直接上代码 两种方式 ImageView 和NetworkImageView
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先自定义全局Application 获取
public classMyApplication extends Application {
private static RequestQueuerequestQueue;
private static MyApplicationapplication;
@Override
public void onCreate() {
// TODO Auto-generated methodstub
super.onCreate();
application = this;
requestQueue =Volley.newRequestQueue(this);
}
public static MyApplicationgetInstance() {
// TODO Auto-generated methodstub
return application;
}
public static RequestQueuegetRequestQueue(){
return requestQueue;
}
}
先上布局文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:Android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ImageView
android:id="@+id/iv_test1"
android:layout_width="match_parent"
android:layout_height="300dp"
android:layout_marginTop="10dp"/>
<com.android.volley.toolbox.NetworkImageView
android:id="@+id/iv_test2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="10dp" >
</com.android.volley.toolbox.NetworkImageView>
</LinearLayout>
方式一用ImageView加载
需要封装一下自定义的BitmapCache类实现图片缓存接口ImageCache
public class BitmapCache implements ImageCache{
public LruCache<String, Bitmap> cache;
public BitmapCache(){
int maxMermorySize = (int)(Runtime.getRuntime().maxMemory()/1024);
cache = new LruCache<String, Bitmap>(maxMermorySize/8){
@Override
protected int sizeOf(String key, Bitmap value) {
// TODO Auto-generated method stub
return value.getRowBytes()*value.getHeight()/1024;
}
};
}
@Override
public Bitmap getBitmap(String key) {
// TODO Auto-generated method stub
return cache.get(key);
}
@Override
public void putBitmap(String key, Bitmap value) {
// TODO Auto-generated method stub
cache.put(key, value);
}
}
方式二 用NetworkImageView记载
封装一个VolleyUtils图片加载并处理缓存的类，使用起来就比较方便了
public class VolleyUtils {
private static ImageLoader imageLoader;
private static LruCache<String,Bitmap> lruCache;
private static HashMap<String,SoftReference<Bitmap>> softmap;
private static void initCache() {
// TODO Auto-generated method stub
//实例化二级缓存
softmap = new HashMap<String, SoftReference<Bitmap>>();
//实例化一级缓存 字节单位 KB
int maxMermorySize = (int)(Runtime.getRuntime().maxMemory()/1024);
lruCache = new LruCache<String, Bitmap>(maxMermorySize/8){
@Override
protected int sizeOf(String key, Bitmap value) {
// TODO Auto-generated method stub
//return lruCache.size()
return value.getRowBytes()*value.getHeight()/1024;//返回KB的大小
}
@Override
protected void entryRemoved(boolean evicted, String key,
Bitmap oldValue, Bitmap newValue) {
//当oldValue被一级缓存逐出时，放入二级缓存中
if (evicted) {
softmap.put(key, new SoftReference<Bitmap>(oldValue));
}
}
};
}
public static ImageLoader getImageLoader(Context context){
if (imageLoader==null) {
initCache();
imageLoader = new ImageLoader(MyApplication.getRequestQueue(), new ImageCache() {
@Override
public void putBitmap(String url, Bitmap bitmap) {
// 存入一级缓存
lruCache.put(url, bitmap);
}
@Override
public Bitmap getBitmap(String url) {
//从一级缓存中获取
Bitmap bitmap = lruCache.get(url);
//判断一级缓存是否存在
if ( bitmap== null) {//一级缓存不存在
//从二级缓存中获取
SoftReference<Bitmap> softRef = softmap.get(url);
if (softRef!=null) {
bitmap = softRef.get();
//获取软引用中图片
//为了便于使用将二级缓存中的图片存放一级缓存中
lruCache.put(url, bitmap);
//将此图片从二级缓存中移除
softmap.remove(url);
}
}
return null;
}
});
}
return imageLoader;
}
}
在Activity或者Fragment或者适配中可以直接调取用，下边是以Activity为实例的代码
private ImageView test1;//用ImageView加载网略图片
private NetworkImageView test2;//用NetworkImageView记载网略图片
@Override
protected void onCreate(Bundle arg0) {
// TODO Auto-generated method stub
super.onCreate(arg0);
test1 = (ImageView)findViewById(R.id.iv_test1);
test2 = (NetworkImageView) findViewById(R.id.iv_test2);
initImage();
}
private void initImage(){
//本人随便找了一张美女的图片
String url = "http://img.pconline.com.cn/images/upload/upc/tx/wallpaper/1205/25/c2/11755122_1337938898582.jpg";
//方式一用ImageView加载
ImageLoader loader = new ImageLoader(MyApplication.getRequestQueue(), new BitmapCache());
ImageListener listener = ImageLoader.getImageListener(test1,
R.drawable.ic_launcher, R.drawable.ic_launcher);
loader.get(url, listener);
//方式二用NetworkImageView加载
ImageLoader imageLoader = VolleyUtils.getImageLoader(this);
test2.setDefaultImageResId(R.drawable.ic_launcher);
test2.setErrorImageResId(R.drawable.ic_launcher);
test2.setImageUrl(url, imageLoader);
}