无法使用浮动按钮AlertDialog在SQLite数据库中插入数据

Question

我是android编程的新手，我正计划构建Todo应用我已经制作了DatabaseHelper.java文件，并且一切都正常了（我已经用过了）[]

问题-浮动浮动按钮AlertDialog对话框打开，并且在插入数据myDB.addData（task）找不到错误时出现一些问题，请帮帮我

public class MainActivity extends AppCompatActivity {
    DatabaseHelper myDB;
    FloatingActionButton floatingActionButton;
    @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    floatingActionButton = findViewById(R.id.floatingActionButton);

    floatingActionButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            final EditText editText = new EditText(MainActivity.this);
            AlertDialog dialog = new AlertDialog.Builder(MainActivity.this)
                    .setTitle("New Task")
                    .setMessage("Add a new Task")
                    .setView(editText)
                    .setPositiveButton("Add", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            String task = editText.getText().toString();
                            boolean isInserted = myDB.addData(task);
                            if(isInserted == true){
                                Toast.makeText(MainActivity.this,"inseretd",Toast.LENGTH_SHORT).show();
                            }
                            else {
                                Toast.makeText(MainActivity.this,"went wrong",Toast.LENGTH_SHORT).show();

                            }
                        }
                    })
                    .setNegativeButton("Cancel",null)
                    .create();
            dialog.show();
        }
    });
}
}

帮助文件-DatabaseHelper.java

public class DatabaseHelper extends SQLiteOpenHelper {
    public final static String DATABASE_NAME = "MyTodo.db";
    public final static String TABLE_NAME = "MyTodo_Table";
    public final static String COL_1 ="ID";
    public final static String COL_2 ="Data";

    public DatabaseHelper(@Nullable Context context) {
        super(context, DATABASE_NAME, null, 1);
    }
@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL("CREATE TABLE IF NOT EXISTS "+TABLE_NAME+" (ID INTEGER PRIMARY KEY AUTOINCREMENT,DATA TEXT)");
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS "+TABLE_NAME);
    onCreate(db);
}
public boolean addData(String data){
    SQLiteDatabase db= this.getReadableDatabase();
    ContentValues contentValues=new ContentValues();
    contentValues.put(COL_2,data);

    long result =db.insert(TABLE_NAME,null,contentValues);
    if(result==-1){
        return false;
    }
    else {
        return true;
    }
}
}

[我是android编程的新手，我正计划构建Todo应用程序，我已经制作了DatabaseHelper.java文件，并且一切都正常了（我已经使用过它了）问题-单击浮动按钮AlertDialog ...

Answer 1

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