如何使用AsyncTask在Android中显示联系人？
我正在尝试列出移动设备中的所有联系人。到目前为止一切工作正常，但当我想在AsyncTask中运行我的代码时，屏幕上什么都没有。
以下是代码段
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_call_list);
lvCallList = (ListView) findViewById(R.id.lv_call_list);
new AsyncTask<Void, Void, Void>()
{
@Override
protected void onPreExecute()
{
pd = ProgressDialog.show(CallListActivity.this,
"Loading..", "Please Wait", true, false);
}// End of onPreExecute method
@Override
protected Void doInBackground(Void... params)
{
getContacts();
return null;
}// End of doInBackground method
@Override
protected void onPostExecute(Void result)
{
pd.dismiss();
lvCallList.setAdapter(new CustomAdapter(CallListActivity.this));
}//End of onPostExecute method
}.execute((Void[]) null);
count = this.displayContactName.size();
thumbnailsselection = new boolean[count];
}
private void getContacts()
{
ContentResolver cr = getContentResolver();
Cursor cur = cr.query(ContactsContract.Contacts.CONTENT_URI, null,null, null, null);
if (cur.getCount() > 0)
{
while (cur.moveToNext())
{
String id = cur.getString(cur.getColumnIndex(ContactsContract.Contacts._ID));
String name = cur.getString(cur.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME));
this.displayContactName.add(name);
if (Integer.parseInt(cur.getString(cur.getColumnIndex(ContactsContract.Contacts.HAS_PHONE_NUMBER))) > 0)
{
Cursor pCur = cr.query( ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
null,
ContactsContract.CommonDataKinds.Phone.CONTACT_ID +" = ?",
new String[]{id},
null);
while (pCur.moveToNext())
{
String phoneNumber = pCur.getString(pCur.getColumnIndex( ContactsContract.CommonDataKinds.Phone.NUMBER));
this.displayContactNumber.add(phoneNumber);
}
pCur.close();
}
}
}
}
public class CustomAdapter extends BaseAdapter
{
/*
* Variables Declaration section
*/
private Context mContext;
public CustomAdapter(Context context)
{
mContext = context;
}//End of CustomAdapter constructor
public int getCount()
{
return count;
}//End of getCount method
public Object getItem(int position)
{
return position;
}//End of getItem method
public long getItemId(int position)
{
return position;
}//End of getItemId method
public View getView(int position, View convertView, ViewGroup parent)
{
return convertView;
}//End of getView method
}//End of CustomAdapter instance inner class
class ViewHolder
{
TextView textviewName;
TextView textviewNumber;
CheckBox checkbox;
int id;
}//End of ViewHolder instance inner class
displayContactName值是
pd.dismiss();我不知道我的代码有什么问题，当我不使用displayContactName ArrayList (id=830007844896)
array Object[12] (id=830007907208)
[0] "Rrs" (id=830007907144)
[1] "Fgsd" (id=830007920424)
[2] null
[3] null
[4] null
[5] null
[6] null
[7] null
[8] null
[9] null
[10] null
[11] null
modCount 2
size 2
时，我的代码工作得很好，但是当我使用AsyncTask问题时。
请帮我解决这个难题。
提前致谢。
4 个答案:
答案 0 :(得分：4)
您无法在doInbackground中更新ui。你应该在ui线程上更新ui。在onPostExecute。
您也可以使用runOnUiThread。
示例
显示联系人姓名。
public class MainActivity extends Activity {
ListView lvCallList;
ProgressDialog pd;
ArrayList<String> aa = new ArrayList<String>();
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lvCallList = (ListView) findViewById(R.id.list);
new AsyncTask<Void, Void, Void>()
{
@Override
protected void onPreExecute()
{
pd = ProgressDialog.show(MainActivity.this,
"Loading..", "Please Wait", true, false);
}// End of onPreExecute method
@Override
protected Void doInBackground(Void... params)
{
getContacts();
return null;
}// End of doInBackground method
@Override
protected void onPostExecute(Void result)
{
pd.dismiss();
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_list_item_1,aa);
lvCallList.setAdapter(arrayAdapter);
}//End of onPostExecute method
}.execute((Void[]) null);
}
private void getContacts()
{
ContentResolver cr = getContentResolver();
Cursor cur = cr.query(ContactsContract.Contacts.CONTENT_URI, null,null, null, null);
if (cur.getCount() > 0)
{
while (cur.moveToNext())
{
String id = cur.getString(cur.getColumnIndex(ContactsContract.Contacts._ID));
String name = cur.getString(cur.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME));
aa.add(name);
if (Integer.parseInt(cur.getString(cur.getColumnIndex(ContactsContract.Contacts.HAS_PHONE_NUMBER))) > 0)
{
Cursor pCur = cr.query( ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
null,
ContactsContract.CommonDataKinds.Phone.CONTACT_ID +" = ?",
new String[]{id},
null);
while (pCur.moveToNext())
{
String phoneNumber = pCur.getString(pCur.getColumnIndex( ContactsContract.CommonDataKinds.Phone.NUMBER));
// this.displayContactNumber.add(phoneNumber);
}
pCur.close();
}
}
}
}
}
在我的手机上快照
编辑：2
public class MainActivity extends Activity {
ListView lvCallList;
ProgressDialog pd;
ArrayList<String> aa = new ArrayList<String>();
ArrayList<String> num= new ArrayList<String>();
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lvCallList = (ListView) findViewById(R.id.list);
new AsyncTask<Void, Void, Void>()
{
@Override
protected void onPreExecute()
{
pd = ProgressDialog.show(MainActivity.this,
"Loading..", "Please Wait", true, false);
}// End of onPreExecute method
@Override
protected Void doInBackground(Void... params)
{
getContacts();
return null;
}// End of doInBackground method
@Override
protected void onPostExecute(Void result)
{
pd.dismiss();
CustomAdapter cus = new CustomAdapter(MainActivity.this);
// ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(MainActivity.this, android.R.layout.simple_list_item_1,aa);
lvCallList.setAdapter(cus);
}//End of onPostExecute method
}.execute((Void[]) null);
}
private void getContacts()
{
ContentResolver cr = getContentResolver();
Cursor cur = cr.query(ContactsContract.Contacts.CONTENT_URI, null,null, null, null);
if (cur.getCount() > 0)
{
while (cur.moveToNext())
{
String id = cur.getString(cur.getColumnIndex(ContactsContract.Contacts._ID));
String name = cur.getString(cur.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME));
aa.add(name);
if (Integer.parseInt(cur.getString(cur.getColumnIndex(ContactsContract.Contacts.HAS_PHONE_NUMBER))) > 0)
{
Cursor pCur = cr.query( ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
null,
ContactsContract.CommonDataKinds.Phone.CONTACT_ID +" = ?",
new String[]{id},
null);
while (pCur.moveToNext())
{
String phoneNumber = pCur.getString(pCur.getColumnIndex( ContactsContract.CommonDataKinds.Phone.NUMBER));
num.add(phoneNumber);
}
pCur.close();
}
}
}
}
public class CustomAdapter extends BaseAdapter
{
/*
* Variables Declaration section
*/
private Context mContext;
public CustomAdapter(Context context)
{
mContext = context;
}//End of CustomAdapter constructor
public int getCount()
{
return aa.size();
}//End of getCount method
public Object getItem(int position)
{
return position;
}//End of getItem method
public long getItemId(int position)
{
return position;
}//End of getItemId method
public View getView(int position, View convertView, ViewGroup parent)
{
ViewHolder holder;
final int pos = position;
if (convertView == null)
{
holder = new ViewHolder();
convertView = LayoutInflater.from(mContext).inflate(R.layout.display_contact, null);
holder.textviewName = (TextView) convertView.findViewById(R.id.textView1);
holder.textviewNumber = (TextView) convertView.findViewById(R.id.textView2);
holder.checkbox = (CheckBox) convertView.findViewById(R.id.checkBox1);
convertView.setTag(holder);
}//End of if condition
else
{
holder = (ViewHolder) convertView.getTag();
}//End of else
holder.checkbox.setId(position);
holder.textviewName.setId(position);
holder.textviewNumber.setId(position);
holder.textviewName.setText(aa.get(position));
holder.textviewNumber.setText("No. "+num.get(position));
holder.id = position;
return convertView;
}//End of getView method
}//End of CustomAdapter instance inner class
static class ViewHolder
{
TextView textviewName;
TextView textviewNumber;
CheckBox checkbox;
int id;
}
}
答案 1 :(得分：0)
您无法在非UI线程中触摸视图。您必须在onPostExecute（）;
中设置适配器使用此:(另外，我希望您将联系人保留在某处，因为我在您的代码段中没有看到联系人变量）
new AsyncTask<Void, Void, Void>()
{
@Override
protected void onPreExecute()
{
pd = ProgressDialog.show(CallListActivity.this,
"Loading..", "Please Wait", true, false);
}// End of onPreExecute method
@Override
protected Void doInBackground(Void... params)
{
getContacts();
return null;
}// End of doInBackground method
@Override
protected void onPostExecute(Void result)
{
arrayAdapter = new ArrayAdapter<String>(CallListActivity.this, R.layout.display_contacts,R.id.tv_single_contact_number,displayContactName);
lvCallList.setAdapter(new CustomAdapter(CallListActivity.this));
pd.dismiss();
}//End of onPostExecute method
}.execute((Void[]) null);
答案 2 :(得分：0)
您正在尝试在未在UI线程上运行的doInBackground中调用setAdapter。您必须将联系人加载的结果从doInBackground（..）传递给onPostExcecute（..），然后您可以创建一个适配器并在列表视图中进行设置。
答案 3 :(得分：0)
我发现了问题，我在设置适配器后尝试初始化count，这就是问题，感谢stackoverflow和@Raghunandan
protected void onPostExecute(Void result)
{
count = displayContactName.size();
thumbnailsselection = new boolean[count];
lvCallList.setAdapter(new CustomAdapter(CallListActivity.this));
pd.dismiss();
}//End of onPostExecute method
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