我正在开发Android
使用 Kotlin 的应用程序。在我的应用程序中包含Tab
with ViewPager
所以我实现了两个选项卡。当我移动到另一个活动并压缩到选项卡视图活动时,应用程序将停止并且logcat
显示下面的错误。
java.lang.RuntimeException:无法启动活动 ComponentInfo{com.crypto.wallet/com.crypto.wallet.activities.MainActivity}:android.support.v4.app.Fragment$InstantiationException:无法实例化片段 com.crypto.wallet .activities.ReceiveFragment:找不到Fragment构造函数
MyFragment.kt
@SuppressLint("ValidFragment")
class ReceiveFragment(private val transactionList: List<TransactionEntity>, val appDatabase: AppDatabase, private val direction: TransactionAdapterDirection,
val networkDefinitionProvider: NetworkDefinitionProvider) : Fragment(){
private var linearLayoutManager: LinearLayoutManager? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
}
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
val rootView = inflater.inflate(R.layout.receive_fragment, container, false)
val recyclerView = rootView.findViewById<RecyclerView>(R.id.transaction_recycler_in) as RecyclerView
linearLayoutManager = LinearLayoutManager(getActivity(), LinearLayout.VERTICAL, false)
recyclerView.layoutManager = linearLayoutManager
recyclerView.adapter = TransactionRecyclerAdapter(transactionList,appDatabase,direction,networkDefinitionProvider)
recyclerView.setHasFixedSize(true);
return rootView
}
}
ViewPager.kt
override fun getItem(position: Int): Fragment? {
var fragment: Fragment? = null
when (position) {
//0 -> fragment = ReceiveFragment(MytransactionList,MyappDatabase,Myincoming,MynetworkDefinitionProvider)
0 -> fragment = ReceiveFragment(MyIT,MyAppDatabase,MyIncoming,MyNetwork)
1 -> fragment = SendFragment()
}
return fragment
}
主要.kt
OnCreate()
val viewPager = findViewById<ViewPager>(R.id.viewpager)
if (viewPager != null) {
val adapter = ViewPagerAdapter(supportFragmentManager,it,appDatabase,INCOMING,networkDefinitionProvider)
viewPager.adapter = adapter
}
val pref = applicationContext.getSharedPreferences("MyPref", 0) // 0 - for private mode
val editor = pref.edit()
val gson = Gson()
val json = gson.toJson(it)
editor.putString("MyObject", json)
editor.apply()
OnResume()
val prefs = applicationContext.getSharedPreferences("MyPref", 0)
val gson = Gson()
val json = prefs.getString("MyObject", "")
val person1: List<TransactionEntity> = gson.fromJson(json, ArrayList<TransactionEntity>()::class.java)
UPDATE:在我尝试这个之后,我得到了同样的错误(我尝试了捆绑包和共享首选项):
companion object {
@JvmStatic
fun newInstance(myIT: List<TransactionEntity>, myAppDatabase: AppDatabase, myIncoming: TransactionAdapterDirection,
myNetwork: NetworkDefinitionProvider,
bundle: Bundle) =
ReceiveFragment(myIT, myAppDatabase, myIncoming, myNetwork,bundle).apply {
arguments = Bundle().apply {
/* val prefs = getActivity()!!.getApplicationContext().getSharedPreferences("myPrefs", 0)
val gson = Gson()
val json = prefs.getString("MyObject", "")
val person1: List<TransactionEntity> = gson.fromJson(json,
ArrayList<TransactionEntity>()::class.java)
Log.d("Karthi", "Frag-GSON " + person1)*/
val dd = bundle.getSerializable("MySerializable")
Log.d("Karthi", "Frag-GSON " + dd)
}
}
}
Main.kt:
val bundle = Bundle()
val gson_budle = Gson()
val json_bundle = gson_budle.toJson(it)
bundle.putSerializable("MySerializable", json_bundle)
val sharedPreferences = getSharedPreferences(myPreferences, Context.MODE_PRIVATE)
val editor = sharedPreferences.edit()
val gson = Gson()
val json = gson.toJson(it)
editor.putString("MyObject", json)
editor.putString("MyObject_json_bundle", json_bundle)
Log.d("Karthi","After - IT" + json)
Log.d("Karthi","After - IT" + json_bundle)
editor.apply()
致命异常:主要
进程:com.crypto.wallet,PID:29313
java.lang.RuntimeException:无法启动活动 ComponentInfo{com.crypto.wallet/com.crypto.wallet.activities.MainActivity}:android.support.v4.app.Fragment$InstantiationException:无法实例化片段 com.crypto.wallet .activities.ReceiveFragment:找不到Fragment构造函数
在 android.support.v4.app.FragmentController.restoreAllState(FragmentController.java:152)
在 android.support.v4.app.FragmentActivity.onCreate(FragmentActivity.java:330)
在 android.support.v7.app.AppCompatActivity.onCreate(AppCompatActivity.java:84)
在 com.crypto.wallet.activities.MainActivity.onCreate(MainActivity.kt:194)