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我在使用 GSON 时遇到问题。

首先，每当我切换活动时，我都会尝试使用 GSON 将对象保存在 SharedPreferences 中。然后我的计划是在我回到活动后再次获取该对象，以便我可以在该页面上重新填充捕获的数据。但是，我的问题是我的 onPause 方法发生了错误。这个错误已经困扰我2天了，希望大家帮忙。我真的需要它。

这是我的 onPause 和 onResume 代码：

    @Override
protected void onPause() {
    super.onPause();

    try {
        SharedPreferences appSharedPrefs = PreferenceManager.getDefaultSharedPreferences(this.getApplicationContext());
        Editor prefsEditor = appSharedPrefs.edit();

        activityDataContainer = convertDataContainers(); //This just gets the data from the page

        prefsEditor.putInt("objectLength", activityDataContainer.size());
        Gson gson = new Gson();
        for(int x = 0; x < activityDataContainer.size(); x++){
            ConnectionObject temp = activityDataContainer.get(x);
            String json = gson.toJson(temp);
            prefsEditor.putString("connectionData"+x, json);
        }

        prefsEditor.commit();
        Toast.makeText(this, "Object stored in SharedPreferences", Toast.LENGTH_SHORT).show();
    } catch (Exception e) {
        Toast.makeText(this, ""+e, Toast.LENGTH_LONG).show();
        e.printStackTrace();
    }

};

@Override
protected void onResume() {
    super.onResume();

    //===== Using SharedPreferences
    SharedPreferences appSharedPrefs = PreferenceManager.getDefaultSharedPreferences(this.getApplicationContext());
    if(appSharedPrefs.contains("objectLength")){

        int length = appSharedPrefs.getInt("objectLength", 0);
        activityDataContainer = new ArrayList<ConnectionObject>();
        Gson gson = new Gson();
        for(int x = 0; x < length; x++){
            String json = appSharedPrefs.getString("connectionData"+x, "");
            ConnectionObject object = gson.fromJson(json, ConnectionObject.class);
            activityDataContainer.add(object);
        }

        revertDataContainers(activityDataContainer); //Repopulates the data
        Toast.makeText(this, "Object retrieved in SharedPreferences", Toast.LENGTH_SHORT).show();
    }
}

这是我得到的错误日志：

05-10 02:14:47.822：E/AndroidRuntime（31718）：致命异常：主要
05-10 02:14:47.822: E/AndroidRuntime(31718): java.lang.RuntimeException: Unable to pause activity {com.NelConsulting.FieldCaptureTool/com.MyClass}: java.lang.IllegalArgumentException: class android.database.sqlite.SQLiteDatabase declares multiple JSON fields named mLock
05-10 02:14:47.822: E/AndroidRuntime(31718):    at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2354)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2311)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at android.app.ActivityThread.handlePauseActivity(ActivityThread.java:2291)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at android.app.ActivityThread.access$1700(ActivityThread.java:117)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:938)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at android.os.Handler.dispatchMessage(Handler.java:99)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at android.os.Looper.loop(Looper.java:130)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at android.app.ActivityThread.main(ActivityThread.java:3683)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at java.lang.reflect.Method.invokeNative(Native Method)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at java.lang.reflect.Method.invoke(Method.java:507)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at dalvik.system.NativeStart.main(Native Method)
05-10 02:14:47.822: E/AndroidRuntime(31718): Caused by: java.lang.IllegalArgumentException: class android.database.sqlite.SQLiteDatabase declares multiple JSON fields named mLock
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:122)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:72)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.Gson.getAdapter(Gson.java:349)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.(ReflectiveTypeAdapterFactory.java:82)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createBoundField(ReflectiveTypeAdapterFactory.java:81)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:118)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:72)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.Gson.getAdapter(Gson.java:349)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.internal.bind.CollectionTypeAdapterFactory.create(CollectionTypeAdapterFactory.java:52)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.Gson.getAdapter(Gson.java:349)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.(ReflectiveTypeAdapterFactory.java:82)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.createBoundField(ReflectiveTypeAdapterFactory.java:81)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.getBoundFields(ReflectiveTypeAdapterFactory.java:118)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory.create(ReflectiveTypeAdapterFactory.java:72)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.Gson.getAdapter(Gson.java:349)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.write(TypeAdapterRuntimeTypeWrapper.java:55)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:96)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.write(CollectionTypeAdapterFactory.java:60)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.Gson.toJson(Gson.java:582)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.Gson.toJson(Gson.java:561)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.Gson.toJson(Gson.java:516)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.google.gson.Gson.toJson(Gson.java:496)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at com.MyClass.onPause(ConnectionsActivity.java:804)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at android.app.Activity.performPause(Activity.java:3851)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at android.app.Instrumentation.callActivityOnPause(Instrumentation.java:1191)
05-10 02:14:47.822: E/AndroidRuntime(31718):    at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2341)

All help will be greatly appreciated. Much thanks in advance.

**EDIT **ConnectionObject is a simple object that stores these values:

private boolean toggleButtonValue;
private int sdGenValue;
private int sdSpecValue;
private int sdCountValue;
private String sdLengthValue;
private int sdCondValue;
private int sdOwnValue;
private String sdDateValue;
private String mLtValue;
private String mLgValue;
private String mAcValue;
private int mPhotoValue;
private List<MeterObject> meterContainer;
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1 回答 1

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I solved it, though I think its just a loop around idea. I just split my object into 2 parts. The first being the String and int values, and the second one being the list. I stored both parts separately then combine them again on resume. Thanks for the ideas guys. It was a lot of help.

于 2012-05-16T13:58:53.133 回答