在Java中从SQLite值创建菜单
我正在尝试使用SQLite数据库中的数据创建一个在Java中从SQLite值创建菜单,java,android,sqlite,Java,Android,Sqlite,我正在尝试使用SQLite数据库中的数据创建一个列表菜单，以定义每个MenuItem的名称。因此，在一个名为menu.java的类中，我定义了数组 String classes [] = {}; 它应该包含每个菜单项的名称 在DBAdapter类中，我创建了一个函数，以便用户可以将信息插入表中（顺便说一句，这一切都很好） 我需要将字符串插入到KEY_NAME中，以填充该字符串数组。有人知道这是否可能吗 非常感谢你们的帮助 如果我通过Sam/Mango实现该功能，程序会崩溃，是我使用的不正确，还
列表菜单MenuItemmenu.javaString classes [] = {};
字符串字符串DBAdapter db = new DBAdapter(this);
String classes [] = db.getClasses();
String classes [] = {"test1", "test2", "test3", etc};
11-11 22:53:39.117: D/dalvikvm(17856): Late-enabling CheckJNI
11-11 22:53:39.297: D/TextLayoutCache(17856): Using debug level: 0 - Debug Enabled: 0
11-11 22:53:39.337: D/libEGL(17856): loaded /system/lib/egl/libGLES_android.so
11-11 22:53:39.337: D/libEGL(17856): loaded /system/lib/egl/libEGL_adreno200.so
11-11 22:53:39.357: D/libEGL(17856): loaded /system/lib/egl/libGLESv1_CM_adreno200.so
11-11 22:53:39.357: D/libEGL(17856): loaded /system/lib/egl/libGLESv2_adreno200.so
11-11 22:53:39.387: I/Adreno200-EGLSUB(17856): <ConfigWindowMatch:2078>: Format RGBA_8888.
11-11 22:53:39.407: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x5c66d000 size:36593664 offset:32825344 fd:65
11-11 22:53:39.417: E/(17856): Can't open file for reading
11-11 22:53:39.417: E/(17856): Can't open file for reading
11-11 22:53:39.417: D/OpenGLRenderer(17856): Enabling debug mode 0
11-11 22:53:39.477: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x5ecd3000 size:40361984 offset:36593664 fd:68
11-11 22:53:40.507: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x61451000 size:7254016 offset:3485696 fd:71
11-11 22:53:41.077: I/Adreno200-EGLSUB(17856): <ConfigWindowMatch:2078>: Format RGBA_8888.
11-11 22:53:41.077: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x61c4c000 size:7725056 offset:7254016 fd:74
11-11 22:53:41.097: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x623aa000 size:8196096 offset:7725056 fd:80
11-11 22:53:41.937: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x62b7b000 size:8667136 offset:8196096 fd:83
11-11 22:53:41.977: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x61c4c000 size:7725056 offset:7254016
11-11 22:53:41.977: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x623aa000 size:8196096 offset:7725056
11-11 22:53:41.977: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x62b7b000 size:8667136 offset:8196096
11-11 22:53:42.167: I/Adreno200-EGLSUB(17856): <ConfigWindowMatch:2078>: Format RGBA_8888.
11-11 22:53:42.177: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x61c5d000 size:17084416 offset:13316096 fd:74
11-11 22:53:42.317: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x63853000 size:20852736 offset:17084416 fd:80
11-11 22:53:42.357: D/OpenGLRenderer(17856): Flushing caches (mode 0)
11-11 22:53:42.357: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x5c66d000 size:36593664 offset:32825344
11-11 22:53:42.357: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x5ecd3000 size:40361984 offset:36593664
11-11 22:53:42.367: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x61451000 size:7254016 offset:3485696
11-11 22:53:42.757: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x5c56d000 size:24621056 offset:20852736 fd:65
11-11 22:53:44.247: D/AndroidRuntime(17856): Shutting down VM
11-11 22:53:44.247: W/dalvikvm(17856): threadid=1: thread exiting with uncaught exception (group=0x40ac3210)
11-11 22:53:44.257: E/AndroidRuntime(17856): FATAL EXCEPTION: main
11-11 22:53:44.257: E/AndroidRuntime(17856): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{x.x.timetable/x.x.timetable.menu}: java.lang.NullPointerException
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1891)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1992)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread.access$600(ActivityThread.java:127)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1158)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.os.Handler.dispatchMessage(Handler.java:99)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.os.Looper.loop(Looper.java:137)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread.main(ActivityThread.java:4441)
11-11 22:53:44.257: E/AndroidRuntime(17856): at java.lang.reflect.Method.invokeNative(Native Method)
11-11 22:53:44.257: E/AndroidRuntime(17856): at java.lang.reflect.Method.invoke(Method.java:511)
11-11 22:53:44.257: E/AndroidRuntime(17856): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:823)
11-11 22:53:44.257: E/AndroidRuntime(17856): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:590)
11-11 22:53:44.257: E/AndroidRuntime(17856): at dalvik.system.NativeStart.main(Native Method)
11-11 22:53:44.257: E/AndroidRuntime(17856): Caused by: java.lang.NullPointerException
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:221)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:157)
11-11 22:53:44.257: E/AndroidRuntime(17856): at x.x.timetable.DBAdapter.getClasses(DBAdapter.java:151)
11-11 22:53:44.257: E/AndroidRuntime(17856): at x.x.timetable.menu.<init>(menu.java:15)
11-11 22:53:44.257: E/AndroidRuntime(17856): at java.lang.Class.newInstanceImpl(Native Method)
11-11 22:53:44.257: E/AndroidRuntime(17856): at java.lang.Class.newInstance(Class.java:1319)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.Instrumentation.newActivity(Instrumentation.java:1023)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1882)
11-11 22:53:44.257: E/AndroidRuntime(17856): ... 11 more
11-11 22:53:46.527: I/Process(17856): Sending signal. PID: 17856 SIG: 9
package x.x.timetable;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class DBAdapter {
static final String KEY_ROWID = "_id";
static final String KEY_NAME = "name";
static final String KEY_CODE = "code";
static final String KEY_LOCATION = "location";
static final String KEY_COMMENTS = "comments";
static final String KEY_DAYS = "days";
static final String KEY_START = "start";
static final String KEY_END = "end";
static final String KEY_TYPE = "type";
static final String TAG = "DBAdapter";
static final String DATABASE_NAME = "MyDB";
static final String DATABASE_TABLE = "timetable";
static final int DATABASE_VERSION = 2;
static final String DATABASE_CREATE =
"create table timetable (_id integer primary key autoincrement, "
+ "name text not null, code text not null, location text not null, comments text not null, days INTEGER not null, start INTEGER not null, end INTEGER not null, type text not null);";
final Context context;
