我是android中的一名初学者并且尝试在过去五天内创建数据库并且我已经尝试了很多但是我仍然无法在AVD中创建数据库。我已经提到了很多关于数据库的内容，我尝试了很多，但我找不到bug，还请检查我的表创建代码。我感谢你的时间和帮助。这是我的代码..
package com.example.kannan.football_manager;
import android.content.ContentValues;
import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
/**
* Created by kannan on 25/1/16.
*/
public class Admin_Database_Operations extends SQLiteOpenHelper
{
public static final String ADMIN_DB="admin_info";
public static final String ADMIN_TB="abmin_table";
public static final String ADMIN_NAME="admin_name";
public static final String ADMIN_PASS="admin_pass";
public static final String ADMIN_ID="admin_id";
public static final int database_version=1;
//creating database
public Admin_Database_Operations(Context c)
{
super(c, ADMIN_DB, null, database_version);
Log.d("database creation", "database created");
// SQLiteDatabase sq=this.getWritableDatabase();
}
@Override
public void onCreate(SQLiteDatabase sqls) {
Log.d("Checking oncreate","Entered OnCreate");
//String CREATE_PRODUCTS_TABLE = "CREATE TABLE " + ADMIN_TB + "(" + ADMIN_ID +" INTEGER PRIMARY KEY AUTOINCREMENT,"+ ADMIN_NAME
// + " TEXT NOT NULL, " + ADMIN_PASS + " TEXT NOT NULL " + ")";
String str_tbl="CREATE TABLE "+ ADMIN_TB +"(admin_id INTEGER PRIMARY KEY AUTOINCREMENT,admin_name TEXT NOT NULL,admin_pass TEXT NOT NULL)";
Log.i("createDB=",str_tbl);
Log.d("Table creatiion", "Table Query executing");
try {
sqls.execSQL(str_tbl);
Log.d("Table creation ", "TABLE CREATED ");
}
catch (Exception e)
{
e.printStackTrace();
e.getMessage();
}
}
@Override
public void onUpgrade(SQLiteDatabase sqls, int i, int i1)
{
String Drop="DROP TABLE IF EXIST"+ADMIN_TB;
sqls.execSQL(Drop);
onCreate(sqls);
}
public void putInformation(Admin_Database_Operations ado,String name,String pass)
{
Log.d("Entering class","Entered class");
SQLiteDatabase sq=ado.getWritableDatabase();
Log.d("Creating database","Database created");
ContentValues cv=new ContentValues();
cv.put(ADMIN_NAME,name);
cv.put(ADMIN_PASS,pass);
long k=sq.insert(ADMIN_TB,null,cv);
sq.close();
}
}
package com.example.kannan.football_manager;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class LoginActivity extends AppCompatActivity {
public Button btn_Admin;
public Button btn_Cancel;
public Button btn_Login;
public Button btn_cngepsw;
public EditText edttxt_name;
public EditText edttxt_pass;
public SQLiteDatabase sqldb;
public Context ctx;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
//Declaring Nodes
btn_Admin=(Button) findViewById(R.id.btn_Admin);
btn_Cancel=(Button) findViewById(R.id.btn_Cancel);
btn_Login=(Button) findViewById(R.id.btn_Login);
btn_cngepsw=(Button) findViewById(R.id.btn_cngepsw);
edttxt_name=(EditText) findViewById(R.id.edttxt_name);
edttxt_pass=(EditText) findViewById(R.id.edttxt_pass);
btn_Login.setOnClickListener(
new Button.OnClickListener()
{
public void onClick(View v)
{
String name="kannan";
String pass="pass";
Admin_Database_Operations ado=new Admin_Database_Operations(ctx);
try {
//ado.onCreate(sqldb);
Log.d("Checking value",name);
Log.d("Entered to clss","trying to insert");
ado.putInformation(ado, name, pass);
Log.d("Checking value",name);
}
catch(Exception e)
{
Log.d("Exception Catch", " ");
e.printStackTrace();
e.getMessage();
}
Log.d("Database operation", "INSERT ONE RAW");
}
}
);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_login, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
//Here is my locat error
02-04 10:21:39.010 1626-1626/? D/dalvikvm: Not late-enabling CheckJNI (already on)
02-04 10:21:39.140 1626-1632/? D/dalvikvm: Debugger has detached; object registry had 1 entries
02-04 10:21:39.290 1626-1626/? W/ActivityThread: Application com.example.kannan.football_manager is waiting for the debugger on port 8100...
