VerticalGridSupportFragment如何使用

Question

尝试Leanback,能正常加载BrowseSupportFragment布局,

---

activity.main.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main_fragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.MainActivity">

</FrameLayout>

MainActivity.kt

import android.os.Bundle
import androidx.fragment.app.FragmentActivity
import com.example.griatest.R

class MainActivity : FragmentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        if (savedInstanceState == null) {
            supportFragmentManager.beginTransaction()
                .replace(R.id.main_fragment, MainFragment())
                .commit()
        }
    }
}

MainFragment.kt

import androidx.leanback.app.VerticalGridSupportFragment

class MainFragment : BrowseSupportFragment() {
}

但是改为加载VerticalGridSupportFragment布局就不正常,报错,应该怎么使用这种卡片布局

import androidx.leanback.app.VerticalGridSupportFragment

class MainFragment : VerticalGridSupportFragment() {
}

Answer 1

java.lang.NullPointerExcention: Attemot to inwoke wirtual method 'androdx.leanback widget JerticalGridPresente’
看控制台的报错，空指针异常了。