Picasso的用法

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private Button btn_net;
    private Button btn_asset;
    private ImageView iv_show;
    private String mUrl = "http://img01.liwushuo.com/image/170111/rmbcji2p7.jpg-w720";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        btn_net = (Button) findViewById(R.id.btn_net);
        btn_asset = (Button) findViewById(R.id.btn_asset);
        iv_show = (ImageView) findViewById(R.id.iv_show);

        btn_net.setOnClickListener(this);
        btn_asset.setOnClickListener(this);


    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.btn_net:
                Picasso.with(this).load(mUrl).
                        placeholder(R.mipmap.ic_launcher) //默认
                        .error(R.mipmap.hello) //三次请求失败,显示错误的图片
                        .noFade() //无淡入淡出
//                        .resize(100, 100)
                        .transform(new Transformation() {
                            @Override
                            public Bitmap transform(Bitmap source) {
                                int height = source.getHeight();
                                int width = source.getWidth();
                                int size = Math.min(height, width);

                                Bitmap bitmap = Bitmap.createBitmap(source, 0, 0, size, size);
                                if (bitmap != null) {
                                    source.recycle();
                                }
                                return bitmap;
                            }

                            @Override
                            public String key() {
                                return "square";
                            }
                        })
                        .rotate(90)
                        .config(Bitmap.Config.RGB_565)
//                        .memoryPolicy(MemoryPolicy.NO_CACHE, MemoryPolicy.NO_STORE) //放弃内存缓存, 很高清的大图片时候
                        .into(iv_show);
                break;
            case R.id.btn_asset:
                Picasso.with(this).load("file:///android_asset/mm.jpg").into(iv_show);
                break;
        }
    }
}

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public class IApp extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        initPicasso();
    }

    private void initPicasso() {

        Picasso picasso = new Picasso.Builder(this)
                .memoryCache(new LruCache(10 << 20))  //内存缓存  10M
                .downloader(new UrlConnectionDownloader(this)) //设置下载图片
                .indicatorsEnabled(true)  // 红色: 网络   蓝色:磁盘  绿色:内存
                .build();
        Picasso.setSingletonInstance(picasso); //设置全局单例设计
    }
}