02-04 10:21:39.300 1626-1626/? I/System.out: Sending WAIT chunk
02-04 10:21:41.310 1626-1632/com.example.kannan.football_manager I/dalvikvm: Debugger is active
02-04 10:21:41.400 1626-1626/com.example.kannan.football_manager I/System.out: Debugger has connected
02-04 10:21:41.400 1626-1626/com.example.kannan.football_manager I/System.out: waiting for debugger to settle...
02-04 10:21:41.610 1626-1626/com.example.kannan.football_manager I/System.out: waiting for debugger to settle...
02-04 10:21:41.820 1626-1626/com.example.kannan.football_manager I/System.out: waiting for debugger to settle...
02-04 10:21:42.030 1626-1626/com.example.kannan.football_manager I/System.out: waiting for debugger to settle...
02-04 10:21:42.240 1626-1626/com.example.kannan.football_manager I/System.out: waiting for debugger to settle...
02-04 10:21:42.450 1626-1626/com.example.kannan.football_manager I/System.out: waiting for debugger to settle...
02-04 10:21:42.660 1626-1626/com.example.kannan.football_manager I/System.out: waiting for debugger to settle...
02-04 10:21:42.870 1626-1626/com.example.kannan.football_manager I/System.out: waiting for debugger to settle...
02-04 10:21:43.080 1626-1626/com.example.kannan.football_manager I/System.out: waiting for debugger to settle...
02-04 10:21:43.290 1626-1626/com.example.kannan.football_manager I/System.out: waiting for debugger to settle...
02-04 10:21:43.500 1626-1626/com.example.kannan.football_manager I/System.out: debugger has settled (1375)
02-04 10:21:43.550 1626-1626/com.example.kannan.football_manager W/dalvikvm: VFY: unable to find class referenced in signature (Landroid/view/SearchEvent;)
02-04 10:21:43.550 1626-1626/com.example.kannan.football_manager I/dalvikvm: Could not find method android.view.Window$Callback.onSearchRequested, referenced from method android.support.v7.view.WindowCallbackWrapper.onSearchRequested
02-04 10:21:43.550 1626-1626/com.example.kannan.football_manager W/dalvikvm: VFY: unable to resolve interface method 17969: Landroid/view/Window$Callback;.onSearchRequested (Landroid/view/SearchEvent;)Z
02-04 10:21:43.550 1626-1626/com.example.kannan.football_manager D/dalvikvm: VFY: replacing opcode 0x72 at 0x0002
02-04 10:21:43.550 1626-1626/com.example.kannan.football_manager I/dalvikvm: Could not find method android.view.Window$Callback.onWindowStartingActionMode, referenced from method android.support.v7.view.WindowCallbackWrapper.onWindowStartingActionMode
02-04 10:21:43.550 1626-1626/com.example.kannan.football_manager W/dalvikvm: VFY: unable to resolve interface method 17973: Landroid/view/Window$Callback;.onWindowStartingActionMode (Landroid/view/ActionMode$Callback;I)Landroid/view/ActionMode;
02-04 10:21:43.550 1626-1626/com.example.kannan.football_manager D/dalvikvm: VFY: replacing opcode 0x72 at 0x0002
02-04 10:21:43.610 1626-1626/com.example.kannan.football_manager I/dalvikvm: Could not find method android.content.res.TypedArray.getChangingConfigurations, referenced from method android.support.v7.widget.TintTypedArray.getChangingConfigurations
02-04 10:21:43.610 1626-1626/com.example.kannan.football_manager W/dalvikvm: VFY: unable to resolve virtual method 423: Landroid/content/res/TypedArray;.getChangingConfigurations ()I
02-04 10:21:43.610 1626-1626/com.example.kannan.football_manager D/dalvikvm: VFY: replacing opcode 0x6e at 0x0002
02-04 10:21:43.610 1626-1626/com.example.kannan.football_manager I/dalvikvm: Could not find method android.content.res.TypedArray.getType, referenced from method android.support.v7.widget.TintTypedArray.getType
02-04 10:21:43.610 1626-1626/com.example.kannan.football_manager W/dalvikvm: VFY: unable to resolve virtual method 445: Landroid/content/res/TypedArray;.getType (I)I
