Question

我已经完成this＆amp; this提出问题，但无法弄清楚为什么列表视图的第一项不可见。我检查了arraylist的大小，这是正确的。

如果有2个项目则只显示1个。
如果有1个项目则显示0。

listview文件：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ListView
        android:id="@+id/videoListView"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:divider="@null"
        android:dividerHeight="0dp" />

</RelativeLayout>

listview项目xml文件：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:paddingTop="10dp">

    <ImageView
        android:layout_width="150dp"
        android:layout_height="90dp"
        android:id="@+id/videoImageView"
        android:layout_marginLeft="10dp"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        />

    <TextView
        android:layout_width="match_parent"
        android:layout_height="35dp"
        android:id="@+id/titleTextView"
        android:layout_marginRight="10dp"
        android:layout_toRightOf="@+id/videoImageView"
        android:layout_marginLeft="10dp"
        android:textSize="12sp"
        android:textColor="#000000"
        android:ellipsize="end"
        android:maxLines="2"
        />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="20dp"
        android:id="@+id/timeTextView"
        android:layout_alignStart="@+id/titleTextView"
        android:layout_alignLeft="@+id/titleTextView"
        android:layout_below="@+id/titleTextView"/>

    <ImageView
        android:layout_width="25dp"
        android:layout_height="25dp"
        android:id="@+id/downloadImageView"
        android:layout_alignStart="@+id/timeTextView"
        android:layout_alignLeft="@+id/timeTextView"
        android:layout_below="@+id/timeTextView"
        android:layout_alignBottom="@+id/videoImageView"
        android:src="@drawable/ic_vector_download"
        android:layout_marginTop="5dp"/>

    <ProgressBar
        android:layout_width="25dp"
        android:layout_height="25dp"
        android:id="@+id/downloadProgressBarView"
        android:layout_alignStart="@+id/timeTextView"
        android:layout_alignLeft="@+id/timeTextView"
        android:layout_below="@+id/timeTextView"
        android:layout_alignBottom="@+id/videoImageView"
        android:layout_marginTop="5dp"
        android:visibility="gone"/>

    <ImageView
        android:layout_width="25dp"
        android:layout_height="25dp"
        android:id="@+id/shareImageView"
        android:layout_below="@+id/timeTextView"
        android:layout_alignBottom="@+id/videoImageView"
        android:layout_toRightOf="@+id/downloadImageView"
        android:layout_marginTop="5dp"
        android:layout_marginLeft="7dp"
        android:src="@drawable/ic_vector_share"/>
</RelativeLayout>

适配器类：

public class OfflineVideoAdapter extends ArrayAdapter<OfflineVideo> {

    Context context;
    OfflineVideoDBHelper db;
    List<OfflineVideo> list;

    public OfflineVideoAdapter(Context context, int resource, List<OfflineVideo> list) {
        super(context, resource, list);
        this.context = context;
        this.list = list;
    }

    @NonNull
    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        final OfflineVideoHolder holder;
        if (convertView == null) {
            holder = new OfflineVideoHolder();
            convertView = LayoutInflater.from(context).inflate(R.layout.video_list_item, parent, false);
            holder.video = (ImageView)convertView.findViewById(R.id.videoImageView);
            holder.title = (TextView)convertView.findViewById(R.id.titleTextView);
            holder.publishedAt = (TextView)convertView.findViewById(R.id.timeTextView);
            holder.delete = (ImageView)convertView.findViewById(R.id.downloadImageView);
            holder.share = (ImageView)convertView.findViewById(R.id.shareImageView);
            convertView.setTag(holder);
        } else {
            holder = (OfflineVideoHolder)convertView.getTag();
        }
        final OfflineVideo offlineVideo = getItem(position);
        Picasso.with(context).load(offlineVideo.imageURL).into(holder.video);
        holder.title.setText(offlineVideo.title);
        holder.publishedAt.setText(CommonUtils.calculateTime(offlineVideo.publishedAt));
        holder.delete.setImageResource(R.drawable.ic_vector_delete);
        return convertView;
    }
}

Answer 1

检查工具栏是否在listviews第一项

上没有重叠

Answer 2

将ListView属性layout_width和layout_height更改为Fill_Parent 它对我有用。

Answer 3

我遇到了同样的问题，因为我的ListView layout_width和layout_height是"match_constraint"，并且工具栏与第一项重叠。只需调整ListView的高度即可。它对我有用。

Android ListView不显示第一项

3 个答案: