Android：強制關閉錯誤

Question

我正在根據O'Really視頻教程編寫Android應用程序（簡單聯繫人列表）。但是我因爲惱人的錯誤而停下腳步，以至於我無法處理自己。請幫忙。

文本在Android模擬器錯誤：

The application ContactList (process my.contactlist) had stopped unexpectedly. Please, try again 

調試後，我發現，在行ContactAdapter出現問題

ci = (ContactItem) View.inflate(context, R.layout.contact_item, null); 

的logcat的說：

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) 

主要代碼和佈局：

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()); 
    } 
} 

有什麼建議嗎？

Answer 1

您膨脹的佈局是一個LinearLayout。您不能將LinearLayout投射到ContactItem，但可以將ContactItem投射到LinearLayout。既然你已經定義了ContactItem，爲什麼不把你的佈局的根改爲ContactItem？