Volley

doGet方法

 private void doGet() {
        //        RequestQueue requestQueue= Volley.newRequestQueue(getApplicationContext());
        StringRequest stringRequest=new StringRequest(Request.Method.GET, "http://192.168.0.30:8080/MyWebTest/MyTestServerlet", new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                mTextViewContent.setText(response);
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                mTextViewContent.setText("網絡連接錯誤");
            }
        });
//                requestQueue.add(stringRequest);
        MySingleton.getInstance(getApplicationContext()).addToRequestQueue(stringRequest);
    }

doPost方法

 private void doPost() {
//        RequestQueue requestQueue= Volley.newRequestQueue(getApplicationContext());
        StringRequest stringRequest=new StringRequest(Request.Method.POST, "http://192.168.0.30:8080/MyWebTest/MyTestServerlet", new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                mTextViewContent.setText(response);
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                mTextViewContent.setText("網絡連接錯誤");
            }
        }){
            @Override
            protected Map<String, String> getParams() throws AuthFailureError {
                HashMap<String,String> map=new HashMap<>();
                map.put("username","liuyu");
                return map;
            }
        };
//                requestQueue.add(stringRequest);
        MySingleton.getInstance(getApplicationContext()).addToRequestQueue(stringRequest);
    }

MySingleton

public class MySingleton {
    private static MySingleton mInstance;
    private RequestQueue mRequestQueue;
    private ImageLoader mImageLoader;
    private static Context mCtx;

    private MySingleton(Context context) {
        mCtx = context;
        mRequestQueue = getRequestQueue();

        mImageLoader = new ImageLoader(mRequestQueue,
                new ImageLoader.ImageCache() {
                    private final LruCache<String, Bitmap>
                            cache = new LruCache<String, Bitmap>(20);

                    @Override
                    public Bitmap getBitmap(String url) {
                        return cache.get(url);
                    }

                    @Override
                    public void putBitmap(String url, Bitmap bitmap) {
                        cache.put(url, bitmap);
                    }
                });

    }

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

    public RequestQueue getRequestQueue() {
        if (mRequestQueue == null) {
            // getApplicationContext() is key, it keeps you from leaking the
            // Activity or BroadcastReceiver if someone passes one in.
            mRequestQueue = Volley.newRequestQueue(mCtx.getApplicationContext());
        }
        return mRequestQueue;
    }

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

    public ImageLoader getImageLoader() {
        return mImageLoader;
    }
}