DatabaseHelper DBHelper;
SQLiteDatabase db;
public DBAdapter(Context ctx)
{
this.context = ctx;
DBHelper = new DatabaseHelper(context);
}
private static class DatabaseHelper extends SQLiteOpenHelper
{
DatabaseHelper(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db)
{
try {
db.execSQL(DATABASE_CREATE);
} catch (SQLException e) {
e.printStackTrace();
}
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS timetable");
db.execSQL("DROP TABLE IF EXISTS contacts");
onCreate(db);
}
}
//---opens the database---
public DBAdapter open() throws SQLException
{
db = DBHelper.getWritableDatabase();
return this;
}
//---closes the database---
public void close()
{
DBHelper.close();
}
public int count(){
db = DBHelper.getWritableDatabase();
String count = "SELECT count(*) FROM table";
Cursor mcursor = db.rawQuery(count, null);
int icount = mcursor.getInt(0);
return icount;
}
//---insert a contact into the database---
public long insertContact(String name, String code, String location, String comments, int days, int start, int end, String type)
{
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_NAME, name);
initialValues.put(KEY_CODE, code);
initialValues.put(KEY_LOCATION, location);
initialValues.put(KEY_COMMENTS, comments);
initialValues.put(KEY_DAYS, days);
initialValues.put(KEY_START, start);
initialValues.put(KEY_END, end);
initialValues.put(KEY_TYPE, type);
return db.insert(DATABASE_TABLE, null, initialValues);
}
//---deletes a particular contact---
public boolean deleteContact(long rowId)
{
return db.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
}
//---retrieves all the Timetable---
public Cursor getAllTimetable()
{
return db.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_NAME,
KEY_CODE, KEY_LOCATION, KEY_COMMENTS, KEY_DAYS, KEY_START, KEY_END, KEY_TYPE}, null, null, null, null, null);
}
//---retrieves a particular contact---
public Cursor getContact(long rowId) throws SQLException
{
Cursor mCursor =
db.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
KEY_NAME, KEY_CODE, KEY_LOCATION, KEY_COMMENTS, KEY_DAYS, KEY_START, KEY_END, KEY_TYPE}, KEY_ROWID + "=" + rowId, null,
null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
//---updates a contact---
public boolean updateContact(long rowId, String name, String code, String location, String comments, int days, int start, int end, String type)
{
ContentValues args = new ContentValues();
args.put(KEY_NAME, name);
args.put(KEY_CODE, code);
args.put(KEY_LOCATION, location);
args.put(KEY_COMMENTS, comments);
args.put(KEY_DAYS, days);
args.put(KEY_START, start);
args.put(KEY_END, end);
args.put(KEY_TYPE, type);
return db.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
}
public String[] getClasses() {
db = DBHelper.getWritableDatabase();
String[] columns = {KEY_NAME};
Cursor c = db.query(DATABASE_TABLE, columns, null, null, null, null, null);
String[] classes = new String [c.getCount()];
int i = 0;
while (c.moveToNext()) {
classes[i] = c.getString(0);
i++;
}
c.close();
return classes;
}
}
11-11 22:53:39.117:D/dalvikvm（17856）：延迟启用CheckJNI
11-11 22:53:39.297:D/TextLayoutCache（17856）：使用调试级别：0-已启用调试：0
11-11 22:53:39.337:D/libEGL（17856）：loaded/system/lib/egl/libGLES_android.so
11-11 22:53:39.337:D/libEGL（17856）：loaded/system/lib/egl/libEGL_adreno200.so
11-11 22:53:39.357:D/libEGL（17856）：loaded/system/lib/egl/libGLESv1_CM_adreno200.so
11-11 22:53:39.357:D/libEGL（17856）：loaded/system/lib/egl/libGLESv2_adreno200.so
11-11 22:53:39.387:I/Adreno200 EGLSUB（17856）：：格式RGBA_8888。
11-11 22:53:39.407:D/memalloc（17856）：/dev/pmem:Mapped buffer base:0x5c66d000 size:36593664 offset:32825344 fd:65
11-11 22:53:39.417:E/（17856）：无法打开文件进行读取
11-11 22:53:39.417:E/（17856）：无法打开文件进行读取
11-11 22:53:39.417:D/OpenGLRenderer（17856）：启用调试模式0
11-11 22:53:39.477:D/memalloc（17856）：/dev/pmem:Mapped buffer base:0x5ecd3000 size:40361984 offset:36593664 fd:68
11-11 22:53:40.507:D/memalloc（17856）：/dev/pmem:Mapped buffer base:0x61451000大小：7254016偏移量：3485696 fd:71
11-11 22:53:41.077:I/Adreno200 EGLSUB（17856）：：格式RGBA_8888。
