Question

为什么当我尝试定义对象方法时：

export class Helper {
    function add(x: number, y: number): number {
        return x + y;
    }
}

我收到以下错误：

Unexpected token. A constructor, method, accessor, or property was expected.

我在此网站上关注了示例：https://www.typescriptlang.org/docs/handbook/functions.html 但是，当我删除function关键字时，它会起作用，但这与官方来源相矛盾。

Answer 1

你不应该在课堂内使用函数！改变它：

import android.app.Service;
import android.content.Intent;
import android.media.MediaRouter;
import android.media.session.MediaSession;
import android.os.Binder;
import android.os.IBinder;
import android.support.v4.media.VolumeProviderCompat;
import android.support.v4.media.session.MediaSessionCompat;
import android.util.Log;
import android.view.KeyEvent;
import android.widget.Toast;

public class HookButtonService extends Service{

    public static final String SESSION_TAG = "SampleApp";

    private MediaSessionCompat mMediaSession;

    private VolumeProviderCompat myVolumeProvider;

    public class ServiceBinder extends Binder {

        public HookButtonService getService() {
            return HookButtonService.this;
        }
    }

    private Binder mBinder = new ServiceBinder();

    private MediaSessionCompat.Callback mMediaSessionCallback = new MediaSessionCompat.Callback() {

        @Override
        public boolean onMediaButtonEvent(Intent mediaButtonEvent) {
            Log.d("SampleApp","Media button received");
            if(!MyApplication.isActivityVisible()) {
                Intent dialogIntent = new Intent(getApplicationContext(), MainActivity.class);
                dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                startActivity(dialogIntent);
            }
            return true;
        }
    };



    public HookButtonService() {
    }

    public MediaSessionCompat.Token getMediaSessionToken() {
        return mMediaSession.getSessionToken();
    }

    @Override
    public IBinder onBind(Intent intent) {
        return mBinder;
    }

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

        mMediaSession = new MediaSessionCompat(this, SESSION_TAG);
        mMediaSession.setCallback(mMediaSessionCallback);

        myVolumeProvider = new VolumeProviderCompat(VolumeProviderCompat.VOLUME_CONTROL_RELATIVE, 100, 50) {
            @Override
            public void onAdjustVolume(int direction) {
                Log.d("SampleApp","Volume change received: "+direction);

            }
        };

        mMediaSession.setActive(true);
        mMediaSession.setFlags(MediaSession.FLAG_HANDLES_MEDIA_BUTTONS |
                MediaSession.FLAG_HANDLES_TRANSPORT_CONTROLS);
        mMediaSession.setPlaybackToRemote(myVolumeProvider);

    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        mMediaSession.release();
    }


}

Typescript不允许函数作为类的成员。所以，把它改成一个方法！

正如 mattjes 所说，你可以使方法也是静态的......

export class Helper {
    add(x: number, y: number): number {
        return x + y;
    }
}

为什么定义对象方法在TypeScript中失败

1 个答案: