Question

我正在解决一个问题。我需要使用PHP将一个类对象传递给另一个类函数。我在下面解释我的代码。

db.php中：

class DBOperations{
    // constructor
    private $conn;
    function __construct() {
        $this->connect();
    }
    // destructor
    function __destruct() {
        // $this->close();
    }
    public function prepare_param(){
        echo 'test';
    }
}
$dbo = new DBOperations();

newclass.php：

require_once('db.php');
class DBhandler
{

    function __construct()
    {

    }
    function __destruct() {
        // $this->close();
    }
    public function select_all_profile(){
        $output=$dbo->prepare_param();
    }
}
$dbh = new DBhandler();
print_r($dbh->select_all_profile());exit;

这里我需要将DBOperations对象（i.e-$dbo）传递给DBhandler类函数来执行未发生的第一个类函数。请帮我解决这个问题。

Answer 1

存储变量时，Require_once在重复功能中可能无法正常工作。

要确保每个函数调用都有可变条，请将require替换为require。例如情况：link

Answer 2

TRIED＆amp;测试。

1st：第1班的public class AuthenticatedActivity extends AppCompatActivity { private final static String TAG = "AuthenticatedActivity"; private static final int RC_SIGN_IN = 123; protected FirebaseUser firebaseUser; private FirebaseAuth auth; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); auth = FirebaseAuth.getInstance(); firebaseUser = auth.getCurrentUser(); if (firebaseUser == null) { GoogleSignInOptions options = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN) .requestIdToken(BuildConfig.WEB_CLIENT_ID) .requestEmail() .build(); // Build a GoogleSignInClient with the options specified by gso. GoogleSignInClient client = GoogleSignIn.getClient(this, options); startActivityForResult(client.getSignInIntent(), RC_SIGN_IN); } } public void onDestroy() { super.onDestroy(); FirebaseAuth.getInstance().signOut(); } @Override public void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); if (requestCode == RC_SIGN_IN) { Task<GoogleSignInAccount> task = GoogleSignIn.getSignedInAccountFromIntent(data); try { GoogleSignInAccount account = task.getResult(ApiException.class); firebaseAuthWithGoogle(account); } catch (ApiException e) { Log.w(TAG, "Google sign in failed", e); // TODO: Handle error } } } private void firebaseAuthWithGoogle(GoogleSignInAccount account) { Log.d(TAG, "firebaseAuthWithGoogle:" + account.getId()); AuthCredential credential = GoogleAuthProvider.getCredential(account.getIdToken(), null); final AuthenticatedActivity activity = this; auth.signInWithCredential(credential) .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() { @Override public void onComplete(@NonNull Task<AuthResult> task) { if (task.isSuccessful()) { Log.d(TAG, "signInWithCredential:success"); activity.firebaseUser = auth.getCurrentUser(); } else { Log.w(TAG, "signInWithCredential:failure", task.getException()); // TODO: Handle error. } } }); } }行会出错。

$this->connect();

Answer 3

您缺少变量范围问题。您在db.php中实例化streamsupport，但此变量在另一个文件的类中不可用。

你应该做更好的实例化，而不仅仅是在文件中，但要解决你的问题，请将DBOperations()对象传递到DBOperations。

db.php中：

DBhandler()

newclass.php：

class DBOperations{

    private $conn;

    function __construct() {
        $this->connect();
    }

    public function prepare_param(){
        echo 'test';
    }
}
$dbo = new DBOperations();

Answer 4

这个常见的构造会将DBOperations值传递给DBhandler类的构造函数，因为它可以重复使用多次。这通常称为依赖注入（DI），用于配置具有任何依赖关系的类，而不是在每个类中创建它们。

require_once('db.php');
class DBhandler
{
    private $dbo;
    function __construct( $dbo )
    {
        $this->dbo = $dbo;
    }
    function __destruct() {
        // $this->close();
    }
    public function select_all_profile(){
        $output=$this->dbo->prepare_param();
    }
}
$dbh = new DBhandler($dbo);
print_r($dbh->select_all_profile());
exit;

如何使用PHP

4 个答案: