android - 简单的 Sqlite 助手

Question

今天我正在学习用于插入和查看插入记录的SQlite。单击保存按钮时，出现错误“不幸的是 AppName 已停止”。有人可以帮忙吗？

Sqlite 数据库助手

public class SqliteDatabaseHelper extends SQLiteOpenHelper {

public static final String DATABASE_NAME="reg";
public static final String TABLE_NAME="user_details";
public static final String COLUMN_ID="id";
public static final String COLUMN_NAME="name";
public static final String COLUMN_EMAIL="email";
public static final String COLUMN_UNAME="uname";
public static final String COLUMN_PASSWORD="pass";
public static final int DATABASE_VERSION=1;


public SqliteDatabaseHelper(Context context){
    super(context,DATABASE_NAME,null,DATABASE_VERSION);

}

@Override
public void onCreate(SQLiteDatabase db) {
    String sql="CREATE TABLE"+TABLE_NAME+"("+COLUMN_ID+"INTEGER PRIMARY KEY AUTO INCREMENT"+COLUMN_NAME+"VARCHAR"+COLUMN_EMAIL+"VARCHAR"
            +COLUMN_UNAME+"VARCHAR"+COLUMN_PASSWORD+"VARCHAR);";
    db.execSQL(sql);
    Log.d("create","Table Created Sucessfully");
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    String sql="DROP TABLE IF EXIST user_details ";
    db.execSQL(sql);
    onCreate(db);
}
public boolean adduser(String name,String email,String uname,String pass)
{

    SQLiteDatabase db=this.getWritableDatabase();

    ContentValues contentValues=new ContentValues();


    contentValues.put(COLUMN_NAME,name);
    contentValues.put(COLUMN_EMAIL,email);
    contentValues.put(COLUMN_UNAME,uname);
    contentValues.put(COLUMN_PASSWORD,pass);

    db.insert(TABLE_NAME, null, contentValues);
    db.close();
    return true;
}
public Cursor getuser(int id)
{
    SQLiteDatabase db=this.getReadableDatabase();
    String sql="SELECT * FROM user_details WHERE id="+id+"; ";
    Cursor cursor= db.rawQuery(sql,null);
    return cursor;
}

主要 Activity

enter code herepublic class MainActivity extends AppCompatActivity  implements View.OnClickListener{

private EditText edname;
private EditText edemail;
private EditText eduname;
private EditText edpass;
private Button bsave;
private Button bview;

SqliteDatabaseHelper db;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    edname= (EditText) findViewById(R.id.fullname);
    edemail= (EditText) findViewById(R.id.email);
    eduname= (EditText) findViewById(R.id.uname);
    edpass= (EditText) findViewById(R.id.pass);
    bsave= (Button) findViewById(R.id.save);
    bview= (Button) findViewById(R.id.view);

    db= new SqliteDatabaseHelper(this);
    bsave.setOnClickListener(this);
    bview.setOnClickListener(this);

} @Override
public void onClick(View v) {
    if (v==bsave){
        insert();


    }
    if (v==bview){
        Intent intent= new Intent(MainActivity.this,ViewUser.class);
        startActivity(intent);

    }

}

public void insert() {

    String name=edname.getText().toString().trim();
    String email=edemail.getText().toString().trim();
    String unmae=eduname.getText().toString().trim();
    String upass=edpass.getText().toString().trim();

    db.adduser(name,email,unmae,upass);


    Toast.makeText(this,"New REcords Inserted Sucessfully",Toast.LENGTH_LONG).show();
}

查看用户

公共(public)类 ViewUser 扩展 AppCompatActivity {

private EditText dispFullname;
private EditText dispEmail;
private EditText dispUname;
private EditText dispass;
private EditText dispuid;
private Button show;
private Button home;

SqliteDatabaseHelper db;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_view_user);

    dispuid= (EditText) findViewById(R.id.uid);
    dispFullname= (EditText) findViewById(R.id.fullnamedisp);
    dispEmail= (EditText) findViewById(R.id.emaildisp);
    dispUname= (EditText) findViewById(R.id.unamedisp);
    dispass= (EditText) findViewById(R.id.passdisp);
    show= (Button) findViewById(R.id.show);
    home= (Button) findViewById(R.id.Home);
    db=  new SqliteDatabaseHelper(this);
    show.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            showuser(Integer.parseInt(dispuid.getText().toString().trim()));
        }
    });
    home.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent= new Intent(ViewUser.this,MainActivity.class);
            startActivity(intent);
        }
    });

}

private void showuser(int id) {
    Cursor c =db.getuser(id);
    c.moveToFirst();
    {
        if (c!=null){
            dispuid.setText(c.getString(c.getColumnIndex(SqliteDatabaseHelper.COLUMN_ID)));
            dispFullname.setText(c.getString(c.getColumnIndex(SqliteDatabaseHelper.COLUMN_NAME)));
            dispEmail.setText(c.getString(c.getColumnIndex(SqliteDatabaseHelper.COLUMN_EMAIL)));
            dispUname.setText(c.getString(c.getColumnIndex(SqliteDatabaseHelper.COLUMN_UNAME)));
            dispass.setText(c.getString(c.getColumnIndex(SqliteDatabaseHelper.COLUMN_PASSWORD)));


        }
    }

}

日志:

09-21 19:38:52.261  16080-16080/com.example.karthi.sqlitedesign E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.karthi.sqlitedesign, PID: 16080
android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0
        at android.database.AbstractCursor.checkPosition(AbstractCursor.java:426)
        at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:136)
        at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:50)
        at com.example.karthi.sqlitedesign.ViewUser.showuser(ViewUser.java:63)
        at com.example.karthi.sqlitedesign.ViewUser.access$100(ViewUser.java:14)
        at com.example.karthi.sqlitedesign.ViewUser$1.onClick(ViewUser.java:43)
        at android.view.View.performClick(View.java:4661)
        at android.view.View$PerformClick.run(View.java:19498)
        at android.os.Handler.handleCallback(Handler.java:733)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:146)
        at android.app.ActivityThread.main(ActivityThread.java:5641)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1288)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1104)
        at dalvik.system.NativeStart.main(Native Method)
09-21 19:39:17.715  17307-17407/? D/show﹕ read firstrelease/release_text from assets
09-21 19:39:42.500  17785-17997/? D/show﹕ read firstrelease/release_text from assets
09-21 19:39:55.252  18211-18293/? D/show﹕ read firstrelease/release_text from assets

Answer 1

致谢 Opiatefuchs @karthickYadav

您缺少 Sqlite CREATE TABLE 语句。

你怎么了

1. 使用AUTOINCREMENT代替AUTO INCREMENT
2. 使用 TEXT 而不是 VARCHAR。

在创建数据库之前，请阅读此 Android SQLite Database Tutorial和 SQLiteDatabase

虚拟示例

String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_TAXONOMY + "("
            + KEY_ID + " INTEGER PRIMARY KEY , " + KEY_TAXONOMY_CODE + " TEXT, "
            + KEY_DISPLAY_NAME+" TEXT )";
    db.execSQL(CREATE_CONTACTS_TABLE);

编辑

String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_NAME + "(" + COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + COLUMN_NAME + " TEXT, "+ COLUMN_EMAIL +"TEXT," + COLUMN_UNAME + "TEXT," + COLUMN_PASSWORD +" TEXT )"; db.execSQL(CREATE_CONTACTS_TABLE);