Question

我正在关注Udacity的谷歌Android教程。我尝试使用标签创建一个简单的viewpager应用，但标签＆＃39;名称不显示。令我很好奇的是，我在教程中完成了相同的编码，而这些添加代码单独创建教程应用程序的选项卡就好了。请帮我。谢谢！

MainActivity：

package com.example.mari.viewpagerpracsec;

import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity {

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

        ViewPager viewPager = (ViewPager) findViewById(R.id.viewPager);
        CustomPagerAdapter adapter = new CustomPagerAdapter(this, getSupportFragmentManager());
        viewPager.setAdapter(adapter);

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

Viewpager适配器：

package com.example.mari.viewpagerpracsec;

import android.content.Context;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.util.Log;

public class CustomPagerAdapter extends FragmentPagerAdapter {

    private Context mContext;

    public CustomPagerAdapter(Context context, FragmentManager fm) {
        super(fm);
        mContext = context;
    }

    @Override
    public int getCount() {return 3;}

    @Override
    public Fragment getItem(int position) {
        if (position==0) {
            return new FirstFragment();
        }else if (position==1) {
            return new SecondFragment();
        }else if (position==2){
            return new ThirdFragment();
        }else {
            return new FirstFragment();
        }
    }

    @Override
    public CharSequence getPageTitle(int position) {
        if (position==0) {
            return mContext.getString(R.string.first);
        } else if (position==1) {
            return mContext.getString(R.string.second);
        } else {
            return mContext.getString(R.string.third);
        }
    }

}

片段1

package com.example.mari.viewpagerpracsec;

import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class FirstFragment extends Fragment {

    public FirstFragment() {
        // Required empty public constructor
    }

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

}

Fragment2

package com.example.mari.viewpagerpracsec;

import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;



public class SecondFragment extends Fragment {

    public SecondFragment() {
        // Required empty public constructor
    }

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

}

片段3

package com.example.mari.viewpagerpracsec;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;


public class ThirdFragment extends Fragment {

    public ThirdFragment() {
        // Required empty public constructor
    }

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

}

activity_main

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:background="@color/colorPrimary"
    android:orientation="vertical"
    tools:context=".MainActivity">

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

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

</LinearLayout>

片段1

<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="com.example.mari.viewpagerpracsec.FirstFragment">

    <ImageView
        android:id="@+id/image_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:src="@drawable/first_image"
        android:scaleType="centerCrop"/>

</FrameLayout>

片段2

<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="com.example.mari.viewpagerpracsec.SecondFragment">

    <ImageView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:src="@drawable/second_image"
        android:scaleType="fitCenter"/>

</FrameLayout>

片段3

<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="com.example.mari.viewpagerpracsec.ThirdFragment">

    <ImageView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:src="@drawable/third_image"
        android:scaleType="centerCrop"/>

</FrameLayout>

颜色

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#3F51B5</color>
    <color name="colorPrimaryDark">#303F9F</color>
    <color name="colorAccent">#FF4081</color>
</resources>

的字符串

<resources>
    <string name="app_name">View Pager Prac sec</string>

    <string name="first">first</string>
    <string name="second">second</string>
    <string name="third">third</string>

</resources>

样式

<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="actionBarStyle">@style/MiwokAppBarStyle</item>
        <item name="android:windowContentOverlay">@null</item>
    </style>

    <!-- App bar style -->
    <style name="MiwokAppBarStyle" parent="style/Widget.AppCompat.Light.ActionBar.Solid.Inverse">
        <!-- Remove the shadow below the app bar -->
        <item name="elevation">0dp</item>
    </style>

    <!-- Style for a tab that displays a category name -->
    <style name="ImageTab" parent="Widget.Design.TabLayout">
        <item name="tabIndicatorColor">@android:color/white</item>
        <item name="tabSelectedTextColor">@android:color/white</item>
        <item name="tabTextAppearance">@style/ImageTabTextAppearance</item>
        <item name="tabBackground">@color/colorPrimary</item>
    </style>

    <!-- Text appearance style for a category tab -->
    <style name="ImageTabTextAppearance" parent="TextAppearance.Design.Tab">
        <item name="android:textColor">#A8A19E</item>
    </style>

</resources>

的build.gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.3"
    defaultConfig {
        applicationId "com.example.mari.viewpagerpracsec"
        minSdkVersion 22
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.3.1'
    compile 'com.android.support:support-v4:25.3.1'
    compile 'com.android.support:design:25.3.1'
    testCompile 'junit:junit:4.12'
}

Answer 1

在 activity_main 中，您的ViewPager有layout_height:match_parent。这会让您的TabLayout屏幕上没有空间。您的 ViewPager 应该是：

    <android.support.v4.view.ViewPager
        android:id="@+id/viewPager"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />

或者您可以将 TabLayout 移到 ViewPager

的上方

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:background="@color/colorPrimary"
    android:orientation="vertical"
    tools:context=".MainActivity">

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

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

</LinearLayout>

Answer 2

尝试使用此activity_main布局的布局。

<LinearLayout 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"
android:orientation="vertical"
tools:context=".MainActivity">

<android.support.design.widget.TabLayout
    android:id="@+id/tabs"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:background="@color/colorPrimary"/>

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

</LinearLayout>

Answer 3

您的viewpager的高度占据了整个屏幕空间。尽量让它变小而不是match_parent。即便你可以像这样添加保证金。

<android.support.v4.view.ViewPager
    android:id="@+id/viewPager"
    android:layout_marginBottom="60dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

使用TabLayout不显示选项卡标题

3 个答案: