我正在关注本教程 [http://vimaltuts.com/android-tutorials/android-load-image-from-sqlite-to-listview][1] 从 sqlite db 创建联系人列表、添加、编辑和删除。完美运行，但现在我想将此 listActivity 更改为 listfragment。到目前为止，我还不能做到这一点，我得到空指针异常（见下文）。我认为片段循环有问题。你能帮忙吗？？
原始我的联系人活动
import com.vimaltuts.mycontacts.R;
import android.os.AsyncTask;
import android.os.Bundle;
import android.app.ListActivity;
import android.content.Intent;
import android.database.Cursor;
import android.view.Menu;
import android.view.MenuItem;
public class MyContactsActivity extends ListActivity {
SQLiteConnector sqlCon;
private CustomContactsAdapter custAdapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
String[] from = new String[] { Contacts.NAME, Contacts.PHONE,Contacts.MAIL };
int[] to = new int[] { R.id.name, R.id.phone, R.id.email };
custAdapter = new CustomContactsAdapter(this,R.layout.contact_list_item, null, from, to);
this.setListAdapter(custAdapter);
}
@Override
protected void onResume() {
super.onResume();
new GetContacts().execute((Object[]) null);
}
@SuppressWarnings("deprecation")
@Override
protected void onStop() {
Cursor cursor = custAdapter.getCursor();
if (cursor != null)
cursor.deactivate();
custAdapter.changeCursor(null);
super.onStop();
}
private class GetContacts extends AsyncTask<Object, Object, Cursor> {
SQLiteConnector dbConnector = new SQLiteConnector(MyContactsActivity.this);
@Override
protected Cursor doInBackground(Object... params) {
return dbConnector.getAllContacts();
}
@Override
protected void onPostExecute(Cursor result) {
custAdapter.changeCursor(result);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_my_contacts, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
Intent addContact = new Intent(MyContactsActivity.this,AddEditContacts.class);
startActivity(addContact);
return super.onOptionsItemSelected(item);
}
}
自定义接触适配器
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.BitmapFactory;
import android.support.v4.widget.SimpleCursorAdapter;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.TextView;
public class CustomContactsAdapter extends SimpleCursorAdapter {
private int layout;
private ImageButton editBtn;
private ImageButton delBtn;
LayoutInflater inflator;
public CustomContactsAdapter(Context context, int layout, Cursor c,String[] from, int[] to) {
super(context, layout, c, from, to,0);
this.layout = layout;
inflator= LayoutInflater.from(context);
}
public View newView(Context context, Cursor cursor, ViewGroup parent) {
View v = inflator.inflate(layout, parent, false);
return v;
}
@Override
public void bindView(View v, final Context context, Cursor c) {
final int id = c.getInt(c.getColumnIndex(Contacts.ID));
final String name = c.getString(c.getColumnIndex(Contacts.NAME));
final String phone = c.getString(c.getColumnIndex(Contacts.PHONE));
final String email = c.getString(c.getColumnIndex(Contacts.MAIL));
final String fb = c.getString(c.getColumnIndex(Contacts.FB));
final byte[] image = c.getBlob(c.getColumnIndex(Contacts.IMAGE));
ImageView iv = (ImageView) v.findViewById(R.id.photo);
if (image != null) {
if (image.length > 3) {
iv.setImageBitmap(BitmapFactory.decodeByteArray(image, 0,image.length));
}
}
TextView tname = (TextView) v.findViewById(R.id.name);
tname.setText(name);
TextView tphone = (TextView) v.findViewById(R.id.phone);
tphone.setText(phone);
TextView temail = (TextView) v.findViewById(R.id.email);
temail.setText(email);
final SQLiteConnector sqlCon = new SQLiteConnector(context);
editBtn=(ImageButton) v.findViewById(R.id.edit_btn);
editBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent=new Intent(context,AddEditContacts.class).setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.putExtra("id", id);
intent.putExtra("name", name);
intent.putExtra("phone", phone);
intent.putExtra("email", email);
intent.putExtra("fb", fb);
intent.putExtra("blob", image);
context.startActivity(intent);
}
});
delBtn=(ImageButton) v.findViewById(R.id.del_btn);
delBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
