Question

我的Android应用程序有问题。之前它工作正常，但它在开始后立即开始崩溃而没有任何错误，我无法弄清楚原因。我在我的课程中评论了很多代码（//），只留下了重要的工作，但仍然是同样的问题。我有一个mainActivity和2个片段。

当我创建片段时，它会自动创建文件夹布局并将java类放在那里。片段java类（List，Set）：

public class List extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_list, container, false);
    }
}

主要活动类：

public class MainActivity extends AppCompatActivity {

    /**
     * The {@link android.support.v4.view.PagerAdapter} that will provide
     * fragments for each of the sections. We use a
     * {@link FragmentPagerAdapter} derivative, which will keep every
     * loaded fragment in memory. If this becomes too memory intensive, it
     * may be best to switch to a
     * {@link android.support.v4.app.FragmentStatePagerAdapter}.
     */
    private SectionsPagerAdapter mSectionsPagerAdapter;

    /**
     * The {@link ViewPager} that will host the section contents.
     */
    private ViewPager mViewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        // Create the adapter that will return a fragment for each of the three
        // primary sections of the activity.
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());

        // Set up the ViewPager with the sections adapter.
        mViewPager = (ViewPager) findViewById(R.id.container);
        mViewPager.setAdapter(mSectionsPagerAdapter);

        TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(mViewPager);

        FloatingActionButton addButton = (FloatingActionButton) findViewById(R.id.add);
        addButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

    }

    /**
     * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
     * one of the sections/tabs/pages.
     */
    public class SectionsPagerAdapter extends FragmentPagerAdapter {

        SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            switch(position) {
                case 0:
                    return new Set();
                case 1:
                    return new List();
                default:
                    return null;
            }
        }

        @Override
        public int getCount() {
            // Show 3 total pages.
            return 2;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            switch (position) {
                case 0:
                    return "ZADÁVÁNÍ";
                case 1:
                    return "SEZNAM";
            }
            return null;
        }
    }
}

activity_main.xml（自动生成）：

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="cz.sudoman281.kubirovacikalkulacka.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingTop="@dimen/appbar_padding_top"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:layout_scrollFlags="scroll|enterAlways"
            app:popupTheme="@style/AppTheme.PopupOverlay">

        </android.support.v7.widget.Toolbar>

        <android.support.design.widget.TabLayout
            android:id="@+id/tabs"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />

    </android.support.design.widget.AppBarLayout>

    <android.support.v4.view.ViewPager
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

</android.support.design.widget.CoordinatorLayout>

片段.xml文件：

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".layout.List">

    <GridLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <TextView
            android:text="List"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/textView6" />

        <ListView
            android:layout_width="match_parent"
            android:layout_height="match_parent" />
    </GridLayout>
</FrameLayout>

Answer 1

从日志输出中，我看到了这一行：

01-01 15：01：58.206 7457-7457 / cz.sudoman281.kubirovacikalkulacka W / System：ClassLoader引用未知路径： /data/app/cz.sudoman281.kubirovacikalkulacka-1/lib/arm64

我想你的本地库有问题，仔细检查你的Make或CMake buid文件，确保你正确地从Java类加载本机库。

如果您在使用Android Nougat的设备/模拟器上运行应用程序，则可能需要检查您的本机库是否未链接到非NDK库，如下所述：https://developer.android.com/about/versions/nougat/android-7.0-changes.html#ndk < / p>

Answer 2

当应用程序启动时，logcat过滤器并不总是显示日志。集成库时我遇到了类似的问题。这就是我发现问题所在的方式。

以调试模式启动应用程序，在SELECT `COLUMN_NAME` FROM `INFORMATION_SCHEMA`.`COLUMNS` WHERE `TABLE_SCHEMA`='yourdatabasename' AND `TABLE_NAME`='yourtablename';方法的第一行设置断点并继续跳过（F8）直到崩溃。

Android应用程序在启动后崩溃，没有任何错误

2 个答案: