我正在制作一个应用程序，我需要阅读联系人并发送短信。我能够阅读联系人，但我无法显示联系人姓名，也无法在列表视图中显示。
< / LI>当我尝试设置C_number时，我的应用程序崩溃了。
我想将短信发送给选定的联系人。
任何帮助以解决我的问题，谢谢。
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<ScrollView
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<CheckBox
android:id="@+id/chk_box"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"/>
<TextView
android:id="@+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="@id/chk_box"
android:textStyle="bold"/>
<TextView
android:id="@+id/number"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/name"
android:layout_toRightOf="@id/chk_box"
android:textStyle="italic"
android:textSize="12sp"/>
</LinearLayout>
</ScrollView>
</RelativeLayout>
这是我阅读所有联系人的主要活动，我正在尝试将它们设置为列表视图。我搜索了很多但我无法找到正确的解决方案。任何让我走的路。
package chypher.listviewexample;
import android.content.ContentResolver;
import android.database.Cursor;
import android.net.Uri;
import android.provider.ContactsContract;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.CompoundButton;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.Switch;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends ActionBarActivity implements CompoundButton.OnCheckedChangeListener {
ListView lv;
ArrayList<Planet> planetlist;
contactadapter cadapter;
Button okbtn;
public String name;
public String phoneNumber;
public List<String> numb= new ArrayList<String>();;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
lv=(ListView)findViewById(R.id.listview);
fetchContacts();
//fetchContacts();
}
private void fetchContacts() {
// int phoneNumber ;
int i=0;
Uri CONTENT_URI = ContactsContract.Contacts.CONTENT_URI;
String _ID = ContactsContract.Contacts._ID;
String DISPLAY_NAME = ContactsContract.Contacts.DISPLAY_NAME;
String HAS_PHONE_NUMBER = ContactsContract.Contacts.HAS_PHONE_NUMBER;
Uri PhoneCONTENT_URI = ContactsContract.CommonDataKinds.Phone.CONTENT_URI;
String Phone_CONTACT_ID = ContactsContract.CommonDataKinds.Phone.CONTACT_ID;
String NUMBER = ContactsContract.CommonDataKinds.Phone.NUMBER;
List<String>output = new ArrayList<String>();
List<String>outputnum=new ArrayList<String>();
ContentResolver contentResolver = getContentResolver();
Cursor cursor = contentResolver.query(CONTENT_URI, null,null, null, null);
// Loop for every contact in the phone
if (cursor.getCount() > 0) {
while (cursor.moveToNext()) {
String contact_id = cursor.getString(cursor.getColumnIndex( _ID ));
name = cursor.getString(cursor.getColumnIndex( DISPLAY_NAME ));
// System.out.println("checking from phonename variable"+fromphonename);
int hasPhoneNumber = Integer.parseInt(cursor.getString(cursor.getColumnIndex( HAS_PHONE_NUMBER )));
if (hasPhoneNumber > 0) {
output.add(name);
// Query and loop for every phone number of the contact
Cursor phoneCursor = contentResolver.query(PhoneCONTENT_URI, null, Phone_CONTACT_ID + " = ?", new String[] { contact_id }, null);
while (phoneCursor.moveToNext()) {
phoneNumber = phoneCursor.getString(phoneCursor.getColumnIndex(NUMBER));
outputnum.add( phoneNumber);
// System.out.println("cursor phoneno:"+phoneNumber);
System.out.println("i value:"+i);
i++;
displayPlanetList(name,phoneNumber);
}
phoneCursor.close();
}
}
System.out.println("read from phone:"+output.size());
System.out.println("read from num:"+outputnum.size());
}
}
private void displayPlanetList(String nam,String nm) {
planetlist =new ArrayList<Planet>();
planetlist.add(new Planet(nam,nm));
cadapter=new contactadapter(planetlist,this);
lv.setAdapter(cadapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
switch (item.getItemId()) {
case R.id.action_next:
System.out.println("selected are :" + numb);
break;
}
return true;
}
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
int pos=lv.getPositionForView(buttonView);
if(pos!=ListView.INVALID_POSITION){
Planet p=planetlist.get(pos);
p.setSelected(isChecked);
Toast.makeText(this,"Clicked on planet:" +p.getName()+" : state :"+isChecked,Toast.LENGTH_SHORT).show();
numb.add(p.getNumber());
}
}
}
package chypher.listviewexample;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.CheckBox;
import android.widget.TextView;
import java.util.List;
/**
* Created by Saqlain Haider on 6/13/2015.
