我在使用SQLite保存和显示图像时遇到问题，然后使用RecyclerView显示数据。我的意图是通过RadioButton获取用户信息，包括其类型，以最终显示数据和区分男人和女人的图像。尝试在没有图像（仅文本）的情况下一切正常，但是当我在图像中添加必要内容时，应用程序失败。
我用"/ * ??HERE * /"指出了我认为有问题的地方。
我真的希望你能帮助我。谢谢。
public class MainActivity extends AppCompatActivity {
EditText edtNames, edtLastNames, edtId;
Button btnRegister, btnShow;
RadioButton rdbtnMale, rdbtnFemale;
int imgStudent;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
edtNames= (EditText) findViewById(R.id.edtNames);
edtLastNames= (EditText) findViewById(R.id.edtLastNames);
//...etc, etc ->linkinkgs
final SQLiteDb sqLiteDb =new SQLiteDb(getApplicationContext());
// ??HERE
if(rdbtnMale.isChecked()){
imgStudent = R.drawable.boy;
}else if(rdbtnFemale.isChecked()){
imgStudent = R.drawable.girl;
}
btnRegister.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
sqLiteDb.AddStudents(edtNames.getText().toString(),
edtLastNames.getText().toString(), edtId.getText().toString(),imgStudent /* ??HERE*/);
Toast.makeText(getApplicationContext(),"Was added correctly",
Toast.LENGTH_SHORT).show();
}
});
btnShow.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent showStudents = new Intent(getApplicationContext(),StudentsActivity.class);
startActivity(showStudents);
}
});
}
}
学生班
public class Student {
private String Names, LastNames, Id;
private int Image;
public Student(String names, String lastnames, String id, int imageStudent) {
//...parameters
}
// + Getters and Setters
}
数据库助手类
public class SQLiteDb extends SQLiteOpenHelper {
private static final String TABLE_STUDENTS = "CREATE TABLE STUDENTS(NAMES TEXT,
LASTNAMES TEXT,ID TEXT, IMAGEN INT)";
public SQLiteDb(Context context) {
super(context, "db_students", null, 1);
}
@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
sqLiteDatabase.execSQL(TABLE_STUDENTS);
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int oldVersion, int newVersion) {
sqLiteDatabase.execSQL("DROP TABLE IF EXISTS TABLE_STUDENTS");
onCreate(sqLiteDatabase);
}
public void AddStudents(String names, String lastnames, String id,/*??HERE*/ int img) {
SQLiteDatabase bd = getWritableDatabase();
if (bd != null) {
bd.execSQL("INSERT INTO STUDENTS VALUES('" + names + "','"
+ lastnames + "','" + id + "','" + img + "')");
bd.close();
}
}
public List<Student> ShowStudents() {
SQLiteDatabase bd = getReadableDatabase();
Cursor cursor = bd.rawQuery("SELECT * FROM STUDENTS", null);
List<Student> students = new ArrayList<>();
if (cursor.moveToFirst()) {
do {
students.add(new Student(cursor.getString(0), cursor.getString(1)
, cursor.getString(2),/*??HERE*/ cursor.getInt(3)));
} while (cursor.moveToNext());
}
return students;
}
}
还有适配器：-
public class AdapterStudentList extends RecyclerView.Adapter<AdapterStudentList.ViewHolder> {
public static class ViewHolder extends RecyclerView.ViewHolder{
private TextView CompleteName;
ImageView ImageStudent;
public ViewHolder(View itemView) {
super(itemView);
CompleteName =(TextView)itemView.findViewById(R.id.tvCompleteName);
ImageStudent = (ImageView)itemView.findViewById(R.id.imgStudent);
}
}
public List<Student> studentsList;
public AdapterStudentList(List<Student>studentsList){
this.studentsList = studentsList;
}
//@NonNull
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_student,parent,false);
ViewHolder viewHolder= new ViewHolder(view);
return viewHolder;
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.CompleteName.setText(studentsList.get(position).getNames()+" "+ studentsList.get(position).getLastNames());
holder.ImageStudent.setImageResource(studentsList.get(position).getImagen());
}
@Override
答案 0 :(得分：2)
考虑评论：-
是的，你是对的。该消息是：“ E / SQLiteLog：（1）表学生 有3列，但提供了4个值。”不假定 表中有4列：
private final static String TABLE_ALUMNOS = "CREATE TABLE STUDENTS (NAMES TEXT, LAST NAME TEXT, ID TEXT, IMAGE TEXT)";
最可能的原因是，尽管您已更改架构（猜测时添加了IMAGE列），但 onCreate 仅在创建数据库时运行。数据库将保留（仅创建一次，数据将存储为应用程序的一部分）。
在开发应用程序时，如果数据消耗惨重，那么最快的解决方法是删除应用程序的数据或卸载应用程序（均删除数据库），然后重新运行应用程序。
随着 onUpgrade 方法删除该表并调用 onCreate ，您还有其他选择可以增加数据库版本号，例如将super(context, "db_students", null, 1);更改为super(context, "db_students", null, 2); （第四个参数是数据库版本）
关于单选按钮的选择，您可以使用类似：-
public class MainActivity extends AppCompatActivity {
RadioButton rdbtnMale, rdbtnFemale;
RadioGroup rgrpGender; //<<<<<<<<<<< ADDED
Button btnRegister;
int imgStudent; //<<<<<<<<<< Not needed
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
rdbtnMale = this.findViewById(R.id.rdbtnMale);
rdbtnFemale = this.findViewById(R.id.rdbtnFemale);
btnRegister = this.findViewById(R.id.btnRegister);
rgrpGender = this.findViewById(R.id.rgrpGender); //<<<<<<<<<< ADDED
// ??HERE - NOTHING COMMENTED OUT
/**
if(rdbtnMale.isChecked()){
imgStudent = R.drawable.boy;
}else if(rdbtnFemale.isChecked()){
imgStudent = R.drawable.girl;
}
**/
//............ other code
btnRegister.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int studentGender;
switch(rgrpGender.getCheckedRadioButtonId()) {
case R.id.rdbtnMale:
studentGender = 0;
break;
case R.id.rdbtnFemale:
studentGender = 1;
break;
default:
studentGender = -1;
break;
}
Log.d("SAVING","Student is gender " + String.valueOf(studentGender) + "\t(1 = Male 0= Female)"); //TODO Remove before publishing
//<<<<<<<<<< COMMENTED OUT FOR DEMO >>>>>>>>>>
//sqLiteDb.AddStudents(edtNames.getText().toString(),edtLastNames.getText().toString(), edtId.getText().toString(),studentGender);
}
});
}
}
以上允许其他性别的其他RadioButton只需添加适当的案例（s）
以上内容可以单独运行并具有适当的布局。
从本质上讲，您并不是在保存图片，而是在显示性别。