java - android studio使用sql报错

Question

我正在制作一个 Android 应用程序来使用 android SQLite 登录和注册。我在登录或注册时遇到错误。

日志猫

03-14 13:07:01.910 19906-19906/com.example.dp_7_kholood.taskone E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.dp_7_kholood.taskone, PID: 19906 java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
at android.view.View.performClick(View.java:5198)
at android.view.View$PerformClick.run(View.java:21147)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: android.database.sqlite.SQLiteException: no such column: uname (code 1): , while compiling: select uname, pass from contacts
at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:887)
at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:498)
at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1316)
at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1255)
at com.example.dp_7_kholood.taskone.DatabaseHelper.searchPass(DatabaseHelper.java:58)
at com.example.dp_7_kholood.taskone.Login.onButtonClick(Login.java:32)
at java.lang.reflect.Method.invoke(Native Method) 
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

联系方式

public class Contact {

    String name, email,username,pass;

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPass() {
        return pass;
    }

    public void setPass(String pass) {
        this.pass = pass;
    }
}

数据库助手

public class DatabaseHelper extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME= "contacts.db";
private static final String TABLE_NAME ="contacts";
private static final String COLUMN_ID ="id";
private static final String COLUMN_NAME ="name";
private static final String COLUMN_EMAIL ="email";
private static final String COLUMN_USERNAME="username";
private static final String COLUMN_PASS="pass";
SQLiteDatabase db;

private static final String TABLE_CREATE= "create table contacts (id integer primary key not null , "+ "name text not null , email text not null , username text not null , pass text not null);";

public DatabaseHelper(Context context){

    super(context , DATABASE_NAME, null,DATABASE_VERSION );
}
@Override
public void onCreate(SQLiteDatabase db) {

    db.execSQL(TABLE_CREATE);
    this.db=db;

}
public void insertContact(Contact c){
db=this.getWritableDatabase();
    ContentValues values=new ContentValues();

    String query= "select * from contacts";
    Cursor cursor=db.rawQuery(query, null);
    int count= cursor.getCount();

    values.put(COLUMN_ID,count);
    values.put(COLUMN_NAME , c.getName());
    values.put(COLUMN_USERNAME, c.getUsername());
    values.put(COLUMN_EMAIL , c.getEmail());
    values.put(COLUMN_PASS , c.getPass());

    db.insert(TABLE_NAME, null, values);
    db.close();
}

public String searchPass(String uname){
    db=this.getReadableDatabase();
    String query=" select uname, pass from "+TABLE_NAME;
    Cursor cursor =db.rawQuery(query,null);

    String a,b;
    b="not found";
    if(cursor.moveToFirst())
    {
        do{
            a=cursor.getString(0);

            if (a.equals(uname)){

            b=cursor.getString(1);
                break;
        }

    }
        while(cursor.moveToNext());
}
return b;
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    String query ="DROP TABLE IF EXISTS "+TABLE_NAME;
    db.execSQL(query);
    this.onCreate(db);
}
}

登录

public class Login extends AppCompatActivity {

DatabaseHelper helper=new DatabaseHelper(this);
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_login);

}

public void onButtonClick(View v){


    if (v.getId() == R.id.Blogin);
    {
        EditText a = (EditText)findViewById(R.id.Tfusername);
        String str= a.getText().toString();
        EditText b = (EditText)findViewById(R.id.Tfpassword);
        String pass= b.getText().toString();
        String password= helper.searchPass(str);

        if(pass.equals(password)){

        Intent i= new Intent(Login.this, SingUp.class);
        i.putExtra("Username",str);
        startActivity(i);

    }

        else{
            Toast t=Toast.makeText(Login.this, "Username and Paasword not match!", Toast.LENGTH_SHORT);
            t.show();
        }}
    if(v.getId()==R.id.BtnSingup){

         Intent i= new Intent(Login.this, SingUp.class);
         startActivity(i);
    }
}
}

注册

public class SingUp extends Activity {

DatabaseHelper helper=new DatabaseHelper(this);
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.signup);

}
public void OnSignUp(View v){
    if (v.getId()==R.id.Bsingup){

        EditText name= (EditText)findViewById(R.id.Tfname);
        EditText username= (EditText)findViewById(R.id.Tfusername);
        EditText email= (EditText)findViewById(R.id.Tfemail);
        EditText pass1= (EditText)findViewById(R.id.Tfpass1);
        EditText pass2= (EditText)findViewById(R.id.Tfpass2);

        String namestr = name.getText().toString();
        String usernamestr = username.getText().toString();
        String emailstr = email.getText().toString();
        String pass1str = pass1.getText().toString();
        String pass2str = pass2.getText().toString();

        if(!pass1str.equals(pass2str)){
            Toast pass=Toast.makeText(SingUp.this, "Paasword not match!", Toast.LENGTH_SHORT);
            pass.show();
        }
        else{

            Contact c =new Contact();
            c.setName(namestr);
            c.setEmail(emailstr);
            c.setUsername(usernamestr);
            c.setPass(pass1str);
            helper.insertContact(c);
        }

    }
}
}

Answer 1

原因

根据您的创建表查询

private static final String TABLE_CREATE= "create table contacts (id integer primary key not null , "+ "name text not null , email text not null , username text not null , pass text not null);";

您拥有的列名称为id、name、email、username和pass.没有列 uname。

解决方案

改变

String query=" select uname, pass from "+TABLE_NAME;

至

String query=" select username, pass from "+TABLE_NAME; // if you want username

或

String query=" select name, pass from "+TABLE_NAME; // if you want name