11-11 22:53:41.077:D/memalloc（17856）：/dev/pmem:Mapped buffer base:0x61c4c000 size:7725056 offset:7254016 fd:74
11-11 22:53:41.097:D/memalloc（17856）：/dev/pmem:Mapped buffer base:0x623aa000 size:8196096 offset:7725056 fd:80
11-11 22:53:41.937:D/memalloc（17856）：/dev/pmem:Mapped buffer base:0x62b7b000大小：8667136偏移量：8196096 fd:83
11-11 22:53:41.977:D/memalloc（17856）：/dev/pmem:Unmapping buffer base:0x61c4c000 size:7725056 offset:7254016
11-11 22:53:41.977:D/memalloc（17856）：/dev/pmem:Unmapping buffer base:0x623aa000 size:8196096 offset:7725056
11-11 22:53:41.977:D/memalloc（17856）：/dev/pmem:Unmapping buffer base:0x62b7b000 size:8667136 offset:8196096
11-11 22:53:42.167:I/Adreno200 EGLSUB（17856）：：格式RGBA_8888。
11-11 22:53:42.177:D/memalloc（17856）：/dev/pmem:Mapped buffer base:0x61c5d000大小：17084416偏移量：133116096 fd:74
11-11 22:53:42.317:D/memalloc（17856）：/dev/pmem:Mapped buffer base:0x63853000大小：20852736偏移量：17084416 fd:80
11-11 22:53:42.357:D/OpenGLRenderer（17856）：刷新缓存（模式0）
11-11 22:53:42.357:D/memalloc（17856）：/dev/pmem:Unmapping buffer base:0x5c66d000 size:36593664 offset:32825344
11-11 22:53:42.357:D/memalloc（17856）：/dev/pmem:Unmapping buffer base:0x5ecd3000 size:40361984 offset:36593664
11-11 22:53:42.367:D/memalloc（17856）：/dev/pmem:Unmapping buffer base:0x61451000 size:7254016 offset:3485696
11-11 22:53:42.757:D/memalloc（17856）：/dev/pmem:Mapped buffer base:0x5c56d000 size:24621056偏移量：20852736 fd:65
11-11 22:53:44.247:D/AndroidRuntime（17856）：关闭虚拟机
11-11 22:53:44.247:W/dalvikvm（17856）：threadid=1:线程退出时出现未捕获异常（组=0x40ac3210）
11-11 22:53:44.257:E/AndroidRuntime（17856）：致命异常：主
11-11 22:53:44.257:E/AndroidRuntime（17856）：java.lang.RuntimeException:无法实例化活动组件信息{x.x.timeline/x.x.timeline.menu}:java.lang.NullPointerException
11-11 22:53:44.257:E/AndroidRuntime（17856）：在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:1891）
11-11 22:53:44.257:E/AndroidRuntime（17856）：在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:1992）
11-11 22:53:44.257:E/AndroidRuntime（17856）：在android.app.ActivityThread.access$600（ActivityThread.java:127）
11-11 22:53:44.257:E/AndroidRuntime（17856）：在android.app.ActivityThread$H.handleMessage（ActivityThread.java:1158）
11-11 22:53:44.257:E/AndroidRuntime（17856）：在android.os.Handler.dispatchMessage（Handler.java:99）上
11-11 22:53:44.257:E/AndroidRuntime（17856）：在android.os.Looper.loop（Looper.java:137）
11-11 22:53:44.257:E/AndroidRuntime（17856）：位于android.app.ActivityThread.main（ActivityThread.java:4441）
11-11 22:53:44.257:E/AndroidRuntime（17856）：位于java.lang.reflect.Method.Invokenactive（本机方法）
11-11 22:53:44.257:E/AndroidRuntime（17856）：在java.lang.reflect.Method.invoke（Method.java:511）
11-11 22:53:44.257:E/AndroidRuntime（17856）：在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run（ZygoteInit.java:823）
11-11 22:53:44.257:E/AndroidRuntime（17856）：位于com.android.internal.os.ZygoteInit.main（ZygoteInit.java:590）
11-11 22:53:44.257:E/AndroidRuntime（17856）：在dalvik.system.NativeStart.main（本机方法）
11-11 22:53:44.257:E/AndroidRuntime（17856）：由以下原因引起：java.lang.NullPointerException
11-11 22:53:44.257:E/AndroidRuntime（17856）：位于android.content.ContextWrapper.openOrCreateDatabase（ContextWrapper.java:221）
11-11 22:53:44.257:E/AndroidRuntime（17856）：在android.database.sqlite.SQLiteOpenHelper.getWritableDatabase（SQLiteOpenHelper.java:157）
11-11 22:53:44.257:E/AndroidRuntime（17856）：在x.x.timeline.DBAdapter.getClasses（DBAdapter.java:151）
11-11 22:53:44.257:E/AndroidRuntime（17856）：在x.x.tim
11-11 22:53:39.117: D/dalvikvm(17856): Late-enabling CheckJNI
11-11 22:53:39.297: D/TextLayoutCache(17856): Using debug level: 0 - Debug Enabled: 0
11-11 22:53:39.337: D/libEGL(17856): loaded /system/lib/egl/libGLES_android.so
11-11 22:53:39.337: D/libEGL(17856): loaded /system/lib/egl/libEGL_adreno200.so
11-11 22:53:39.357: D/libEGL(17856): loaded /system/lib/egl/libGLESv1_CM_adreno200.so
11-11 22:53:39.357: D/libEGL(17856): loaded /system/lib/egl/libGLESv2_adreno200.so
11-11 22:53:39.387: I/Adreno200-EGLSUB(17856): <ConfigWindowMatch:2078>: Format RGBA_8888.
