无法在method();中运行SqLite

Question

我遇到了这个未知的问题，我就是无法解决这个问题，当我在android中从sqlite中检索值时，它工作得很好，我在两个类中做了同样的事情，它都很好，它做了我想做的事，但当我在一个方法中这样做时，它不起作用，它给了我一个空指针异常，它在除方法外的所有地方都起作用错误，我的应用程序关闭。

我的数据库在这里工作

public class Activity5 extends Activity {
public  static String  tableler; 
final Context cont = this;
static String a1,a2,a3,a4,a5,a6,a7,a8;
static String out,out2,out3,out4,out5,out6,out7,out8;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity5);
final EditText edt = (EditText)findViewById(R.id.replayedit);
Button btnsave = (Button) findViewById(R.id.btnSaveChange);
Button btncancel = (Button) findViewById(R.id.btnCancel);
SQLiteDatabase db = openOrCreateDatabase("ComDB", MODE_PRIVATE, null);
Cursor c = db.rawQuery("SELECT REPLAYS FROM Rtm WHERE ID = "+Activity3.replays, null);
c.moveToFirst();
out = c.getString(c.getColumnIndex("REPLAYS"));
db.close();
c.close();
if(Activity3.replays.contains("1"))
{
edt.setText("great"+out);
}if(Activity3.replays.contains("2"))
{
edt.setText("great"+out);
}if(Activity3.replays.contains("3"))
{
edt.setText("great"+out);
}if(Activity3.replays.contains("4"))
{
edt.setText("great"+out);
}if(Activity3.replays.contains("5"))
{
edt.setText("great"+out);
}if(Activity3.replays.contains("6"))
{
edt.setText("great"+out);
}if(Activity3.replays.contains("7"))
{
edt.setText("great"+out);
}if(Activity3.replays.contains("8"))
{
edt.setText("great"+out);
}

// this.vieww();
// this.edit();
btnsave.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
String updates = edt.getText().toString();
updater(Activity3.replays, updates);
Toast.makeText(cont, "Your Implementation   complete",Toast.LENGTH_LONG ).show();
}
});

btncancel.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
}
});   


}

public void updater(String sid,String vals)
{
String tableNb = "REPLAYS";
String tablela = "Rtm";
String ID = "ID";
SQLiteDatabase db = openOrCreateDatabase("ComDB", MODE_PRIVATE, null);  
ContentValues cv = new ContentValues();
cv.put(tableNb, vals);
db.update(tablela, cv, ID+"="+sid, null);
//  Cursor c = db.rawQuery("SELECT REPLAYS FROM Rtm WHE", selectionArgs)
db.close();

}

}  

它在这里给出错误并关闭我的应用

public class SendGlass extends Activity{
static String replay;


public void sms (String phone,String Sms )
{
SmsManager  smsManager = SmsManager.getDefault();
String phoneNo = phone;
String sms = Sms;
String api = "You Entered one";
String api2 = "You Entered two";
String api3 = "Nothing great";
String rep = sms.replace(phoneNo+" :", "");

SQLiteDatabase db = openOrCreateDatabase("ComDB", MODE_PRIVATE, null);
Cursor c = db.rawQuery("SELECT REPLAYS FROM Rtm WHERE ID = 1", null);
while(c.moveToNext())
{
replay = c.getString(c.getColumnIndex("REPLAYS"));
if(rep.equals("1"))
{
//  String replay = c.getString(c.getColumnIndex("REPLAYS"));
smsManager.sendTextMessage(phoneNo, null, replay, null, null);
}if(rep.equals("2"))
{

//  String replay = c.getString(c.getColumnIndex("REPLAYS"));
smsManager.sendTextMessage(phoneNo, null, replay, null, null);
}if(rep.equals("3"))
{
smsManager.sendTextMessage(phoneNo, null, replay, null, null);
}if(rep.equals("4"))
{
smsManager.sendTextMessage(phoneNo, null, replay, null, null);
}if(rep.equals("5"))
{
smsManager.sendTextMessage(phoneNo, null, replay, null, null);
}if(rep.equals("6"))
{
smsManager.sendTextMessage(phoneNo, null, replay, null, null);
}if(rep.equals("7"))
{
smsManager.sendTextMessage(phoneNo, null, replay, null, null);
}if(rep.equals("8"))
{
smsManager.sendTextMessage(phoneNo, null, replay, null, null);
}
}
}  

我的BroadCast类从中获取sendGlass 的参数

public class BroadCastRecivers extends BroadcastReceiver{
static String from;
static String body;
@Override
public void onReceive(Context cont, Intent intent) {
// TODO Auto-generated method 
//  SmsManager  smsManager = SmsManager.getDefault();

// TODO Auto-generated method s
//---get the SMS message passed in---
Bundle bundle = intent.getExtras();        
SmsMessage[] msgs = null;
String str = "";            
if (bundle != null)
{
//---retrieve the SMS message received---
Object[] pdus = (Object[]) bundle.get("pdus");
msgs = new SmsMessage[pdus.length];            
for (int i=0; i<msgs.length; i++){
msgs[i] = SmsMessage.createFromPdu((byte[])pdus[i]);                
from =   str +=  "SMS from " + msgs[i].getOriginatingAddress();              
str += " :";
body =  str += msgs[i].getMessageBody().toString();
str += "n";
}
//---display the new SMS message---
Toast.makeText(cont, str, Toast.LENGTH_LONG).show();
// ret = str;
//   int tos =  Integer.valueOf(body);
//  obj.Decision(from, tos);
// sms(from, body);     
//    String phoneNo = phone;
//  String sms = Sms;
//  SmsManager  smsManager = SmsManager.getDefault();
//  smsManager.sendTextMessage(phoneNo, null, sms, null, null);   

