很抱歉问这个问题，但我真的找不到我的数据库抛出异常的原因。这是代码，请看一下。整个想法是制作一个刽子手游戏作为一个学校项目，我想创建一个地方，用户可以看到所有当前的单词，并根据需要添加更多单词或删除现有单词(这是在要求中)。我认为我在 populateListView 方法中犯了一个错误，因为我认为我以前没有使用过光标，但查看了一些在线 Material ，所以我尝试进行相应的调整。如果有更简单的方法 -> 我全力以赴。提前致谢 !
这是 DBAdapter 文件:
public class DBAdapter {
private static final String TAG = "DBAdapter"; //used for logging database version changes
// Field Names:
public static final String KEY_ROWID = "_id";
public static final String KEY_WORD = "word";
public static final String[] ALL_KEYS = new String[] {KEY_ROWID, KEY_WORD};
// Column Numbers for each Field Name:
public static final int COL_ROWID = 0;
public static final int COL_WORD = 1;
// DataBase info:
public static final String DATABASE_NAME = "dbToDo";
public static final String DATABASE_TABLE = "mainToDo";
public static final int DATABASE_VERSION = 2; // The version number must be incremented each time a change to DB structure occurs.
//SQL statement to create database
private static final String DATABASE_CREATE_SQL =
"CREATE TABLE " + DATABASE_TABLE
+ " (" + KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ KEY_WORD + " TEXT NOT NULL"
+ ");";
private final Context context;
private DatabaseHelper myDBHelper;
private SQLiteDatabase db;
public DBAdapter(Context ctx) {
this.context = ctx;
myDBHelper = new DatabaseHelper(context);
}
// Open the database connection.
public DBAdapter open() {
db = myDBHelper.getWritableDatabase();
return this;
}
// Close the database connection.
public void close() {
myDBHelper.close();
}
// Add a new set of values to be inserted into the database.
public long insertRow(String word) {
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_WORD, word);
// Insert the data into the database.
return db.insert(DATABASE_TABLE, null, initialValues);
}
// Delete a row from the database, by rowId (primary key)
public boolean deleteRow(long rowId) {
String where = KEY_ROWID + "=" + rowId;
return db.delete(DATABASE_TABLE, where, null) != 0;
}
public void deleteAll() {
Cursor c = getAllRows();
long rowId = c.getColumnIndexOrThrow(KEY_ROWID);
if (c.moveToFirst()) {
do {
deleteRow(c.getLong((int) rowId));
} while (c.moveToNext());
}
c.close();
}
// Return all data in the database.
public Cursor getAllRows() {
String where = null;
Cursor c = db.query(true, DATABASE_TABLE, ALL_KEYS, where, null, null, null, null, null);
if (c != null) {
c.moveToFirst();
}
return c;
}
// Get a specific row (by rowId)
public Cursor getRow(long rowId) {
String where = KEY_ROWID + "=" + rowId;
Cursor c = db.query(true, DATABASE_TABLE, ALL_KEYS,
where, null, null, null, null, null);
if (c != null) {
c.moveToFirst();
}
return c;
}
// Change an existing row to be equal to new data.
public boolean updateRow(long rowId, String word) {
String where = KEY_ROWID + "=" + rowId;
ContentValues newValues = new ContentValues();
newValues.put(KEY_WORD, word);
// Insert it into the database.
