Today brings you the first Android network communication framework,Volley request

• Volley is introduced
• Will do the operation
• StringRequest Indicates a text request
• JsonObjectRequest gets JSON string GET and POST requests
• • A GET request
  • A POST request
• ImageRequest sets the image
• ImageLolder

Volley is introduced

Volley introduced a new network communication framework at Google I/O conference in 2013. Its design goal is to be very suitable for network operations with small amount of data but frequent communication. For network operations with large amount of data, such as downloading files, Volley’s performance is very poor.

Will do the operation

StringRequest Indicates a text request

• You need to get the RequestQueue object first
• Then we get the StringRequest object
• Then set the StringRequest object in using the RequestQueue object.add() method

/**
     * Creates a new GET request.
     *
     * @param url URL to fetch the string at
     * @param listener Listener to receive the String response
     * @param errorListener Error listener, or null to ignore errors
     */
    public StringRequest(String url, Listener<String> listener, @Nullable ErrorListener errorListener)
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/ / RequestQueue object
RequestQueue queue = Volley.newRequestQueue(this);
		// Get the StringRequest object // Here the URL is not easy to reveal, but you can see the result
        StringRequest stringRequest = new StringRequest(STRINGREQUEST_URL, new Response.Listener<String>() {
            @Override// Return correctly
            public void onResponse(String response) {
                    Log.i("StringRequestResponse",response);
            }   // Error return
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {

                Log.i("onErrorResponse",error.getMessage()); }});// Set the RequestQueue object with the add() method
        queue.add(stringRequest);
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Note :StringRequest() is only recommended to request text information

Kangkang Log returns the result:

JsonObjectRequest gets JSON string GET and POST requests

 /**
     * Creates a new request.
     *
     * @param method the HTTP method to use
     * @param url URL to fetch the JSON from
     * @param jsonRequest A {@link JSONObject} to post with the request. Null indicates no
     *     parameters will be posted along with request.
     * @param listener Listener to receive the JSON response
     * @param errorListener Error listener, or null to ignore errors.
     */
    public JsonObjectRequest(
            int method,
            String url,
            @Nullable JSONObject jsonRequest,
            Listener<JSONObject> listener,
            @Nullable ErrorListener errorListener)
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A GET request

// Get the RequestQueue object
RequestQueue queue = Volley.newRequestQueue(this);
// Get the JsonObjectRequest object
 JsonObjectRequest jsonObjectRequest = new JsonObjectRequest("http://www.weather.com.cn/data/city3jdata/china.html".null.new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                Log.i("JsonObjectResponse", response.toString()); }},new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Log.i("JsonObjectResponse", error.getMessage()); }});// Use the RequestQueue object.add () method to set the JsonObjectRequest object
        queue.add(jsonObjectRequest);
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Come to Kangkang Log:

As you can see, the JSONObject is returned, and you still need to go through native JSONObject parsing to get the desired result, so this method is not recommended for requesting network data. Retrofit or OkHttp is recommended, etc

A POST request

		Map params = new HashMap();

        params.put("app_key"."74D2E724FE2B69EF7EA3F38E9400CF71");
        // Create a native JSONObject and set the map to it
        JSONObject jsonObject = new JSONObject(params);
        /** * Parameter 1 :POST declaration * Parameter 2: request POST path * Parameter 3 :JSONObject Set the key and value of POST * Parameter 4: Return JSONObject on success * Parameter 5: return error */
 JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.POST,url, jsonObject , new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                Log.i("JsonObjectResponse", response.toString()); }},new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
               
                Log.i("JsonObjectonResponse", response.toString()); }}); queue.add(jsonObjectRequest);Copy the code

ImageRequest sets the image

/**
     * Creates a new image request, decoding to a maximum specified width and height. If both width
     * and height are zero, the image will be decoded to its natural size. If one of the two is
     * nonzero, that dimension will be clamped and the other one will be set to preserve the image's
     * aspect ratio. If both width and height are nonzero, the image will be decoded to be fit in
     * the rectangle of dimensions width x height while keeping its aspect ratio.
     *
     * @param url URL of the image
     * @param listener Listener to receive the decoded bitmap
     * @param maxWidth Maximum width to decode this bitmap to, or zero for none
     * @param maxHeight Maximum height to decode this bitmap to, or zero for none
     * @param scaleType The ImageViews ScaleType used to calculate the needed image size.
     * @param decodeConfig Format to decode the bitmap to
     * @param errorListener Error listener, or null to ignore errors
     */
public ImageRequest(
            String url,
            Response.Listener<Bitmap> listener,
            int maxWidth,
            int maxHeight,
            Config decodeConfig,
            Response.ErrorListener errorListener)
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Usage has been basically, here is not detailed, to have parameters do not understand, you can see the source notes!

// Get the RequestQueue object
RequestQueue queue = Volley.newRequestQueue(this);
// Get the ImageRequest object

/** The fifth parameter is used to specify the color properties of the image. Several constants under bitmap. Config can be used here, with ARGB_8888 showing the best color properties and 4 bytes per image pixel and RGB_565 showing 2 bytes per image pixel */

ImageRequest imageRequest = new ImageRequest("http://api.map.baidu.com/images/weather/day/zhenyu.png".new Response.Listener<Bitmap>() {
            @Override
            public void onResponse(Bitmap response) {
            // Set the bitmap image
                Log.i("ImageRequestResponse"."1111"); mImage.setImageBitmap(response); }},0.0, Bitmap.Config.ARGB_8888, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                    Log.i("onErrorResponse111",error.getMessage()+""); }}); queue.add(imageRequest);Copy the code

You can see that the image is set successfully!

ImageLolder

/ / RequestQueue object.
 RequestQueue requestQueue = Volley.newRequestQueue(this);
        /** * ImageCache() object */
        ImageLoader imageLoader = new ImageLoader(requestQueue, new ImageLoader.ImageCache() {
            @Override   //
            public Bitmap getBitmap(String url) {
                Log.i("ImageLoadergetBitmap",url+"");
                return null;
            }

            @Override
            public void putBitmap(String url, Bitmap bitmap) {
            // Set the image to image2
                image2.setImageBitmap(bitmap);
                Log.i("ImageLoaderputBitmap",url+"\t\t"+bitmap); }});/** * Parameter 1: ImageView object to set * Parameter 2: display default image during image loading * parameter 3: display failed image loading */
         // Set the image to image
        ImageLoader.ImageListener imageListener = ImageLoader.getImageListener(mImage, R.drawable.ic_launcher_foreground, R.drawable.ic_launcher_background);

        / * * * parameters: photo interface * parameter 2: ImageLoader. ImageListener object * three parameters: maximum width * four parameters: maximum height * /
        imageLoader.get("http://api.map.baidu.com/images/weather/night/duoyun.png",imageListener,200.200);
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