java - 使用带有 GridLayoutManager 的 RecyclerView 将动态按钮添加到手机和平板电脑的不同布局

Question

我正在向布局添加动态按钮。每个按钮一次添加一个，如果根据用户的操作添加了新按钮，则布局必须自行更新。所以布局可以有 3 个按钮，或 16 个，或其他，这取决于用户的操作。按钮可以在不同的时间添加。因此，如果用户打开应用程序并添加一个按钮，然后离开并返回应用程序并添加另一个按钮，则必须保留旧按钮。

我希望将我的按钮一个接一个地添加到这样的布局中:

我四处查看如何执行此操作，并向我推荐我将 RecyclerView 与 GridLayoutManager 结合使用。我已将此添加到我的代码中，但问题是当我添加一个按钮时，如果我添加另一个按钮，第二个按钮将添加到第一个按钮之上。因此，如果用户操作说应该制作 16 个按钮，我只是将 16 个按钮放在彼此之上，而不是我想要的布局。

这是我的代码:

启动 RecyclerView 的主要 fragment :我有另一个启动“createButton”方法并传递可绘制对象和字符串的 Activity 。这些可绘制对象和字符串根据用户的操作一次一个地传递给此方法，并一次一个地创建一个图像按钮

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);

}


}

这是 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();
}
}

项目对象

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;
}
}

和我的布局 (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>

回答:

这是我如何让我的布局在手机和平​​板电脑上有所不同(手机上 2 行，平板电脑上 3 行)

此代码已添加到我的 MyFragment 的 onCreateView 方法中

 // 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);

Answer 1

您可以使用此 answer 检测屏幕尺寸.

如果屏幕尺寸为 Configuration.SCREENLAYOUT_SIZE_LARGE 或 Configuration.SCREENLAYOUT_SIZE_XLARGE 那么它可能是平板电脑。

  int spanCount = 2;
  if (screenSize == Configuration.SCREENLAYOUT_SIZE_LARGE 
        or screenSize == Configuration.SCREENLAYOUT_SIZE_XLARGE) {
    spanCount = 3;
  }