit different.
1) Their difference is the same as it of DialogFragment and Dialog, and they both are modal. If you need persistent dialog, use BottomSheetBehaviour instead (I found out that both dialogs had to be modal in my app).
2) I have to answer the third question with some code first, and then it will be easy to answer the second one.
3) Create a new public class, which extends BottomSheetDialogFragment, I called it FragmentRandomEventPoll. There are two two things which have to be implemented here.
Override method onCreateView. It is nearly the same as onCreate method in Activities, except for that it returns the View it should inflate:
// We will need it later
private static String headerItem;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_random_event_poll, container, false);
header = (TextView) v.findViewById(R.id.uRnd_fragment_bottom_sheet_poll_header);
skip = (Button) v.findViewById(R.id.uRnd_fragment_bottom_sheet_button_skip);
header.setText(...);
// I implemented View.OnClickListener interface in my class
skip.setOnClickListener(this);
return v;
}
Static method which you can pass necessary data to and get new instance of this class (Probably I could have just used a regular constructor, I'll have to experiment with it a bit more). URandomEventListItem is the data model class.
public static FragmentRandomEventPoll newInstance(URandomEventListItem item) {
FragmentRandomEventPoll fragment = new FragmentRandomEventPoll();
headerItem = item.getHeader();
return fragment;
}
2) To get input events in activity or any other place, define an interface with necessary methods and create setter method for it's instance:
private PollButtonClickListener listener;
public void setListener(PollButtonClickListener listener) {
this.listener = listener;
}
public interface PollButtonClickListener {
void onAnyButtonClick(Object data)
}
And in the place you want to get your data ("dialog_event_poll" tag was specified in the layout):
FragmentRandomEventPoll poll = FragmentRandomEventPoll.newInstance(events.get(id));
poll.setListener(new FragmentRandomEventPoll.PollButtonClickListener() {
#Override
public void onAnyButtonClick(Object data) {
// Do what you want with your data
}
});
poll.show(getSupportFragmentManager(), "dialog_event_poll");
}
If there is anything unclear, my project files could be found on Github.
About handling events from DialogFragment/BottomSheetDialogFragment.
For applications with many activities, this method is great:
context as MyDialogFragmentListener
But I have a problem with an application with single activity and multiple fragments. Since there can be a lot of fragments, it seems like a very bad option to transfer all events to the necessary fragments through the main activity. Therefore, I decided to do this:
private inline fun <reified T> findListeners(): ArrayList<T> {
val listeners = ArrayList<T>()
context?.let {
if (it is T) listeners.add(it)
if (it is AppCompatActivity) {
it.supportFragmentManager.fragments.forEach { fragment ->
if (fragment is T) listeners.add(fragment)
fragment.childFragmentManager.fragments.forEach { childFragment ->
if (childFragment is T) listeners.add(childFragment)
}
}
}
}
return listeners
}
Code in DialogFragment:
private val listeners by lazy { findListeners<MyDialogFragmentListener>() }
Of course, fragments can contain as many other fragments as you like and probably need to be checked through recursion, but in my case this is superfluous.
I would like to improve the way i created the following UI. Currently i am creating each tablerow programmatically according to each object's type attribute.
class objectDTO {
private type; //enum
public boolean isMultiple(){...}
public boolean isSingle(){...}
}
I am trying to find a more dynamic solution like having a class for each type that might not requires programmatically adding layouts and components as i do in the fragment class,
if(objectDTO.isMultiple()) {
//Create TableRow + Multiple radiobuttons
}
else if(objectDTO.isSingle() {
//Create TableRow + Add One Checkbox
{
else {
//Create default invalid object Interface or skip
}
Havind a listadapter and applying the different ui there will just move the design problem to other class.
Early thanks for your contribution
Well, the simple solution for you would be to have a class hierarchy- a base objectDTO class and a child for each type. When you load the object list, have a factory method create the proper type of object. Each type would override a createView method which would create the view for that type. Then your table creation function becomes:
for(objectDTO object : allObjects){
View view = object.createView();
tableView.addView(view, lp);
}
But if you're creating a view for an object type, there's always going to need to be someone that dynamically creates view objects (createView in this case), and there's always going to need to be some function that knows what class to make an object (the factory in this case). Its just a matter of where you want that complexity to be.
DogActivity is using a custom View. The custom view handles some logic and so has fields. When a particular field reaches a certain value, I want to start a fragment whose parent is DogActivity. How would I do that?
Is it advisable to put a callback inside a custom view so that it calls its parent activity? Or is there a simpler way?
When programming you should always look for consistency, i.e. look around you and see how similar stuff to what you want to do is done. The Android SDK makes heavy use of callback listeners, so they are the way to go here.
In fact we don't even need to know what kind of View your CustomView really is, we can build a general purpose solution. Don't forget to adapt/optimize according to your specific surroundings however. And think about abstraction and generalisation once you get to a point where all your Views are spammed with listeners!
