android的volley框架使用日志1

看了一下volley框架的简单demo，发现使用后，如获取Json文件之类的，所写的代码非常的简单

如

public class JsonRequestAcitivity extends Activity implements OnClickListener,Listener<JSONObject>,ErrorListener{
private Button requestBtn;
private TextView dispText;
RequestQueue rq;
Request request;
private static final String URL = "http://httpbin.org/get?param1=hello";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_json_request);
requestBtn = (Button) findViewById(R.id.requestBtn);
dispText = (TextView) findViewById(R.id.dispText);
requestBtn.setOnClickListener(this);
}
@Override
public void onClick(View v) {
dispText.setText("请求中...");
doJsonRequest();
}

private void doJsonRequest() {
//第三个参数
//A JSONObject to post with the request. Null is allowed and indicates no parameters will be posted along with request.
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(
Request.Method.GET,URL,null, JsonRequestAcitivity.this,JsonRequestAcitivity.this);
jsonObjectRequest.setTag(JsonRequestAcitivity.class.getSimpleName());//设置tag callAll的时候使用
VolleyTool.getInstance(this).getmRequestQueue().add(jsonObjectRequest);
}
@Override
public void onResponse(JSONObject response) {
//success 
dispText.setText("Success::"+response.toString());
}
@Override
public void onErrorResponse(VolleyError error) {
dispText.setText("Fail::"+error.toString());
}
@Override
protected void onDestroy() {
super.onDestroy();
VolleyTool.getInstance(this).getmRequestQueue().cancelAll(JsonRequestAcitivity.class.getSimpleName());
}


}

显而易见，TextView中的setText方法并无直接的调用，而数据之间传递和交互只在那句简单的

         

VolleyTool.getInstance(this).getmRequestQueue().add(jsonObjectRequest);

首先是实例化一个VolleyTool，然后获取一个请求队列，然后将jsonObjectRequest放入队列之中执行；

而VolleyTool文件中，最关键的一句便是

mRequestQueue = Volley.newRequestQueue(context);

public class VolleyTool {private static VolleyTool mInstance = null;    private RequestQueue mRequestQueue;    private ImageLoader mImageLoader;        private VolleyTool(Context context) {    mRequestQueue = Volley.newRequestQueue(context);    mImageLoader = new ImageLoader(mRequestQueue, new BitmapCache());    }        public static VolleyTool getInstance(Context context){        if(mInstance == null){    mInstance = new VolleyTool(context);        }        return mInstance;    }    public RequestQueue getmRequestQueue() {return mRequestQueue;}public ImageLoader getmImageLoader() {return mImageLoader;}public void release() {this.mImageLoader = null;this.mRequestQueue = null;mInstance = null;}}

因为这一句话，直接从Volley.jar包中调用了volley的这个类，从而获取里面的方法。

public class Volley {

    /** Default on-disk cache directory. */
    private static final String DEFAULT_CACHE_DIR = "volley";

    /**
     * Creates a default instance of the worker pool and calls {@link RequestQueue#start()} on it.
     *
     * @param context A {@link Context} to use for creating the cache dir.
     * @param stack An {@link HttpStack} to use for the network, or null for default.
     * @return A started {@link RequestQueue} instance.
     */
    public static RequestQueue newRequestQueue(Context context, HttpStack stack) {
        File cacheDir = new File(context.getCacheDir(), DEFAULT_CACHE_DIR);

        String userAgent = "volley/0";
        try {
            String packageName = context.getPackageName();

            PackageInfo info = context.getPackageManager().getPackageInfo(packageName, 0);
            userAgent = packageName + "/" + info.versionCode;
        } catch (NameNotFoundException e) {
        }

        if (stack == null) {
            if (Build.VERSION.SDK_INT >= 9) {
                stack = new HurlStack();
            } else {
                // Prior to Gingerbread, HttpUrlConnection was unreliable.
                // See: http://android-developers.blogspot.com/2011/09/androids-http-clients.html
                stack = new HttpClientStack(AndroidHttpClient.newInstance(userAgent));
            }
        }

        Network network = new BasicNetwork(stack);

        RequestQueue queue = new RequestQueue(new DiskBasedCache(cacheDir), network);
        queue.start();

        return queue;
    }

    /**
     * Creates a default instance of the worker pool and calls {@link RequestQueue#start()} on it.
     *
     * @param context A {@link Context} to use for creating the cache dir.
     * @return A started {@link RequestQueue} instance.
     */
    public static RequestQueue newRequestQueue(Context context) {
        return newRequestQueue(context, null);
    }
}

而后，从代码中显而易见的是queue.start（）方法的执行，就可以从RequestQueue中的networkparseResponse（）方法，获取真正的response并实例化。

若是自己也下载了这个volley.jar，便可以知道，实例化时所用的构造方法中，调用了success()方法，从而间接的实现了文本的获取。

-总结：

 - 要活用eclipse中的search功能，一步一步的解析问题，把问题简单话。

 -不懂解压包里面的文件就解压出来，一步步看，还可以改写。