问题
I am adding dynamic buttons to a layout. Each button is added one at a time, and the layout must update itself if new buttons were added based on a user's action. So the layout could have 3 buttons, or 16, or whatever, depending on the user's action. And the buttons can be added at different times. So if the user opens the app and adds a button, then leaves and returns to the app and adds another button, the old one must remain.
I want my buttons to be added, one by one, into a layout like this:
I have looked around about how to do this, and it was recommended to me that I use a RecyclerView with a GridLayoutManager. I have added this to my code, but the problem is that when I add a button, and then if I add another button, the second one is added on top of the first. So if the user action says that 16 buttons should be made, I am just getting 16 buttons on top of each other and not in the layout that I want.
Here is my code:
My Main Fragment that Initiates the RecyclerView: I have another activity that initiates "createButton" method and passes a drawable and string. These drawables and strings are passed to this method one at a time based on the user's action, and create an image button one at a time
public class MyFragment extends Fragment {
private GridLayoutManager lLayout;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
// onCreateView
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.my_fragment, container, false);
// Create an empty list to initialize the adapter (or else get nullPointerException error)
List<ItemObject> myList = new ArrayList<ItemObject>();
lLayout = new GridLayoutManager(getActivity(), 4, GridLayoutManager.HORIZONTAL, false);
RecyclerView rView = (RecyclerView)view.findViewById(R.id.recycler_view);
rView.setHasFixedSize(true);
rView.setLayoutManager(lLayout);
RecyclerViewAdapter rcAdapter = new RecyclerViewAdapter(getActivity(),myList);
rView.setAdapter(rcAdapter);
return view;
}
private List<ItemObject> getAllItemList(String applicationName, Drawable app_drawable){
List<ItemObject> allItems = new ArrayList<ItemObject>();
allItems.add(new ItemObject(applicationName, app_drawable));
return allItems;
}
public void createButton (Drawable d, String appName){
List<ItemObject> rowListItem = getAllItemList(appName, d);
lLayout = new GridLayoutManager(getActivity(), 2, GridLayoutManager.HORIZONTAL, false);
RecyclerView rView = (RecyclerView)getView().findViewById(R.id.recycler_view);
rView.setHasFixedSize(true);
rView.setLayoutManager(lLayout);
RecyclerViewAdapter rcAdapter = new RecyclerViewAdapter(getActivity(), rowListItem);
rView.setAdapter(rcAdapter);
}
}
Here is RecyclerViewHolders:
public class RecyclerViewHolders extends RecyclerView.ViewHolder implements View.OnClickListener{
public TextView AppName;
public ImageButton AppButton;
public RecyclerViewHolders(View itemView) {
super(itemView);
itemView.setOnClickListener(this);
AppName = (TextView)itemView.findViewById(R.id.new_app_name);
AppButton = (ImageButton)itemView.findViewById(R.id.new_app_button);
}
@Override
public void onClick(View v) {
}
}
RecyclerViewAdapter
public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewHolders> {
private List<ItemObject> itemList;
private Context context;
public RecyclerViewAdapter(Context context, List<ItemObject> itemList) {
this.itemList = itemList;
this.context = context;
}
@Override
public RecyclerViewHolders onCreateViewHolder(ViewGroup parent, int viewType) {
View layoutView = LayoutInflater.from(parent.getContext()).inflate(R.layout.home_fragment, null);
RecyclerViewHolders rcv = new RecyclerViewHolders(layoutView);
return rcv;
}
@Override
public void onBindViewHolder(RecyclerViewHolders holder, int position) {
holder.AppName.setText(itemList.get(position).getName());
holder.AppButton.setImageDrawable(itemList.get(position).getPhoto());
}
@Override
public int getItemCount() {
return this.itemList.size();
}
}
ItemObject
public class ItemObject {
private String name;
private Drawable d;
public ItemObject(String name, Drawable d) {
this.name = name;
this.d = d;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Drawable getPhoto() {
return d;
}
public void setPhoto(Drawable d) {
this.d = d;
}
}
and my layout (my_fragment)
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_horizontal"
android:layout_marginTop="15dp"
android:id="@+id/my_fragment"
>
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scrollbars="horizontal" />
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/new_app_button"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/new_app_name"
android:gravity="center"
android:layout_below="@+id/new_app_button"
/>
</RelativeLayout>
</LinearLayout>
ANSWER:
HERE IS HOW I GOT MY LAYOUT TO BE DIFFERENT ON THE PHONE AND TABLET (2 rows on the phone, 3 rows on the tablet)
This code was added to my onCreateView method of MyFragment
// Get screen size so we can have different layouts for phone and tablet
int screenSize = getResources().getConfiguration().screenLayout &
Configuration.SCREENLAYOUT_SIZE_MASK;
String toastMsg;
switch(screenSize) {
case Configuration.SCREENLAYOUT_SIZE_LARGE:
toastMsg = "Large screen";
Log.d("tag_name", "Large screen");
break;
case Configuration.SCREENLAYOUT_SIZE_NORMAL:
toastMsg = "Normal screen";
Log.d("tag_name", "Normal screen");
break;
case Configuration.SCREENLAYOUT_SIZE_SMALL:
toastMsg = "Small screen";
Log.d("tag_name", "Small screen");
break;
default:
toastMsg = "Screen size is neither large, normal or small";
Log.d("tag_name", "Screen size is not large, normal, or small");
}
Toast.makeText(getActivity(), toastMsg, Toast.LENGTH_LONG).show();
// Create an empty list to initialize the adapter (or else get nullPointerException error)
List<ItemObject> myList = new ArrayList<ItemObject>();
if (screenSize == Configuration.SCREENLAYOUT_SIZE_LARGE
|| screenSize == Configuration.SCREENLAYOUT_SIZE_XLARGE) {
lLayout = new GridLayoutManager(getActivity(), 3, GridLayoutManager.HORIZONTAL, false);
}
else lLayout = new GridLayoutManager(getActivity(), 2, GridLayoutManager.HORIZONTAL, false);
回答1:
You can detect screen size with this answer.
If the screen size is Configuration.SCREENLAYOUT_SIZE_LARGE or Configuration.SCREENLAYOUT_SIZE_XLARGE then it maybe a tablet.
int spanCount = 2;
if (screenSize == Configuration.SCREENLAYOUT_SIZE_LARGE
or screenSize == Configuration.SCREENLAYOUT_SIZE_XLARGE) {
spanCount = 3;
}
来源：https://stackoverflow.com/questions/37150975/adding-dynamic-buttons-to-different-layouts-for-phone-and-tablet-using-recyclerv