FloatingActionButton 被复制到 ListView 的每一行

Question

我想要做的是片段中只有一个 FAB，但我在 ListView 的每一行中都得到了 FAB。我也在使用自定义 ListAdapter。

此片段正在使用带有 ListView 的布局。

    import android.os.Bundle;
    import android.support.design.widget.BottomNavigationView;
    import android.support.design.widget.FloatingActionButton;
    import android.support.v4.app.Fragment;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.ListView;

    import com.google.gson.Gson;

    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.IOException;
    import java.util.ArrayList;
    import java.util.Arrays;
    import java.util.List;


    /**
     * A simple {@link Fragment} subclass.
     */
    public class Todos extends Fragment {


        private ListView myListView;

        public Todos() {
            // Required empty public constructor
        }

        FloatingActionButton.OnClickListener listener = new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                BottomNavigationView navigation = (BottomNavigationView) getActivity().findViewById(R.id.navigation);
                navigation.setSelectedItemId(R.id.navigation_new_task);
                getFragmentManager().beginTransaction().replace(R.id.main_layout, new NewTask()).addToBackStack(null).commit();
            }

        };

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            final View view = inflater.inflate(R.layout.fragment_todos, container, false);
            myListView = view.findViewById(R.id.listTodos);
            myListView.setClickable(true);
            final FloatingActionButton button = view.findViewById(R.id.addTaskButton);
            button.setOnClickListener(listener);

            printAllTasks();

            // Inflate the layout for this fragment
            return view;
        }

        private void printAllTasks() {
            final Gson gson = new Gson();

            final Task[] tasksArray = gson.fromJson(fetchAllData(), Task[].class);
            if (tasksArray != null) {
                final List<Task> tasks = new ArrayList<>(Arrays.asList(tasksArray));
                TaskListAdapter adapter = new TaskListAdapter(getContext(), R.layout.fragment_todos, tasks);
                myListView.setAdapter(adapter);
            }
        }

        private String fetchAllData() {
            String text = "";
            try {
                final FileInputStream fin = getActivity().getApplicationContext().openFileInput("TaskJson");
                int tmp;
                while ((tmp = fin.read()) != -1) {
                    text = text + Character.toString((char) tmp);
                }
                fin.close();
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return text;
        }
    }

我的自定义适配器：

    import android.content.Context;
    import android.support.annotation.NonNull;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.ArrayAdapter;
    import android.widget.TextView;

    import java.util.List;

    class TaskListAdapter extends ArrayAdapter<Task> {

        private Context mContext;
        private int mResource;


        public TaskListAdapter(Context context, int resource, List<Task> objects) {
            super(context, resource, objects);
            this.mContext = context;
            this.mResource = resource;
        }

        @NonNull
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            View v = convertView;

            if (v == null) {
                LayoutInflater vi;
                vi = LayoutInflater.from(mContext);
                v = vi.inflate(mResource, null);
            }

            final int id = getItem(position).getId();
            final String name = getItem(position).getName();
            final String description = getItem(position).getDescription();
            final int xp = getItem(position).getXp();
            final String color = getItem(position).getColor();

            TextView tvName = (TextView) v.findViewById(R.id.textName);
            TextView tvDescription = (TextView) v.findViewById(R.id.textDescription);
            TextView tvXP = (TextView) v.findViewById(R.id.textXps);

            tvName.setText(name);
            tvDescription.setText(description);
            tvXP.setText(Integer.toString(xp));

            return v;
        }
    }

   <?xml version="1.0" encoding="utf-8"?>
    <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ListView
            android:id="@+id/listTodos"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:layout_marginBottom="16dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="1.0"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="1.0" />

        <TextView
            android:id="@+id/textDescription"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="36dp"
            android:layout_marginTop="40dp"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/textName"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="16dp"
            android:layout_marginTop="16dp"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/textXps"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="24dp"
            android:layout_marginEnd="24dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <android.support.design.widget.FloatingActionButton
            android:id="@+id/addTaskButton"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginEnd="32dp"
            android:layout_marginBottom="32dp"
            android:clickable="true"
            android:focusable="true"
            android:src="@drawable/ic_baseline_add_24dp"
            app:backgroundTint="#ff0000"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent" />

    </android.support.constraint.Co

nstraintLayout>

我想要什么：

Answer 1

这段代码（FAB 小部件）

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/addTaskButton"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="32dp"
        android:layout_marginBottom="32dp"
        android:clickable="true"
        android:focusable="true"
        android:src="@drawable/ic_baseline_add_24dp"
        app:backgroundTint="#ff0000"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent" />

应该在片段的视图（fragment_todos）而不是列表项的视图中。

结合起来，您的 ListView 的列表项应该是一个单独的布局文件，而不是与片段相同的布局文件，这似乎是您在这里所做的：

    TaskListAdapter adapter = new TaskListAdapter(getContext(), R.layout.fragment_todos, tasks);
    myListView.setAdapter(adapter);

---

尝试查看本教程：https://www.journaldev.com/10416/android-listview-with-custom-adapter-example-tutorial

另一方面，我强烈建议学习如何使用 RecyclerView。

Answer 2

代码在我看来没问题，可能是 ListView 的渲染错误（已弃用），我建议您尝试改用 RecyclerView，它与 ListView 非常相似，可能您只需要修改你的适配器可以在 RecyclerView 上工作，但它是值得的，因为它们更通用。

这里有一个可能有用的指南链接https://developer.android.com/guide/topics/ui/layout/recyclerview