Question

我正在尝试从列表中检索所选项目以添加到用户列表中。

用户将选择将在不同活动中添加到用户的项目，然后返回主活动，并将新添加的项目添加到列表中。

当用户点击活动中显示的浮动按钮时，用户从列表中选择多个或单个项目时，应该完成添加功能。

活动

    public class ProjectSelectionActivity extends AppCompatActivity {
    private ArrayList<Project> Projects;
    private Player Player;
    private ProjectSelectionAdapter Adapter;
    private ListView ProjectSelectionLV;
    private FloatingActionButton AddProject;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_project_selection);


        AddProject = (FloatingActionButton) findViewById(R.id.ProjectSelectionFloatingActionButton);

        Player = (Player)getIntent().getSerializableExtra("Player");
        Projects = (ArrayList<Project>) getIntent().getSerializableExtra("Projects");
        Adapter = new ProjectSelectionAdapter(getApplicationContext(), Projects);

        ProjectSelectionLV = (ListView)findViewById(R.id.ProjectSelectionListView);
        ProjectSelectionLV.setAdapter(Adapter);

        AddProject.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

            }
        });
    }
 }

适配器：

    public class ProjectSelectionAdapter extends BaseAdapter {

    private Context context;
    private ArrayList<Project> projects;
    private LayoutInflater inflator;
    private View view;

    public ProjectSelectionAdapter(Context context, ArrayList<Project> projects) {
        this.context = context;
        this.projects = projects;
    }

    @Override
    public int getCount() {
        return projects.size();
    }

    @Override
    public Object getItem(int position) {
        return projects.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        inflator = (LayoutInflater)context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
        if(convertView == null){
            view = new View(context);
            view = inflator.inflate(R.layout.project_selection_view, null);

            TextView Title = (TextView)view.findViewById(R.id.ProjectSelectionTitleTextView);
            TextView Value = (TextView)view.findViewById(R.id.ProjectSelectionValueTextView);
            TextView Revenue = (TextView)view.findViewById(R.id.ProjectSelectionRevenueTextView);
            ImageView Image = (ImageView)view.findViewById(R.id.ProjectSelectionImage);

            Title.setText(projects.get(position).getTitle());
            Value.setText("التكلفة: " + Integer.toString(projects.get(position).getValue()));
            Revenue.setText("الربح: " + Integer.toString(projects.get(position).getRevenue()));
            Image.setImageResource(projects.get(position).getImage());
        }
        return view;
    }
}

项目视图

    <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="5dp"
    android:paddingBottom="5dp"
    android:paddingTop="5dp"
    android:paddingRight="5dp">

    <TextView
        android:id="@+id/ProjectSelectionTitleTextView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Title"
        android:layout_alignParentTop="true"
        android:layout_toLeftOf="@+id/ProjectSelectionImage"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <ImageView
        android:id="@+id/ProjectSelectionImage"
        android:layout_width="100sp"
        android:layout_height="100sp"
        app:srcCompat="@drawable/farm_fruit"
        android:layout_alignParentTop="true"
        android:layout_toLeftOf="@+id/ProjectSelectionCheckbox"
        android:layout_toStartOf="@+id/ProjectSelectionCheckbox" />

    <TextView
        android:id="@+id/ProjectSelectionValueTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Value"
        android:layout_marginBottom="24dp"
        android:layout_above="@+id/ProjectSelectionRevenueTextView"
        android:layout_toLeftOf="@+id/ProjectSelectionImage"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <TextView
        android:id="@+id/ProjectSelectionRevenueTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Revenue"
        android:layout_alignBottom="@+id/ProjectSelectionImage"
        android:layout_toLeftOf="@+id/ProjectSelectionImage"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <CheckBox
        android:id="@+id/ProjectSelectionCheckbox"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/ProjectSelectionValueTextView"
        android:layout_alignBottom="@+id/ProjectSelectionValueTextView"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true" />

</RelativeLayout>

Answer 1

制作另一个Arraylist，它将存储您活动中的所有选定项目。
```
private ArrayList<Project> selectedProjects;
```

2.您可以在Listview上添加onItemClickListener（），如下所示 -

ProjectSelectionLV.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
               //inside this check if your checkbox corresponding to this item is selected or not. You can do this by taking checkbox from **parent** which you are getting in this method and checking if this checkbox is selected or not. 
              //If the checkbox is selected, then add the project of this position to your selectedProjects ArrayList -
              //selectedProjects.add(Projects.get(position));
              //Make sure to check that selectedProjects does not contain this already to avoid duplicates
            }
        });

当用户单击浮动按钮时，在其onClick（）方法中，您可以使用selectedProjects传递intent extras ArrayList。请参阅此link以了解如何在活动之间传递对象。
最后，在您的其他活动中，使用selectedProjects Arraylist添加新项目。从notifyDataSetChanged()添加新项目后，请致电selectedProjects。

编辑 - 要获取第2步中的复选框，您可以执行 -

RelativeLayout rl = (RelativeLayout) parent.getAdapter().getItem(position);
CheckBox cb = (CheckBox) rl.getChildAt(4);

Android - 检索CheckBox中的选定项目

1 个答案: