android– 获取空指针异常？

概述我试图将一个数组中的联系人名称和他们的类型放在另一个数组中,但是无法通过空指针异常来完成.这是我的代码.我已经指出了我得到空指针异常的行.请帮忙..提前致谢.packageapplication.test;importandroid.app.Activity;importandroid.content.ContentResolver;importandro

我试图将一个数组中的联系人名称和他们的类型放在另一个数组中,但是无法通过空指针异常来完成.这是我的代码.我已经指出了我得到空指针异常的行.请帮忙..提前致谢.

package application.test;import androID.app.Activity;import androID.content.ContentResolver;import androID.database.Cursor;import androID.database.sqlException;import androID.os.Bundle;import androID.provIDer.ContactsContract;import androID.provIDer.ContactsContract.CommonDataKinds.Phone;  import androID.provIDer.ContactsContract.Contacts.Data;import androID.util.Log;import androID.vIEw.LayoutInflater;import androID.vIEw.VIEwGroup.LayoutParams;import androID.Widget.linearLayout;import androID.Widget.@R_404_6818@VIEw;import androID.Widget.relativeLayout;public final class TestActivity extends Activity {String[] name;String[] phoneType;@R_404_6818@VIEw lv;@R_404_6818@VIEwAdapter lva;    public static final String TAG = "ContactManager";@OverrIDepublic voID onCreate(Bundle savedInstanceState){    Log.v(TAG, "Activity State: onCreate()");    super.onCreate(savedInstanceState);    LayoutParams params = new relativeLayout.LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.WRAP_CONTENT);            linearLayout mainLayout=new linearLayout(this);    mainLayout.setorIEntation(linearLayout.VERTICAL);                   LayoutInflater layoutInflater = getLayoutInflater();            mainLayout.addVIEw(layoutInflater.inflate(R.layout.main,null));    mainLayout.addVIEw(layoutInflater.inflate(R.layout.extra,null));    this.addContentVIEw(mainLayout, params);      lv = (@R_404_6818@VIEw)findVIEwByID(androID.R.ID.@R_404_6818@);     lva = new @R_404_6818@VIEwAdapter(this,name,phoneType);     lv.setAdapter(lva);    testGetContacts();}private voID testGetContacts() {         ContentResolver cr = getContentResolver();        String[] projection = new String[] { Data._ID,                ContactsContract.Contacts.disPLAY_name, Phone.TYPE};         Cursor cur = cr.query(ContactsContract.Data.CONTENT_URI,                projection, null, null, null);         if (cur != null && cur.movetoFirst()) {         try {            int indexID =  cur.getColumnIndexOrThrow(ContactsContract.Contacts._ID);            int indexname = cur.getColumnIndexOrThrow(ContactsContract.Contacts.disPLAY_name);             int indexPhoneType = cur.getColumnIndexOrThrow(Phone.TYPE);          while (cur.movetoNext()) {             int  i=1;              String ID = cur.getString(indexID);     //HERE LIES NulL POINTER EXCEPTION   name[i] = cur.getString(indexname);   //HERE TOO              phoneType[i] =  cur.getString(indexPhoneType);             i++;              System.out.println(ID + "\n");              System.out.println(name + "\n");              System.out.println(phoneType + "\n");          }        } catch (sqlException sqle) {           //handling exception               } finally {          if (!cur.isClosed()) {             cur.close();         }          }        }}}

解决方法:

在使用之前初始化String []名称.
你可以这样做：

name=new String[cur.getCount()];String s="";while (cur.movetoNext()) {     int  i=1;     String ID = cur.getString(indexID);         name[i] = cur.getString(indexname);       phoneType[i] =  cur.getString(indexPhoneType);              //System.out.println(ID + "\n");     //System.out.println(name + "\n");     //System.out.println(phoneType + "\n");     s=s+"ID="+ID+" name="+name[i]+" phoneType="+phoneType[i]+"\n";     i++;}Toast.makeText(getApplicationContext(),i+" - "+s).show();

编辑：

在布局文件夹中创建一个xml文件.

main.xml中

<linearLayout    xmlns:androID="http://schemas.androID.com/apk/res/androID"    androID:layout_wIDth="fill_parent"    androID:layout_height="fill_parent" androID:orIEntation="vertical" >        <@R_404_6818@VIEw        androID:layout_wIDth="fill_parent"        androID:layout_height="fill_parent"        androID:ID="@+ID/@R_404_6818@vIEw"        androID:cachecolorHint="#0000"        /></linearLayout>

现在在你的TestActivity.class中：

public final class TestActivity extends Activity {String[] name;String[] phoneType;@R_404_6818@VIEw lv;String s[];public static final String TAG = "ContactManager";@OverrIDepublic voID onCreate(Bundle savedInstanceState){    super.onCreate(savedInstanceState);    setContentVIEw(R.ID.main);            testGetContacts();    lv = (@R_404_6818@VIEw)findVIEwByID(R.ID.@R_404_6818@vIEw);    ArrayAdapter<String> sa=new ArrayAdapter<String>(context, androID.R.layout.simple_@R_404_6818@_item_1,s);    lv.setAdapter(sa);        }private voID testGetContacts() {     ContentResolver cr = getContentResolver();        String[] projection = new String[] { Data._ID,                ContactsContract.Contacts.disPLAY_name, Phone.TYPE};         Cursor cur = cr.query(ContactsContract.Data.CONTENT_URI,                projection, null, null, null);         if (cur != null && cur.movetoFirst()) {         try {            int indexID =  cur.getColumnIndexOrThrow(ContactsContract.Contacts._ID);            int indexname = cur.getColumnIndexOrThrow(ContactsContract.Contacts.disPLAY_name);             int indexPhoneType = cur.getColumnIndexOrThrow(Phone.TYPE);          name=new String[cur.getCount()];          s=new String[cur.getCount()];          while (cur.movetoNext()) {               int  i=1;               String ID = cur.getString(indexID);                   name[i-1] = cur.getString(indexname);                 phoneType[i-1] =  cur.getString(indexPhoneType);                     String temp="ID="+ID+"-name="+name[i-1]+"-phoneType="+phoneType[i-1];              s[i-1]=temp;              i++;}    

}

总结

以上是内存溢出为你收集整理的android – 获取空指针异常？全部内容，希望文章能够帮你解决android – 获取空指针异常？所遇到的程序开发问题。

如果觉得内存溢出网站内容还不错，欢迎将内存溢出网站推荐给程序员好友。