作为项目的一部分，我正在制作用于跟踪用户在健身房锻炼的Android应用程序。随着锻炼和锻炼与各种设置，重量和代表。
我希望用户命名他们的锻炼然后被用来添加锻炼活动，当他们添加锻炼活动时，它会填充列表视图。然后我计划添加一个完成按钮并使用选择练习保存锻炼。因为这将是一对多的关系。
下面的代码是我拥有的数据库助手以及查看锻炼和练习的活动。但SimpleCursorAdapter给了我一些问题。
试图修复此错误的圈子可以帮助我修复它，好吗？ _id在主键中，所以我不知道是什么错。之前我也有AUTOINCREMENT，但它也给出了错误。
日志cat如下：
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.cormac.gym12m/com.example.cormac.gym12m.ViewWorkoutsActivity}: java.lang.IllegalArgumentException: column '_id' does not exist
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.access$900(ActivityThread.java:150)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
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)
Caused by: java.lang.IllegalArgumentException: column '_id' does not exist
at android.database.AbstractCursor.getColumnIndexOrThrow(AbstractCursor.java:333)
at android.widget.CursorAdapter.init(CursorAdapter.java:180)
at android.widget.CursorAdapter.<init>(CursorAdapter.java:157)
at android.widget.ResourceCursorAdapter.<init>(ResourceCursorAdapter.java:96)
at android.widget.SimpleCursorAdapter.<init>(SimpleCursorAdapter.java:104)
at com.example.cormac.gym12m.ViewWorkoutsActivity.onCreate(ViewWorkoutsActivity.java:42)
at android.app.Activity.performCreate(Activity.java:6294)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1108)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.access$900(ActivityThread.java:150)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
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)
I/Process: Sending signal. PID: 16275 SIG: 9
Application terminated.
DBHelper
public class DBHelper extends SQLiteOpenHelper {
public static String DATABASE_NAME = "gym_db";
private static final int DATABASE_VERSION = 1;
public static final String TABLE_WORKOUT = "workout_table";
public static final String WORKOUT_ID = "_id";
public static final String WORKOUT_NAME = "workout_name";
public static final String TABLE_EXERCISE = "exercise_table";
public static final String EXERCISE_ID = "exercise_id";
public static final String EXERCISE_NAME = "exercise_name";
public static final String EXERCISE_SET = "exercise_set";
public static final String EXERCISE_WEIGHT = "exercise_weight";
public static final String EXERCISE_REP = "exercise_rep";
public static final String createWorkoutTable = "CREATE TABLE " + TABLE_WORKOUT + "("
+ WORKOUT_ID + " _id INTEGER PRIMARY KEY, "
+ WORKOUT_NAME + " TEXT NOT NULL " +
")";
public static final String createExerciseTable = " CREATE TABLE " + TABLE_EXERCISE + "("
+ EXERCISE_ID + " _id INTEGER PRIMARY KEY, "
+ EXERCISE_NAME + " TEXT NOT NULL, "
+ EXERCISE_SET + " INTEGER NOT NULL, "
+ EXERCISE_WEIGHT + " INTEGER NOT NULL, "
+ EXERCISE_REP + " INTEGER NOT NULL, "
+ "FOREIGN KEY(" + EXERCISE_ID + ") REFERENCES " + TABLE_WORKOUT + "(id)" +
")";
public DBHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(createWorkoutTable);
db.execSQL(createExerciseTable);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS '" + createWorkoutTable + " ' ");
db.execSQL("DROP TABLE IF EXISTS '" + createExerciseTable + " ' ");
onCreate(db);
}
private static void setForeignKeyConstraintEnabled(@NonNull SQLiteDatabase db){
if (!db.isReadOnly()){
db.execSQL("PRAGMA foreign_keys=1");
}
}
private static void setForeignKeyConstraintDisabled(@NonNull SQLiteDatabase db){
if (!db.isReadOnly()){
db.execSQL("PRAGMA foreign_keys=0");
}
}
public void addExercise(long l, String name, String set, String weight, String reps){
SQLiteDatabase db = this.getWritableDatabase();
//adding exercise name in exercise table
ContentValues cv = new ContentValues();
cv.put(EXERCISE_NAME, name);
cv.put(EXERCISE_SET, set);
cv.put(EXERCISE_WEIGHT,weight);
cv.put(EXERCISE_REP,reps);
db.insert(TABLE_EXERCISE, null, cv);
}
public long addWorkout(String name){
SQLiteDatabase db = this.getWritableDatabase();
//adding workout name in workout table
ContentValues values = new ContentValues();
values.put(WORKOUT_NAME, name);
return this.getWritableDatabase().insert(TABLE_WORKOUT,null,values);
}
public Cursor getWorkouts(){
return this.getWritableDatabase().query(TABLE_WORKOUT, null,null,null,null,null,null);
}
public long addExercise(String name, String set, String weight, String reps){
SQLiteDatabase db = this.getWritableDatabase();
//adding exercise name in exercise table
ContentValues cv = new ContentValues();
cv.put(EXERCISE_NAME, name);
cv.put(EXERCISE_SET, set);
cv.put(EXERCISE_WEIGHT,weight);
cv.put(EXERCISE_REP,reps);
return this.getWritableDatabase().insert(TABLE_EXERCISE,null,cv);
}
public Cursor getWorkoutExercises(long exerciseid){
return this.getWritableDatabase().query(TABLE_EXERCISE, null,
EXERCISE_ID+"=?",
new String[]{Long.toString(exerciseid)},
null,null,null);
}
public Cursor getAllWorkoutsExercises(int i){
SQLiteDatabase db = this.getReadableDatabase();
String SELECT_QUERY = "SELECT * FROM '" + TABLE_WORKOUT + "'JOIN'" + TABLE_EXERCISE + "' ON '" + EXERCISE_ID + "' GROUP BY '" + EXERCISE_ID + "'ORDER BY'" + WORKOUT_NAME + "'";
Cursor mCursor = db.rawQuery(SELECT_QUERY, null);
return mCursor;
}
}
查看锻炼活动
public class ViewWorkoutsActivity extends AppCompatActivity{
ListView workoutlist;
ListView exerciselist;
Cursor workoutsCursor;
Cursor exercisesCursor;
SimpleCursorAdapter sca_workEx;
SimpleCursorAdapter sca_workouts;
DBHelper dbh = new DBHelper(this);
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_workouts);
workoutlist = (ListView) findViewById(R.id.workoutlist);
exerciselist = (ListView) findViewById(R.id.exerciselist);
exercisesCursor = dbh.getWorkoutExercises(-1);
workoutsCursor = dbh.getWorkouts();
sca_workEx = new SimpleCursorAdapter(this,
android.R.layout.simple_list_item_1,
exercisesCursor,
new String[]{DBHelper.WORKOUT_NAME},
new int[]{android.R.id.text1},0);
sca_workouts = new SimpleCursorAdapter(this,
android.R.layout.simple_list_item_1,
workoutsCursor,
new String[]{DBHelper.WORKOUT_NAME},
new int[]{android.R.id.text1},0);
workoutlist.setAdapter(sca_workouts);
workoutlist.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
exercisesCursor = dbh.getAllWorkoutsExercises(1);
sca_workouts.swapCursor(exercisesCursor);
}
});
}
}
答案 0 :(得分：1)
public static final String EXERCISE_ID = "exercise_id";
...
+ EXERCISE_ID + " _id INTEGER PRIMARY KEY, "
此表没有名为_id的列。它有一个名为exercise_id的列，数据类型为_id INTEGER PRIMARY KEY。
答案 1 :(得分：0)
游标适配器，例如 SimplCursorAdapter （ CursorAdapter 类的子类），正如您所使用的那样，需要一个名为onItemClick。
Cursor必须包含名为＆＃34; _id＆＃34;的列。或者这个班不会 工作
这就是你得到错误的原因。
有两种可能的修复方法。
第一种方法是使用 _id 作为EXCERCISE_ID列名。
e.g。代码public static final String EXERCISE_ID = "_id";
这将需要删除表格，如果丢失当前数据不是问题，可能是最简单的方法，即删除应用程序的数据或卸载应用程序并重新运行上述更改。另一种方法是进行更改，然后增加数据库版本，例如private static final int DATABASE_VERSION = 2;并重新运行App（这将调用DBHelper的onUpgrade方法，删除表并调用onCreate方法。）
第二种方法是将 _id 列作为Cursor中的派生列提供。
您可以通过以下方式更改getWorkoutExercises方法来实现此目的： -
public Cursor getWorkoutExercises(long exerciseid){
String[] columns = new String[]{EXERCISE_ID + " AS _id","*"}
return this.getWritableDatabase().query(TABLE_EXERCISE, columns,
EXERCISE_ID+"=?",
new String[]{Long.toString(exerciseid)},
null,null,null);
}
String columns = new String[]{"*",EXERCISE_ID + " AS _id"} String columns = new String[]{"*","rowid AS _id"} String columns = new String[]{"rowid AS _id","*"} 我建议重命名列名称是更好的方法。