/**      Activity5 obj = new Activity5();
String rep = body.replace("from"+" :", "");
if(rep.equals("1"))
{
Activity3.replays = rep;
obj.select(from, rep);
}if(rep.equals("2"))
{
Activity3.replays = rep;
obj.select(from, rep);
}if(rep.equals("3"))
{
Activity3.replays = rep;
obj.select(from, rep);
}if(rep.equals("4"))
{
Activity3.replays = rep;
obj.select(from, rep);
}if(rep.equals("5"))
{
Activity3.replays = rep;
obj.select(from, rep);
}if(rep.equals("6"))
{
Activity3.replays = rep;
obj.select(from, rep);
}if(rep.equals("7"))
{
Activity3.replays = rep;
obj.select(from, rep);
}if(rep.equals("8"))
{
Activity3.replays = rep;
obj.select(from, rep);
}else
{
rep = "Sorry man";
obj.select(from, rep);
}
**/

from = "somehing";
body = "exception";
SendGlass obj = new SendGlass();
obj.sms(from, body);

}}

我的日志猫。

12-05 23:37:38.507: D/AndroidRuntime(267): Shutting down VM
12-05 23:37:38.507: W/dalvikvm(267): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
12-05 23:37:38.597: E/AndroidRuntime(267): FATAL EXCEPTION: main
12-05 23:37:38.597: E/AndroidRuntime(267): java.lang.RuntimeException: Unable to start receiver automator.mator.BroadCastRecivers: java.lang.NullPointerException
12-05 23:37:38.597: E/AndroidRuntime(267):    at android.app.ActivityThread.handleReceiver(ActivityThread.java:2821)
12-05 23:37:38.597: E/AndroidRuntime(267):    at android.app.ActivityThread.access$3200(ActivityThread.java:125)
12-05 23:37:38.597: E/AndroidRuntime(267):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2083)
12-05 23:37:38.597: E/AndroidRuntime(267):    at android.os.Handler.dispatchMessage(Handler.java:99)
12-05 23:37:38.597: E/AndroidRuntime(267):    at android.os.Looper.loop(Looper.java:123)
12-05 23:37:38.597: E/AndroidRuntime(267):   at android.app.ActivityThread.main(ActivityThread.java:4627)
12-05 23:37:38.597: E/AndroidRuntime(267):   at java.lang.reflect.Method.invokeNative(Native Method)
12-05 23:37:38.597: E/AndroidRuntime(267):   at java.lang.reflect.Method.invoke(Method.java:521)
12-05 23:37:38.597: E/AndroidRuntime(267):   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
12-05 23:37:38.597: E/AndroidRuntime(267):   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
12-05 23:37:38.597: E/AndroidRuntime(267):   at dalvik.system.NativeStart.main(Native Method)
12-05 23:37:38.597: E/AndroidRuntime(267): Caused by: java.lang.NullPointerException
12-05 23:37:38.597: E/AndroidRuntime(267):   at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:203)
12-05 23:37:38.597: E/AndroidRuntime(267):   at automator.mator.SendGlass.<init>(SendGlass.java:12)
12-05 23:37:38.597: E/AndroidRuntime(267):   at automator.mator.BroadCastRecivers.onReceive(BroadCastRecivers.java:100)
12-05 23:37:38.597: E/AndroidRuntime(267):   at  android.app.ActivityThread.handleReceiver(ActivityThread.java:2810)
12-05 23:37:38.597: E/AndroidRuntime(267):   ... 10 more
12-05 23:37:43.027: I/Process(267): Sending signal. PID: 267 SIG: 9

如果我使用硬编码字符串，那么我的the方法有效，它只会在从数据库获取值时出错。

Answer 1

您对openOrCreateDatabase()的调用看起来很糟糕。我没有看到任何使用这些类型的方法的签名。我在javadoc中看到的是这三个签名：

• openOrCreateDatabase(字符串路径，SQLiteDatabase.CursorFactory工厂，DatabaseErrorHandler错误处理程序)
• openOrCreateDatabase(字符串路径，SQLiteDatabase.CursorFactory工厂)
• openOrCreateDatabase(文件文件，SQLiteDatabase.CursorFactory工厂)

这些都不符合您的使用情况，这似乎是openOrCreateDatabase(路径路径，int模式，对象)

我还注意到，您试图使用数据库变量"db"，而不首先检查它是否包含某些内容。这不是一个好的编程实践。我从不认为打开的文件或数据库已经起作用；没有人知道。

此外，您尝试在Cursor"c"上调用c.moveToNext()，而不首先验证c是否存在并包含一行。这绝对不是一个好的编程实践总是测试c！=null，并测试c.moveToFirst==true。这确保了数据库调用有效(也就是说，它没有返回null)，并且您得到了返回行(c.MoveToFirst有效)。

Answer 2

您还没有在SendGlass中使用任何Activity方法。。。

• 您必须通过调用startActivity(Intent)来启动"活动">
• 必须等待调用onCreate()后才能使用"活动"的上下文
• 不能用new SendGlass().sms(phone, sms)调用sms()

否则，您将在ContextWrapper类中看到这些NullPointerException被抛出。

例如，SendGlass应该更像这样：

public class SendGlass extends Activity{
static String replay;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent intent = getIntent();
if(intent != null) {
sms(intent.getStringExtra("phone", ""), intent.getStringExtra("sms", ""));
}
}
...    

---

添加
我看到您添加了BroadcastReceiver代码。就像我猜的那样，你正试图用启动你的活动

SendGlass obj = new SendGlass();
obj.sms(from, body);

正如我所说，您必须使用Intents和startActivity():

Intent intent = new Intent(cont, SendGlass.class);
intent.putExtra("phone", from);
intent.putExtra("sms", body);
cont.startActivity(intent);