You will need 3 things:
A listener interface
public interface OnCountReachedListener {
public void onCountReached();
}
A place to accept the listener and a place to alert the listener in your CustomView
public class CustomView extends View {
private int theCount;
private OnCountReachedListener mListener;
public void setOnCountReachedListener(OnCountReachedListener listener) {
mListener = listener;
}
private void doSomething() {
while (theCount < 100) {
theCount++;
}
// The count is where we want it, alert the listener!
if (mListener != null) {
mListener.onCountReached();
}
}
An implementation of the interface in your Activity
public class DogActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
View myView = new CustomView();
myView.setOnCountReachedListener(new OnCountReachedListener() {
#Override
public void onCountReached() {
Log.w("tag", "COUNT REACHED!");
// START YOUR FRAGMENT TRANSACTION HERE
}
});
}
}
For further information look at the source code of the View class and all the On**XY**Listener interfaces in the Android SDK. They should give you plenty to think about
What is the type of the field? Is it an EditText? SeekBar? Depending on the View, you'll be able to specify different listeners/callbacks to determine when they have changed and if they've reached a certain threshold. I would attach these listeners within onCreate of DogActivity. When the threshold is reached, use a FragmentTransaction to add your Fragment as the child of a container View in DogActivity.
I'm new to android, so maybe I'm doing something horribly wrong. I want to have a particular Activity that shows details about an instance of a "Creature" class for a game. Name, damage taken, that sort of thing.
I'm having a problem getting the creature data to be properly shown in the GUI objects. Both at initial creation (where it should copy the creature's name into the name field) and when a damage mark is added (where it doesn't update to show the proper image).
Here's my mini-example of what I have:
public class CreatureDetailActivity2 extends Activity
{
Creature creature;
public void addMark(View v)
{
// connected to the button via android:onClick="addMark" in the XML
creature.getTrack().addDamage(DamageType.Normal, 1);
refreshDisplay();
new AlertDialog.Builder(this).setTitle(creature.getName())
.setMessage(creature.getTrack().toString()).show();
}
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_creature_detail);
creature = new Creature("Example");
refreshDisplay();
}
public void refreshDisplay()
{
final View creatureDetailView = this.getLayoutInflater().inflate(
R.layout.activity_creature_detail, null);
final EditText nameField = (EditText) (creatureDetailView
.findViewById(R.id.textbox_creature_name));
nameField.setText(creature.getName());
final ImageView damageBox0 = (ImageView) (creatureDetailView.findViewById(R.id.damageBox0));
damageBox0.setImageResource(R.drawable.__n);
// in the full program this does the same for 0 through 9, but this is a sample
// also, in the full program, this is a dynamic lookup for the correct pic
// but again, this is just a sample version.
}
}
Now the problem is that the app will load up and start, but then none of the widgets will update properly. You can click the button, and it'll show the AlertDialog, and the text of the AlertDialog will change, but the textfield in the activity won't be changed, and the ImageView doesn't change at any point from what it starts as to the one it's supposed to change to.
So I'm very stumped. I can post more about the project's setup if I'm leaving out something important, but I'm not even sure what the problem going on is so I'm not sure what else to include in my question.
final View creatureDetailView = this.getLayoutInflater().inflate(
R.layout.activity_creature_detail, null);
Inflates your Activity's layout into basically nothing, just returning the View it inflated. setContentView is what actually inflates your layout into the Activity's View hierarchy.
Once you inflate your layout you don't need to do it again. Just use findViewById without the reference to a dangling unattached View.
Change your refreshDisplay method to this:
public void refreshDisplay()
{
final EditText nameField = (EditText) findViewById(R.id.textbox_creature_name);
nameField.setText(creature.getName());
final ImageView damageBox0 = (ImageView) findViewById(R.id.damageBox0);
damageBox0.setImageResource(R.drawable.__n);
// in the full program this does the same for 0 through 9, but this is a sample
// also, in the full program, this is a dynamic lookup for the correct pic
// but again, this is just a sample version.
}
Nothing changes because You do it completely wrong.
If You wish to update any view element of current activity You do it like this
View v = findViewById(R.id.element);
v.setText("text");
this is just simple example.
You would need to cast a returned element to correct type like to be able to access all available methods.
What You do wrong is trying to inflate a layout again.
There are quite a few questions about this subject, but could not find any with the specific problem I have...
In my layout.xml, I use the android:onClick tag for a Button to call the right onClickListener. I get the error :
java.lang.IllegalStateException: Could not find a method handle_cancel(View) in the activity class com.matthieu.HelloWorldApplication for onClick handler on view class android.widget.Button with id 'button_cancel'
I have that method implemented in the Activity, but it is looking for it in the class that extends Application... I don't understand why. The View and all that is setup only in the Activity.
If anyone needs, here is the declaration of that method (in my activity, NOT in HelloWorldApplication):
public void handle_cancel(View v) {
// do something useful here
}
Edit (from adamp request)... and probably answering my own question :
Here is part of the code where that layout is used...
public class AddVocabularyActivity extends Activity
{
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.top); // that layout contains an empty LinearLayout id/main_content
}
private some_other_function() {
LinearLayout main_content = (LinearLayout) findViewById(R.id.main_content);
main_content.removeAllViews();
View.inflate(getApplicationContext(), R.layout.hello, main_content); // layout.hello is the one containing the button
}
// some other stuff
}
While copy/paste this code, I am guessing the problem is that I used getApplicationContext to inflate the View with that Button...
As mentioned in my edit, changing the getApplicationContext() with the Activity context fixes it...
The convention works like this:
In the layout xml file, you give this attribute:
android:onClick:"methodname"
Then, inside a class, you define a method like this:
public void methodname(View v){
//your method code
}
Any other way of doing this is not documented. If you need parameters, just call another method inside that method.