02-04 10:21:43.610 1626-1626/com.example.kannan.football_manager D/dalvikvm: VFY: replacing opcode 0x6e at 0x0002
02-04 10:21:43.670 1626-1626/com.example.kannan.football_manager I/dalvikvm: Could not find method android.content.res.Resources.getDrawable, referenced from method android.support.v7.widget.ResourcesWrapper.getDrawable
02-04 10:21:43.670 1626-1626/com.example.kannan.football_manager W/dalvikvm: VFY: unable to resolve virtual method 386: Landroid/content/res/Resources;.getDrawable (ILandroid/content/res/Resources$Theme;)Landroid/graphics/drawable/Drawable;
02-04 10:21:43.680 1626-1626/com.example.kannan.football_manager D/dalvikvm: VFY: replacing opcode 0x6e at 0x0002
02-04 10:21:43.680 1626-1626/com.example.kannan.football_manager I/dalvikvm: Could not find method android.content.res.Resources.getDrawableForDensity, referenced from method android.support.v7.widget.ResourcesWrapper.getDrawableForDensity
02-04 10:21:43.680 1626-1626/com.example.kannan.football_manager W/dalvikvm: VFY: unable to resolve virtual method 388: Landroid/content/res/Resources;.getDrawableForDensity (IILandroid/content/res/Resources$Theme;)Landroid/graphics/drawable/Drawable;
02-04 10:21:43.680 1626-1626/com.example.kannan.football_manager D/dalvikvm: VFY: replacing opcode 0x6e at 0x0002
02-04 10:21:44.070 1626-1626/com.example.kannan.football_manager W/EGL_emulation: eglSurfaceAttrib not implemented
02-04 10:21:44.110 1626-1626/com.example.kannan.football_manager D/OpenGLRenderer: Enabling debug mode 0
02-04 10:21:44.160 1626-1626/com.example.kannan.football_manager D/dalvikvm: GC_FOR_ALLOC freed 232K, 10% free 3112K/3452K, paused 3ms, total 6ms
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager D/database creation: database created
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager D/Checking value: kannan
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager D/Entered to clss: trying to insert
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager D/Entering class: Entered class
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager D/Exception Catch:
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: java.lang.NullPointerException
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:224)
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164)
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: at com.example.kannan.football_manager.Admin_Database_Operations.putInformation(Admin_Database_Operations.java:81)
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: at com.example.kannan.football_manager.LoginActivity$1.onClick(LoginActivity.java:61)
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: at android.view.View.performClick(View.java:4438)
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: at android.view.View$PerformClick.run(View.java:18422)
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: at android.os.Handler.handleCallback(Handler.java:733)
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: at android.os.Handler.dispatchMessage(Handler.java:95)
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: at android.os.Looper.loop(Looper.java:136)
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: at android.app.ActivityThread.main(ActivityThread.java:5001)
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: at java.lang.reflect.Method.invokeNative(Native Method)
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: at java.lang.reflect.Method.invoke(Method.java:515)
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager W/System.err: at dalvik.system.NativeStart.main(Native Method)
02-04 10:22:00.550 1626-1626/com.example.kannan.football_manager D/Database operation: INSERT ONE RAW