我是android studio的新手，并已复制示例代码示例以适合我的应用程序。目的是阅读我所有的公司记录。我尝试了几种方法，但均未成功。我收到的错误指示无法将Customer（）应用于：下面的字段列表。我有12个表，每个表都有CRUD方法。所有表的相同错误是相同的。
我已经构建了所有单独的table.java文件，并希望在继续操作main.java文件之前完成所有CRUD功能而不会出错。
// Get All CompanyData =========================================================
public List<CompanyData> GetAllCompanyData() {
List<CompanyData> compdataList = new ArrayList<>();
String selectQuery = "SELECT * FROM " + TABLE_CompanyData;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
if (cursor.moveToFirst()) {
do {
CompanyData compdata;
compdata = new CompanyData();
compdata.setcompanyid(Long.parseLong(cursor.getString(0))); // <==============================================================
compdata.setcompanyname(cursor.getString(1));
compdata.setcompanyaddress1(cursor.getString(2));
compdata.setcompanyaddress2(cursor.getString(3));
compdata.setcompanycity(cursor.getString(4));
compdata.setcompanystate(cursor.getString(5));
compdata.setcompanyzipcode(cursor.getString(6));
compdata.setcompanyphone(cursor.getString(7));
compdata.setcompanyemail(cursor.getString(8));
compdata.setcompanybusinesslicense(cursor.getString(9));
compdata.setcompanytype(cursor.getString(10));
compdataList.add(compdata);
} while (cursor.moveToNext());
}
return compdataList;
}
答案 0 :(得分：0)
<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginTop="12dp"
android:gravity="center"
android:text="Username"
android:textSize="18sp"
android:textStyle="bold|italic" />
<EditText
android:id="@+id/editName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_below="@+id/textView"
android:ems="10"
android:gravity="center_vertical|center"
android:hint="Enter Name"
android:inputType="textPersonName"
android:textStyle="bold|italic" />
<TextView
android:id="@+id/textView2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_below="@+id/editName"
android:layout_marginTop="13dp"
android:gravity="center"
android:hint="Enter Password"
android:text="password"
android:textSize="18sp"
android:textStyle="bold|italic" />
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/button"
android:layout_alignBottom="@+id/button"
android:layout_alignEnd="@+id/button4"
android:layout_alignRight="@+id/button4"
android:onClick="viewdata"
android:text="view data"
android:textSize="18sp"
android:textStyle="bold|italic" />
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_below="@+id/editPass"
android:layout_marginLeft="28dp"
android:layout_marginStart="28dp"
android:layout_marginTop="23dp"
android:onClick="addUser"
android:text="add user"
android:textSize="18sp"
android:textStyle="bold|italic" />
<Button
android:id="@+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/button4"
android:layout_alignStart="@+id/button4"
android:layout_below="@+id/editText3"
android:layout_marginTop="13dp"
android:onClick="update"
android:text="Update"
android:textStyle="normal|bold" />
<EditText
android:id="@+id/editText6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignTop="@+id/button4"
android:layout_toLeftOf="@+id/button2"
android:layout_toStartOf="@+id/button2"
android:ems="10"
android:freezesText="false"
android:hint="Enter Name to Delete Data"
android:inputType="textPersonName" />
<Button
android:id="@+id/button4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="41dp"
android:layout_marginEnd="21dp"
android:layout_marginRight="21dp"
android:onClick="delete"
android:text="delete"
android:textStyle="normal|bold"
tools:ignore="RelativeOverlap" />
<EditText
android:id="@+id/editText3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_below="@+id/button"
android:layout_marginLeft="7dp"
android:layout_marginStart="7dp"
android:layout_marginTop="47dp"
android:ems="10"
android:hint="Current Name"
android:inputType="textPersonName"
android:textSize="14sp"
android:textStyle="bold|italic" />
<EditText
android:id="@+id/editPass"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_below="@+id/textView2"
android:layout_marginTop="11dp"
android:ems="10"
android:gravity="center_vertical|center"
android:hint="Enter Password"
android:inputType="textPassword"
android:textAllCaps="false"
android:textSize="18sp"
android:textStyle="normal|bold" />
<EditText
android:id="@+id/editText5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/editText3"
android:layout_alignStart="@+id/editText3"
android:layout_alignTop="@+id/button3"
android:layout_marginTop="32dp"
android:ems="10"
android:hint="New Name"
android:inputType="textPersonName"
android:textSize="14sp"
android:textStyle="bold|italic" />
</RelativeLayout>'
main activityjava
import android.app.Activity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
public class MainActivity extends Activity {
EditText Name, Pass , updateold, updatenew, delete;
DbAdapter helper;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Name= (EditText) findViewById(R.id.editName);
Pass= (EditText) findViewById(R.id.editPass);
updateold= (EditText) findViewById(R.id.editText3);
updatenew= (EditText) findViewById(R.id.editText5);
delete = (EditText) findViewById(R.id.editText6);
helper = new DbAdapter(this);
}
public void addUser(View view)
{
String t1 = Name.getText().toString();
String t2 = Pass.getText().toString();
if(t1.isEmpty() || t2.isEmpty())
{
Message.message(getApplicationContext(),"Enter Both Name and Password");
}
else
{
long id = helper.insertData(t1,t2);
if(id<=0)
{
Message.message(getApplicationContext(),"Insertion Unsuccessful");
Name.setText("");
Pass.setText("");
} else
{
Message.message(getApplicationContext(),"Insertion Successful");
Name.setText("");
Pass.setText("");
}
}
}
public void viewdata(View view)
{
String data = helper.getData();
Message.message(this,data);
}
public void update( View view)
{
String u1 = updateold.getText().toString();
String u2 = updatenew.getText().toString();
if(u1.isEmpty() || u2.isEmpty())
{
Message.message(getApplicationContext(),"Enter Data");
}
else
{
int a= helper.updateName( u1, u2);
if(a<=0)
{
Message.message(getApplicationContext(),"Unsuccessful");
updateold.setText("");
updatenew.setText("");
} else {
Message.message(getApplicationContext(),"Updated");
updateold.setText("");
updatenew.setText("");
}
}
}
public void delete( View view)
{
String uname = delete.getText().toString();
if(uname.isEmpty())
{
Message.message(getApplicationContext(),"Enter Data");
}
else{
int a= helper.delete(uname);
if(a<=0)
{
Message.message(getApplicationContext(),"Unsuccessful");
delete.setText("");
}
else
{
Message.message(this, "DELETED");
delete.setText("");
}
}
}
}'
DbAdapterjava
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DbAdapter extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "myDatabase"; // Database Name
private static final String TABLE_NAME = "myTable"; // Table Name
private static final int DATABASE_Version = 1; // Database Version
private static final String UID = "_id"; // Column I (Primary Key)
private static final String NAME = "Name"; //Column II
private static final String MyPASSWORD = "Password"; // Column III
private static final String CREATE_TABLE = "CREATE TABLE " + TABLE_NAME +
" (" + UID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + NAME + " VARCHAR(255) ," + MyPASSWORD + " VARCHAR(225));";
private static final String DROP_TABLE = "DROP TABLE IF EXISTS " + TABLE_NAME;
private Context context;
public DbAdapter(Context context) {
super(context, DATABASE_NAME, null, DATABASE_Version);
this.context = context;
}
public long insertData(String name, String pass) {
SQLiteDatabase dbb = getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(NAME, name);
contentValues.put(MyPASSWORD, pass);
long id = dbb.insert(TABLE_NAME, null, contentValues);
return id;
}
public String getData() {
SQLiteDatabase db = getWritableDatabase();
String[] columns = {UID, NAME, MyPASSWORD};
Cursor cursor = db.query(TABLE_NAME, columns, null, null, null, null, null);
StringBuffer buffer = new StringBuffer();
while (cursor.moveToNext()) {
int cid = cursor.getInt(cursor.getColumnIndex(UID));
String name = cursor.getString(cursor.getColumnIndex(NAME));
String password = cursor.getString(cursor.getColumnIndex(MyPASSWORD));
buffer.append(cid + " " + name + " " + password + " \n");
}
return buffer.toString();
}
public int delete(String uname) {
SQLiteDatabase db = this.getWritableDatabase();
String[] whereArgs = {uname};
int count = db.delete(TABLE_NAME, NAME + " = ?", whereArgs);
return count;
}
public int updateName(String oldName, String newName) {
SQLiteDatabase db = getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(NAME, newName);
String[] whereArgs = {oldName};
int count = db.update(TABLE_NAME, contentValues, NAME + " = ?", whereArgs);
return count;
}
@Override
public void onCreate(SQLiteDatabase db) {
try {
db.execSQL(CREATE_TABLE);
} catch (Exception e) {
Message.message(context, "" + e);
}
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
try {
Message.message(context, "OnUpgrade");
db.execSQL(DROP_TABLE);
onCreate(db);
} catch (Exception e) {
Message.message(context, "" + e);
}
}
}'
Messagejava
import android.content.Context;
import android.widget.Toast;
public class Message {
public static void message(Context context, String message) {
Toast.makeText(context, message, Toast.LENGTH_LONG).show();
}
}'