工具列在我將其添加到布局時顯示，activity_main但至少setSupportActionbar()在MainActivity外觀上似乎沒有任何區別。
我真的不明白為什么應用程式標題沒有顯示。我已經嘗試在布局中添加它并以編程方式MainActivity
我不確定我的問題是主題還是ToolBar我正在使用的版本
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">
<androidx.appcompat.widget.Toolbar
android:id="@ id/my_toolbar"
android:layout_width="0dp"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
android:elevation="4dp"
android:paddingTop="?attr/actionBarSize"
app:barrierAllowsGoneWidgets="false"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="@ id/nav_host_fragment"
app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
app:title="@string/app_name"
app:titleTextAppearance="@style/TextAppearance.AppCompat.Display1"
app:titleTextColor="@color/black" />
<fragment
android:id="@ id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="0dp"
android:layout_height="0dp"
app:defaultNavHost="true"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:navGraph="@navigation/nav_graph" />
</androidx.constraintlayout.widget.ConstraintLayout>
MainActivity.kt
class MainActivity : AppCompatActivity(),NewSongFragment.NewSongListener {
private val songViewModel: SongViewModel by viewModels {
SongViewModelFactory((application as SongApplication).repository)
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
//setup toolbar
setSupportActionBar(findViewById(R.id.my_toolbar))
supportActionBar?.title = "My title"
//create view
val recyclerView = findViewById<RecyclerView>(R.id.recycler_view)
val adapter = ItemAdapter(this,
ItemAdapter.OnClickListener { rating -> songViewModel.insertRating(rating) }
)
recyclerView.adapter = adapter
recyclerView.layoutManager = LinearLayoutManager(this)
//initialize data
songViewModel.allSongs.observe(this) { song ->
// Update the cached copy of the songs in the adapter.
song.let { adapter.submitList(it) }
}
// Use this setting to improve performance if you know that changes
// in content do not change the layout size of the RecyclerView
recyclerView.setHasFixedSize(true)
//add song button
val fab = findViewById<FloatingActionButton>(R.id.fab)
fab.setOnClickListener {
showNewSongDialog()
}
}
private fun showNewSongDialog() {
// Create an instance of the dialog fragment and show it
val dialog = NewSongFragment()
dialog.show(supportFragmentManager, "NewSongFragment")
}
override fun onDialogPositiveClick(newSongTitle: String, newSongBPM: Int) {
// User touched the dialog's positive button
if(TextUtils.isEmpty(newSongTitle)){
}else{
val newSong = Song(newSongTitle,newSongBPM)
songViewModel.insertSong(newSong)
val rating = Rating(System.currentTimeMillis(),newSong.songTitle, 50)
songViewModel.insertRating(rating)
}
}
override fun onDialogNegativeClick(dialog: DialogFragment) {
// User touched the dialog's negative button
}
}
主題.xml
<resources xmlns:tools="http://schemas.android.com/tools">
<!-- Base application theme. -->
<style name="Theme.Songs" parent="Theme.AppCompat.Light.NoActionBar">
<!-- Primary brand color. -->
<item name="colorPrimary">@color/fuchsia_001</item>
<item name="colorPrimaryVariant">@color/blue_500</item>
<item name="colorOnPrimary">@color/black</item>
<!-- Secondary brand color. -->
<item name="colorSecondary">@color/teal_200</item>
<item name="colorSecondaryVariant">@color/teal_200</item>
<item name="colorOnSecondary">@color/black</item>
<!-- Status bar color. -->
<item name="android:statusBarColor" tools:targetApi="l">?attr/colorPrimaryVariant</item>
<!-- Customize your theme here. -->
</style>
</resources>
清單.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.songs">
<application
android:name=".SongApplication"
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/Theme.Songs">
<activity
android:name=".MainActivity"
android:exported="true">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
如果我需要分解我的 gradle 檔案，請告訴我。
uj5u.com熱心網友回復：
您的代碼似乎沒問題，但是在您的 XML 布局檔案中，您正在用片段隱藏您的工具列。更改您的代碼如下：
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">
<!-- remove this line android:paddingTop="?attr/actionBarSize"-->
<androidx.appcompat.widget.Toolbar
android:id="@ id/my_toolbar"
android:layout_width="0dp"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
android:elevation="4dp"
app:barrierAllowsGoneWidgets="false"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
app:title="@string/app_name"
app:titleTextAppearance="@style/TextAppearance.AppCompat.Display1"
app:titleTextColor="@color/black" />
<fragment
android:id="@ id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="0dp"
android:layout_height="0dp"
app:defaultNavHost="true"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="@id/my_toolbar"
app:navGraph="@navigation/nav_graph" />
</androidx.constraintlayout.widget.ConstraintLayout>
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