有些天沒有寫東西了,今晚來一發,以前我寫Android的網絡部分基本上都是用多線程。然而前段時間無意中發現其實谷歌早在2013年就推出過Volley框架。
![谷歌官方圖片](https://img-blog.csdn.net/20151012224158106)
通過圖片我們大概可以瞭解Volley框架主要是爲了解決網絡併發,以及對網絡請求做了一些優化。其實原理還是在基於多線程,只是谷歌將它好好的封裝了,給我們開發者省去了不少麻煩。而且加載網絡圖片還給增加了緩存。接下來不羅嗦,直接上代碼,這是一個加載本地服務器圖片的Demo
(ps:註釋的部分是另一種處理方法)
public class MainActivity extends Activity {
private ImageView imageview;
private NetworkImageView mNetworkImageView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
private void loadImageviewByVolley() {
String url = "http://192.168.191.1:8080/Demo/01.jpg";
imageview = (ImageView) findViewById(R.id.image_img);
RequestQueue mQueue = Volley.newRequestQueue(getApplicationContext());
ImageLoader imageLoader = new ImageLoader(mQueue, new BitmapCache());
ImageListener listener = ImageLoader.getImageListener(imageview,R.drawable.default_image, R.drawable.default_image);
imageLoader.get("http://192.168.191.1:8080/Demo/01.jpg", listener);
}
private void showImageByNetworkImageView() {
String imageUrl = "http://192.168.191.1:8080/Demo/01.jpg";
RequestQueue requestQueue = Volley.newRequestQueue(this);
final LruCache<String, Bitmap> lruCache = new LruCache<String, Bitmap>(
20);
ImageCache imageCache = new ImageCache() {
@Override
public void putBitmap(String key, Bitmap value) {
lruCache.put(key, value);
}
@Override
public Bitmap getBitmap(String key) {
return lruCache.get(key);
}
};
ImageLoader imageLoader = new ImageLoader(requestQueue, imageCache);
mNetworkImageView.setTag("url");
mNetworkImageView.setImageUrl(imageUrl, imageLoader);
}
public void displayImg(View view){
ImageView imageView = (ImageView)this.findViewById(R.id.image_img);
RequestQueue mQueue = Volley.newRequestQueue(getApplicationContext());
ImageLoader imageLoader = new ImageLoader(mQueue, new BitmapCache());
ImageListener listener = ImageLoader.getImageListener(imageView,R.drawable.default_image, R.drawable.default_image);
imageLoader.get("http://192.168.191.1:8080/Demo/01.jpg", listener);
}
}
這是處理緩存類
public class BitmapCache implements ImageCache {
private LruCache<String, Bitmap> cache;
public BitmapCache() {
cache = new LruCache<String, Bitmap>(8 * 1024 * 1024) {
@Override
protected int sizeOf(String key, Bitmap bitmap) {
return bitmap.getRowBytes() * bitmap.getHeight();
}
};
}
@Override
public Bitmap getBitmap(String url) {
return cache.get(url);
}
@Override
public void putBitmap(String url, Bitmap bitmap) {
cache.put(url, bitmap);
}
}