在以下代码中，错误为：Can not resolve the symbol 'firstname','lastname' and 'email'。我还在.xml文件中交叉验证了相同的变量，但它仍然显示错误。
import android.R;
import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.graphics.Color;
import android.graphics.Typeface;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;
import android.widget.TableLayout.*;
public class MainActivity extends Activity
{
String fname, lname, email;
SQLiteDatabase db;
TableRow tableRow;
String firstname, lastname;
TextView textView, textView1, textView2, textView3, textView4, textView5;
EditText editText1, editText2, editText3;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list_item);
db = openOrCreateDatabase("MyDB1", MODE_PRIVATE, null);
db.execSQL("CREATE TABLE IF NOT EXIST Student(fname VARCHAR,lname VARCHAR,email VARCHAR);");
}
public void Adddata(View view)
{
editText1 = (EditText) finViewById(R.id.firstname);
editText2 = (EditText) finViewById(R.id.lastname);
editText3 = (EditText) finViewById(R.id.email);
fname = editText1.getText().toString();
fname = editText2.getText().toString();
fname = editText3.getText().toString();
db.execSQL("INSERT INTO Studnet VALUES('" + fname + "','" + lname + "','" + email + "');");
}
private void Showdata(View view)
{
Cursor c = db.rawQuery("SELECT * from Student", null);
int count = c.getCount();
c.moveToFirst();
TableLayout tableLayout = new TableLayout(getApplicationContext());
tableLayout.setVerticalScrollBarEnabled(true);
tableRow = new TableRow(getApplicationContext());
textView = new TextView(getApplicationContext());
textView.setText("Firstname");
textView.setTextColor(Color.RED);
textView.setTypeface(null, Typeface.BOLD);
textView.setPadding(20, 20, 20, 20);
tableRow.addView(textView);
textView4 = new TextView(getApplicationContext());
textView4.setText("Lastname");
textView4.setTextColor(Color.RED);
textView4.setTypeface(null, Typeface.BOLD);
textView4.setPadding(20, 20, 20, 20);
tableRow.addView(textView4);
textView5 = new TextView(getApplicationContext());
textView5.setText("Email");
textView5.setTextColor(Color.RED);
textView5.setTypeface(null, Typeface.BOLD);
textView5.setPadding(20, 20, 20, 20);
tableRow.addView(textView5);
tableLayout.addView(tableRow);
for (Integer j = 0; j <= count; j++)
{
tableRow = new TableRow(getApplicationContext());
textView1 = new TextView(getApplicationContext());
textView1.setText(c.getString(c.getColumnIndex("fname")));
textView2 = new TextView(getApplicationContext());
textView2.setText(c.getString(c.getColumnIndex("lname")));
textView3 = new TextView(getApplicationContext());
textView3.setText(c.getString(c.getColumnIndex("email")));
textView1.setPadding(20, 20, 20, 20);
textView2.setPadding(20, 20, 20, 20);
textView3.setPadding(20, 20, 20, 20);
tableRow.addView(textView1);
tableRow.addView(textView2);
tableRow.addView(textView3);
tableLayout.addView(tableLayout);
db.close();
}
}
public void close(View view)
{
System.exit(0);
}
}
XML代码是：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@style/AppBaseTheme"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="22dp"
android:layout_marginTop="34dp"
android:text="FirstName" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView1"
android:layout_below="@+id/textView1"
android:layout_marginTop="43dp"
android:text="LastName" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView2"
android:layout_alignRight="@+id/textView1"
android:layout_below="@+id/textView2"
android:layout_marginTop="49dp"
android:text="E-mail" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView3"
android:layout_centerVertical="true"
android:onClick="Adddata"
android:text="create" />
<Button
android:id="@+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/button1"
android:layout_below="@+id/button1"
android:layout_marginTop="32dp"
android:onClick="Showdata"
android:text="Show Table" />
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/button3"
android:layout_toRightOf="@+id/button3"
android:onClick="close"
android:text="close" />
<EditText
android:id="@+id/firstname"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView1"
android:layout_alignBottom="@+id/textView1"
android:layout_toRightOf="@+id/button3"
android:ems="10"
android:inputType="textPersonName" >
<requestFocus />
</EditText>
<EditText
android:id="@+id/lastname"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView2"
android:layout_alignBottom="@+id/textView2"
android:layout_alignLeft="@+id/editText1"
android:ems="10"
android:inputType="textPersonName" />
<EditText
android:id="@+id/email"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/textView3"
android:layout_alignLeft="@+id/editText2"
android:ems="10"
android:inputType="textEmailAddress" />
</RelativeLayout>
清单文件是：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.studentdatabase"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.studentdatabase.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>