sqlCon.deleteContact(id);
Intent intent=new Intent(context,ChildrenListFragment.class).setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(intent);
}
});
v.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent=new Intent(context,ViewContact.class).setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.putExtra("id", id);
intent.putExtra("name", name);
intent.putExtra("phone", phone);
intent.putExtra("email", email);
intent.putExtra("fb", fb);
intent.putExtra("blob", image);
context.startActivity(intent);
}
});
}
}
更改了我的联系人活动
public class MyContactsActivity extends ListFragment{
SQLiteConnector sqlCon;
private CustomContactsAdapter custAdapter;
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
Activity activity = getActivity();
if (activity != null) {
String[] from = new String[] { Contacts.NAME, Contacts.PHONE,Contacts.MAIL };
int[] to = new int[] { R.id.name, R.id.phone, R.id.email };
CustomContactsAdapter custAdapter = new CustomContactsAdapter(activity,R.layout.contact_list_item, null, from, to);
this.setListAdapter(custAdapter);
SQLiteConnector dbConnector = new SQLiteConnector(activity);
}
}
@Override
public void onResume() {
super.onResume();
new GetContacts().execute((Object[]) null);
}
@SuppressWarnings("deprecation")
@Override
public void onStop() {
Cursor cursor = custAdapter.getCursor();
if (cursor != null)
cursor.deactivate();
custAdapter.changeCursor(null);
super.onStop();
}
private class GetContacts extends AsyncTask<Object, Object, Cursor> {
Activity activity = getActivity();
SQLiteConnector dbConnector = new SQLiteConnector(activity);
@Override
protected Cursor doInBackground(Object... params) {
return dbConnector.getAllContacts();
}
@Override
protected void onPostExecute(Cursor result) {
if (isDestroyed) return;
custAdapter.changeCursor(result);
}
}
public void onCreateOptionsMenu(Menu menu,MenuInflater inflater) {
//getActivity().getMenuInflater().inflate(R.menu.activity_my_contacts, menu);
super.onCreateOptionsMenu(menu, inflater);
menu.clear();
inflater.inflate(R.menu.activity_my_contacts, menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
Activity activity = getActivity();
Intent addContact = new Intent(activity,AddEditContacts.class);
startActivity(addContact);
return super.onOptionsItemSelected(item);
}
}
错误
07-17 22:01:33.959: E/AndroidRuntime(10924): java.lang.NullPointerException
07-17 22:01:33.959: E/AndroidRuntime(10924): at com.ektroid.graphico.MyContactsActivity$GetContacts.onPostExecute(MyContactsActivity.java:95)
07-17 22:01:33.959: E/AndroidRuntime(10924): at com.ektroid.graphico.MyContactsActivity$GetContacts.onPostExecute(MyContactsActivity.java:1)
07-17 22:01:33.959: E/AndroidRuntime(10924): at android.os.AsyncTask.finish(AsyncTask.java:602)
07-17 22:01:33.959: E/AndroidRuntime(10924): at android.os.AsyncTask.access$600(AsyncTask.java:156)
07-17 22:01:33.959: E/AndroidRuntime(10924): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:615)
07-17 22:01:33.959: E/AndroidRuntime(10924): at android.os.Handler.dispatchMessage(Handler.java:99)
07-17 22:01:33.959: E/AndroidRuntime(10924): at android.os.Looper.loop(Looper.java:137)
07-17 22:01:33.959: E/AndroidRuntime(10924): at android.app.ActivityThread.main(ActivityThread.java:4424)
07-17 22:01:33.959: E/AndroidRuntime(10924): at java.lang.reflect.Method.invokeNative(Native Method)
07-17 22:01:33.959: E/AndroidRuntime(10924): at java.lang.reflect.Method.invoke(Method.java:511)
07-17 22:01:33.959: E/AndroidRuntime(10924): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
07-17 22:01:33.959: E/AndroidRuntime(10924): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
07-17 22:01:33.959: E/AndroidRuntime(10924): at dalvik.system.NativeStart.main(Native Method)
07-17 22:01:34.569: I/dalvikvm(10924): threadid=3: reacting to signal 3
07-17 22:01:34.569: I/dalvikvm(10924): Wrote stack traces to '/data/anr/traces.txt'
07-17 22:01:35.859: I/Process(10924): Sending signal. PID: 10924 SIG: 9