致命异常,java语言空指针异常
我下面的代码没有显示错误,但不会执行致命异常,java语言空指针异常,java,android,eclipse,Java,Android,Eclipse,我下面的代码没有显示错误,但不会执行 package my.project.mil; import android.content.Context; import android.content.Intent; import android.database.sqlite.SQLiteDatabase; import android.os.Bundle; import android.view.View; import android.widget.Button; import android
package my.project.mil;
import android.content.Context;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class Cbdata extends MainActivity {
public String str;
public void onReceive(Context context, Intent intent) {
//---get the CB message passed in---
Bundle bundle = intent.getExtras();
SmsCbMessage[] msgs = null;
str = "";
if (bundle != null) {
//---retrieve the SMS message received---
Object[] pdus = (Object[]) bundle.get("pdus");
msgs = new SmsCbMessage[pdus.length];
for (int i=0; i<msgs.length; i++) {
msgs[i] = SmsCbMessage.createFromPdu((byte[])pdus[i]);
str += "CB " + msgs[i].getGeographicalScope() + msgs[i].getMessageCode() + msgs[i].getMessageIdentifier() + msgs[i].getUpdateNumber();
str += " :";
str += msgs[i].getMessageBody().toString();
str += "\n";
}}
}
SQLiteDatabase cd = openOrCreateDatabase("MLIdb", MODE_WORLD_READABLE, null);
Button submit;
Button viewdb;
EditText name;
@Override
public void onCreate(Bundle savedInstanceState)
{
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.seventh);
viewdb = (Button) findViewById(R.id.viewdb);
submit = (Button) findViewById(R.id.submit);
name = (EditText) findViewById(R.id.name);
submit.setOnClickListener(new View.OnClickListener()
{
public void onClick(View arg0) {
String locname = name.getText().toString();
if (locname.length()>0)
{
cd.execSQL("CREATE TABLE IF NOT EXITSTS MLITable (CblocationCode INT(10), CblocationName VARCHAR);");
cd.execSQL("INSERT INTO MLITable VALUES (' ',' ');" +str +locname);
Toast.makeText(getBaseContext(), "value successfully entered.", Toast.LENGTH_LONG).show();
}
else
{
Toast.makeText(getBaseContext(), "Please enter the location name, for example 'Home'.", Toast.LENGTH_LONG).show();
}
}
});
cd.close();
viewdb.setOnClickListener(new View.OnClickListener()
{
public void onClick(View arg0) {
// TODO Auto-generated method stub
// here comes the code for viewing the database
}
});
}
}
包my.project.mil;
导入android.content.Context;
导入android.content.Intent;
导入android.database.sqlite.SQLiteDatabase;
导入android.os.Bundle;
导入android.view.view;
导入android.widget.Button;
导入android.widget.EditText;
导入android.widget.Toast;
公共类Cbdata扩展main活动{
公共字符串str;
公共void onReceive(上下文、意图){
//---获取传入的CB消息---
Bundle=intent.getExtras();
SmsCbMessage[]msgs=null;
str=“”;
if(bundle!=null){
//---检索收到的SMS消息---
Object[]pdus=(Object[])bundle.get(“pdus”);
msgs=新的SmsCbMessage[pdus.length];
对于(int i=0;i0)
{
execSQL(“如果不存在,则创建表MLITable(CblocationCode INT(10),CblocationName VARCHAR);”;
execSQL(“插入到MLITable值(“”,”);“+str+locname);
Toast.makeText(getBaseContext(),“值已成功输入”,Toast.LENGTH_LONG.show();
}
其他的
{
Toast.makeText(getBaseContext(),“请输入位置名称,例如“Home.”,Toast.LENGTH_LONG).show();
}
}
});
cd.close();
