我正在尝试将名称和密码添加到sqlite数据库android，但出现一些错误
我是编程新手，我想向数据库添加名称和密码 使用sqlite //主要活动
package com.example.databasetutorial;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.example.databasetutorial.Database.DBHandler;
public class MainActivity extends AppCompatActivity {
EditText name,password;
DBHandler dbHandler;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
name = findViewById(R.id.name);
password = findViewById(R.id.password);
dbHandler = new DBHandler(this);
}
public void addUser(View view) {
String uname = name.getText().toString();
String password = name.getText().toString();
long result = dbHandler.addInfo(uname,password);
if(result > 0 ) {
Toast.makeText(this, "Success", Toast.LENGTH_LONG);
}
else {
Toast.makeText(this,"ERROR!",Toast.LENGTH_LONG);
}
}
}
//DBHABDLER.JAVA
package com.example.databasetutorial.Database;
import android.provider.BaseColumns;
public final class UserMaster {
private UserMaster(){}
protected static class Users implements BaseColumns {
public static final String TABLE_NAME = "users";
public static final String COLUMN_NAME_USERNAME = "username";
public static final String COLUMN_NAME_PASSWORD = "username";
}
}
package com.example.databasetutorial.Database;
import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DBHandler extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "userInfo.db";
public DBHandler(Context context) {
super(context,DATABASE_NAME,null,2);
}
@Override
public void onCreate(SQLiteDatabase db) {
String SQL_CREATE_ENTRIES =
"CREATE TABLE " + UserMaster.Users.TABLE_NAME + " (" +
UserMaster.Users._ID + " INTEGER PRIMARY KEY," +
UserMaster.Users.COLUMN_NAME_PASSWORD + " TEXT," +
UserMaster.Users.COLUMN_NAME_PASSWORD + " TEXT) ";
db.execSQL(SQL_CREATE_ENTRIES);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int
newVersion) {
}
public long addInfo(String userName , String password){
SQLiteDatabase db = getWritableDatabase();
ContentValues values = new ContentValues();
values.put(UserMaster.Users.COLUMN_NAME_USERNAME,userName);
values.put(UserMaster.Users.COLUMN_NAME_PASSWORD,password);
long newRowID =
db.insert(UserMaster.Users.TABLE_NAME,null,values);
return newRowID;
}
}
//XML FILE
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<EditText
android:id="@+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
android:ems="10"
android:inputType="textPersonName"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.164" />
<EditText
android:id="@+id/password"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
android:ems="10"
android:inputType="textPersonName"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/name"
app:layout_constraintVertical_bias="0.033" />
<Button
android:id="@+id/register"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="32dp"
android:layout_marginEnd="8dp"
android:text="Regiser"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/password"
android:onClick="addUser"/>
</android.support.constraint.ConstraintLayout>
运行时出现此错误：
I/AssistStructure: Flattened final assist data: 2652 bytes, containing 1 windows, 9 views
E/SQLiteLog: (1) duplicate column name: username
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.databasetutorial, PID: 13586
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:390)
at android.view.View.performClick(View.java:6597)
at android.view.View.performClickInternal(View.java:6574)
at android.view.View.access$3100(View.java:778)
at android.view.View$PerformClick.run(View.java:25885)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385)
at android.view.View.performClick(View.java:6597)
at android.view.View.performClickInternal(View.java:6574)
at android.view.View.access$3100(View.java:778)
at android.view.View$PerformClick.run(View.java:25885)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: android.database.sqlite.SQLiteException: duplicate column name: username (code 1 SQLITE_ERROR): , while compiling: CREATE TABLE users (_id INTEGER PRIMARY KEY,username TEXT,username TEXT)
at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:903)
at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:514)
at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
at android.database.sqlite.SQLiteStatement.<init>(SQLiteStatement.java:31)
at android.database.sqlite.SQLiteDatabase.executeSql(SQLiteDatabase.java:1769)
at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1698)
at com.example.databasetutorial.Database.DBHandler.onCreate(DBHandler.java:27)
at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:393)
at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:298)
at com.example.databasetutorial.Database.DBHandler.addInfo(DBHandler.java:37)
at com.example.databasetutorial.MainActivity.addUser(MainActivity.java:43)
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385)
at android.view.View.performClick(View.java:6597)
at android.view.View.performClickInternal(View.java:6574)
at android.view.View.access$3100(View.java:778)
at android.view.View$PerformClick.run(View.java:25885)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
I/Process: Sending signal. PID:
答案 0 :(得分：2)
这里：
由以下原因引起：android.database.sqlite.SQLiteException：重复的列名称：用户名（代码1 SQLITE_ERROR）：，而在编译时：CREATE TABLE用户（_id INTEGER PRIMARY KEY，用户名TEXT，用户名TEXT）
当您仔细查看时：... 键，用户名TEXT，用户名TEXT）
因此，只需删除重复的username TEXT
UserMaster.Users.COLUMN_NAME_PASSWORD + " TEXT) ";的秒
真实答案：仔细阅读这些异常堆栈跟踪。尤其是以由引起的开头。因为最有可能找到问题的原因！