[英]Android: Error with cursor in a SQLite database
我编写了一些效果很好的代码,但是在对某些代码进行较小的清理之后,我得到了这个错误,并且我将其追溯到代码中的curser-action。 它记录Log.d("Start-up",name)
而不记录Log.d("Start-up","Efter")
。 我真的不知道出了什么问题,希望您能帮助我!
db.execSQL("CREATE TABLE " + DATABASE_TABLE2 + " (" +
KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
NAME + " TEXT NOT NULL, " +
PLAYER_1 + " TEXT NOT NULL, " +
PLAYER_2 + " TEXT NOT NULL, " +
PLAYER_3 + " TEXT NOT NULL, " +
PLAYER_4 + " TEXT NOT NULL, " +
PLAYER_5 + " TEXT NOT NULL, " +
ANTAL + " TEXT NOT NULL, " +
OVERSIDDER + " TEXT NOT NULL, " +
G + " TEXT NOT NULL, " +
LOFT + " TEXT NOT NULL);"
);
public boolean doesNameExist(String name){
String[] columns = new String[]{NAME};
Log.d("Start-up",name);
Cursor c = ourDatabase.query(DATABASE_TABLE2, columns, NAME + " = '"+ name + "'", null, null, null, null);
Log.d("Start-up","Efter");
return c.moveToFirst();
}
这是我的日志:
05-02 16:20:58.168: W/dalvikvm(22533): threadid=1: thread exiting with uncaught exception (group=0x400259f8)
05-02 16:20:58.178: E/AndroidRuntime(22533): FATAL EXCEPTION: main
05-02 16:20:58.178: E/AndroidRuntime(22533): java.lang.NullPointerException
05-02 16:20:58.178: E/AndroidRuntime(22533): at com.jesper.whist.DBHelpeR.doesNameExist(DBHelpeR.java:217)
05-02 16:20:58.178: E/AndroidRuntime(22533): at com.jesper.whist.Indstillinger$2.onClick(Indstillinger.java:87)
05-02 16:20:58.178: E/AndroidRuntime(22533): at android.view.View.performClick(View.java:2408)
05-02 16:20:58.178: E/AndroidRuntime(22533): at android.view.View$PerformClick.run(View.java:8817)
05-02 16:20:58.178: E/AndroidRuntime(22533): at android.os.Handler.handleCallback(Handler.java:587)
05-02 16:20:58.178: E/AndroidRuntime(22533): at android.os.Handler.dispatchMessage(Handler.java:92)
05-02 16:20:58.178: E/AndroidRuntime(22533): at android.os.Looper.loop(Looper.java:144)
05-02 16:20:58.178: E/AndroidRuntime(22533): at android.app.ActivityThread.main(ActivityThread.java:4937)
05-02 16:20:58.178: E/AndroidRuntime(22533): at java.lang.reflect.Method.invokeNative(Native Method)
05-02 16:20:58.178: E/AndroidRuntime(22533): at java.lang.reflect.Method.invoke(Method.java:521)
05-02 16:20:58.178: E/AndroidRuntime(22533): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
05-02 16:20:58.178: E/AndroidRuntime(22533): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
05-02 16:20:58.178: E/AndroidRuntime(22533): at dalvik.system.NativeStart.main(Native Method)
编辑:整个类
package com.jesper.whist;
public class Indstillinger extends Activity{
//Variables
public static final String MY_SETTINGS = "MySettings";
EditText name,G,loft,player1,player2,player3,player4,player5;
String antal;
TextView playertext5, overskrift;
Typeface tf;
CheckBox femSpiller;
SharedPreferences settings;
Toast display;
int id;
Button ok_inst;
DBHelpeR entry;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Remove app-name
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
// Set heading font
setContentView(R.layout.indstillinger);
tf = Typeface.createFromAsset(getAssets(), "FargoFaroNF.ttf");
overskrift = (TextView) findViewById(R.id.indstillinger);
overskrift.setTypeface(tf);
// Setting up Shared prefenceres and database
settings = getSharedPreferences(MY_SETTINGS, 0);
entry = new DBHelpeR(Indstillinger.this);
// More variables
G = (EditText) findViewById(R.id.etG);
G.setText("15");
loft = (EditText) findViewById(R.id.etLoft);
loft.setText("10000");
name = (EditText) findViewById(R.id.etName);
player1 = (EditText) findViewById(R.id.etPlayer1);
player2 = (EditText) findViewById(R.id.etPlayer2);
player3 = (EditText) findViewById(R.id.etPlayer3);
player4 = (EditText) findViewById(R.id.etPlayer4);
player5 = (EditText) findViewById(R.id.etPlayer5);
playertext5 = (TextView) findViewById(R.id.tvPlayer5);
femSpiller = (CheckBox) findViewById(R.id.cb_fem);
ok_inst = (Button) findViewById(R.id.bInst);
// Toast
display = Toast.makeText(this, "Navnet er optaget! Vælg et nyt!", Toast.LENGTH_SHORT);
// Get id from Shared Preferences
id = settings.getInt("game_id", 0);
// Hvis 5-spillere-checkboxen checkes, vis indstillingsmuligheder
femSpiller.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener(){
@Override
public void onCheckedChanged(CompoundButton buttonView,
boolean isChecked) {
playertext5.setVisibility(View.VISIBLE); // Vis TextView
player5.setVisibility(View.VISIBLE); // Vis EditText
}
});
// Ved klik på ok-knappen
ok_inst.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Check if name exist
if(entry.doesNameExist(name.getText().toString())==true){
display.show(); // Vis toast
}
// Hvis navnet ikke eksistere
else{
if(femSpiller.isChecked()){antal = "5";} // Hvis der er 5 spillere
else{antal = "4";} // Hvis der er 4 spillere
entry.open();
// Lav entry i Spil_table: spil navn, spillernavne, antal, oversidder=5 så sidste man sidder over i første runde, grundtakst, loft
entry.createEntrySpil(name.getText().toString(), player1.getText().toString(), player2.getText().toString(), player3.getText().toString(), player4.getText().toString(), player5.getText().toString(), antal,"5", G.getText().toString(), loft.getText().toString());
entry.createEntryPenge(id,"0","0","0","0","0"); // Lav en nul-entry så det virker
entry.close();
// Start WHIST! og afslut denne proces
startActivity(new Intent("com.jesper.whist.WHIST"));
finish();
}
}
});
}
}
好吧,从您的logcat来看,我将在两个地方查看...
第87行附近的Indstillinger
和
围绕217行的DBHelpeR
发布这些代码部分,也许我们会有所帮助。
编辑
好的,我看到光标位已发布(刚刚醒来,对不起)。 我确实没有发现该查询有任何问题(假设您已经定义了ourDatabase
因为您没有在发布的代码中显示该信息),所以我将看一下第87行的Indstillinger。这似乎是第一个参考错误日志中的代码。
第二编辑
您正在使用一种要求在打开数据库之前将其打开的方法。 在调用dosNameExist之前,请执行entry.open()。
没有特定的错误,这只是一个猜测,但是:
经过一些代码的小幅清理后,我得到此错误
您更改了表格结构吗? 如果是这样,则需要重建数据库,最简单的方法是增加DATABASE_VERSION。
加成
空指针异常表示尚未定义变量,可能是ourDatabase
。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.