android - java.lang.RuntimeException : Unable to instantiate service {. ...} 无法实例化类；没有空的构造函数

Question

尝试在我的 Android APP 中启动服务时出现错误我在暂停 Activity 之前启动服务，因此我可以将一些信息上传到服务器。

    java.lang.RuntimeException: Unable to instantiate service  can't instantiate class ; no empty constructor

启动服务时出现问题:

 protected void onPause() {
    super.onPause();

    EditText nicknameText = (EditText) findViewById(R.id.EditText_Nickname);
    EditText emailText = (EditText) findViewById(R.id.EditText_Email);

    String strNickname = nicknameText.getText().toString();
    String strEmail = emailText.getText().toString();

    SharedPreferences.Editor editor = mGameSettings.edit();
    editor.putString(GAME_PREFERENCES_NICKNAME, strNickname);
    editor.putString(GAME_PREFERENCES_EMAIL, strEmail);

    editor.commit();

    //Antes de salir lanzamos una actividad nueva para hacer el upload de la info

    Intent uploadService = new Intent(getApplicationContext(),UploaderService.class);
    startService(uploadService);


}

然后 Service 会启动一个 AsyncTask

public  class UploaderService extends Service{

    public UploaderService(){
        super();
    }

    private UpLoadUserData upLoadUserData;

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        upLoadUserData = new UpLoadUserData();
        upLoadUserData.execute();
        Log.d(DEBUG_TAG, "Settings and image upload requested");
        return START_REDELIVER_INTENT;
    }

    @Override
    public IBinder onBind(Intent intent) {
        // no binding
        return null;
    }
}

list :

    <?xml version="1.0" encoding="utf-8"?>
<manifest
    xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.androidbook.btdt.hour6"
    android:versionCode="1"
    android:versionName="1.0"
    android:installLocation="auto">
    <uses-sdk
        android:minSdkVersion="11"
        android:targetSdkVersion="10"></uses-sdk>

    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

    <application
        android:icon="@drawable/icon"
        android:label="@string/app_name"
        android:debuggable="true">
        <activity
            android:name=".QuizSplashActivity"
            android:label="@string/app_name">
            <intent-filter>
                <action
                    android:name="android.intent.action.MAIN" />
                <category
                    android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="QuizHelpActivity"></activity>
        <activity
            android:name="QuizMenuActivity"></activity>
        <activity
            android:name="QuizScoresActivity"></activity>
        <activity
            android:name="QuizSettingsActivity"></activity>
        <activity
            android:name="QuizGameActivity"></activity>
        <service android:name="QuizSettingsActivity$UploaderService"></service>
    </application>
</manifest>

Answer 1

首先，您不能拥有一个普通嵌套类的 Service。它必须是一个 static 嵌套类。

其次，Service 是Activity 的static 嵌套类，这很奇怪。

第三，让 Service 生成 AsyncTask，而不是仅仅使用 IntentService，这很奇怪。

第四，将getApplicationContext()替换为this。仅当您知道为什么要使用 getApplicationContext() 时才使用 getApplicationContext()，此处不需要它。