Question

我正在使用PayPal MECL库：

在活动A中显示“Pay with PayPal”按钮
在活动B中启动付款流程

由于显而易见的原因，我不想初始化PayPal库两次（每次活动一次），因为这需要时间并且不必要地让用户等待。

如何在两个活动之间共享对库的引用？

这是我的代码（目前在活动A和B中）（取自PayPal示例）：

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    //...

    //Show PayPal-Button
    initializePayPal();

}

public void initializePayPal() {
    //Time to launch the library but first we need to initialize
    setSupportProgressBarIndeterminateVisibility(true);

    //Create a separate thread to do the initialization
    Thread libraryInitializationThread = new Thread() {
        public void run() {
            //Initialize the library
            initLibrary();

            // The library is initialized so let's launch it by notifying our handler
            if (PayPal.getInstance().isLibraryInitialized()) {
                hRefresh.sendEmptyMessage(INITIALIZE_SUCCESS);
            }
            else {
                hRefresh.sendEmptyMessage(INITIALIZE_FAILURE);
            }
        }
    };
    libraryInitializationThread.start();
}

private void initLibrary() {
    // This is the main initialization call that takes in your Context, the Application ID, the server you would like to connect to, and your PayPalListener
    PayPal.fetchDeviceReferenceTokenWithAppID(this, CompletePaymentActivity.appID, CompletePaymentActivity.server, new ResultDelegate());

    // -- These are required settings.
    PayPal.getInstance().setLanguage(SharedFunctions.getCurrentLocaleString()); // Sets the language for the library.
    // --
}

// This handler will allow us to properly update the UI. You cannot touch Views from a non-UI thread.
Handler hRefresh = new Handler(){
    @Override
    public void handleMessage(Message msg) {
        switch(msg.what){
            case INITIALIZE_SUCCESS:
                //We have initialized the application, close the dialog and show the PayPal Button
                setSupportProgressBarIndeterminateVisibility(false);
                showPayPalButton();
                break;
            case INITIALIZE_FAILURE:
                //Initialization failure, close the dialog, update the page and show a toast
                setSupportProgressBarIndeterminateVisibility(false);
                Toast.makeText(mContext, mContext.getString(R.string.paypal_initialization_failed), Toast.LENGTH_LONG).show();
                finish();
                break;
        }
    }
};

public void showPayPalButton() {
    //...

    PayPal pp = PayPal.getInstance();
    // get the checkoutbutton
    launchPayPalButton = pp.getCheckoutButton(this, PayPal.BUTTON_194x37,
            CheckoutButton.TEXT_PAY);
    //...
}

Answer 1

制作基本活动并将其扩展到其他活动。

在基础活动中，编写用于初始化paypal进程的代码或任何你想要做的事情。

public class BaseActivity extends Activity {
 .....
 .....
 .....
}

public class ActivityA extends BaseActivity {
 .....
 .....
 .....

}

Answer 2

使用 singleton claas，在Class的构造函数中你可以初始化paypal库，并且可以随时随地使用它，它不会再次初始化，

singleton doc

Answer 3

我最终声明了一个扩展Application的类，我在那里初始化了一次库，并且可以被所有活动使用。

仅针对多个活动初始化PayPal库一次

3 个答案: