Retrofit 泛型解析遇到com.google.gson.internal.LinkedTreeMap cannot be cast to object

在Retrofit网络请求数据，使用泛型解析json时，出现了com.google.gson.internal.LinkedTreeMap cannot be cast to com.xylife.community.bean.Exercise的异常，折腾了好久总算解决了。

先看下异常log：

java.lang.ClassCastException: com.google.gson.internal.LinkedTreeMap cannot be cast to com.xylife.community.bean.Exercise

at com.xylife.community.adapter.ExerciseListAdapter.onBindViewHolder(ExerciseListAdapter.java:36)

at jp.wasabeef.recyclerview.adapters.AnimationAdapter.onBindViewHolder(AnimationAdapter.java:54)

at com.cundong.recyclerview.HeaderAndFooterRecyclerViewAdapter.onBindViewHolder(HeaderAndFooterRecyclerViewAdapter.java:258)

at android.support.v7.widget.RecyclerViewAdapter.onBindViewHolder(RecyclerView.java:5471)atandroid.support.v7.widget.RecyclerViewAdapter.onBindViewHolder(RecyclerView.java:5471)
at android.support.v7.widget.RecyclerViewAdapter.bindViewHolder(RecyclerView.java:5504)

at android.support.v7.widget.RecyclerViewRecycler.getViewForPosition(RecyclerView.java:4741)atandroid.support.v7.widget.RecyclerViewRecycler.getViewForPosition(RecyclerView.java:4741)
at android.support.v7.widget.RecyclerViewRecycler.getViewForPosition(RecyclerView.java:4617)

at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:1994)

at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1390)

at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1353)

at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:574)

at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3028)

at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:2906)

at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3283)

at android.view.View.layout(View.java:15718)

at android.view.ViewGroup.layout(ViewGroup.java:5039)

at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)

at android.widget.FrameLayout.onLayout(FrameLayout.java:514)

at android.view.View.layout(View.java:15718)

at android.view.ViewGroup.layout(ViewGroup.java:5039)

at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1077)

at android.view.View.layout(View.java:15718)

at android.view.ViewGroup.layout(ViewGroup.java:5039)

at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)

at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)

at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)

at android.view.View.layout(View.java:15718)

at android.view.ViewGroup.layout(ViewGroup.java:5039)

at android.support.v4.view.ViewPager.onLayout(ViewPager.java:1695)

at android.view.View.layout(View.java:15718)

at android.view.ViewGroup.layout(ViewGroup.java:5039)

at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)

at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)

at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)

at android.view.View.layout(View.java:15718)

at android.view.ViewGroup.layout(ViewGroup.java:5039)

at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)

at android.widget.FrameLayout.onLayout(FrameLayout.java:514)

at android.view.View.layout(View.java:15718)

at android.view.ViewGroup.layout(ViewGroup.java:5039)

at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)

at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)

at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)

at android.view.View.layout(View.java:15718)

at android.view.ViewGroup.layout(ViewGroup.java:5039)

at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)

at android.widget.FrameLayout.onLayout(FrameLayout.java:514)

at android.view.View.layout(View.java:15718)

at android.view.ViewGroup.layout(ViewGroup.java:5039)

at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)

at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)

at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)

at android.view.View.layout(View.java:15718)

at android.view.ViewGroup.layout(ViewGroup.java:5039)

at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)

at android.widget.FrameLayout.onLayout(FrameLayout.java:514)

at android.view.View.layout(View.java:15718)

at android.view.ViewG

下面我们分析下。

先看json数据。

{
"state": "1001",
"resut": {
"data": {
"total": "9",
"list": [
{
"name": "微博",
"desc": "本地相机即拍即传，随时随地分享身边新鲜事",
"size": "36.58M",
"icon": "http://p18.qhimg.com/t0194819784f6b3224b.png",
"url": "http://shouji.360tpcdn.com/150723/de6fd89a346e304f66535b6d97907563/com.sina.weibo_2057.apk"
},
{
"name": "开心消消乐",
"desc": "宇宙超人气三消休闲游戏“开心消消乐”",
"size": "55.49M",
"icon": "http://p17.qhimg.com/t01f9c104ccb2614350.png",
"url": "http://shouji.360tpcdn.com/150707/2ef5e16e0b8b3135aa714ad9b56b9a3d/com.happyelements.AndroidAnimal_25.apk"
}
]
}
}
}

这里要感谢有心课堂的stay4it给我写的测试接口（虽然我们不熟），如果你幸运，还能打开链接：http://api.stay4it.com/test/jdsjlzx.php

这里不再讲解Retrofit和RxJava的知识，有需要请看扔物线大神的讲解：http://gank.io/post/560e15be2dca930e00da1083

Retrofit快速入门：/article/11841984.html

先看个简单的根据json数据来创建一个Response数据对象：

public class Response<T> {

public boolean isSuccess() {
return state == 1001;
}

public int total;
public int state;
public String reason;
public T result;
}

根据http://api.stay4it.com/test/jdsjlzx.php接口返回的json数据，我们写出如下数据对象：

public class ListResponse<T> extends HttpResponse {

public ListEntity resut;

public class ListEntity{
public Data data;
}

public class Data<T>{
public int total;
public List<T> list;
}

}

HttpResponse代码

public class HttpResponse{

public boolean isSuccess() {
return state == 1001;
}

public int state;
}

调试中就毫不留情的抛出了异常。



查找资料，找各种办法。

问题没有解决之前，还找到了篇好文章：

Java泛型让声明方法返回子类型

不经意的那么一瞬间，有个念头闪过脑海，赶紧试了下，没有想到解决了问题。

快来看看吧。

public class ListResponse<T> extends HttpResponse {

public ListEntity<T> resut;

public class ListEntity<T>{
public Data<T> data;
}

public class Data<T>{
public int total;
public List<T> list;
}

}

写到这里已经是深夜23：52了，当解决问题的那一刻我哭了。。。。

分享知识，希望这个思路能够帮助其他人！

至于泛型为什么非要那么写才能解决问题，我还没有理解到位，如果有高人知道请指教！

如果你是Java编程，上面的思路如果不行，请参考：http://www.ways2u.com/?post=535