11-11 22:53:39.407: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x5c66d000 size:36593664 offset:32825344 fd:65
11-11 22:53:39.417: E/(17856): Can't open file for reading
11-11 22:53:39.417: E/(17856): Can't open file for reading
11-11 22:53:39.417: D/OpenGLRenderer(17856): Enabling debug mode 0
11-11 22:53:39.477: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x5ecd3000 size:40361984 offset:36593664 fd:68
11-11 22:53:40.507: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x61451000 size:7254016 offset:3485696 fd:71
11-11 22:53:41.077: I/Adreno200-EGLSUB(17856): <ConfigWindowMatch:2078>: Format RGBA_8888.
11-11 22:53:41.077: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x61c4c000 size:7725056 offset:7254016 fd:74
11-11 22:53:41.097: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x623aa000 size:8196096 offset:7725056 fd:80
11-11 22:53:41.937: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x62b7b000 size:8667136 offset:8196096 fd:83
11-11 22:53:41.977: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x61c4c000 size:7725056 offset:7254016
11-11 22:53:41.977: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x623aa000 size:8196096 offset:7725056
11-11 22:53:41.977: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x62b7b000 size:8667136 offset:8196096
11-11 22:53:42.167: I/Adreno200-EGLSUB(17856): <ConfigWindowMatch:2078>: Format RGBA_8888.
11-11 22:53:42.177: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x61c5d000 size:17084416 offset:13316096 fd:74
11-11 22:53:42.317: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x63853000 size:20852736 offset:17084416 fd:80
11-11 22:53:42.357: D/OpenGLRenderer(17856): Flushing caches (mode 0)
11-11 22:53:42.357: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x5c66d000 size:36593664 offset:32825344
11-11 22:53:42.357: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x5ecd3000 size:40361984 offset:36593664
11-11 22:53:42.367: D/memalloc(17856): /dev/pmem: Unmapping buffer base:0x61451000 size:7254016 offset:3485696
11-11 22:53:42.757: D/memalloc(17856): /dev/pmem: Mapped buffer base:0x5c56d000 size:24621056 offset:20852736 fd:65
11-11 22:53:44.247: D/AndroidRuntime(17856): Shutting down VM
11-11 22:53:44.247: W/dalvikvm(17856): threadid=1: thread exiting with uncaught exception (group=0x40ac3210)
11-11 22:53:44.257: E/AndroidRuntime(17856): FATAL EXCEPTION: main
11-11 22:53:44.257: E/AndroidRuntime(17856): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{x.x.timetable/x.x.timetable.menu}: java.lang.NullPointerException
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1891)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1992)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread.access$600(ActivityThread.java:127)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1158)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.os.Handler.dispatchMessage(Handler.java:99)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.os.Looper.loop(Looper.java:137)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread.main(ActivityThread.java:4441)
11-11 22:53:44.257: E/AndroidRuntime(17856): at java.lang.reflect.Method.invokeNative(Native Method)
11-11 22:53:44.257: E/AndroidRuntime(17856): at java.lang.reflect.Method.invoke(Method.java:511)
11-11 22:53:44.257: E/AndroidRuntime(17856): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:823)
11-11 22:53:44.257: E/AndroidRuntime(17856): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:590)
11-11 22:53:44.257: E/AndroidRuntime(17856): at dalvik.system.NativeStart.main(Native Method)
11-11 22:53:44.257: E/AndroidRuntime(17856): Caused by: java.lang.NullPointerException
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:221)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:157)
11-11 22:53:44.257: E/AndroidRuntime(17856): at x.x.timetable.DBAdapter.getClasses(DBAdapter.java:151)
11-11 22:53:44.257: E/AndroidRuntime(17856): at x.x.timetable.menu.<init>(menu.java:15)
11-11 22:53:44.257: E/AndroidRuntime(17856): at java.lang.Class.newInstanceImpl(Native Method)
11-11 22:53:44.257: E/AndroidRuntime(17856): at java.lang.Class.newInstance(Class.java:1319)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.Instrumentation.newActivity(Instrumentation.java:1023)
11-11 22:53:44.257: E/AndroidRuntime(17856): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1882)
11-11 22:53:44.257: E/AndroidRuntime(17856): ... 11 more
11-11 22:53:46.527: I/Process(17856): Sending signal. PID: 17856 SIG: 9
package x.x.timetable;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class DBAdapter {
static final String KEY_ROWID = "_id";
static final String KEY_NAME = "name";
static final String KEY_CODE = "code";
static final String KEY_LOCATION = "location";
static final String KEY_COMMENTS = "comments";
static final String KEY_DAYS = "days";
static final String KEY_START = "start";
static final String KEY_END = "end";
static final String KEY_TYPE = "type";
static final String TAG = "DBAdapter";
static final String DATABASE_NAME = "MyDB";
static final String DATABASE_TABLE = "timetable";
static final int DATABASE_VERSION = 2;
static final String DATABASE_CREATE =
"create table timetable (_id integer primary key autoincrement, "
+ "name text not null, code text not null, location text not null, comments text not null, days INTEGER not null, start INTEGER not null, end INTEGER not null, type text not null);";
final Context context;
DatabaseHelper DBHelper;
SQLiteDatabase db;
public DBAdapter(Context ctx)
{
this.context = ctx;
DBHelper = new DatabaseHelper(context);
}
private static class DatabaseHelper extends SQLiteOpenHelper
{
DatabaseHelper(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db)
{
try {
db.execSQL(DATABASE_CREATE);
} catch (SQLException e) {
e.printStackTrace();
}
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS timetable");
db.execSQL("DROP TABLE IF EXISTS contacts");
onCreate(db);
}
}
//---opens the database---
public DBAdapter open() throws SQLException
{
db = DBHelper.getWritableDatabase();
return this;
}
//---closes the database---
public void close()
{
DBHelper.close();
}
public int count(){
db = DBHelper.getWritableDatabase();
String count = "SELECT count(*) FROM table";
Cursor mcursor = db.rawQuery(count, null);
int icount = mcursor.getInt(0);
return icount;
}
//---insert a contact into the database---
public long insertContact(String name, String code, String location, String comments, int days, int start, int end, String type)
{
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_NAME, name);
initialValues.put(KEY_CODE, code);
initialValues.put(KEY_LOCATION, location);
initialValues.put(KEY_COMMENTS, comments);
initialValues.put(KEY_DAYS, days);
initialValues.put(KEY_START, start);
initialValues.put(KEY_END, end);
initialValues.put(KEY_TYPE, type);
return db.insert(DATABASE_TABLE, null, initialValues);
}
//---deletes a particular contact---
public boolean deleteContact(long rowId)
{
return db.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
}
//---retrieves all the Timetable---
public Cursor getAllTimetable()
{
return db.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_NAME,
KEY_CODE, KEY_LOCATION, KEY_COMMENTS, KEY_DAYS, KEY_START, KEY_END, KEY_TYPE}, null, null, null, null, null);
}
//---retrieves a particular contact---
public Cursor getContact(long rowId) throws SQLException
{
Cursor mCursor =
db.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
KEY_NAME, KEY_CODE, KEY_LOCATION, KEY_COMMENTS, KEY_DAYS, KEY_START, KEY_END, KEY_TYPE}, KEY_ROWID + "=" + rowId, null,
null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
//---updates a contact---
public boolean updateContact(long rowId, String name, String code, String location, String comments, int days, int start, int end, String type)
{
ContentValues args = new ContentValues();
args.put(KEY_NAME, name);
args.put(KEY_CODE, code);
args.put(KEY_LOCATION, location);
args.put(KEY_COMMENTS, comments);
args.put(KEY_DAYS, days);
args.put(KEY_START, start);
args.put(KEY_END, end);
args.put(KEY_TYPE, type);
return db.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
}
public String[] getClasses() {
db = DBHelper.getWritableDatabase();
String[] columns = {KEY_NAME};
Cursor c = db.query(DATABASE_TABLE, columns, null, null, null, null, null);
String[] classes = new String [c.getCount()];
int i = 0;
while (c.moveToNext()) {
classes[i] = c.getString(0);
i++;
}
c.close();
return classes;
}
}
ArrayList<String> list= new ArrayList<String>();
list.add(name);
list.get(ELEMENT_AT);
public String[] getClasses() {
String[] columns = {KEY_NAME};
Cursor c = db.query(DATABASE_TABLE, columns, null, null, null, null, null);
String[] classes = new String [c.getCount()];
int i = 0;
while (c.moveToNext()) {
classes[i] = c.getString(0);
i++;
}
c.close();
return classes;
}
public class menu extends ListActivity{
DBAdapter db;
String[] classes; // = {"test", "test11", "test1", "test2", "test3",};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
db = new DBAdapter(this);
db.open();
classes = db.getClasses();
setListAdapter(new ArrayAdapter<String>(menu.this, android.R.layout.simple_list_item_1, classes));
}