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我想知道爲什麼我無法打開我的應用程序。另外，我試圖從SQLite數據庫檢索數據並插入微調器。打開Android應用程序的問題
的logcat的說：
08-06 09:37:41.262: I/dalvikvm(532): threadid=3: reacting to signal 3
08-06 09:37:41.343: I/dalvikvm(532): Wrote stack traces to '/data/anr/traces.txt'
08-06 09:37:41.643: D/gralloc_goldfish(532): Emulator without GPU emulation detected.
08-06 09:37:41.773: I/dalvikvm(532): threadid=3: reacting to signal 3
08-06 09:37:41.793: I/dalvikvm(532): Wrote stack traces to '/data/anr/traces.txt'
08-06 09:37:43.293: D/AndroidRuntime(532): Shutting down VM
08-06 09:37:43.303: W/dalvikvm(532): threadid=1: thread exiting with uncaught exception (group=0x409c01f8)
08-06 09:37:43.312: E/AndroidRuntime(532): FATAL EXCEPTION: main
08-06 09:37:43.312: E/AndroidRuntime(532): java.lang.RuntimeException: Unable to start activity ComponentInfo{main.page/main.page.PersonalInfo}: java.lang.NullPointerException
08-06 09:37:43.312: E/AndroidRuntime(532): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
08-06 09:37:43.312: E/AndroidRuntime(532): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
08-06 09:37:43.312: E/AndroidRuntime(532): at android.app.ActivityThread.access$600(ActivityThread.java:123)
08-06 09:37:43.312: E/AndroidRuntime(532): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
08-06 09:37:43.312: E/AndroidRuntime(532): at android.os.Handler.dispatchMessage(Handler.java:99)
08-06 09:37:43.312: E/AndroidRuntime(532): at android.os.Looper.loop(Looper.java:137)
08-06 09:37:43.312: E/AndroidRuntime(532): at android.app.ActivityThread.main(ActivityThread.java:4424)
08-06 09:37:43.312: E/AndroidRuntime(532): at java.lang.reflect.Method.invokeNative(Native Method)
08-06 09:37:43.312: E/AndroidRuntime(532): at java.lang.reflect.Method.invoke(Method.java:511)
08-06 09:37:43.312: E/AndroidRuntime(532): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
08-06 09:37:43.312: E/AndroidRuntime(532): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
08-06 09:37:43.312: E/AndroidRuntime(532): at dalvik.system.NativeStart.main(Native Method)
08-06 09:37:43.312: E/AndroidRuntime(532): Caused by: java.lang.NullPointerException
08-06 09:37:43.312: E/AndroidRuntime(532): at main.page.InfoDBAdapter.getAllContacts(InfoDBAdapter.java:113)
08-06 09:37:43.312: E/AndroidRuntime(532): at main.page.PersonalInfo.onCreate(PersonalInfo.java:41)
08-06 09:37:43.312: E/AndroidRuntime(532): at android.app.Activity.performCreate(Activity.java:4465)
08-06 09:37:43.312: E/AndroidRuntime(532): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
08-06 09:37:43.312: E/AndroidRuntime(532): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
08-06 09:37:43.312: E/AndroidRuntime(532): ... 11 more
08-06 09:37:43.694: I/dalvikvm(532): threadid=3: reacting to signal 3
08-06 09:37:43.713: I/dalvikvm(532): Wrote stack traces to '/data/anr/traces.txt'
08-06 09:37:43.923: I/dalvikvm(532): threadid=3: reacting to signal 3
08-06 09:37:43.933: I/dalvikvm(532): Wrote stack traces to '/data/anr/traces.txt'
下面是從檢索數據庫中的數據編碼並投入微調。
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.info);
Cursor c = infoDB.getAllContacts();
startManagingCursor(c);
//Create an array to specify which fields want to display
String[] from = new String[] {"name"};
//Create an array of the display item want to bind our data to
int[] to = new int[] {R.id.fName};
SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, android.R.layout.simple_spinner_item, c, from, to);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
nameSpinner.setAdapter(adapter);
nameSpinner = (Spinner) findViewById(R.id.nameSpinner);
哦，是的，在我輸入代碼（上面的那個）之前，我可以打開應用程序。但是在輸入代碼後，我無法打開應用程序。我不確定這是否與代碼有關。
下面是將對DBAdapter類：
public static final String KEY_ROWID = "_id";
public static final String KEY_NAME = "name";
public static final String KEY_DATE = "date";
public static final String KEY_TYPE = "type";
public static final String KEY_LIKES = "likes";
public static final String KEY_DISLIKES = "dislikes";
private static final String TAG = "InfoDBAdapter";
private static final String DATABASE_NAME = "friendsDB";
private static final String DATABASE_TABLE = "friends_info";
private static final int DATABASE_VERSION = 2;
private static final String DATABASE_CREATE = "create table friends_info(name_id integer primary key autoincrement, "
+ "name text not null, date text not null, type text not null, likes text not null, dislikes text not null);";
private final Context context;
private DatabaseHelper DBHelper;
private SQLiteDatabase db;
public InfoDBAdapter(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();
}
}// end onCreate()
@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 friends_info");
onCreate(db);
}// end onUpgrade()
}// end DatabaseHelper
public InfoDBAdapter open() throws SQLException
{
db = DBHelper.getWritableDatabase();
return this;
}// end open()
public void close()
{
DBHelper.close();
}// end close()
public long insertContact(String name, String date, String type, String likes, String dislikes)
{
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_NAME, name);
initialValues.put(KEY_DATE, date);
initialValues.put(KEY_TYPE, type);
initialValues.put(KEY_LIKES, likes);
initialValues.put(KEY_DISLIKES, dislikes);
return db.insert(DATABASE_TABLE, null, initialValues);
}// end insertContact()
public boolean deleteContact(long rowId)
{
return db.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
}// end deleteContact()
public Cursor getAllContacts()
{
return db.query(DATABASE_TABLE, new String[]
{ KEY_ROWID, KEY_NAME, KEY_DATE, KEY_TYPE, KEY_LIKES, KEY_DISLIKES }, null, null, null, null, null);
}// end getAllContacts()
public Cursor getContact(long rowId) throws SQLException
{
Cursor mCursor = db.query(true, DATABASE_TABLE, new String[] {
KEY_ROWID, KEY_NAME, KEY_DATE, KEY_TYPE, KEY_LIKES, KEY_DISLIKES }, KEY_ROWID + "=" + rowId,
null, null, null, null, null);
if (mCursor != null)
{
mCursor.moveToFirst();
}
return mCursor;
}// end getContact()
public boolean updateContact(long rowId, String name, String date, String type, String likes, String dislikes)
{
ContentValues args = new ContentValues();
args.put(KEY_NAME, name);
args.put(KEY_DATE, date);
args.put(KEY_TYPE, type);
args.put(KEY_LIKES, likes);
args.put(KEY_DISLIKES, dislikes);
return db.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
}// end updateContact()
我感謝提供任何幫助。哦，如果有人知道其他方式從數據庫中檢索數據並放入微調，我將不勝感激的幫助。
感謝=）
提供完整的堆棧跟蹤，這將精確確定問題所在。 – hatcyl 2012-08-06 01:56:38
嗨，我剛剛編輯了我的問題。我提供了完整的堆棧跟蹤 – Preeyah 2012-08-06 02:00:21
這段代碼導致了這個問題：'Cursor c = infoDB.getAllContacts（）;'你能發佈更完整的課程代碼嗎？如何申報'infoDB'？ – hatcyl 2012-08-06 02:15:05