Android-Volley框架

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Volley网络请求框架

引入Volley

  记得在清单文件中添加网络请求权限

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compile 'com.android.volley:volley:1.2.1'

get请求

  使用Volley发送一条get请求

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  private void sendGet() {
//      请求地址
      String url = "https://www.httpbin.org/get";
//      请求器
      RequestQueue requestQueue = Volley.newRequestQueue(this);
//      请求对象
      StringRequest stringRequest = new StringRequest(url,
              new Response.Listener<String>() {
//                  请求成功时
                  @Override
                  public void onResponse(String response) {
                      Log.d(TAG, "onResponse: " + response);
                  }
              },
              new Response.ErrorListener() {
//                  请求失败时
                  @Override
                  public void onErrorResponse(VolleyError error) {
                      Log.d(TAG, "onErrorResponse: " + error);
                  }
              });
//      把请求对象添加进请求器，当有多个请求对象时，完全可以添加进一个请求器
      requestQueue.add(stringRequest);
  }

POST请求

  使用Volley发送一条post请求

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  private void sendPost() {
      String url = "https://www.httpbin.org/post";
//      请求器
      RequestQueue requestQueue = Volley.newRequestQueue(this);
//      请求对象，注意这里添加了Request.Method.Post参数
      StringRequest stringRequest = new StringRequest(Request.Method.POST, url,
              new Response.Listener<String>() {
//                  请求成功时
                  @Override
                  public void onResponse(String response) {
                      Log.d(TAG, "onResponse: " + response);
                  }
              },
              new Response.ErrorListener() {
//                  请求失败时
                  @Override
                  public void onErrorResponse(VolleyError error) {
                      Log.d(TAG, "onErrorResponse: " + error);
                  }
              }){
//          重写getParams方法，以此获得POST参数
          @Nullable
          @Override
          protected Map<String, String> getParams() throws AuthFailureError {
              Map<String, String> map = new HashMap<>();
              map.put("value1","1111");
              return map;
          }
      };
      requestQueue.add(stringRequest);
  }

JsonRequest

请求Json格式的数据

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//  这样返回的直接就是一个Json对象
  private void sendJson() {
      String url = "https://www.httpbin.org/get";
      RequestQueue requestQueue = Volley.newRequestQueue(this);
      JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(url,
              new Response.Listener<JSONObject>() {
                  @Override
                  public void onResponse(JSONObject response) {
                      try {
                          Log.d(TAG, "onResponse: " + response.getString("origin"));
                      } catch (JSONException e) {
                          e.printStackTrace();
                      }
                  }
              },
              new Response.ErrorListener() {
                  @Override
                  public void onErrorResponse(VolleyError error) {
                      Log.d(TAG, "onErrorResponse: " + error);
                  }
              });
      requestQueue.add(jsonObjectRequest);
  }

加载图片

ImageRequest

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    private void loadImageView() {
        String url = "https://www.httpbin.org/image/png";
        RequestQueue requestQueue = Volley.newRequestQueue(this);
        ImageRequest imageRequest = new ImageRequest(url,
                new Response.Listener<Bitmap>() {
//                    请求成功时加载请求到的图片
                    @Override
                    public void onResponse(Bitmap response) {
                        imageView.setImageBitmap(response);
                    }
                }, 1000, 100, Bitmap.Config.ARGB_8888, //最大宽度，最大高度，图片画质
                new Response.ErrorListener() {
//                    失败时加载的图片
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        imageView.setImageResource(R.drawable.ic_launcher_background);
                    }
                });
        requestQueue.add(imageRequest);
    }

ImageLoader

  ImageLoader更牛逼的地方是它可以指定加载完毕前和加载失败后显示的图片，同时建立图片缓存

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    private void loadImageView() {
        String url = "https://www.httpbin.org/image/png";
        RequestQueue requestQueue = Volley.newRequestQueue(this);
//        创建一个ImageLoader对象
        ImageLoader imageLoader = new ImageLoader(requestQueue, new ImageLoader.ImageCache() {
            @Nullable
            @Override
            public Bitmap getBitmap(String url) {
                return null;
            }

            @Override
            public void putBitmap(String url, Bitmap bitmap) {

            }
        });
//        图片监听器，指定网络图片加载成功之前显示的图片，和加载失败时显示的图片
        ImageLoader.ImageListener imageListener = ImageLoader.getImageListener(imageView,
                R.drawable.ic_launcher_foreground,R.drawable.ic_launcher_background);
//        指定图片链接，指定监听器，指定最大宽高
        imageLoader.get(url, imageListener, 1000, 1000);
    }

  现在是一个空的ImageLoader，如果要实现缓存，需要重写它

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public class BitmapCache implements ImageLoader.ImageCache{
    private LruCache<String, Bitmap> lruCache;

    public BitmapCache() {
        int maxSize = 10 * 1024 * 1024;
        lruCache = new LruCache<String, Bitmap>(maxSize) {
            @Override
            protected int sizeOf(String key, Bitmap bitmap) {
                return bitmap.getRowBytes() * bitmap.getHeight();
            }
        };
    }

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

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

  ImageLoader这样的话就是

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    private void loadImageView() {
        String url = "https://www.httpbin.org/image/png";
        RequestQueue requestQueue = Volley.newRequestQueue(this);
//        创建一个ImageLoader对象
        ImageLoader imageLoader = new ImageLoader(requestQueue, new BitmapCache());
//        图片监听器，指定网络图片加载成功之前显示的图片，和加载失败时显示的图片
        ImageLoader.ImageListener imageListener = ImageLoader.getImageListener(imageView,
                R.drawable.ic_launcher_foreground,R.drawable.ic_launcher_background);
//        指定图片链接，指定监听器，指定最大宽高
        imageLoader.get(url, imageListener, 1000, 1000);
    }
	
    public class BitmapCache implements ImageLoader.ImageCache{
        private LruCache<String, Bitmap> lruCache;

        public BitmapCache() {
            int maxSize = 10 * 1024 * 1024;
            lruCache = new LruCache<String, Bitmap>(maxSize) {
                @Override
                protected int sizeOf(String key, Bitmap bitmap) {
                    return bitmap.getRowBytes() * bitmap.getHeight();
                }
            };
        }

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

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

NetworkImageView

  首先需要在布局文件中添加NetworkImageView

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<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    tools:context=".volley.VolleyActivity">
    <com.android.volley.toolbox.NetworkImageView
        android:id="@+id/networkImageView"
        android:layout_width="50dp"
        android:layout_height="50dp"/>
</LinearLayout>

  加载图片

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    private void loadImageView() {
        String url = "https://www.httpbin.org/image/png";
        RequestQueue requestQueue = Volley.newRequestQueue(this);
        ImageLoader imageLoader = new ImageLoader(requestQueue, new BitmapCache());
//        加载完毕前显示的图片
        networkImageView.setDefaultImageResId(R.drawable.ic_launcher_foreground);
//        加载失败时显示的图片
        networkImageView.setErrorImageResId(R.drawable.ic_launcher_background);
//        加载图片
        networkImageView.setImageUrl(url,imageLoader);
    }

    public class BitmapCache implements ImageLoader.ImageCache{
        private LruCache<String, Bitmap> lruCache;

        public BitmapCache() {
            int maxSize = 10 * 1024 * 1024;
            lruCache = new LruCache<String, Bitmap>(maxSize) {
                @Override
                protected int sizeOf(String key, Bitmap bitmap) {
                    return bitmap.getRowBytes() * bitmap.getHeight();
                }
            };
        }

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

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