Question

我是android开发的新手。我想在public IEnumerable<ViewModel> BuildModel( Expression<Func<ReportRecord, bool>> predicate) { IEnumerable<ReportPart> items = GetList<ReportPart, ReportRecord>(predicate); }中插入json string并收到错误：

Sqlite database

这是我的代码：

DbAdapter.java

java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=1212, result=0, data=null} to activity : java.lang.NullPointerException.

MainActivity.java：

   static final String DATABASE_FEEDBACK="CREATE TABLE IF NOT EXISTS "+" feedbackjson "+
        "("+"FeedbackId"+" integer primary key autoincrement, "+" JSON text, Fullname text, Email text, AdminId text);";


 public void insertJSONFeedback(String json,String fullName,String email)
{
    Log.i("Data Insert reached", "yes");

    ContentValues newValues = new ContentValues();
    Log.i("JSON STRING to be insert1",json);
    newValues.put("JSON", json);
    newValues.put("Fullname",fullName);
    newValues.put("Email",email);
    newValues.put("AdminId","1");
    db.insert("feedbackjson", null, newValues);
    Toast.makeText(context, "Data Is Successfully Saved", Toast.LENGTH_LONG).show();
    Log.i("context", "Toast");

}

这里我的json String :: public class MainActivity extends ActionBarActivity { DbAdapter databaseadapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); databaseadapter=new DbAdapter (this); databaseadapter=databaseadapter.open(); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); Log.i("Result Code", resultCode + ""); fullName_et=(EditText) findViewById(R.id.name_et); email_et=(EditText) findViewById(R.id.email_et); String detailInformation = ""; LinkedHashMap<String, String> userFields = new LinkedHashMap<String, String>(); userFields = UtilityClass.EDIT_PROFILE_WITH_FIELD_NAME; String fieldValueAndPrivacy = null;// = new Gson gson = new Gson(); String json = gson.toJson(userFields, LinkedHashMap.class); Log.i("User Fields",json); databaseadapter.insertJSONFeedback(json, fullName_et.getText().toString(), email_et.getText().toString()); LinkedHashMap<String, ArrayList<String>> editProfileHashValues = new LinkedHashMap<String, ArrayList<String>>(); Iterator fieldIterator = userFields.entrySet().iterator(); while (fieldIterator.hasNext()) { Map.Entry fieldPairs = (Map.Entry) fieldIterator.next(); String fieldName = (String) fieldPairs.getKey(); String fieldRunTimeValue = (String) fieldPairs.getValue(); detailInformation += fieldName + " => " + fieldRunTimeValue + "\n"; Log.i("Detail Information", detailInformation); } }

我在这行中收到错误{"Full Name":"gyt","Email Address":"ggfh","Contact Number":"987654568","Rate Quality of Food":"2.5","Service Quality":"3.0","Overall Experience":"3.0","Restaurant Branch":"Vadodara","Comments":"okh"}：

databaseadapter.insertJSONFeedback（JSON， fullName_et.getText（）。toString（），email_et.getText（）。toString（））;

提前谢谢。

Answer 1

因为看起来你的“databaseadapter”对象是对null的引用。因此它会抛出nullpointerexception ....

做一件事并检查它是否崩溃...添加行databaseadapter = new DbAdapter（this）; databaseadapter = databaseadapter.open（）;在onActivityResult（）...

Answer 2

您的活动setContentView(int resId)错过了onCreate()。

Android：数据仍然可用NullPointerException错误

2 个答案: