转换JsonString到自定义的Java的ArrayList [英] Convert JsonString to a custom java ArrayList

问题描述

我qestion是，我怎么能转换成一个保存的Json斯汀回到一个ArrayList的定制

My qestion is, how I can convert an saved Json Sting back to an custom ArrayList.

这是我如何保存我的ArrayList

This is how I save my ArrayList:

public void saveLocList(ArrayList<LocItem> locList) {
    SharedPreferences.Editor e = returnPref.edit();
    Gson gson = new Gson();
    String json = gson.toJson(locList);
    e.putString(LOCLIST, json);
    e.commit();
}

而现在，当我恢复的ArrayList（JSON字符串），它不会与此code工作：

And now, when I restore the ArrayList (Json String) it doesn't work with this code:

public ArrayList<LocItem> getLocList() {
    String json = returnPref.getString(LOCLIST, "");
    Type type = (Type) new TypeToken<ArrayList<LocItem>>() {
    }.getType();
    ArrayList<LocItem> inpList = new Gson().fromJson(json, (java.lang.reflect.Type) type);
    return inpList;
}

这是我的日志：

12-30 22:19:19.395: E/AndroidRuntime(2254): FATAL EXCEPTION: main
12-30 22:19:19.395: E/AndroidRuntime(2254): java.lang.RuntimeException: Unable to start activity ComponentInfo{mypackagename.MainActivity}: java.lang.ClassCastException: com.google.gson.internal.$Gson$Types$ParameterizedTypeImpl cannot be cast to android.renderscript.Type
12-30 22:19:19.395: E/AndroidRuntime(2254):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2339)
12-30 22:19:19.395: E/AndroidRuntime(2254):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2389)
12-30 22:19:19.395: E/AndroidRuntime(2254):     at android.app.ActivityThread.access$600(ActivityThread.java:153)
12-30 22:19:19.395: E/AndroidRuntime(2254):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1269)
12-30 22:19:19.395: E/AndroidRuntime(2254):     at android.os.Handler.dispatchMessage(Handler.java:99)
12-30 22:19:19.395: E/AndroidRuntime(2254):     at android.os.Looper.loop(Looper.java:137)
12-30 22:19:19.395: E/AndroidRuntime(2254):     at android.app.ActivityThread.main(ActivityThread.java:5289)
12-30 22:19:19.395: E/AndroidRuntime(2254):     at java.lang.reflect.Method.invokeNative(Native Method)
12-30 22:19:19.395: E/AndroidRuntime(2254):     at java.lang.reflect.Method.invoke(Method.java:525)
12-30 22:19:19.395: E/AndroidRuntime(2254):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:739)
12-30 22:19:19.395: E/AndroidRuntime(2254):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:555)
12-30 22:19:19.395: E/AndroidRuntime(2254):     at dalvik.system.NativeStart.main(Native Method)
12-30 22:19:19.395: E/AndroidRuntime(2254): Caused by: java.lang.ClassCastException: com.google.gson.internal.$Gson$Types$ParameterizedTypeImpl cannot be cast to android.renderscript.Type
12-30 22:19:19.395: E/AndroidRuntime(2254):     at mypackagename.helper.Preferences.getLocList(Preferences.java:152)
12-30 22:19:19.395: E/AndroidRuntime(2254):     at mypackagename.MainActivity.onCreate(MainActivity.java:137)
12-30 22:19:19.395: E/AndroidRuntime(2254):     at android.app.Activity.performCreate(Activity.java:5133)
12-30 22:19:19.395: E/AndroidRuntime(2254):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
12-30 22:19:19.395: E/AndroidRuntime(2254):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2293)
12-30 22:19:19.395: E/AndroidRuntime(2254):     ... 11 more

我不知道是什么改变，也许有与savingformat问题（但它工作）;

I don't know what to change, maybe there is a problem with the savingformat (but it works);

感谢

推荐答案

该错误信息是告诉你它与铸造一个问题。

The error message is telling you it's a problem with casting.

TypeToken.getType（）返回类 ParameterizedTypeImpl ，它实现了的java对象.lang.reflect.Type 。

但是，因为我假设你有 android.renderscript.Type ，爪哇正试图施放 ParameterizedTypeImpl一个import语句的到 android.renderscript.Type 。

However, because of an import statement that I'm assuming you have for android.renderscript.Type, Java is trying to cast the ParameterizedTypeImpl to an android.renderscript.Type.

简单修复import语句或使用完全限定域名（ java.lang.reflect.Type ）为你做了code更高版本。

Simply fix the import statement or use the fully qualified name (java.lang.reflect.Type) as you do later in the code.

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