这是数据库类。它在 getReadableDatabase() 中显示错误。下面是日志文件。请帮我看看错在哪里。
package achira.test;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DatabaseHelper extends SQLiteOpenHelper {
static final String dbName="achira";
static final String employeeTable="patient";
static final String colID="UID";
static final String colName="patientName";
static final String colAge="Age";
static final String colDept="Test";
static final String deptTable="Test1";
static final String colDeptID="TestID";
static final String colDeptName="TesttName";
static final String viewEmps="ViewPatient";
public DatabaseHelper(Context context) {
super(context, dbName, null,40);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("CREATE TABLE "+deptTable+" ("+colDeptID+ " INTEGER PRIMARY KEY , "+
colDeptName+ " TEXT)");
db.execSQL("CREATE TABLE "+employeeTable+" ("+colID+" INTEGER PRIMARY KEY AUTOINCREMENT, "+
colName+" TEXT, "+colAge+" Integer, "+colDept+" INTEGER NOT NULL ,FOREIGN KEY ("+colDept+") REFERENCES "+deptTable+" ("+colDeptID+"));");
db.execSQL("CREATE TRIGGER fk_empdept_deptid " +
" BEFORE INSERT "+
" ON "+employeeTable+
" FOR EACH ROW BEGIN"+
" SELECT CASE WHEN ((SELECT "+colDeptID+" FROM "+deptTable+" WHERE "+colDeptID+"=new."+colDept+" ) IS NULL)"+
" THEN RAISE (ABORT,'Foreign Key Violation') END;"+
" END;");
db.execSQL("CREATE VIEW "+viewEmps+
" AS SELECT "+employeeTable+"."+colID+" AS _id,"+
" "+employeeTable+"."+colName+","+
" "+employeeTable+"."+colAge+","+
" "+deptTable+"."+colDeptName+""+
" FROM "+employeeTable+" JOIN "+deptTable+
" ON "+employeeTable+"."+colDept+" ="+deptTable+"."+colDeptID
);
//Inserts pre-defined departments
InsertDepts(db);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS "+employeeTable);
db.execSQL("DROP TABLE IF EXISTS "+deptTable);
db.execSQL("DROP TRIGGER IF EXISTS dept_id_trigger");
db.execSQL("DROP TRIGGER IF EXISTS dept_id_trigger22");
db.execSQL("DROP TRIGGER IF EXISTS fk_empdept_deptid");
db.execSQL("DROP VIEW IF EXISTS "+viewEmps);
onCreate(db);
}
void patient(patient emp)
{
SQLiteDatabase db= this.getWritableDatabase();
ContentValues cv=new ContentValues();
cv.put(colName, emp.getName());
cv.put(colAge, emp.getAge());
cv.put(colDept, emp.getDept());
//cv.put(colDept,2);
db.insert(employeeTable, colName, cv);
db.close();
}
int getEmployeeCount()
{
SQLiteDatabase db=this.getWritableDatabase();
Cursor cur= db.rawQuery("Select * from "+employeeTable, null);
int x= cur.getCount();
cur.close();
return x;
}
Cursor getAllEmployees()
{
SQLiteDatabase db=this.getWritableDatabase();
//Cursor cur= db.rawQuery("Select "+colID+" as _id , "+colName+", "+colAge+" from "+employeeTable, new String [] {});
Cursor cur= db.rawQuery("SELECT * FROM "+viewEmps,null);
return cur;
}
Cursor getAllDepts()
{
SQLiteDatabase db=this.getReadableDatabase();
Cursor cur=db.rawQuery("SELECT "+colDeptID+" as _id, "+colDeptName+" from "+deptTable,new String [] {});
return cur;
}
void InsertDepts(SQLiteDatabase db)
{
ContentValues cv=new ContentValues();
cv.put(colDeptID, 1);
cv.put(colDeptName, "XYZ");
db.insert(deptTable, colDeptID, cv);
cv.put(colDeptID, 2);
cv.put(colDeptName, "ABC");
db.insert(deptTable, colDeptID, cv);
cv.put(colDeptID, 3);
cv.put(colDeptName, "HIV");
db.insert(deptTable, colDeptID, cv);
cv.put(colDeptID, 4);
cv.put(colDeptName, "HIV");
db.insert(deptTable, colDeptID, cv);
db.insert(deptTable, colDeptID, cv);
}
public String GetDept(int ID)
{
SQLiteDatabase db=this.getReadableDatabase();
String[] params=new String[]{String.valueOf(ID)};
Cursor c=db.rawQuery("SELECT "+colDeptName+" FROM"+ deptTable+" WHERE "+colDeptID+"=?",params);
c.moveToFirst();
int index= c.getColumnIndex(colDeptName);
return c.getString(index);
}
public Cursor getEmpByDept(String Dept)
