Question

我使用Google排球库创建了一个Image加载器。我的问题是我不知道如何为每个请求设置优先级。有人可以帮我一样吗？下面显示的是代码。我应该在哪里设置优先级？

 Main Activity

public class MainActivity extends ActionBarActivity {

ListView list;
ImageLoader mImageLoader;
ImageAdapter imageAdapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    list = (ListView) findViewById(R.id.list);

    mImageLoader = MyVolley.getInstance(this).getImageLoader();
    imageAdapter = new ImageAdapter(this, mImageLoader);

    list.setAdapter(imageAdapter);

}

}

      Adapter class

                  public class ImageAdapter extends BaseAdapter {

Context context;
NetworkImageView nImgView;
ImageLoader mImageLoader;

public ImageAdapter(Context context, ImageLoader mImageLoader) {
    this.context = context;
    this.mImageLoader = mImageLoader;

}

@Override
public int getCount() {

    return ImageLinkArray.imageUrl.length;
}

@Override
public Object getItem(int position) {

    return null;
}

@Override
public long getItemId(int position) {

    return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    LayoutInflater mInflater = (LayoutInflater) context
            .getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
    if (convertView == null) {
        convertView = mInflater.inflate(R.layout.list_adapter_layout,
                parent, false);
    }

    nImgView = (NetworkImageView) convertView
            .findViewById(R.id.networkImageView);

    nImgView.setAdjustViewBounds(true);
    nImgView.setImageUrl(ImageLinkArray.imageUrl[position], mImageLoader);
    return convertView;
}

}

      MyVolley class


       public class MyVolley {

private static MyVolley mVolleyInstance;
private RequestQueue mRequestQueue;
private ImageLoader mImageLoader;
private static Context mContext;

private MyVolley(Context context) {
    mContext = context;
    mRequestQueue = getRequestQueue();


    mImageLoader = new ImageLoader(mRequestQueue,
            new ImageLoader.ImageCache() {
                private final LruCache<String, Bitmap> cache = new LruCache<>(
                        ImageLinkArray.imageUrl.length);

                @Override
                public void putBitmap(String url, Bitmap bitmap) {
                    // TODO Auto-generated method stub
                    cache.put(url, bitmap);
                }

                @Override
                public Bitmap getBitmap(String url) {
                    // TODO Auto-generated method stub
                    return cache.get(url);

                }
            });

}

public static synchronized MyVolley getInstance(Context context) {
    if (mVolleyInstance == null) {
        mVolleyInstance = new MyVolley(context);
    }
    return mVolleyInstance;
}

public RequestQueue getRequestQueue() {
    if (mRequestQueue == null) {
        // use the application context
        mRequestQueue = Volley.newRequestQueue(mContext
                .getApplicationContext());
    }
    return mRequestQueue;
}

public <T> void addToRequestQueue(Request<T> req) {

    getRequestQueue().add(req);

}

public ImageLoader getImageLoader() {
    return mImageLoader;
}

}

Answer 1

试试这段代码

private Priority priority = Priority.HIGH;

StringRequest strReq = new StringRequest(Method.GET, Const.URL_STRING_REQ,
        new Response.Listener<String>() {

            @Override
            public void onResponse(String response) {
                Log.d(TAG, response.toString());
                msgResponse.setText(response.toString());
                hideProgressDialog();

            }
        }, new Response.ErrorListener() {

            @Override
            public void onErrorResponse(VolleyError error) {
                VolleyLog.d(TAG, "Error: " + error.getMessage());
                hideProgressDialog();
            }
        }) {
    @Override
    public Priority getPriority() {
        return priority;
    }

};

来自androidhive

<强>更新

这是另一个可行的example

设置Request的优先级，您必须将一些代码段添加到示例的AppController类

转换

public <T> void addToRequestQueue(Request<T> req) {
    req.setTag(TAG);
    getRequestQueue().add(req);
}

到

public <T> void addToRequestQueue(Request<T> req) {
    req.setTag(TAG);
    com.android.volley.Request.Priority pr = req.getPriority();
    pr = com.android.volley.Request.Priority.HIGH;
    getRequestQueue().add(req);
}

并通过使用一些额外的参数

调用该方法使其可行

Answer 2

查看Volley的ImageRequest课程。它是由Google开发人员为图像加载创建的，您只需要扩展它并实现setPriority（）。

// default priority
private Priority mPriority = Priority.LOW;

@Override
public Priority getPriority() {
    return mPriority;
}

// priority setter
public void setPriority(Priority priority) {
    mPriority = priority;
}

Priority是来自Request类的ENUM。

来自stackoverflow

每个请求都有从Request类继承的getPriority()方法。 Volley RequestQueue内部使用此方法来确定此队列中的请求优先级。

要使用此功能，您的Request必须覆盖getPriority（），并且必须在请求中实现setPriority()方法，如上所示。

设置Volley ImageLoader的优先级

2 个答案: