Question

我已经使用BaseAdapter创建了一个自定义ListView。当我开始活动时，我看到一个没有条目的空ListView。

这是Adapter班级：

public class SpeiseplanListAdapter extends BaseAdapter {

private ArrayList<SpeiseplanEntry> data;
private Context context;


public SpeiseplanListAdapter(ArrayList<SpeiseplanEntry> data, Context context) {
    this.data = data;
    this.context = context;
}

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

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

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

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View entry = inflater.inflate(R.layout.layout_list_entry, parent, false);

    TextView day = (TextView) entry.findViewById(R.id.text_day);
    TextView date = (TextView) entry.findViewById(R.id.text_date);
    TextView firstDish = (TextView) entry.findViewById(R.id.text_first_dish);
    TextView secondDish = (TextView) entry.findViewById(R.id.text_second_dish);

    SpeiseplanEntry current = data.get(position);

    day.setText(current.getDay());
    date.setText(current.getDate());
    firstDish.setText(current.getFirstDish());
    secondDish.setText(current.getSecondDish());

    return entry;
}
}

OnCreate()方法：

protected void onCreate(Bundle savedInstanceState) {

    ...

    ListView listView = (ListView) findViewById(R.id.list_speiseplan);
    SpeiseplanListAdapter adapter = new SpeiseplanListAdapter(entries, getApplicationContext());
    listView.setAdapter(adapter);

    ...

}

单行布局：

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
                                         xmlns:app="http://schemas.android.com/apk/res-auto"
                                         xmlns:tools="http://schemas.android.com/tools"
                                         android:orientation="vertical"
                                         android:layout_width="match_parent"
                                         android:layout_height="120dp">

<TextView
        android:text="MO"
        android:layout_width="wrap_content"
        android:layout_height="35dp" android:id="@+id/text_day" android:fontFamily="monospace"
        android:typeface="monospace" android:textSize="30sp"
        android:textColor="@color/colorPrimary"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_marginTop="24dp" android:layout_marginLeft="28dp"
        app:layout_constraintLeft_toLeftOf="parent" android:layout_marginStart="28dp"/>
<TextView
        android:layout_width="250dp"
        android:layout_height="38dp"
        android:id="@+id/text_first_dish"
        app:layout_constraintTop_toTopOf="parent" android:layout_marginTop="16dp"
        app:layout_constraintLeft_toRightOf="@+id/text_day" android:layout_marginLeft="40dp"
        android:textSize="16sp" android:textAlignment="textStart"
        android:text="firstDish"
        android:gravity="center_vertical"
        android:layout_marginStart="40dp"/>
<TextView
        android:layout_width="250dp"
        android:layout_height="38dp"
        android:id="@+id/text_second_dish"
        app:layout_constraintBottom_toBottomOf="parent" android:layout_marginBottom="16dp"
        app:layout_constraintLeft_toRightOf="@+id/text_day" android:layout_marginLeft="40dp"
        android:textSize="16sp" android:text="secondDish"
        android:gravity="center_vertical"
        android:layout_marginStart="40dp"/>
<TextView
        android:text="21.09."
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" android:id="@+id/text_date"
        android:layout_marginLeft="16dp" app:layout_constraintLeft_toLeftOf="parent" android:textSize="18sp"
        android:fontFamily="monospace" android:typeface="monospace" android:textColor="@color/colorAccent"
        app:layout_constraintBottom_toBottomOf="parent" android:layout_marginBottom="32dp"
        android:layout_marginStart="16dp"/>

Activity的布局：

<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="de.gymoth.goapp.SpeiseplanActivity" tools:layout_editor_absoluteY="81dp"
    tools:layout_editor_absoluteX="0dp">
<ListView
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:id="@+id/list_speiseplan"
        tools:layout_constraintTop_creator="1"
        tools:layout_constraintRight_creator="1"
        tools:layout_constraintBottom_creator="1"
        android:layout_marginStart="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        android:layout_marginEnd="0dp"
        app:layout_constraintRight_toRightOf="parent"
        android:layout_marginTop="8dp"
        tools:layout_constraintLeft_creator="1"
        android:layout_marginBottom="0dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_marginLeft="0dp"
        android:layout_marginRight="0dp" app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintVertical_bias="0.0" android:divider="@color/divider" android:dividerHeight="1dp"/>

我用于单行的ConstraintLayout是否有问题？或Adapter问题是什么？ 感谢任何帮助。

Answer 1

像这样使用

protected void onCreate(Bundle savedInstanceState) {
...

ListView listView = (ListView) findViewById(R.id.list_speiseplan);
SpeiseplanListAdapter adapter = new SpeiseplanListAdapter(entries, YourActivityName.this);
listView.setAdapter(adapter);

...
}

Answer 2

首先在充气时加上条件......

if(convertView==null){
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View entry = inflater.inflate(R.layout.layout_list_entry, parent, false);
}

然后在适配器中使用支架..

自定义ListView不显示条目

2 个答案: