我的代码在模拟器上运行良好，但在设备上运行不正常。没有这种方法查询时出错。
package testing.login;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DBHelper extends SQLiteOpenHelper {
public DBHelper(Context context) {
//Create database
super(context, "MyDatabase.db", null, 1);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
//Create tables
db.execSQL("CREATE TABLE ANDRO(ID INTEGER,NAME TEXT,ADDRESS TEXT);");
db.execSQL("CREATE TABLE QUESTIONS(ID INTEGER,QUESTION TEXT,OPTION_A TEXT,OPTION_B TEXT,OPTION_C TEXT,OPTION_D TEXT,ANSWER TEXT);");
}
@Override
public void onUpgrade(SQLiteDatabase db, int arg1, int arg2) {
//Delete tables
db.execSQL("drop table if exists ANDRO");
db.execSQL("drop table if exists QUESTION");
}
}
package testing.login;
import android.os.Bundle;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
@SuppressLint("NewApi")
public class MainActivity extends Activity {
//Declaring Variables
SQLiteDatabase db;
EditText name, address;
String sname, saddress;
boolean namenotequal = true;
DBHelper dbHelper;
DatabaseBean dbb;
boolean upwrong = true;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
dbHelper = new DBHelper(getBaseContext()); //Accesing Database helper class
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
//On click function of sign up button
public void signup(View view) {
dbHelper.close();
//Intent used to access sign up class
Intent intent = new Intent(this, Signup.class);
// intent.putExtra("sachithkn", dbHelper);
startActivity(intent);
}
@Override
public void onBackPressed() {}
//On click function of sign in button
@SuppressLint("ShowToast")
public void signin(View view) {
//Reading values from text fields
name = (EditText) findViewById(R.id.editText1);
address = (EditText) findViewById(R.id.editText2);
sname = name.getText().toString();
saddress = address.getText().toString();
//Encrypting password using md5
saddress = Signup.md5(saddress);
String[] values = new String[] {
"ID",
"NAME",
"ADDRESS"
};
db = dbHelper.getReadableDatabase(); //Opening database
if (sname.equals("") || saddress.equals("")) //Checking whether text fields are empty or not
Toast.makeText(getApplicationContext(), "Field cannot be empty", 2000).show();
else {
//Reading values from database
Cursor cursor = db.query(false, "ANDRO", values, null, null, null, null, null, null, null);
if (cursor.moveToFirst()) {
do {
String dbname = cursor.getString(1);
String dbaddress = cursor.getString(2);
if (dbname.equals(sname) && dbaddress.equals(saddress)) //Checking whether values are in database or not
{
upwrong = false; //Variable set to run toast correctly
Toast.makeText(getApplicationContext(), "You have successfully logedin", 2000).show();
dbHelper.close();
Intent intent2 = new Intent(this, Questions.class); //Accesing questions activity
intent2.putExtra("passname", dbname);
startActivity(intent2);
}
} while (cursor.moveToNext());
if (upwrong) //Variable set to run toast correctly
{
//Toast set to show when password or user name is wrong
Toast.makeText(getApplicationContext(), "Wrong username or password ,Try again", 2000).show();
setContentView(R.layout.activity_main);
}
}
}
}
}
这是错误：
02-16 12:34:44.804: W/dalvikvm(26832): VFY: unable to resolve virtual method 255: Landroid/database/sqlite/SQLiteDatabase;.query (ZLjava/lang/String;[Ljava/lang/String;Ljava/lang/String;[Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Landroid/os/CancellationSignal;)Landroid/database/Cursor; 02-16 12:34:44.804: D/dalvikvm(26832): VFY: replacing opcode 0x74 at 0x007f 02-16 12:34:44.804: D/dalvikvm(26832): VFY: dead code 0x0082-00e8 in Ltesting/login/MainActivity;.signin (Landroid/view/View;)V 02-16 12:34:47.929: W/dalvikvm(26832): VFY: unable to resolve virtual method 255: Landroid/database/sqlite/SQLiteDatabase;.query (ZLjava/lang/String;[Ljava/lang/String;Ljava/lang/String;[Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Landroid/os/CancellationSignal;)Landroid/database/Cursor; 02-16 12:34:47.929: D/dalvikvm(26832): VFY: replacing opcode 0x74 at 0x0077 02-16 12:34:47.929: D/dalvikvm(26832): VFY: dead code 0x007a-00ec in Ltesting/login/Signup;.signup (Landroid/view/View;)V 02-16 12:34:57.148: D/AndroidRuntime(26832): Shutting down VM 02-16 12:34:57.148: W/dalvikvm(26832): threadid=1: thread exiting with uncaught exception (group=0x40018578) 02-16 12:34:57.195: E/AndroidRuntime(26832): FATAL EXCEPTION: main 02-16 12:34:57.195: E/AndroidRuntime(26832): java.lang.IllegalStateException: Could not execute method of the activity 02-16 12:34:57.195: E/AndroidRuntime(26832): at android.view.View$1.onClick(View.java:2144) 02-16 12:34:57.195: E/AndroidRuntime(26832): at android.view.View.performClick(View.java:2485) 02-16 12:34:57.195: E/AndroidRuntime(26832): at android.view.View$PerformClick.run(View.java:9080) 02-16 12:34:57.195: E/AndroidRuntime(26832): at android.os.Handler.handleCallback(Handler.java:587) 02-16 12:34:57.195: E/AndroidRuntime(26832): at android.os.Handler.dispatchMessage(Handler.java:92) 02-16 12:34:57.195: E/AndroidRuntime(26832): at android.os.Looper.loop(Looper.java:130) 02-16 12:34:57.195: E/AndroidRuntime(26832): at android.app.ActivityThread.main(ActivityThread.java:3687) 02-16 12:34:57.195: E/AndroidRuntime(26832): at java.lang.reflect.Method.invokeNative(Native Method) 02-16 12:34:57.195: E/AndroidRuntime(26832): at java.lang.reflect.Method.invoke(Method.java:507) 02-16 12:34:57.195: E/AndroidRuntime(26832): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867) 02-16 12:34:57.195: E/AndroidRuntime(26832): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625) 02-16 12:34:57.195: E/AndroidRuntime(26832): at dalvik.system.NativeStart.main(Native Method) 02-16 12:34:57.195: E/AndroidRuntime(26832): Caused by: java.lang.reflect.InvocationTargetException 02-16 12:34:57.195: E/AndroidRuntime(26832): at java.lang.reflect.Method.invokeNative(Native Method) 02-16 12:34:57.195: E/AndroidRuntime(26832): at java.lang.reflect.Method.invoke(Method.java:507) 02-16 12:34:57.195: E/AndroidRuntime(26832): at android.view.View$1.onClick(View.java:2139) 02-16 12:34:57.195: E/AndroidRuntime(26832): ... 11 more 02-16 12:34:57.195: E/AndroidRuntime(26832): Caused by: java.lang.NoSuchMethodError: android.database.sqlite.SQLiteDatabase.query 02-16 12:34:57.195: E/AndroidRuntime(26832): at testing.login.MainActivity.signin(MainActivity.java:77) 02-16 12:34:57.195: E/AndroidRuntime(26832): ... 14 more