Android 網絡圖片Url 轉 Bitmap

注意：該方法必須要在子線程中調用，因為涉及網絡請求

public Bitmap getBitmap(String url) {
        Bitmap bm = null;
        try {
            URL iconUrl = new URL(url);
            URLConnection conn = iconUrl.openConnection();
            HttpURLConnection http = (HttpURLConnection) conn;
            
            int length = http.getContentLength();
            
            conn.connect();
            // 獲得圖像的字符流
            InputStream is = conn.getInputStream();
            BufferedInputStream bis = new BufferedInputStream(is, length);
            bm = BitmapFactory.decodeStream(bis);
            bis.close();
            is.close();// 關閉流
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        return bm;
    }