我创建了一个用于在数据库中插入数据并从数据库中检索数据的应用程序。当第一次活动开始然后数据插入数据库并从数据库中检索数据，但是当我重新启动活动并单击按钮从数据库中检索数据时，我的应用程序关闭时出错.Pleas帮助我??
DataBaseHelper类
public class DataBaseHelper extends SQLiteOpenHelper
{
public DataBaseHelper(Context context, String name,CursorFactory factory, int version)
{
super(context, name, factory, version);
}
// Called when no database exists in disk and the helper class needs
// to create a new one.
@Override
public void onCreate(SQLiteDatabase _db)
{
_db.execSQL(DetailDataBaseAdapter.DATABASE_CREATE);
}
// Called when there is a database version mismatch meaning that the version
// of the database on disk needs to be upgraded to the current version.
@Override
public void onUpgrade(SQLiteDatabase _db, int _oldVersion, int _newVersion)
{
// Log the version upgrade.
Log.w("TaskDBAdapter", "Upgrading from version " +_oldVersion + " to " +_newVersion + ", which will destroy all old data");
// Upgrade the existing database to conform to the new version. Multiple
// previous versions can be handled by comparing _oldVersion and _newVersion
// values.
// The simplest case is to drop the old table and create a new one.
_db.execSQL("DROP TABLE IF EXISTS " + "TEMPLATE");
// Create a new one.
onCreate(_db);
}
}
DataBaseAdapter类
public class DetailDataBaseAdapter{
static final String DATABASE_NAME = "phone.db";
static final int DATABASE_VERSION = 1;
public static final int NAME_COLUMN = 1;
// TODO: Create public field for each column in your table.
// SQL Statement to create a new database.
static final String DATABASE_CREATE = "create table "+"PHONE"+
"( " +"ID"+" integer primary key autoincrement,"+ "NUMBER text,SIM text,IMEI text); ";
// Variable to hold the database instance
public SQLiteDatabase db;
// Context of the application using the database.
private final Context context;
// Database open/upgrade helper
private DataBaseHelper dbHelper;
public DetailDataBaseAdapter(Context _context)
{
context = _context;
dbHelper = new DataBaseHelper(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public DetailDataBaseAdapter open() throws SQLException
{
db = dbHelper.getWritableDatabase();
return this;
}
public void close()
{
db.close();
}
public SQLiteDatabase getDatabaseInstance()
{
return db;
}
public void insertEntry(String number,String sim,String imei)
{
ContentValues newValues = new ContentValues();
// Assign values for each row.
newValues.put("NUMBER", number);
newValues.put("SIM",sim);
newValues.put("IMEI",imei);
// Insert the row into your table
db.insert("PHONE", null, newValues);
///Toast.makeText(context, "Reminder Is Successfully Saved", Toast.LENGTH_LONG).show();
}
public String getData(String number)
{
Cursor cursor=db.query("PHONE", null, " NUMBER=?", new String[]{number}, null, null, null);
if(cursor.getCount()<1) // UserName Not Exist
{
cursor.close();
return "NOT EXIST";
}
cursor.moveToFirst();
String sim_id= cursor.getString(cursor.getColumnIndex("NUMBER"));
cursor.close();
return sim_id;
}
}
MainActivity类
public class MainActivity extends Activity{
TextView tv;
String telNumber,simID,IMEI;
Button btn,bt;
TelephonyManager tm;
DetailDataBaseAdapter detailDataBaseAdapter;
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tm = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
btn = (Button) findViewById(R.id.ok);
detailDataBaseAdapter=new DetailDataBaseAdapter(this);
detailDataBaseAdapter=detailDataBaseAdapter.open();
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
simID = tm.getSimSerialNumber();
if (simID != null) {
tv=(TextView)findViewById(R.id.tv_sim_no);
tv.setText(simID);
}
// ---get the phone number---
telNumber = tm.getLine1Number();
if (telNumber != null) {
tv=(TextView)findViewById(R.id.tv_phone_no);
tv.setText(telNumber);
}
// ---get the IMEI number---
IMEI = tm.getDeviceId();
if (IMEI != null) {
tv=(TextView)findViewById(R.id.tv_imei_no);
tv.setText(IMEI);
}
detailDataBaseAdapter.insertEntry(telNumber,simID,IMEI);
}
});
bt=(Button)findViewById(R.id.getDetail);
bt.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String storedPassword=detailDataBaseAdapter.getData(telNumber);
Toast.makeText(MainActivity.this, storedPassword, Toast.LENGTH_LONG).show();
}
});
}
}
logcat的
FATAL EXCEPTION: main
Process: com.example.phone_detail, PID: 10548
E/AndroidRuntime(10548): java.lang.IllegalArgumentException: the bind value at index 1 is null
at android.database.sqlite.SQLiteProgram.bindString(SQLiteProgram.java:164)
at android.database.sqlite.SQLiteProgram.bindAllArgsAsStrings(SQLiteProgram.java:200)
at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:47)
at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1316)
at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1163)
at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1034)
at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1202)
at com.example.phone_detail.DetailDataBaseAdapter.getData(DetailDataBaseAdapter.java:59)
at com.example.phone_detail.MainActivity$2.onClick(MainActivity.java:59)
答案 0 :(得分：2)
logCat表示你绑定null来查询你的getData方法 - 所以也许你用null参数调用这个方法。在调用db.query
答案 1 :(得分：0)
我相信在你的数据库助手的onCreate（...）方法中，你应首先检查数据库是否存在于所需的路径“/ data / data / app-package / databases”中，如果它不存在则创建它“T。或者，您可能需要考虑将IF NOT EXISTS添加到您的create语句中。