我有一个ListView，它使用CardView来放大其布局。当用户单击ListView中的第一项时，这将更改Fragment。但是，我不确定如何执行此操作。我试图更改适配器类（CustomAdapter.java）中的Fragment，但它不起作用。我也尝试过在ListView所在的Fragment中执行此操作，但它也不起作用（当我单击其中一项时，应用程序也没有崩溃-什么也没发生）：
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Fragment fragment = null;
switch (position) {
case 0:
fragment = new DesignsWorkshopFragment();
break;
}
if (fragment != null) {
FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.replace(R.id.content_frame, fragment);
ft.addToBackStack(null);
ft.commit();
}
}
});
SuppliersFragment.java：
public class SuppliersFragment extends Fragment {
CustomAdapter adapter;
ListView lv;
public SuppliersFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_suppliers, container, false);
lv = view.findViewById(R.id.lvFragmentSuppliers);
adapter = new CustomAdapter(getContext(), getData());
lv.setAdapter(adapter);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Fragment fragment = null;
switch (position) {
case 0:
fragment = new DesignsWorkshopFragment();
break;
}
if (fragment != null) {
FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.replace(R.id.content_frame, fragment);
ft.addToBackStack(null);
ft.commit();
}
}
});
return view;
}
private ArrayList getData() {
ArrayList<SuppliersCardview> suppliersCardview = new ArrayList<>();
SuppliersCardview s = new SuppliersCardview();
s.setThumbnail(R.drawable.designs_workshop_logo);
s.setName("Designs Workshop");
suppliersCardview.add(s);
s = new SuppliersCardview();
s.setThumbnail(R.drawable.organic_clothing_logo);
s.setName("Organic Clothing Industries");
suppliersCardview.add(s);
s = new SuppliersCardview();
s.setThumbnail(R.drawable.suns_sewing_ltd);
s.setName("Sun's Sewing Ltd");
suppliersCardview.add(s);
return suppliersCardview;
}}
CustomAdapter.java：
public class CustomAdapter extends BaseAdapter {
Context c;
ArrayList<SuppliersCardview> suppliersCardview;
public CustomAdapter(Context c, ArrayList<SuppliersCardview> suppliersCardview) {
this.c = c;
this.suppliersCardview = suppliersCardview;
}
@Override
public int getCount() {
return suppliersCardview.size();
}
@Override
public Object getItem(int position) {
return suppliersCardview.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(final int position, View convertView, final ViewGroup parent) {
if (convertView == null) {
convertView = LayoutInflater.from(c).inflate(R.layout.cardview_layout, parent, false);
}
final SuppliersCardview s = (SuppliersCardview) this.getItem(position);
ImageView imageView = convertView.findViewById(R.id.ivSupplierLogo);
TextView textView = convertView.findViewById(R.id.tvSupplierName);
imageView.setImageResource(s.getThumbnail());
textView.setText(s.getName());
convertView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//Attempted to change fragment here in a switch statement
}
});
return convertView;
}
SuppliersCardview.java：
public class SuppliersCardview {
private String name;
private int thumbnail;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getThumbnail() {
return thumbnail;
}
public void setThumbnail(int thumbnail) {
this.thumbnail = thumbnail;
}}
SuppliersFragment XML：
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.miguelpeachey.marketplacesimulator.Fragments.SuppliersFragment">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="@+id/tvBrowseSuppliersHeader"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#bfbdbd"
android:fontFamily="@font/nunito_sans"
android:paddingBottom="5dp"
android:paddingStart="10dp"
android:paddingTop="10dp"
android:text="Browse Suppliers"
android:textSize="25sp" />
<ListView
android:layout_marginLeft="40dp"
android:layout_marginRight="40dp"
android:id="@+id/lvFragmentSuppliers"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:divider="@color/colorTransparent"
android:dividerHeight="20dip"/>
</LinearLayout>
CardView XML：
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/tools"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="@+id/cardView"
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_margin="40dp"
android:orientation="vertical"
app:cardPreventCornerOverlap="false"
app:ignore="NamespaceTypo"
card_view:cardBackgroundColor="#cccbcb"
card_view:cardCornerRadius="15dp"
card_view:cardElevation="5dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:orientation="vertical">
<ImageView
android:id="@+id/ivSupplierLogo"
android:layout_width="150dp"
android:layout_height="120dp"
android:layout_centerHorizontal="true"
android:layout_marginTop="10dp"
android:src="@drawable/ic_launcher_background" />
<TextView
android:id="@+id/tvSupplierName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/ivSupplierLogo"
android:layout_centerHorizontal="true"
android:layout_marginTop="10dp"
android:fontFamily="@font/brawler"
android:text="Supplier"
android:textColor="#232323"
android:textSize="22sp" />
</RelativeLayout>
那么我该如何替换/更改使用CardView作为其布局的ListView项单击上的片段？别人的解决方案对我没有帮助。
我已使用this website作为教程来创建CardView并填充ListView的布局（此处的某些代码来自网站）。
答案 0 :(得分：0)
您有了片段对象，现在您需要使用片段管理器，并用要显示的片段替换现有片段。
DesignsWorkshopFragment fragment2=new DesignsWorkshopFragment();
FragmentManager fragmentManager=getActivity().getFragmentManager();
FragmentTransaction fragmentTransaction=fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.content_main,fragment2,"tag");
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
仅创建片段的实例不会在活动中显示它。
答案 1 :(得分：0)
在活动内部添加和替换片段。您需要在ListView中单击项目视图时通知您的活动。这可以通过界面完成。
创建一个界面：
public interface ClickListener{
public void onClick();
}
在您的活动中实现此接口。当您创建Fragment时，请在片段的构造函数中传递“ this”作为引用。
fragment = new DesignsWorkshopFragment(this);
在片段内部，您需要创建接口引用。
private ClickListener clickListener ;
内部片段初始化此接口引用
DesignsWorkshopFragment(ClickListener clickListener){
this.clickListener = clickListener;
}
现在，在创建适配器时执行相同的操作。
adapter = new CustomAdapter(getContext(), getData(),clickListener);
内部适配器创建并初始化接口引用。
private ClickListener clickListener ;
public CustomAdapter(Context c, ArrayList<SuppliersCardview> suppliersCardview,
ClickListener clickListener ) {
this.c = c;
this.suppliersCardview = suppliersCardview;
this.clickListener = clickListener;
}
，以及每当发生点击时。只需调用接口方法即可。
convertView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
clickListener.onClick();
}
});
这将在您的活动的界面实现内部进行回调。在这里
public void onClick(){
//write your code for adding or replacing fragment.
}
答案 2 :(得分：0)
我设法通过删除
来使其正常工作convertView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
}
});
在我的 CustomAdapter.java 类中。