安卓：崩潰是由於添加另一個光標

Question

這是我ContactManager.java

package com.example.android.contactmanager; 

import android.app.Activity; 
import android.content.Intent; 
import android.database.Cursor; 
import android.net.Uri; 
import android.os.Bundle; 
import android.provider.ContactsContract; 
import android.util.Log; 
import android.view.View; 
import android.widget.AdapterView; 
import android.widget.AdapterView.OnItemClickListener; 
import android.widget.Button; 
import android.widget.CheckBox; 
import android.widget.CompoundButton; 
import android.widget.CompoundButton.OnCheckedChangeListener; 
import android.widget.ListView; 
import android.widget.SimpleCursorAdapter; 

public final class ContactManager extends Activity implements OnItemClickListener 
{ 

    public static final String TAG = "ContactManager"; 

    private Button mAddAccountButton; 
    private ListView mContactList; 
    private boolean mShowInvisible; 
    //public BooleanObservable ShowInvisible = new BooleanObservable(false); 
    private CheckBox mShowInvisibleControl; 

    /** 
    * Called when the activity is first created. Responsible for initializing the UI. 
    */ 

    @Override 
    public void onCreate(Bundle savedInstanceState) 
    { 


     Log.v(TAG, "Activity State: onCreate()"); 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.contact_manager); 

     // Obtain handles to UI objects 
     mAddAccountButton = (Button) findViewById(R.id.addContactButton); 
     mContactList = (ListView) findViewById(R.id.contactList); 
     mShowInvisibleControl = (CheckBox) findViewById(R.id.showInvisible); 

     // Initialise class properties 
     mShowInvisible = false; 
     mShowInvisibleControl.setChecked(mShowInvisible); 

     // Register handler for UI elements 
     mAddAccountButton.setOnClickListener(new View.OnClickListener() { 
      public void onClick(View v) { 
       Log.d(TAG, "mAddAccountButton clicked"); 
       launchContactAdder(); 
      } 
     }); 
     mShowInvisibleControl.setOnCheckedChangeListener(new OnCheckedChangeListener() 
     { 
      public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) 
      { 
       Log.d(TAG, "mShowInvisibleControl changed: " + isChecked); 
       mShowInvisible = isChecked; 
       populateContactList(); 
      } 
     }); 

     mContactList = (ListView) findViewById(R.id.contactList); 
     mContactList.setOnItemClickListener(this); 

     // Populate the contact list 
     populateContactList(); 
    } 

    /** 
    * Populate the contact list based on account currently selected in the account spinner. 
    */ 
    private void populateContactList() { 
     // Build adapter with contact entries 
     Cursor cursor = getContacts(); 

     String[] fields = new String[] { 
       ContactsContract.Data.DISPLAY_NAME, 

     }; 


     SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.layout.contact_entry, cursor, 
       fields, new int[] {R.id.contactEntryText}); 
     mContactList.setAdapter(adapter); 
    } 

    /** 
    * Obtains the contact list for the currently selected account. 
    * 
    * @return A cursor for for accessing the contact list. 
    */ 
    private Cursor getContacts() 
    { 
     // Run query 
     Uri uri = ContactsContract.Contacts.CONTENT_URI; 
     //Log.i("Uri ContactsContract.Contacts.CONTENT_URI" + ContactsContract.Contacts.CONTENT_URI, null, null); 

     String[] projection = new String[]{ 
       ContactsContract.Contacts._ID, 
       ContactsContract.Contacts.DISPLAY_NAME, 
       //ContactsContract.CommonDataKinds.Email.DATA1 
       }; 

     String selection = ContactsContract.Contacts.IN_VISIBLE_GROUP + " = '" + (mShowInvisible ? "0" : "1") + "'"; 
     //String selection = ContactsContract.Contacts.IN_VISIBLE_GROUP + " = '" + (mShowInvisible.get() ? "0" : "1") + "'"; 
     String[] selectionArgs = null; 
     String sortOrder = ContactsContract.Contacts.DISPLAY_NAME + " COLLATE LOCALIZED ASC"; 

     return this.managedQuery(uri, projection, selection, selectionArgs, sortOrder); 
    } 



