安卓自定义适配器挂起，直到我向下滚动

Question

我正在尝试用Android填充列表视图，我对此很陌生...还没有在这里看到问题的确切解决方案。 问题似乎出在我的自定义适配器中的 getView(...( 方法中。 当我运行该应用程序时，它立即崩溃。 当我调试时，列表会得到很好的填充，直到它到达视图的底部 - 然后它挂起，直到我物理向下滚动，并再次填充直到它到达底部......重复该过程，直到完全填充。 尽管此问题似乎已在此处解决，但在这种情况下，没有任何解决方案有效。 任何安卓大师都有什么建议吗？

下面是列表视图 xml：

<?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"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.heytow.challenge.heycontacts.ContactsActivity">
<ListView
android:layout_width="368dp"
android:layout_height="495dp"
android:id="@+id/customListView"
tools:layout_editor_absoluteY="8dp"
tools:layout_editor_absoluteX="8dp">
</ListView>

和项目布局：

<?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="match_parent"
android:orientation="vertical"
android:paddingTop="10dp"
android:paddingBottom="10dp">
<ImageView
android:id="@+id/contact_image"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_marginRight="10dp"
android:contentDescription="Property Image" />
<LinearLayout
android:id="@+id/contact_info"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_toRightOf="@+id/image"
android:orientation="vertical">
<TextView
android:id="@+id/contact_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="10dp"
android:text="Street Address"
android:textSize="18sp"/>
<TextView
android:id="@+id/contact_company"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="10dp"
android:text="Description"
android:textSize="15sp"/>
</LinearLayout>
</RelativeLayout>

我的自定义适配器：

public class ContactAdapter extends ArrayAdapter<Contact> {
private final String TAG = ContactAdapter.class.getSimpleName();
private Context mContext;
private List<Contact> mContactList;

//constructor, call on creation
public ContactAdapter(Context context, int resource, ArrayList<Contact> objects) {
super(context, resource, objects);
this.mContext = context;
this.mContactList = objects;
}
@Override
public int getCount() {
return mContactList.size();
}

//called when rendering the list
public View getView(int position, View convertView, ViewGroup parent) {
//get the property we are displaying
Contact contact = mContactList.get(position);
//get the inflater and inflate the XML layout for each item
LayoutInflater inflater;
View view = convertView;
if(view == null) {
ViewHolder holder = new ViewHolder();
if (contact.isFavorite() == true) {
inflater = ((Activity)mContext).getLayoutInflater();
view = inflater.inflate(R.layout.favorite_contact_layout, null);
} else {
inflater = ((Activity)mContext).getLayoutInflater();
view = inflater.inflate(R.layout.contact_layout, null);
}
}
TextView name = (TextView) view.findViewById(R.id.contact_name);
TextView company = (TextView) view.findViewById(R.id.contact_company);
ImageView image = (ImageView) view.findViewById(R.id.contact_image);
//set address and description
if(contact.getName() != null) {
name.setText(contact.getName());
}
if(contact.getCompanyName() != null) {
company.setText(contact.getCompanyName());
}

//get the image associated with this contact
ImageParser parser = new ImageParser();
AsyncTask<String, Void, Bitmap> urlImage = parser.execute(contact.getSmallImageURL());
try {
image.setImageBitmap(urlImage.get());
} catch (InterruptedException e) {
Log.e(TAG, "Error accessing image URL: " + e.getMessage());
} catch (ExecutionException e) {
Log.e(TAG, "Error accessing image URL: " + e.getMessage());
}
return view;
}
}

还有我的MainActivity类中的调用，onCreate。

ArrayAdapter<Contact> adapter = new ContactAdapter(ContactsActivity.this, 0, mContacts);
ListView listView = (ListView) findViewById(R.id.customListView);
listView.setAdapter(adapter);

我只是尝试从数组列表中填充列表视图。任何帮助将不胜感激。 谢谢！

*编辑*

这是新的getView - 相同的效果 - 它挂起...当数据不在视图中时，它会显示"应用程序正在运行"，并且 getView 在我滚动之前不会继续：

public View getView(int position, View convertView, ViewGroup parent) {
//get the property we are displaying
Contact contact = mContactList.get(position);
ViewHolder viewHolder;
//get the inflater and inflate the XML layout for each item
LayoutInflater inflater;
if(convertView == null) {
viewHolder = new ViewHolder();
if (contact.isFavorite() == true) {
inflater = ((Activity)mContext).getLayoutInflater();
convertView = inflater.inflate(R.layout.favorite_contact_layout, parent, false);
} else {
inflater = ((Activity)mContext).getLayoutInflater();
convertView = inflater.inflate(R.layout.contact_layout, parent, false);
}
viewHolder.contactName = (TextView) convertView.findViewById(R.id.contact_name);
viewHolder.contactCompany = (TextView) convertView.findViewById(R.id.contact_company);
viewHolder.contactImage = (ImageView) convertView.findViewById(R.id.contact_image);
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}

//set address and description
if(contact.getName() != null) {
viewHolder.contactName.setText(contact.getName());
}
if(contact.getCompanyName() != null) {
viewHolder.contactCompany.setText(contact.getCompanyName());
}

//get the image associated with this contact
ImageParser parser = new ImageParser();
AsyncTask<String, Void, Bitmap> urlImage = parser.execute(contact.getSmallImageURL());
try {
viewHolder.contactImage.setImageBitmap(urlImage.get());
} catch (InterruptedException e) {
Log.e(TAG, "Error accessing image URL: " + e.getMessage());
} catch (ExecutionException e) {
Log.e(TAG, "Error accessing image URL: " + e.getMessage());
}
return convertView;
}

Answer 1

ListView 重用视图。您似乎正在为视图膨胀两种不同的布局。尝试通过合并两者来使用相同的布局，并仅为必要的部分设置可见性。

Answer 2

我建议您执行以下操作： a( 将所有这些视图声明移入 静态类(您的视图(：

static class ViewHolder{
public TextView name;
public TextView company;
public ImageView image;
}

b( 在以下块内分配您的查看者视图：(对于 可重用性(

View view= convertView;
if(view == null) {
if (contact.isFavorite() == true) {
inflater = ((Activity)mContext).getLayoutInflater();
view = inflater.inflate(R.layout.favorite_contact_layout, null);
} else {
inflater = ((Activity)mContext).getLayoutInflater();
view = inflater.inflate(R.layout.contact_layout, null);
}
ViewHolder holder= new ViewHolder();
holder.name = (TextView) view.findViewById(R.id.contact_name);
holder.company = (TextView) view.findViewById(R.id.contact_company);
holder.image = (ImageView) view.findViewById(R.id.contact_image);
view.setTag(viewHolder);
}
ViewHolder holder = (ViewHolder) view.getTag();
//below do the proper assignments:
//set address and description
if(contact.getName() != null) {
holder.name.setText(contact.getName());
}
if(contact.getCompanyName() != null) {
holder.company.setText(contact.getCompanyName());
}

使用毕加索设置图像视图：

1(首先添加对 gradle 文件的依赖：

compile 'com.squareup.picasso:picasso:2.5.2'

2(使用毕加索设置图像视图：

Picasso.with(context).load(contact.getSmallImageURL()).into(holder.image);