Day25-Android新手筆記-TabLayout+ViewPage

2022 iThome 鐵人賽

DAY 25

Mobile Development

Android studio 30天新手筆記系列第 25 篇

14th鐵人賽

tsanyi0119

團隊nutc imac 老扛寶

2022-10-06 20:48:50

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Tablayout

介紹過Fragment與ViewPage後，本篇來結合Tablayout。Tablayout可以與ViewPage連動，當ViewPage滑動切換時，Tablayout的標籤也會跟著變動。

Tablayout屬性

這邊提兩個常用的屬性：

app:tabGravity

    app:tabGravity="fill"          //填充顯示
    app:tabGravity="center"        //居中顯示

app:tabMode

    app:tabMode="fixed"            //當Tab較多時壓縮顯示
    app:tabMode="scrollable"       //當Tab較多超出屏幕邊界時，可以滑動顯示

添加Tablayout與ViewPage

Tablayout

<com.google.android.material.tabs.TabLayout
        android:id="@+id/tabLayout"
        android:layout_width="409dp"
        android:layout_height="wrap_content"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <com.google.android.material.tabs.TabItem
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="FragmentA"
            />

        <com.google.android.material.tabs.TabItem
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="FragmentB"
            />

        <com.google.android.material.tabs.TabItem
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="FragmentC"
            />
    </com.google.android.material.tabs.TabLayout>

ViewPage

<androidx.viewpager2.widget.ViewPager2
        android:id="@+id/viewPage"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tabLayout" />

建立Fragment

建立以下三個Fragment：

fragment_a.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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".FragmentA">

    <!-- TODO: Update blank fragment layout -->
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="50dp"
        android:text="FragmentA" />

</FrameLayout>

fragment_b.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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".FragmentB">

    <!-- TODO: Update blank fragment layout -->
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="50dp"
        android:text="FragmentB" />

</FrameLayout>

fragment_c.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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".FragmentC">

    <!-- TODO: Update blank fragment layout -->
    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:textSize="50dp"
        android:text="FragmentC" />

</FrameLayout>

建立PageAdapter

建立一個class繼承FragmentStateAdapter

public class PageAdapter extends FragmentStateAdapter {

    FragmentA fragmentA;
    FragmentB fragmentB;
    FragmentC fragmentC;

    public PageAdapter(@NonNull FragmentManager fragmentManager, @NonNull Lifecycle lifecycle) {
        super(fragmentManager, lifecycle);
    }


    @NonNull
    @Override
    public Fragment createFragment(int position) {
        //position當前ViewPage編號
        switch (position) {
            case 0:
                fragmentA = new FragmentA();
                return fragmentA;
            case 1:
                fragmentB = new FragmentB();
                return fragmentB;
            case 2:
                fragmentC = new FragmentC();
                return fragmentC;
            default:
                return null;
        }
    }

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

綁定ViewPage Adapter

viewPager.setAdapter(new PageAdapter(getSupportFragmentManager(),getLifecycle()));

創建TabLayoutMediator

把TabLayout與ViewPager2連動：

new TabLayoutMediator(tabLayout, viewPager, true, new TabLayoutMediator.TabConfigurationStrategy() {
            @Override
            public void onConfigureTab(@NonNull TabLayout.Tab tab, int position) {
                viewPager.setCurrentItem(tab.getPosition());
            }
        }).attach();

Tab標籤文字

基本上做到這邊差不多結束，但attach()會造成Tab文字消失，較簡單的解決方式是直接重新賦值給Tablayout：

private String[] tab_title = {"FragmentA","FragmentB","FragmentC"};
...
for(int i = 0 ; i < tabLayout.getTabCount() ; i++){
            tabLayout.getTabAt(i).setText(tab_title[i]);
        }

Tablayout Tab自動大寫解決

建立style檔案，並加入：

<style name="TabLayoutTextStyle" parent="TextAppearance.Design.Tab">
        <item name="android:textAllCaps">false</item>
        <item name="textAllCaps">false</item>
</style>

於Tablayout控件中綁定：

app:tabTextAppearance="@style/TabLayoutTextStyle"

完整程式碼

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <com.google.android.material.tabs.TabLayout
        android:id="@+id/tabLayout"
        android:layout_width="409dp"
        app:tabTextAppearance="@style/TabLayoutTextStyle"
        android:layout_height="wrap_content"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <com.google.android.material.tabs.TabItem
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="FragmentA"
            />

        <com.google.android.material.tabs.TabItem
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="FragmentB"
            />

        <com.google.android.material.tabs.TabItem
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="FragmentC"
            />
    </com.google.android.material.tabs.TabLayout>

    <androidx.viewpager2.widget.ViewPager2
        android:id="@+id/viewPage"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tabLayout" />

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity {
    private TabLayout tabLayout;
    private ViewPager2 viewPager;
    private String[] tab_title = {"FragmentA","FragmentB","FragmentC"};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        tabLayout = findViewById(R.id.tabLayout);
        viewPager = findViewById(R.id.viewPage);

        viewPager.setAdapter(new PageAdapter(getSupportFragmentManager(),getLifecycle()));

        new TabLayoutMediator(tabLayout, viewPager, true, new TabLayoutMediator.TabConfigurationStrategy() {
            @Override
            public void onConfigureTab(@NonNull TabLayout.Tab tab, int position) {
                viewPager.setCurrentItem(tab.getPosition());
            }
        }).attach();
        //設定Tab標籤文字
        for(int i = 0 ; i < tabLayout.getTabCount() ; i++){
            tabLayout.getTabAt(i).setText(tab_title[i]);
        }
    }
}

PageAdapter.java

public class PageAdapter extends FragmentStateAdapter {

    FragmentA fragmentA;
    FragmentB fragmentB;
    FragmentC fragmentC;

    public PageAdapter(@NonNull FragmentManager fragmentManager, @NonNull Lifecycle lifecycle) {
        super(fragmentManager, lifecycle);
    }


    @NonNull
    @Override
    public Fragment createFragment(int position) {
        //position當前ViewPage編號
        switch (position) {
            case 0:
                fragmentA = new FragmentA();
                return fragmentA;
            case 1:
                fragmentB = new FragmentB();
                return fragmentB;
            case 2:
                fragmentC = new FragmentC();
                return fragmentC;
            default:
                return null;
        }
    }

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