如何使用 Map 在 flutter 中查看此 json 数据<key,value></key,value>

Question

我正在将我的数据从这里获取到我的fetch数据类型中

Map fetch = new Map();

eos.Transaction transaction = eos.Transaction()..actions = actions;
    _eosClient.pushTransaction(transaction, broadcast: true).then((trx) {
       print(trx); //for printing in console

      setState(() {
        fetch = trx;
      });
    });

并试图在我的屏幕上显示这些数据

Expanded(
                child: new ListView.builder(
                    itemCount: fetch.length,
                    itemBuilder: (BuildContext context, int index) {
                      String key = fetch.keys.elementAt(index);
                      return Column(
                        children: <Widget>[
                          Text(key),
                          Padding(
                            padding: const EdgeInsets.all(12.0),
                            child: Text(
                              '${fetch['processed']['action_traces']}',
                            ),
                          ),
                        ],
                      );
                    }),
              ),

控制台中的数据如下所示，只想打印粗体数据

processed :{id: 93ae1319f9927becf0c164722fbb58a33518358e9b148f5af92140f6ab01543c, block_num: 51432026, block_time: 2019-09-25T06:21:11.000, producer_block_id: null, receipt: {status: executed, cpu_usage_us: 264, net_usage_words: 13}, elapsed: 264, net_usage: 104 , scheduled: false, action_traces : [{action_ordinal: 1, creator_action_ordinal: 0, closest_unnotified_ancestor_action_ordinal: 0, receipt: {receiver: guru11111111, act_digest: 55e9b8f98bde721c3f3e53cf98a20814a5d426290b0bf55f842d97866bc71f6c, global_sequence: 488625827, recv_sequence: 353, auth_sequence: [[guru11111111, 423]], code_sequence: 25, abi_sequence: 14}, receiver: guru11111111, act: {account: guru11111111, name: getborrower, 授权: [{actor: guru11111111, permission: active}], data: {acc_name: guru}, hex_data: 0000000000a0af66} , context_free: false, elapsed: 69, console: Borrower Name: guru ID: 1 Location: varanasi Phone Number: 8563070443 Loan amount: 4652007308841189376 , trx_id: 93ae1319f9927becf0c164722fbb58a33518358e9b148f

我试图让它看起来像这样

{
    transaction_id: c459d2da5100afb1b4ab0352debfa4736aadd8c2e36529fe0861c9c8cadddeae, 
    processed: {
        id: c459d2da5100afb1b4ab0352debfa4736aadd8c2e36529fe0861c9c8cadddeae, 
        block_num: 51299894, 
        block_time: 2019-09-24T11:40:11.500, 
        producer_block_id: null, 
        receipt: {
            status: executed, 
            cpu_usage_us: 226, 
            net_usage_words: 13
        }, 
        elapsed: 226, 
        net_usage: 104, 
        scheduled: false, 
        action_traces: [
                        {
                            action_ordinal: 1, 
                            creator_action_ordinal: 0, 
                            closest_unnotified_ancestor_action_ordinal: 0, 
                            receipt: {
                                        receiver: guru11111111, 
                                        act_digest: 55e9b8f98bde721c3f3e53cf98a20814a5d426290b0bf55f842d97866bc71f6c, 
                                        global_sequence: 488304782, 
                                        recv_sequence: 329, 
                                        auth_sequence: [
                                            [guru11111111, 399]
                                        ], 
                                        code_sequence: 25, 
                                        abi_sequence: 14
                                        }, 
                            receiver: guru11111111, 
                            act: {
                                    account: guru11111111, 
                                    name: getborrower, 
                                    authorization: [
                                                        {
                                                            actor: guru11111111, 
                                                            permission: active
                                                        }
                                                    ], 
                                    data: 
                                        {
                                            acc_name: guru
                                        }, 
                                    hex_data: 0000000000a0af66
                                }, 
                            context_free: false, 
                            elapsed: 60, 
                            console: 
                            Borrower Name: guru
                            ID: 1
                            Location: varanasi
                            Phone Number: 8563070443, 
                            Loan Amount:465200 
                        }

文本('${fetch['processed']['action_traces']}'),

我可以打印到“action_traces”，但不能在“action_traces”内打印

Answer 1

在action_traces之后有一个数组，所以我给出了数组的索引，我们也可以为此使用 foreach 循环。

//Text('${fetch['processed']['action_traces'][0]['console']}',)


Expanded(
                child: ListView.builder(
                    itemCount: fetch.length,
                    itemBuilder: (BuildContext context, int index) {
//                      String key = fetch.keys.elementAt(index);
                      print('${fetch[fetch.keys.elementAt(index)]}');
                      return Center(
                        child: Text(
                          '${fetch['processed']['action_traces'][0]['console']}',
                          style: TextStyle(
                            color: Colors.white,
                            fontWeight: FontWeight.bold,
                            fontSize: 20,
                          ),
                        ),
                      );
                    }),
              )

Answer 2

首先，您需要创建正确的 model 来解析此 JSON，为此您可以使用 Dart 的官方 package json_annotation 。 After you have created model classes you will need to desrialise the json into Dart model and then use them as you want in your code.