我根据O'Really视频教程编写了Android应用程序（简单的联系人列表）。但是我因令人讨厌的错误而停下来，因为我无法应付自己。请帮忙。
android模拟器中错误的文本：
The application ContactList (process my.contactlist) had stopped unexpectedly. Please, try again
调试后，我发现该问题发生在第行的ContactAdapter中
ci = (ContactItem) View.inflate(context, R.layout.contact_item, null);
LogCat说：
12-19 12:19:30.727: ERROR/AndroidRuntime(522): FATAL EXCEPTION: main
java.lang.ClassCastException: android.widget.LinearLayout
at my.contactlist.ContactAdapter.getView(ContactAdapter.java:45)
at android.widget.AbsListView.obtainView(AbsListView.java:1430)
at android.widget.ListView.makeAndAddView(ListView.java:1745)
at android.widget.ListView.fillDown(ListView.java:670)
at android.widget.ListView.fillFromTop(ListView.java:727)
at android.widget.ListView.layoutChildren(ListView.java:1598)
at android.widget.AbsListView.onLayout(AbsListView.java:1260)
at android.view.View.layout(View.java:7175)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:912)
at android.view.View.layout(View.java:7175)
at android.widget.FrameLayout.onLayout(FrameLayout.java:338)
at android.view.View.layout(View.java:7175)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1254)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1130)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1047)
at android.view.View.layout(View.java:7175)
at android.widget.FrameLayout.onLayout(FrameLayout.java:338)
at android.view.View.layout(View.java:7175)
at android.view.ViewRoot.performTraversals(ViewRoot.java:1140)
at android.view.ViewRoot.handleMessage(ViewRoot.java:1859)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:3683)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
at dalvik.system.NativeStart.main(Native Method)
主要类别和布局的代码：
public class MainActivity extends ListActivity {
private ContactApp app;
private ContactAdapter adapter;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
setUpViews();
app = (ContactApp) getApplication();
app.getContacts().add(new Contact("AAA", "BBB", "CCC"));
adapter = new ContactAdapter(this, app.getContacts());
setListAdapter(adapter);
Toast.makeText(this, "count="+adapter.getCount(), Toast.LENGTH_SHORT).show();
}
private void setUpViews() {
Button addButton = (Button) findViewById(R.id.newContact);
addButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, AddContactActivity.class);
startActivity(intent);
}
});
}
@Override
protected void onResume() {
super.onResume();
// adapter.notifyDataSetChanged();
}
}
ContactAdapter.java：
public class ContactAdapter extends BaseAdapter {
private ArrayList<Contact> contacts;
private Context context;
public ContactAdapter(Context context, ArrayList<Contact> contacts) {
super();
this.contacts = contacts;
this.context = context;
}
@Override
public int getCount() {
return contacts.size();
}
@Override
public Contact getItem(int i) {
return (contacts == null) ? null : contacts.get(i);
}
@Override
public long getItemId(int i) {
return i;
}
@Override
public View getView(int i, View view, ViewGroup viewGroup) {
ContactItem ci;
if (view == null) {
ci = (ContactItem) View.inflate(context, R.layout.contact_item, null);
} else {
ci = (ContactItem)view;
}
ci.setContact(contacts.get(i));
return ci;
}
public void forceReload() {
notifyDataSetChanged();
}
}
Contact.java：
public class Contact {
private String lastname;
private String name;
private String phoneNumber;
public Contact(String lastname, String name, String phoneNumber) {
this.lastname = lastname;
this.name = name;
this.phoneNumber = phoneNumber;
}
public String getLastname() {
return lastname;
}
public String getName() {
return name;
}
public String getPhoneNumber() {
return phoneNumber;
}
public void setLastname(String lastname) {
this.lastname = lastname;
}
public void setName(String name) {
this.name = name;
}
public void setPhoneNumber(String phoneNumber) {
this.phoneNumber = phoneNumber;
}
}
contact_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal">
<ImageView
android:id="@+id/img"
android:src="@drawable/person"
android:layout_width="24px"
android:layout_height="24px"
android:layout_marginLeft="2px"
android:layout_marginRight="5px"
android:layout_marginTop="5px"
/>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<TextView
android:id="@+id/show_name"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:textSize="12px"
android:textColor="#AAAAFF"
/>
<TextView
android:id="@+id/show_phone"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:textSize="12px"
android:textColor="#AAAAFF"
/>
</LinearLayout>
</LinearLayout>
ContactItem.java
public class ContactItem extends LinearLayout {
// private Contact contact;
private TextView name;
private TextView phone;
public ContactItem(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
protected void onFinishInflate() {
super.onFinishInflate();
name = (TextView) findViewById(R.id.show_name);
phone = (TextView) findViewById(R.id.show_phone);
}
public void setContact(Contact contact) {
//this.contact = contact;
name.setText(contact.getLastname());//+" "+contact.getName());
phone.setText(contact.getPhoneNumber());
}
}
有什么建议么？
最佳答案
您膨胀的布局是LinearLayout。您不能将LinearLayout强制转换为ContactItem，但是可以将ContactItem强制强制转换为LinearLayout。既然已经定义了ContactItem，为什么不将布局的根目录更改为ContactItem？