使 TabLayout 的元素适合屏幕

Question

我的 Android 应用程序中有一个 Activity，其中包含用于在不同片段之间切换的 TabLayout。我实现了一个自定义 FragmentStatePagerAdapter 来插入我的列并使用 tabLayout.setupWithViewPager(mViewPager) 方法在我的 Activity 中初始化它。

我的问题是，如果我在我的 tabLayout 中使用 TabLayout.MODE_FIXED，我最终会得到其中一个元素，即讨论，如下图所示：

在另一种情况下，如果我使用 TabLayout.MODE_SCROLLABLE，我最终会将 tabLayout 的所有预定义元素都缩小到应用程序的左角，并且有大量空白 space，无论我指定的重力是这样的：

我试图获得的结果是：

1) 固定模式下没有两个内衬或重叠元素的 TabLayout，或者；

2) 可滚动模式下的 TabLayout 至少覆盖所有空 space 可用 and/or 覆盖超过给定的 space 因为只要用户可以在 TabLayout 中滚动就可以接受查看和访问不可见的选项卡。

相关源代码和资源代码如下。如果需要更多信息，请告诉我。

我的activity代码：

import android.os.Bundle;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import swe574.boun.edu.androidproject.adapters.GroupTabPagerAdapter;

public class GroupActivity 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 GroupTabPagerAdapter mSectionsPagerAdapter;

    /**
     * The {@link ViewPager} that will host the section contents.
     */
    private ViewPager mViewPager;
    private List<String> mTitles;

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

        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.
        mTitles = new ArrayList<>();
        mTitles.addAll(Arrays.asList(new String[]{"Home" , "Meetings" , "Discussions" , "Notes"}));
        mSectionsPagerAdapter = new GroupTabPagerAdapter(getSupportFragmentManager(), mTitles, 4);

        // 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);
        tabLayout.setTabMode(TabLayout.MODE_SCROLLABLE);
        tabLayout.setTabGravity(TabLayout.GRAVITY_CENTER);

    }


    @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_group, 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);
    }

}

我的 GroupTabPagerAdapter 代码：

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;

import java.util.List;

import swe574.boun.edu.androidproject.fragments.DiscussionFragment;
import swe574.boun.edu.androidproject.fragments.GroupHomeFragment;
import swe574.boun.edu.androidproject.fragments.MeetingFragment;
import swe574.boun.edu.androidproject.fragments.NoteFragment;

public class GroupTabPagerAdapter extends FragmentStatePagerAdapter {
    private List<String> mTitles;
    private int mNumOfTabs;

    public GroupTabPagerAdapter(FragmentManager fm, List<String> mTitles, int mNumOfTabs) {
        super(fm);
        this.mTitles = mTitles;
        this.mNumOfTabs = mNumOfTabs;
    }

    @Override
    public Fragment getItem(int position) {
        Fragment fragment = null;
        switch (position) {
            case 0:
                fragment = new GroupHomeFragment();
                break;
            case 1:
                fragment = new MeetingFragment();
                break;
            case 2:
                fragment = new DiscussionFragment();
                break;
            case 3:
                fragment = new NoteFragment();
                break;
        }
        return fragment;
    }

    @Override
    public int getCount() {
        return mNumOfTabs;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return mTitles.get(position);
    }


}

我的Activity布局：

<?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="swe574.boun.edu.androidproject.GroupActivity">

    <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>

感谢您的帮助。

Answer 1

我通过在自定义 class 中扩展 TabLayout 并使用以下方法覆盖 onMeasure 方法来解决此问题：

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    try {
        if (getTabCount() == 0){
            return;
        }
        Field field = TabLayout.class.getDeclaredField("mTabMinWidth");
        field.setAccessible(true);
        field.set(this, (int) (getMeasuredWidth() / (float) getTabCount()) * 1);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

使 TabLayout 的元素适合屏幕

Fitting Elements of the TabLayout into Screen

android

android-layout

android-tablayout