viewdb.setOnClickListener(新视图.OnClickListener()
{
公共void onClick(视图arg0){
//TODO自动生成的方法存根
//下面是查看数据库的代码
}
});
}
}
我的错误日志如下所示,我也检查了我的清单和MainActivity文件,但没有任何运气
我的代码应该收集用户的基站区号,并将其保存在用户选择名称的数据库上,该数据库由两个属性组成,一个是从用户处收集的位置名称,另一个是从onReceive方法获得的基站广播塔信息,单独使用onReceive方法可以很好地工作
只有当我将数据库集成到代码中时,才会出现此问题。多谢各位
SQLiteDatabase cd = openOrCreateDatabase("MLIdata", MODE_WORLD_WRITEABLE, null);
试着把这条线换成
SQLiteDatabase cd = openOrCreateDatabase("MLIdata", MODE_WORLD_WRITEABLE);
我在上述代码中的错误
public class Cbdata extends MainActivity {
public String str;
public void onReceive(Context context, Intent intent) {
//---get the CB message passed in---
Bundle bundle = intent.getExtras();
SmsCbMessage[] msgs = null;
str = "";
if (bundle != null) {
//---retrieve the SMS message received---
Object[] pdus = (Object[]) bundle.get("pdus");
msgs = new SmsCbMessage[pdus.length];
for (int i=0; i<msgs.length; i++) {
msgs[i] = SmsCbMessage.createFromPdu((byte[])pdus[i]);
str += "CB " + msgs[i].getGeographicalScope() + msgs[i].getMessageCode() + msgs[i].getMessageIdentifier() + msgs[i].getUpdateNumber();
str += " :";
str += msgs[i].getMessageBody().toString();
str += "\n";
}}
}
Button submit;
Button viewdb;
EditText name;
@Override
public void onCreate(Bundle savedInstanceState)
{
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.seventh);
viewdb = (Button) findViewById(R.id.viewdb);
submit = (Button) findViewById(R.id.submit);
name = (EditText) findViewById(R.id.name);
submit.setOnClickListener(new View.OnClickListener()
{
public void onClick(View arg0) {
String locname = name.getText().toString();
if (locname.length()>0)
{
SQLiteDatabase cd = openOrCreateDatabase("mydata", MODE_WORLD_READABLE, null);
cd.execSQL("CREATE TABLE IF NOT EXISTS MLITable (CblocationCode INT(10), CblocationName VARCHAR);");
cd.execSQL("INSERT INTO MLITable VALUES ('"+str+ "','"+locname+ "');");
Toast.makeText(getBaseContext(), "value successfully entered.", Toast.LENGTH_LONG).show();
cd.close();
}
else
{
Toast.makeText(getBaseContext(), "Please enter the location name, for example 'Home'.", Toast.LENGTH_LONG).show();
}
}
});
viewdb.setOnClickListener(new View.OnClickListener()
{
public void onClick(View arg0) {
// TODO Auto-generated method stub
// here comes the code for viewing the database
}
});
}
}
public类Cbdata扩展main活动{
公共字符串str;
公共void onReceive(上下文、意图){
//---获取传入的CB消息---
Bundle=intent.getExtras();
SmsCbMessage[]msgs=null;
str=“”;
if(bundle!=null){
//---检索收到的SMS消息---
Object[]pdus=(Object[])bundle.get(“pdus”);
msgs=新的SmsCbMessage[pdus.length];
对于(int i=0;i0)
{
SQLiteDatabase cd=openOrCreateDatabase(“mydata”,模式为世界可读,空);
execSQL(“如果不存在创建表MLITable(CblocationCode INT(10),CblocationName VARCHAR);”;
execSQL(“插入到MLITable值(““+str+”,“+locname+”);”;
Toast.makeText(getBaseContext(),“值已成功输入”,Toast.LENGTH_LONG.show();
cd.close();
}
其他的
{
Toast.makeText(getBaseContext(),“请输入位置名称,例如“Home.”,Toast.LENGTH_LONG).show();
}
}
});
viewdb.setOnClickListener(新视图.OnClickListener()
{
公共void onClick(视图arg0){
//TODO自动生成的方法存根
//下面是查看数据库的代码
}
});
}
}
我已经按照您的建议进行了更改,但运气不好!他们之间有什么区别?