*/
class Planet{
String name;
String number;
boolean selected=false;
public Planet(String name,String number){
super();
this.name=name;
this.number=number;
}
public boolean isSelected() {
return selected;
}
public void setSelected(boolean selected) {
this.selected = selected;
}
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
public class contactadapter extends ArrayAdapter<Planet> {
private List<Planet>planetList;
private Context context;
public contactadapter(List<Planet> planetList, Context context) {
super(context, R.layout.single_listview_item,planetList);
this.planetList=planetList;
this.context=context;
}
private static class planetholder{
public TextView cName,Cnumber;
public CheckBox checkBox;
}
@Override
public View getView(int position,View convertView,ViewGroup parent){
View v=convertView;
planetholder holder=new planetholder();
if(convertView==null){
LayoutInflater inflater=(LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v=inflater.inflate(R.layout.single_listview_item,null);
holder.cName=(TextView)v.findViewById(R.id.name);
holder.Cnumber=(TextView)v.findViewById(R.id.number);
holder.checkBox=(CheckBox)v.findViewById(R.id.chk_box);
holder.checkBox.setOnCheckedChangeListener((MainActivity)context);
}
else
{
holder=(planetholder)v.getTag();
}
Planet p=planetList.get(position);
holder.cName.setText(p.getName());
holder.Cnumber.setText(p.getNumber());
holder.checkBox.setChecked(p.isSelected());
holder.checkBox.setTag(p);
return v;
}
}
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView
android:id="@+id/listview"
android:layout_width="match_parent"
android:layout_height="match_parent"></ListView>
</LinearLayout>
06-14 00:01:59.972 10362-10362/chypher.listviewexample E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
at chypher.listviewexample.contactadapter.getView(contactadapter.java:82)
at android.widget.AbsListView.obtainView(AbsListView.java:2063)
at android.widget.ListView.makeAndAddView(ListView.java:1792)
at android.widget.ListView.fillDown(ListView.java:676)
at android.widget.ListView.fillGap(ListView.java:640)
at android.widget.AbsListView.trackMotionScroll(AbsListView.java:4901)
at android.widget.AbsListView.scrollIfNeeded(AbsListView.java:2923)
at android.widget.AbsListView.startScrollIfNeeded(AbsListView.java:2868)
at android.widget.AbsListView.onInterceptTouchEvent(AbsListView.java:3738)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1639)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2019)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1754)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2019)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1754)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2019)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1754)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2019)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1754)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2019)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1754)
at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2019)
at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1754)
at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1928)
at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1387)
at android.app.Activity.dispatchTouchEvent(Activity.java:2388)
at android.support.v7.internal.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:59)
at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1876)
at android.view.View.dispatchPointerEvent(View.java:5733)
at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3104)
at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2666)
at android.view.ViewRootImpl.processInputEvents(ViewRootImpl.java:900)
at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2675)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4666)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:809)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:576)
at dalvik.system.NativeStart.main(Native Method)
06-14 01:24:17.271 14698-14698/chypher.listviewexample W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x40e4c258)
06-14 01:24:17.305 14698-14698/chypher.listviewexample E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.NullPointerException
at android.widget.AdapterView.getPositionForView(AdapterView.java:594)
at chypher.listviewexample.MainActivity.onCheckedChanged(MainActivity.java:153)
at android.widget.CompoundButton.setChecked(CompoundButton.java:125)
at chypher.listviewexample.contactadapter.getView(contactadapter.java:84)
at android.widget.AbsListView.obtainView(AbsListView.java:2063)
at android.widget.ListView.makeAndAddView(ListView.java:1792)
at android.widget.ListView.fillUp(ListView.java:709)
at android.widget.ListView.fillGap(ListView.java:649)
at android.widget.AbsListView.trackMotionScroll(AbsListView.java:4901)
at android.widget.AbsListView$FlingRunnable.run(AbsListView.java:4074)
at android.os.Handler.handleCallback(Handler.java:605)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4666)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:809)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:576)
at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：0)
问题是，您永远不会将planetholder（实际上应该以驼峰形式编写）设置为项目视图的标记。
这对于第一项是可以的，因为它们无论如何都需要充气。一旦开始滚动并重新使用膨胀的视图，就会遇到这个块：
} else {
holder=(planetholder)v.getTag();
}
由于永远不会在v上设置代码，v.getTag()将返回null。在Java中，您可以将null投射到任何内容（请参阅this discussion），这会导致holder为null。
现在，当您致电holder.cName时，您正试图访问null - 引用的属性，这会导致NullPointerException。
修复方法是改变这个：
holder.checkBox.setTag(p);
到此：
v.setTag(holder);