return db.update(DATABASE_TABLE, newValues, where, null) != 0;
}
private static class DatabaseHelper extends SQLiteOpenHelper
{
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase _db) {
_db.execSQL(DATABASE_CREATE_SQL);
}
@Override
public void onUpgrade(SQLiteDatabase _db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading application's database from version " + oldVersion
+ " to " + newVersion + ", which will destroy all old data!");
// Destroy old database:
_db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
// Recreate new database:
onCreate(_db);
}
}
这是另一个崩溃的地方:
public class EditWords extends Activity {
ListView listViewWords;
EditText editTextNewWord;
Button buttonAddWord;
Button buttonDeleteWord;
DBAdapter myDb;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_edit_words);
listViewWords = (ListView) findViewById(R.id.listViewWords);
editTextNewWord = (EditText) findViewById(R.id.editTextNewWord);
buttonAddWord = (Button) findViewById(R.id.buttonAddWord);
buttonDeleteWord = (Button) findViewById(R.id.buttonDeleteWord);
populateListView();
openDB();
}
private void openDB(){
myDb = new DBAdapter(this);
myDb.open();
}
private void populateListView() {
Cursor cursor = myDb.getAllRows();
String[] fromFieldNames = new String[] {DBAdapter.KEY_ROWID,DBAdapter.KEY_WORD};
int[] toViewIDs = new int[]{R.id.editTextNewWord};
SimpleCursorAdapter myCursorAdapter;
myCursorAdapter = new SimpleCursorAdapter(getBaseContext(),R.id.listViewWords,cursor,fromFieldNames,toViewIDs,0);
listViewWords.setAdapter(myCursorAdapter);
}
public void onClick_AddWord(View v) {
if(!TextUtils.isEmpty(editTextNewWord.getText().toString())) {
myDb.insertRow(editTextNewWord.getText().toString());
}
populateListView();
}
}
堆栈跟踪:
03-30 12:13:39.603 8800-9926/com.example.daniel.hangman I/OpenGLRenderer: Initialized EGL, version 1.4
03-30 12:13:39.603 8800-9926/com.example.daniel.hangman W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...
03-30 12:13:42.570 8800-8800/com.example.daniel.hangman D/AndroidRuntime: Shutting down VM
03-30 12:13:42.571 8800-8800/com.example.daniel.hangman E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.daniel.hangman, PID: 8800
android.content.res.Resources$NotFoundException: Resource ID #0x7f070009 type #0x12 is not valid
at android.content.res.Resources.loadXmlResourceParser(Resources.java:2779)
at android.content.res.Resources.getLayout(Resources.java:1165)
at android.view.LayoutInflater.inflate(LayoutInflater.java:421)
at android.widget.ResourceCursorAdapter.newView(ResourceCursorAdapter.java:135)
at android.widget.CursorAdapter.getView(CursorAdapter.java:285)
at android.widget.AbsListView.obtainView(AbsListView.java:2346)
at android.widget.ListView.makeAndAddView(ListView.java:1875)
at android.widget.ListView.fillDown(ListView.java:702)
at android.widget.ListView.fillFromTop(ListView.java:763)
at android.widget.ListView.layoutChildren(ListView.java:1684)
at android.widget.AbsListView.onLayout(AbsListView.java:2148)
at android.view.View.layout(View.java:16630)
at android.view.ViewGroup.layout(ViewGroup.java:5437)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1743)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1586)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1495)
at android.view.View.layout(View.java:16630)
at android.view.ViewGroup.layout(ViewGroup.java:5437)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:336)
at android.widget.FrameLayout.onLayout(FrameLayout.java:273)
at android.view.View.layout(View.java:16630)
at android.view.ViewGroup.layout(ViewGroup.java:5437)
at com.android.internal.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:493)
at android.view.View.layout(View.java:16630)
at android.view.ViewGroup.layout(ViewGroup.java:5437)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:336)
at android.widget.FrameLayout.onLayout(FrameLayout.java:273)
at com.android.internal.policy.PhoneWindow$DecorView.onLayout(PhoneWindow.java:2678)
at android.view.View.layout(View.java:16630)
at android.view.ViewGroup.layout(ViewGroup.java:5437)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2171)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1931)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1107)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6013)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:858)
at android.view.Choreographer.doCallbacks(Choreographer.java:670)
at android.view.Choreographer.doFrame(Choreographer.java:606)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:844)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)最佳答案
您调用:
populateListView();
之前使用“myDb”:
openDB();
初始化“myDb”
关于java - Android 模拟器因 Db 崩溃(找不到错误 - 新手)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/43117239/