public class PayService extends Service {
    private static final String TAG = "PayService";
    private ThirdPartPayImpl mThirdPartPay;

    @Override
    public IBinder onBind(Intent intent) {

        String action = intent.getAction();
        Log.d(TAG, "onBind");
        if (action != null && "com.alibaba.alipay.THIRD_PART_PAY".equals(action)) {
            mThirdPartPay = new ThirdPartPayImpl();
//----------------------------------------------
        }
            return mThirdPartPay;
//------------------------------------------
    }

    public class PayAction extends Binder {
        public void pay(float payMoney) {
            Log.d(TAG, "PayAction Money --> " + payMoney);
            if (mThirdPartPay != null) {
                mThirdPartPay.paySuccess();
            }
        }

        public void onUserCancel() {
            mThirdPartPay.payFailed(1, "userCancel");
        }
    }

    private class ThirdPartPayImpl extends ThirdPartPayAction.Stub  {
        private ThirdPartPayResult mCallback;

        @Override
        public void requestPay(String orderInfo, float payMoney, ThirdPartPayResult callback) {
            this.mCallback = callback;
            Intent intent = new Intent();
            intent.setClass(PayService.this, PayActivity.class);
            intent.putExtra(Constants.KEY_BILL_INFO, orderInfo);
            intent.putExtra(Constants.KEY_PAY_MONEY, payMoney);
            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(intent);
        }

        public void paySuccess() {
            try {
                if (mCallback != null) {
                    mCallback.onPaySuccess();
                }
            } catch (RemoteException e) {
                e.printStackTrace();
            }
        }

        public void payFailed(int errorCode, String errorMsg) {
            try {
                if (mCallback != null) {
                    mCallback.onPayFailes(errorCode, errorMsg);
                }
            } catch (RemoteException e) {
                e.printStackTrace();
            }
        }
    }
}

上面的和下面的，如果action正常的话，都是返回mThirdPartPay，但上面的写法，在其它app调用的时候，调用不了mThirdPartPay中的requetPay，，，，也没报错，，

不理解。

都是回返mThirdPartPay，一个在if里面,一个在if外面，结果却不一样，

下面的是成功的，在另一个app，点击按钮， 调用mThirdPartPay 的requestPay方法 ，成功跳转到指定界面

上面的，在另一个app中调用没反应，，，，

还有下面中返回的 new PayAction()，它在action正确的时候不会调用，那它是干嘛用的

public class PayService extends Service {
    private static final String TAG = "PayService";
    private ThirdPartPayImpl mThirdPartPay;

    @Override
    public IBinder onBind(Intent intent) {

        String action = intent.getAction();
        Log.d(TAG, "onBind");
        if (action != null && "com.alibaba.alipay.THIRD_PART_PAY".equals(action)) {
            mThirdPartPay = new ThirdPartPayImpl();
//----------------------------------------------
            return mThirdPartPay;
        }
        return new PayAction();
//------------------------------------------

    }

    public class PayAction extends Binder {
        public void pay(float payMoney) {
            Log.d(TAG, "PayAction Money --> " + payMoney);
            if (mThirdPartPay != null) {
                mThirdPartPay.paySuccess();
            }
        }

        public void onUserCancel() {
            mThirdPartPay.payFailed(1, "userCancel");
        }
    }

    private class ThirdPartPayImpl extends ThirdPartPayAction.Stub  {
        private ThirdPartPayResult mCallback;

        @Override
        public void requestPay(String orderInfo, float payMoney, ThirdPartPayResult callback) {
            this.mCallback = callback;
            Intent intent = new Intent();
            intent.setClass(PayService.this, PayActivity.class);
            intent.putExtra(Constants.KEY_BILL_INFO, orderInfo);
            intent.putExtra(Constants.KEY_PAY_MONEY, payMoney);
            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(intent);
        }

        public void paySuccess() {
            try {
                if (mCallback != null) {
                    mCallback.onPaySuccess();
                }
            } catch (RemoteException e) {
                e.printStackTrace();
            }
        }

        public void payFailed(int errorCode, String errorMsg) {
            try {
                if (mCallback != null) {
                    mCallback.onPayFailes(errorCode, errorMsg);
                }
            } catch (RemoteException e) {
                e.printStackTrace();
            }
        }
    }
}