了java.lang.RuntimeException：無法實例化服務......沒有無參數的構造

Question

我有一個PictureHDFragment中，我使用的方法Html.fromHtml(String source, Html.ImageGetter imageGetter, Html.TagHandler tagHandler);我想的方法getDrawable以下載圖像出來的片段的，並避免所有應用的阻擋啓動一個線程（其由Html.fromHtml當遇到標記img自動調用）。

然後我創建了一個外部類HttpImageGetter，它實現了ImageGetter並擴展了IntentService。

public class HttpImageGetter extends IntentService implements Html.ImageGetter { 

private Bitmap bitmap = null; 
private Context context; 

public HttpImageGetter(Context context) { 
    super("get HTML Image"); 
    this.context = context; 
} 

@Override 
public Drawable getDrawable(String source) { 
    //mvc.controller.getDrawable(getContext(), source); 

    //Context context = getApplicationContext(); 
    startService(context, source); 
    BitmapDrawable bitmapDrawable; 

    if (bitmap == null) 
     bitmapDrawable = null; 
    else { 
     //bitmapDrawable = bitmapDrawableIterator.next(); 
     bitmapDrawable = new BitmapDrawable(bitmap); 
     bitmapDrawable.setBounds(0, 0, bitmapDrawable.getIntrinsicWidth(), bitmapDrawable.getIntrinsicHeight()); 
    } 
    //BitmapDrawable bitmapDrawableExample = new BitmapDrawable(mvc.model.getHDImage()); 
    //bitmapDrawableExample.setBounds(0, 0, bitmapDrawableExample.getIntrinsicWidth(), bitmapDrawableExample.getIntrinsicHeight()); 

    return bitmapDrawable/*bitmapDrawableExample*/; 
} 

private final static String ACTION = "getImage"; 

private void startService(Context context, String source){ 
    Intent intent = new Intent(context/*getApplicationContext()*/, HttpImageGetter.class); 
    intent.setAction(ACTION); 
    intent.putExtra("source", source); 
    context.startService(intent); 
} 

@Override 
protected void onHandleIntent(@Nullable Intent intent) { 
    String source = intent.getStringExtra("source"); 
    //Bitmap dr = null; 

    try { 
     URL url = new URL(source); 
     HttpURLConnection conn = (HttpURLConnection) url.openConnection(); 
     conn.setDoInput(true); 
     conn.connect(); 
     InputStream is = conn.getInputStream(); 
     bitmap = BitmapFactory.decodeStream(is); 
     //dr.setBounds(0, 0, dr.getIntrinsicWidth(), dr.getIntrinsicHeight()); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
} 

但這不工作，並啓動RuntimeException，特別是：

java.lang.RuntimeException: Unable to instantiate service com.android.mattia.flickclient.Controller.HttpImageGetter: java.lang.InstantiationException: java.lang.Class<com.android.mattia.flickclient.Controller.HttpImageGetter> has no zero argument constructor 
                        at android.app.ActivityThread.handleCreateService(ActivityThread.java:3446) 
                        at android.app.ActivityThread.-wrap6(ActivityThread.java) 
                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1725) 
                        at android.os.Handler.dispatchMessage(Handler.java:102) 
                        at android.os.Looper.loop(Looper.java:154) 
                        at android.app.ActivityThread.main(ActivityThread.java:6692) 
                        at java.lang.reflect.Method.invoke(Native Method) 
                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468) 
                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358) 
                       Caused by: java.lang.InstantiationException: java.lang.Class<com.android.mattia.flickclient.Controller.HttpImageGetter> has no zero argument constructor 
                        at java.lang.Class.newInstance(Native Method) 
                        at android.app.ActivityThread.handleCreateService(ActivityThread.java:3443) 
                        at android.app.ActivityThread.-wrap6(ActivityThread.java)  
                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1725)  
                        at android.os.Handler.dispatchMessage(Handler.java:102)  
                        at android.os.Looper.loop(Looper.java:154)  
                        at android.app.ActivityThread.main(ActivityThread.java:6692)  
                        at java.lang.reflect.Method.invoke(Native Method)  
                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468)  
                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358)  

所以，我明白，這個問題是傳遞給製造商的參數，那我也tryed到刪除，並獲得上下文直接在HttpImageGetter類的方法getApplicationContext但這扔NullPointerException異常。

我該如何解決這個問題？

感謝

Answer 1

嘗試添加這個代替現有的構造方法：public HttpImageGetter() {super("get HTML Image");} 如果您需要在服務方面，只使用服務作爲背景。