查看“Picasso 带 Cookies 加载图片”的源代码

[[Category:Android]]
2019-04-15 11:50

== 用途 ==
　　在加载验证码的时候，如果 Picasso 直接请求图片而不加上 Cookies，可能导致 API 返回验证码错误的问题。<br>

== 版本 ==
<pre>
compile 'com.squareup.picasso:picasso:2.5.2'
</pre>

== 解决方法 ==
　　设置一个 CookieImageDownloader。<br>
<pre>
public class CookieImageDownloader extends UrlConnectionDownloader {

    public CookieImageDownloader(Context context) {
        super(context);
    }

    @Override
    protected HttpURLConnection openConnection(Uri path) throws IOException {
        HttpURLConnection conn = super.openConnection(path);
        conn.setRequestProperty("Cookie", BaseApplication.getCookies());
        return conn;
    }
}
</pre>
　　在 openConnection(Uri path) 中的 BaseApplication.getCookies() 是一个字符串，样式为：<br>
<pre>
key=value; key=value; key=value
</pre>
　　因为每人所用的网络框架都不同，因此这里只举出我所使用的 OkGo 3 的例子：<br>
<pre>
StringBuilder cookieBuilder = new StringBuilder();

        for (int i = 0; i < cookieStore.getAllCookie().size(); i++) {
            cookieBuilder.append(cookieStore.getAllCookie().get(i).name());
            cookieBuilder.append("=");
            cookieBuilder.append(cookieStore.getAllCookie().get(i).value());

            if (i < cookieStore.getAllCookie().size() - 1) {
                cookieBuilder.append(";");
            }
        }

        BaseApplication.cookies = cookieBuilder.toString();
</pre>
　　最后在需要加载图片的地方：<br>
<pre>
Picasso picasso = new Picasso.Builder(activity).downloader(new CookieImageDownloader(activity)).build();
picasso.load(NetRequest.getCodeImg)
        .fit()
        .networkPolicy(NetworkPolicy.NO_STORE, NetworkPolicy.NO_CACHE)
        .memoryPolicy(MemoryPolicy.NO_STORE, MemoryPolicy.NO_CACHE)
        .centerCrop()
        .config(Bitmap.Config.RGB_565)
        .into(activity.binding.ivCode);
</pre>
　　大功告成。<br>