Question

如果一个孩子为空（在expandable listview填充并使用external sqlite database的{{1}}中，我试图将view（在list_child中）设置为不可见。 />我试图这样做：
1.在simplecursortreeadapater内初始化视图，并在viewbinder class中设置条件。.但是我得到了view.setvisibility的空指针（当应用崩溃时）..我在做什么错？谢谢

case.child2

list_child.xml

 public class MyViewBinder implements SimpleCursorTreeAdapter.ViewBinder {
    View view1=(View)findViewById(R.id.view1);
            @Override
            public boolean setViewValue(View view, final Cursor cursor, int columnIndex) {
                int viewID = view.getId();
                switch (viewID) {
                    case R.id.group1:
                        TextView groupName = (TextView) view;
                        String groupname;
                        groupname = cursor.getString(cursor.getColumnIndex(Database.DATABASE_GROUP_1));
                        groupName.setText(Html.fromHtml(groupname));

                        break;
                case R.id.child1:
                    TextView friendName = (TextView) view;
                    String friend_name;
                    friend_name = cursor.getString(cursor.getColumnIndex(Database.DATABASE_CHILD_1));
                    friendName.setText(Html.fromHtml(friend_name));
                    break;

                case R.id.child2:
                    final ImageView url = (ImageView) view;
                    final String urls;
                    urls = cursor.getString(cursor.getColumnIndex(Database.DATABASE_CHILD_2));
                    if (urls != null) {
                        Glide.with(AnatomyNostrils.this).load(urls).apply(new RequestOptions().dontTransform().format(DecodeFormat.PREFER_ARGB_8888)).into(url);
                        view.findViewById(R.id.child2).setVisibility(View.VISIBLE);
view1.setVisibility(View.VISIBLE);

                    } else {
                        view.findViewById(R.id.child2).setVisibility(View.GONE);
view1.setVisibility(View.GONE);
                    }
                    url.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View view) {
                            AlertDialog.Builder mBuilder = new AlertDialog.Builder(AnatomyNostrils.this);
                            View mView = getLayoutInflater().inflate(R.layout.dialog_custom_layout, null);
                            PhotoView photoView = mView.findViewById(R.id.imageView);
                            photoView.setLayoutParams(new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
                            photoView.setImageDrawable(((ImageView) view).getDrawable());
                            Glide.with(AnatomyNostrils.this).load(urls).apply(new RequestOptions().dontTransform().format(DecodeFormat.PREFER_ARGB_8888)).into(photoView);
                            mBuilder.setView(mView);
                            AlertDialog mDialog = mBuilder.create();
                            mDialog.show();
                        }
                    });
                    break;

来自仿真器的图像：https://i.imgur.com/cj9dWSX.png

Answer 1

如果执行了export class AppComponent { addClass(id: any) { this.id = id; } ...中的代码，则case R.id.child2:是要显示/隐藏的视图，因此请替换：

view

具有：

view.findViewById(R.id.child2).setVisibility(...);

无法将“视图”设置为不可见

1 个答案: