在 android 默认选项卡式 activity 中，片段不适合屏幕，因为高度和 actionBar 是可移动的

Question

我只是在 Android Studio 1.5.1 上创建了一个 TabbedActivity。我没有更改任何代码，但 Fragment 的高度不适合屏幕，而 ActionBar 是可移动的。

Views 底部是不可见的。我需要向上移动 ActionBar 才能看到底视图。（请看视频：Video）

所以，我有 2 个问题：

将ListView放入Fragment后，如何在用户滚动ListView时平滑地向上移动ActionBar？（WhatsApp 和 Viber 正在使用这种技术）

2.How 我可以阻止 ActionBar 移动并将 Fragment 对齐到屏幕底部吗？

这是 android 创建的 Main Activity：

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 fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.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();
        }
    });

}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

/**
 * A placeholder fragment containing a simple view.
 */
public static class PlaceholderFragment extends Fragment {
    /**
     * The fragment argument representing the section number for this
     * fragment.
     */
    private static final String ARG_SECTION_NUMBER = "section_number";

    public PlaceholderFragment() {
    }

    /**
     * Returns a new instance of this fragment for the given section
     * number.
     */
    public static PlaceholderFragment newInstance(int sectionNumber) {
        PlaceholderFragment fragment = new PlaceholderFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_main, container, false);
        TextView textView = (TextView) rootView.findViewById(R.id.section_label);
        textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
        return rootView;
    }
}

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

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

    @Override
    public Fragment getItem(int position) {
        // getItem is called to instantiate the fragment for the given page.
        // Return a PlaceholderFragment (defined as a static inner class below).
        return PlaceholderFragment.newInstance(position + 1);
    }

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

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
            case 0:
                return "SECTION 1";
            case 1:
                return "SECTION 2";
            case 2:
                return "SECTION 3";
        }
        return null;
      }
   }
}

Activity_main.xml:

<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="com.example.eren.siiilllfdjfds.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.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="end|bottom"
        android:layout_margin="@dimen/fab_margin"
        android:src="@android:drawable/ic_dialog_email" />

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

编辑：

我想我需要更改这行容器：

app:layout_behavior="@string/appbar_scrolling_view_behavior"

EDIT2: 当我删除我在 1.edit 中提到的代码时，片段对齐到底部但片段的开始对齐到屏幕顶部，我的意思是片段落后于 actionBar.

Answer 1

After i put ListView in fragment, how can i move ActionBar up smoothly when user scrolls listView? (WhatsApp and Viber are using this technique)

首先，better/or假设你必须使用RecyclerView：

app:layout_behavior="@string/appbar_scrolling_view_behavior"

如这里所述：（在下面添加）

https://github.com/codepath/android_guides/wiki/Handling-Scrolls-with-CoordinatorLayout#responding-to-scroll-events

关于 WhatsApp 这样的设计，我使用了以下代码：

<android.support.design.widget.CoordinatorLayout
        android:id="@+id/root_coordinator"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical"
            app:layout_behavior="@string/appbar_scrolling_view_behavior">

            <android.support.design.widget.TabLayout
                android:id="@+id/tab_layout"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="?attr/colorPrimary"
                android:minHeight="?attr/actionBarSize"
                app:tabIndicatorColor="#ffffff"
                app:tabIndicatorHeight="4dp"
                app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" />

            <android.support.v4.view.ViewPager
                android:id="@+id/pager"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />

        </LinearLayout>

        <android.support.design.widget.AppBarLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:elevation="0dp">

            <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/ThemeOverlay.AppCompat.Light"
                app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" />

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

        <android.support.design.widget.FloatingActionButton
            android:id="@+id/fab"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom|end"
            android:layout_margin="@dimen/fab_margin"
            android:src="@drawable/ic_send_white_18dp"
            app:backgroundTint="@color/colorAccent" />

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

When i delete the code that i mention in 1. edit, fragment align to bottom but start of fragment align to top of screen, i mean fragment goes behind actionBar.

您必须添加：

app:layout_behavior="@string/appbar_scrolling_view_behavior"

使用AppBarLayout下的内容并修复所有内容。

参见：https://github.com/codepath/android_guides/wiki/Handling-Scrolls-with-CoordinatorLayout#responding-to-scroll-events

其中说：

Note: AppBarLayout currently expects to be the first child nested within a CoordinatorLayout according to the official Google docs.

Next, we need to define an association between the AppBarLayout and the View that will be scrolled. Add an app:layout_behavior to a RecyclerView or any other View capable of nested scrolling such as NestedScrollView. The support library contains a special string resource @string/appbar_scrolling_view_behavior that maps to AppBarLayout.ScrollingViewBehavior, which is used to notify the AppBarLayout when scroll events occur on this particular view. The behavior must be established on the view that triggers the event.

编辑： 如果您需要将 Toolbar 固定在那里，只需使用：

app:layout_collapseMode="pin"

最后：

       <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_collapseMode="pin">

Answer 2

我是运行 Android 2，所以我不确定这是否适用于1.5。

在主要 activity xml 内部，由 Android 自动生成，有工具栏小部件：

<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">

当我删除此行时：

        app:layout_scrollFlags="scroll|enterAlways"

...所有问题都解决了。

屏幕不再滚动并且屏幕高度计算正确，因此您可以看到显示内容（片段或 activity）内的所有视图

所以我会集中精力调查那条线：

    app:layout_scrollFlags="scroll|enterAlways"

在 android 默认选项卡式 activity 中，片段不适合屏幕，因为高度和 actionBar 是可移动的

In android default tabbed activity, fragment doesn't fit the screen as height and actionBar is movable

android

android-fragments

android-coordinatorlayout

androiddesignsupport