版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/Ae_fring/article/details/52458377
搞Android的都知道对图片的下载和缓存处理非常的麻烦至极,动不动就发生OOM之类的情况。特别是在Listview,GridView,ViewPage等控件里面。至此介绍Picasso图片缓存框架使用。相对ImageLoad等框架更为方便快速开发者使用。介绍下Picasso;
Picasso是Square公司开源的一个Android图形缓存库,地址http://square.github.io/picasso/,可以实现图片下载和缓存功能。仅仅只需要一行代码就能完全实现图片的异步加载。
Picasso.with(context).load("http://i.imgur.com/DvpvklR.png").into(imageView);
Picasso不仅实现了图片异步加载的功能,还解决了android中加载图片时需要解决的一些常见问题:
1.在adapter中需要取消已经不在视野范围的ImageView图片资源的加载,否则会导致图片错位,Picasso已经解决了这个问题。
2.使用复杂的图片压缩转换来尽可能的减少内存消耗
3.自带内存和硬盘二级缓存功能。
下面分别附上Eclipse的使用JAR包和Android Studio使用的gradle
jar包地址:http://download.csdn.net/detail/ae_fring/9624010
Studio:compile 'com.squareup.picasso:picasso:2.5.2'代码部分我就分享使用studio写的:使用ListView展示访问网络图片并且缓存起来使用。
请求网络数据我使用了xutils3.3.36。
Studio:compile 'org.xutils:xutils:3.3.36'
MainActivity页面
@ContentView(R.layout.activity_main)
public class MainActivity extends Activity {
@ViewInject(R.id.lv)
private ListView lv;
private PicassoAdapter adapter;
@ViewInject(R.id.cache_tv)
private TextView cache_tv;
/**
* 获取数据的接口
*/
private String[] data = {
"http://img3.redocn.com/20101213/20101211_0e830c2124ac3d92718fXrUdsYf49nDl.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383291_6518.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383291_8239.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383290_9329.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383290_1042.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383275_3977.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383265_8550.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383264_3954.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383264_4787.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383264_8243.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383248_3693.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383243_5120.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383242_3127.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383242_9576.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383242_1721.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383219_5806.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383214_7794.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383213_4418.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383213_3557.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383210_8779.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383172_4577.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383166_3407.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383166_2224.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383166_7301.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383165_7197.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383150_8410.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383131_3736.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383130_5094.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383130_7393.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383129_8813.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383100_3554.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383093_7894.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383092_2432.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383092_3071.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383091_3119.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383059_6589.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383059_8814.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383059_2237.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383058_4330.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406383038_3602.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382942_3079.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382942_8125.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382942_4881.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382941_4559.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382941_3845.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382924_8955.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382923_2141.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382923_8437.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382922_6166.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382922_4843.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382905_5804.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382904_3362.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382904_2312.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382904_4960.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382900_2418.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382881_4490.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382881_5935.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382880_3865.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382880_4662.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382879_2553.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382862_5375.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382862_1748.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382861_7618.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382861_8606.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382861_8949.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382841_9821.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382840_6603.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382840_2405.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382840_6354.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382839_5779.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382810_7578.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382810_2436.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382809_3883.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382809_6269.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382808_4179.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382790_8326.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382789_7174.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382789_5170.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382789_4118.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382788_9532.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382767_3184.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382767_4772.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382766_4924.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382766_5762.jpg",
"http://img.my.csdn.net/uploads/201407/26/1406382765_7341.jpg"
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
x.view().inject(this);
adapter = new PicassoAdapter(MainActivity.this, data);
lv.setAdapter(adapter);
lv.setOnScrollListener(onScrollListener);
cache_tv.setText(CacheClearUtilManager.getTotalCacheSize(MainActivity.this));
cache_tv.setOnClickListener(onclicklistener);
}
private View.OnClickListener onclicklistener = new View.OnClickListener() {
@Override
public void onClick(View v) {
CacheClearUtilManager.clearPicassoAllCache(MainActivity.this);
cache_tv.setText(CacheClearUtilManager.getTotalCacheSize(MainActivity.this));
}
};
private AbsListView.OnScrollListener onScrollListener = new AbsListView.OnScrollListener() {
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
final Picasso picasso = Picasso.with(MainActivity.this);
if (scrollState == SCROLL_STATE_IDLE || scrollState == SCROLL_STATE_TOUCH_SCROLL) {
picasso.resumeTag(MainActivity.this);
} else {
picasso.pauseTag(MainActivity.this);
}
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
}
};
}
至于 Picasso我进行了一个简单的封装便于使用:
**
* Created by zqf on 2016/8/8.
*/
public class PicassoUtil {
/**
* 加载指定宽高的图片
*
* @param context
* @param path
* @param width
* @param height
* @param imageView
*/
public static void loadImageWithSize(Context context, String path, int width, int height, int placeholderresId, int errorResId, ImageView imageView) {
Picasso.with(context).load(path).resize(width, height).centerCrop().placeholder(placeholderresId).error(errorResId).into(imageView);
}
public static void loadImageWithHodler(Context context, String path, int resId, ImageView imageView) {
Picasso.with(context).load(path).fit().placeholder(resId).into(imageView);
}
public static void loadImageWithCrop(Context context, String path, ImageView imageView) {
Picasso.with(context).load(path).transform(new CustomImageCrop()).into(imageView);
}
/**
* 实现自定义图片裁剪
*/
private static class CustomImageCrop implements Transformation {
@Override
public Bitmap transform(Bitmap source) {
int size = Math.min(source.getWidth(), source.getHeight());
int x = (source.getWidth() - size) / 2;
int y = (source.getHeight() - size) / 2;
Bitmap result = Bitmap.createBitmap(source, x, y, size, size);
if (result == null) {
result.recycle();
}
return result;
}
@Override
public String key() {
return "square()";
}
}
}
适配器页面:
/**
* Created by zqf on 2016/8/7.
*/
public class PicassoAdapter extends BaseAdapter {
private LayoutInflater inflater;
private String[] data;
private Context context;
public PicassoAdapter(Context context, String[] data) {
this.data = data;
this.inflater = LayoutInflater.from(context);
this.context = context;
}
@Override
public int getCount() {
return data.length;
}
@Override
public Object getItem(int position) {
return data[position];
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = inflater.inflate(R.layout.item, null);
holder = new ViewHolder();
holder.iv = (ImageView) convertView.findViewById(R.id.iv);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
PicassoUtil.loadImageWithSize(context, data[position], 100, 100, R.mipmap.ic_launcher, R.mipmap.ic_launcher, holder.iv);
return convertView;
}
private class ViewHolder {
ImageView iv;
}
}
是不是感觉到了非常简单,就几行代码完全搞定了。访问起来流畅并不会出现卡顿现象。如果觉得想试试赶紧试试吧!
当然了有写的不好的各位见谅,欢迎指出。