android - 使用android Studio在gson反序列化中出错

Question

我正在开发一个在我的应用程序中使用 Android 手机联系人的应用程序。因此，首先获取联系人详细信息并将其存储到 ArrayList 中。之后，我使用 gson 库序列化了那个 arrayList，当我反序列化它时出现错误。 我使用 gson-2.1.jar 序列化和反序列化联系人详细信息。我收到以下错误日志。

  AndroidRuntime﹕ FATAL EXCEPTION: main
        com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 8
                at com.google.gson.Gson.fromJson(Gson.java:766)
                at com.google.gson.Gson.fromJson(Gson.java:721)
                at com.google.gson.Gson.fromJson(Gson.java:670)
                at com.google.gson.Gson.fromJson(Gson.java:642)
                at com.braintechnix.autoloveapp.util.MyGson.deserializer(MyGson.java:28)
                at com.braintechnix.autoloveapp.fragment.ContactListFragment.onStart(ContactListFragment.java:69)
                at android.support.v4.app.Fragment.performStart(Fragment.java:1986)
                at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1061)
                at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1207)
                at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:738)
                at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1572)
                at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:493)
                at android.os.Handler.handleCallback(Handler.java:739)
                at android.os.Handler.dispatchMessage(Handler.java:95)
                at android.os.Looper.loop(Looper.java:135)
                at android.app.ActivityThread.main(ActivityThread.java:5312)
                at java.lang.reflect.Method.invoke(Native Method)
                at java.lang.reflect.Method.invoke(Method.java:372)
                at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:901)
                at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:696)

     Caused by: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was STRING at line 1 column 8
                at com.google.gson.stream.JsonReader.expect(JsonReader.java:339)
                at com.google.gson.stream.JsonReader.beginArray(JsonReader.java:306)
                at com.google.gson.internal.bind.ArrayTypeAdapter.read(ArrayTypeAdapter.java:70)
                at com.google.gson.Gson.fromJson(Gson.java:755)
                at com.google.gson.Gson.fromJson(Gson.java:721)
                at com.google.gson.Gson.fromJson(Gson.java:670)
                at com.google.gson.Gson.fromJson(Gson.java:642)
                at com.braintechnix.autoloveapp.util.MyGson.deserializer(MyGson.java:28)
                at com.braintechnix.autoloveapp.fragment.ContactListFragment.onStart(ContactListFragment.java:69)
                at android.support.v4.app.Fragment.performStart(Fragment.java:1986)
                at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1061)
                at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1207)
                at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:738)
                at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1572)
                at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:493)
                at android.os.Handler.handleCallback(Handler.java:739)
                at android.os.Handler.dispatchMessage(Handler.java:95)
                at android.os.Looper.loop(Looper.java:135)
                at android.app.ActivityThread.main(ActivityThread.java:5312)
                at java.lang.reflect.Method.invoke(Native Method)
                at java.lang.reflect.Method.invoke(Method.java:372)
                at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:901)
                at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:696)

以下是我使用的代码:

public ArrayList<Contact> deserializer(String jsonString){

        //Type collectionType = new TypeToken<Collection<Contact>>(){}.getType();
    //  Collection<Contact> enums = gson.fromJson(jsonString, collectionType);

        Contact[] contacts = gson.fromJson(jsonString, Contact[].class);
        ArrayList<Contact> contactsList = new ArrayList<Contact>();
        for(int i = 0; i< contacts.length; i++){
            contactsList.add(contacts[i]);
        }
        return contactsList;
    }

Answer 1

如果没有你得到的 json 响应，真的很难回答，但是从你的错误中我可以看出下面的代码会帮助你

更新了答案

public ArrayList<Contact> deserializer(String jsonString){

    //Type collectionType = new TypeToken<Collection<Contact>>(){}.getType();
//  Collection<Contact> enums = gson.fromJson(jsonString, collectionType);


    ArrayList<Contact> contactsList =  (new Gson()).fromJson(jsonString,new TypeToken<ArrayList<Contact>>() {}.getType());

    return contactsList;
}

以下是一些可能对您使用 Gson 库有帮助的示例

ExampleOne

ExampleTwo