{
SQLiteDatabase db=this.getReadableDatabase();
String [] columns=new String[]{"_id",colName,colAge,colDeptName};
Cursor c=db.query(viewEmps, columns, colDeptName+"=?", new String[]{Dept}, null, null, null);
return c;
}
public int GetDeptID(String Dept)
{
SQLiteDatabase db=this.getReadableDatabase();
Cursor c=db.query(deptTable, new String[]{colDeptID+" as _id",colDeptName},colDeptName+"=?", new String[]{Dept}, null, null, null);
//Cursor c=db.rawQuery("SELECT "+colDeptID+" as _id FROM "+deptTable+" WHERE "+colDeptName+"=?", new String []{Dept});
c.moveToFirst();
return c.getInt(c.getColumnIndex("_id"));
}
public int UpdateEmp(patient emp)
{
SQLiteDatabase db=this.getWritableDatabase();
ContentValues cv=new ContentValues();
cv.put(colName, emp.getName());
cv.put(colAge, emp.getAge());
cv.put(colDept, emp.getDept());
return db.update(employeeTable, cv, colID+"=?", new String []{String.valueOf(emp.getID())});
}
public void DeleteEmp(patient emp)
{
SQLiteDatabase db=this.getWritableDatabase();
db.delete(employeeTable,colID+"=?", new String [] {String.valueOf(emp.getID())});
db.close();
}
}
这是日志文件：
06-19 13:17:32.854: W/dalvikvm(873): threadid=1: thread exiting with uncaught exception (group=0x409c01f8)
06-19 13:17:32.934: E/AndroidRuntime(873): FATAL EXCEPTION: main
06-19 13:17:32.934: E/AndroidRuntime(873): java.lang.RuntimeException: Unable to start activity ComponentInfo{achira.test/achira.test.GridList}: java.lang.NullPointerException
06-19 13:17:32.934: E/AndroidRuntime(873): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
06-19 13:17:32.934: E/AndroidRuntime(873): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
06-19 13:17:32.934: E/AndroidRuntime(873): at android.app.ActivityThread.access$600(ActivityThread.java:123)
06-19 13:17:32.934: E/AndroidRuntime(873): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
06-19 13:17:32.934: E/AndroidRuntime(873): at android.os.Handler.dispatchMessage(Handler.java:99)
06-19 13:17:32.934: E/AndroidRuntime(873): at android.os.Looper.loop(Looper.java:137)
06-19 13:17:32.934: E/AndroidRuntime(873): at android.app.ActivityThread.main(ActivityThread.java:4424)
06-19 13:17:32.934: E/AndroidRuntime(873): at java.lang.reflect.Method.invokeNative(Native Method)
06-19 13:17:32.934: E/AndroidRuntime(873): at java.lang.reflect.Method.invoke(Method.java:511)
06-19 13:17:32.934: E/AndroidRuntime(873): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
06-19 13:17:32.934: E/AndroidRuntime(873): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
06-19 13:17:32.934: E/AndroidRuntime(873): at dalvik.system.NativeStart.main(Native Method)
06-19 13:17:32.934: E/AndroidRuntime(873): Caused by: java.lang.NullPointerException
06-19 13:17:32.934: E/AndroidRuntime(873): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:157)
06-19 13:17:32.934: E/AndroidRuntime(873): at android.database.sqlite.SQLiteOpenHelper.getReadableDatabase(SQLiteOpenHelper.java:231)
06-19 13:17:32.934: E/AndroidRuntime(873): at achira.test.DatabaseHelper.getAllDepts(DatabaseHelper.java:126)
06-19 13:17:32.934: E/AndroidRuntime(873): at achira.test.Utilities.ManageDeptSpinner(Utilities.java:13)
06-19 13:17:32.934: E/AndroidRuntime(873): at achira.test.GridList.onCreate(GridList.java:35)
06-19 13:17:32.934: E/AndroidRuntime(873): at android.app.Activity.performCreate(Activity.java:4465)
06-19 13:17:32.934: E/AndroidRuntime(873): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
06-19 13:17:32.934: E/AndroidRuntime(873): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
06-19 13:17:32.934: E/AndroidRuntime(873): ... 11 more
06-19 13:17:33.114: D/dalvikvm(873): GC_CONCURRENT freed 62K, 2% free 11769K/11975K, paused 5ms+60ms