    /** 
    * Launches the ContactAdder activity to add a new contact to the selected account. 
    */ 
    protected void launchContactAdder() 
    { 
     Intent i = new Intent(this, ContactAdder.class); 
     startActivity(i); 
    } 

    public void onItemClick(AdapterView<?> l, View v, int position, long id) { 
     Log.i("TAG", "You clicked item " + id + " at position " + position); 



     Cursor cursor = getContacts(); 
     Cursor emailCur = getContactsEmail(); 
     emailCur.isNull(emailCur.getColumnIndex(ContactsContract.CommonDataKinds.Email.DATA)); 

     cursor.moveToPosition(position); 

     String name = cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME)); 
//  String email = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Email.DATA)); 
     //String name = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Email.DATA)); 

     //Log.i("Address", "Testing" + cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Email.DATA))); 

     // Launching new Activity on selecting single List Item 
     Intent i = new Intent(getApplicationContext(), SingleListContact.class); 
//  SingleListContact.PutDetails(ContactsContract.Contacts._ID, name, address, position, null, null); 
     SingleListContact.PutDetails(ContactsContract.Contacts._ID, name, null); 

     Log.i("Show Contact Clicked: ", name + "Email: " + null); 

     startActivity(i); 

    } 

    private Cursor getContactsEmail() 
    { 
     // Run query 
     Uri uri = ContactsContract.Contacts.CONTENT_URI; 
     //Log.i("Uri ContactsContract.Contacts.CONTENT_URI" + ContactsContract.Contacts.CONTENT_URI, null, null); 

     String[] projection = new String[] 
       { 
       ContactsContract.Contacts._ID, 
       ContactsContract.CommonDataKinds.Email.DATA, 
//    ContactsContract.CommonDataKinds.StructuredPostal.DATA1 
       //ContactsContract.CommonDataKinds.Phone.DATA 
       }; 
     String selection = ContactsContract.Contacts.IN_VISIBLE_GROUP + " = '" + (mShowInvisible ? "0" : "1") + "'"; 
     //String selection = ContactsContract.Contacts.IN_VISIBLE_GROUP + " = '" + (mShowInvisible.get() ? "0" : "1") + "'"; 
     String[] selectionArgs = null; 
     String sortOrder = ContactsContract.CommonDataKinds.Email.DATA + " COLLATE LOCALIZED ASC"; 
// 
     return this.managedQuery(uri, projection, null, selectionArgs, null); 
    } 


} 

加入emailCur之前，一切工作正常，但在添加代碼，以獲得contactperson細節後，一切都崩潰！我可以在這裏解決嗎？ Logcat如下：

12-27 22:20:11.129: E/AndroidRuntime(9792): java.lang.IllegalArgumentException: Invalid column data1 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:144) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:114) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at android.content.ContentProviderProxy.bulkQueryInternal(ContentProviderNative.java:330) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at android.content.ContentProviderProxy.query(ContentProviderNative.java:366) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at android.content.ContentResolver.query(ContentResolver.java:262) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at android.app.Activity.managedQuery(Activity.java:1550) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at com.example.android.contactmanager.ContactManager.getContactsEmail(ContactManager.java:193) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at com.example.android.contactmanager.ContactManager.onItemClick(ContactManager.java:153) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at android.widget.AdapterView.performItemClick(AdapterView.java:284) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at android.widget.ListView.performItemClick(ListView.java:3749) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at android.widget.AbsListView$PerformClick.run(AbsListView.java:1986) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at android.os.Handler.handleCallback(Handler.java:587) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at android.os.Handler.dispatchMessage(Handler.java:92) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at android.os.Looper.loop(Looper.java:130) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at android.app.ActivityThread.main(ActivityThread.java:3687) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at java.lang.reflect.Method.invokeNative(Native Method) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at java.lang.reflect.Method.invoke(Method.java:507) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625) 
12-27 22:20:11.129: E/AndroidRuntime(9792):  at dalvik.system.NativeStart.main(Native Method) 

Answer 1

在從它訪問值之前添加null檢查emailCur。