如何用kotlin使用cursorloader
我尝试将我的java项目转换为kotlin，但有一个问题让我困惑。
项目结构：
App ：用于声明全局变量的应用程序
MainActivity ：AppCompatActivity
Provider ：ContentProvider
SectionsPagerAdapter ：FragmentPagerAdapter
fragment0 ：
fragment1 ：片段实现LoaderManager.LoaderCallbacks
当我尝试将fragment1转换为kotlin时，它会抛出FC。
fragment1 java代码：
class fragment1 : Fragment(), LoaderManager.LoaderCallbacks<Cursor> { private var mMainView: View? = null private var adapter: SimpleCursorAdapter? = null private var cursor: Cursor? = null private var date: Date? = null private var kadaihao: Array<String?>? = null private val uri: Uri? = null override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) val inflater = activity.layoutInflater mMainView = inflater.inflate(R.layout.fragment1, activity.findViewById(R.id.container) as ViewGroup, false) } override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? { return mMainView } override fun onViewCreated(view: View?, savedInstanceState: Bundle?) { super.onViewCreated(view, savedInstanceState) val lv = mMainView!!.findViewById(R.id.lv1) as ListView val uiBindFrom = arrayOf("_id", "shuakae", "kadaihao", "shijian", "feilv", "beizhu") val uiBindTo = intArrayOf(R.id.ID1, R.id.tv_shuakae1, R.id.tv_kadaihao1, R.id.tv_shijian1, R.id.tv_feilv1, R.id.tv_beizhu1) loaderManager.initLoader(1, null, this) adapter = SimpleCursorAdapter( context, R.layout.item_zhangdan, null, uiBindFrom, uiBindTo, CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER) lv.adapter = adapter } override fun onCreateLoader(id: Int, args: Bundle): Loader<Cursor> { val projection = arrayOf("_id", "shuakae", "kadaihao", "shijian", "feilv", "beizhu") val selection = "yihuan=0" return CursorLoader(context, App.Uri_ZhangDan, projection, selection, null, "kadaihao asc,shijian desc") } override fun onLoadFinished(loader: Loader<Cursor>, data: Cursor) { adapter!!.swapCursor(data) } override fun onLoaderReset(loader: Loader<Cursor>) { adapter!!.swapCursor(null) } }
尝试运行并抛出FC：
java.lang.IllegalArgumentException: Parameter specified as non-null is null: method kotlin.jvm.internal.Intrinsics.checkParameterIsNotNull, parameter args at com.codeme.ccm.fragment1.onCreateLoader(fragment1.kt:0) at android.support.v4.app.LoaderManagerImpl.createLoader(LoaderManager.java:539) at android.support.v4.app.LoaderManagerImpl.createAndInstallLoader(LoaderManager.java:548) at android.support.v4.app.LoaderManagerImpl.initLoader(LoaderManager.java:603) at com.codeme.ccm.fragment1.onViewCreated(fragment1.kt:73) at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1314) at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1528) at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1595) at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:758) at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2363) at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2149) at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2103) at android.support.v4.app.FragmentManagerImpl.execSingleAction(FragmentManager.java:1984) at android.support.v4.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:626) at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:143) at android.support.v4.view.ViewPager.populate(ViewPager.java:1268) at android.support.v4.view.ViewPager.populate(ViewPager.java:1116) at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1642) at android.view.View.measure(View.java:18811) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5952) at android.support.design.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:714) at android.support.design.widget.HeaderScrollingViewBehavior.onMeasureChild(HeaderScrollingViewBehavior.java:90) at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onMeasureChild(AppBarLayout.java:1391) at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:784) at android.view.View.measure(View.java:18811) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5952) at android.widget.FrameLayout.onMeasure(FrameLayout.java:194) at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:139) at android.view.View.measure(View.java:18811) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5952) at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1465) at android.widget.LinearLayout.measureVertical(LinearLayout.java:748) at android.widget.LinearLayout.onMeasure(LinearLayout.java:630) at android.view.View.measure(View.java:18811) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5952) at android.widget.FrameLayout.onMeasure(FrameLayout.java:194) at android.view.View.measure(View.java:18811) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5952) at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1465) at android.widget.LinearLayout.measureVertical(LinearLayout.java:748) at android.widget.LinearLayout.onMeasure(LinearLayout.java:630) at android.view.View.measure(View.java:18811) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5952) at android.widget.FrameLayout.onMeasure(FrameLayout.java:194) at com.android.internal.policy.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2643) at android.view.View.measure(View.java:18811) at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2127) at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1243) at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1479) at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1134) at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6050) at android.view.Choreographer$CallbackRecord.run(Choreographer.java:860) at android.view.Choreographer.doCallbacks(Choreographer.java:672) at android.view.Choreographer.doFrame(Choreographer.java:608) at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:846) at android.os.Handler.handleCallback(Handler.java:742) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:5524) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:740) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:630)
如何解决？
我没有用Android中的CursorLoader做很多事情，但是通过堆栈跟踪来判断它看起来像Bundle参数可以是null，但是你声明它是不可空的，所以Kotlin插入了一些检查来验证你。
尝试改变
override fun onCreateLoader(id: Int, args: Bundle)
至
override fun onCreateLoader(id: Int, args: Bundle?)