如何在 Android 中使用 Kotlin 建立分頁文字?
此示例演示瞭如何在 Android 中使用 Kotlin 建立分頁文字。
步驟 1 − 在 Android Studio 中建立一個新專案,轉到檔案 ⇒ 新建專案,並填寫所有必要資訊以建立新專案。
步驟 2 − 將以下程式碼新增到 res/layout/activity_main.xml。
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingLeft="16dp" android:paddingTop="16dp" android:paddingRight="16dp" android:paddingBottom="16dp"> <LinearLayout android:layout_width="match_parent" android:layout_height="match_parent"> <Button android:id="@+id/buttonBack" style="?android:attr/buttonBarButtonStyle" android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="1" android:background="@android:color/transparent" /> <Button android:id="@+id/buttonForward" style="?android:attr/buttonBarButtonStyle" android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="1" android:background="@android:color/transparent" /> </LinearLayout> <TextView android:id="@+id/tv" android:layout_width="match_parent" android:layout_height="match_parent" /> </RelativeLayout>
步驟 3 − 將以下程式碼新增到 src/MainActivity.kt
import android.graphics.Color import android.graphics.Typeface import android.os.Bundle import android.text.Html import android.text.Spannable import android.text.SpannableString import android.text.TextUtils import android.text.style.ForegroundColorSpan import android.text.style.RelativeSizeSpan import android.text.style.StyleSpan import android.view.ViewTreeObserver import android.widget.Button import android.widget.TextView import androidx.appcompat.app.AppCompatActivity class MainActivity : AppCompatActivity() { lateinit var buttonBack: Button lateinit var buttonForward: Button private lateinit var textView: TextView private var pagination: Pagination? = null private lateinit var charSequence: CharSequence private var currentIndex = 0 override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) title = "KotlinApp" buttonBack = findViewById(R.id.buttonBack) buttonForward = findViewById(R.id.buttonForward) textView = findViewById(R.id.tv) val htmlString = Html.fromHtml(getString(R.string.html_string)) val spanString = SpannableString(getString(R.string.long_string)) spanString.setSpan(ForegroundColorSpan(Color.BLUE), 0, 24, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE) spanString.setSpan(RelativeSizeSpan(2f), 0, 24, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE) spanString.setSpan(StyleSpan(Typeface.MONOSPACE.style), 0, 24, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE) spanString.setSpan(ForegroundColorSpan(Color.BLUE), 536, spanString.length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE) spanString.setSpan(RelativeSizeSpan(2f), 536, spanString.length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE) spanString.setSpan(StyleSpan(Typeface.MONOSPACE.style), 536, spanString.length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE) charSequence = TextUtils.concat(htmlString, spanString) textView.viewTreeObserver.addOnGlobalLayoutListener(object : ViewTreeObserver.OnGlobalLayoutListener { override fun onGlobalLayout() { // Removing layout listener to avoid multiple calls textView.viewTreeObserver.removeOnGlobalLayoutListener(this) pagination = Pagination( charSequence, textView.width, textView.height, textView.paint, textView.lineSpacingMultiplier, textView.lineSpacingExtra, textView.includeFontPadding ) update() } }) buttonBack.setOnClickListener { currentIndex = if ((currentIndex > 0)) currentIndex - 1 else 0 update() } buttonForward.setOnClickListener { currentIndex = if ((currentIndex <pagination!!.size() - 1)) currentIndex + 1 else pagination!!.size() - 1 update() } } private fun update() { val text = pagination!![currentIndex] if (text != null) textView.text = text } }
步驟 4 − 建立一個 Kotlin 類並新增以下程式碼 -
import android.graphics.Color import android.graphics.Typeface import android.os.Bundle import android.text.Html import android.text.Spannable import android.text.SpannableString import android.text.TextUtils import android.text.style.ForegroundColorSpan import android.text.style.RelativeSizeSpan import android.text.style.StyleSpan import android.view.ViewTreeObserver import android.widget.Button import android.widget.TextView import androidx.appcompat.app.AppCompatActivity class MainActivity : AppCompatActivity() { lateinit var buttonBack: Button lateinit var buttonForward: Button private lateinit var textView: TextView private var pagination: Pagination? = null private lateinit var charSequence: CharSequence private var currentIndex = 0 override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) title = "KotlinApp" buttonBack = findViewById(R.id.buttonBack) buttonForward = findViewById(R.id.buttonForward) textView = findViewById(R.id.tv) val htmlString = Html.fromHtml(getString(R.string.html_string)) val spanString = SpannableString(getString(R.string.long_string)) spanString.setSpan(ForegroundColorSpan(Color.BLUE), 0, 24, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE) spanString.setSpan(RelativeSizeSpan(2f), 0, 24, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE) spanString.setSpan(StyleSpan(Typeface.MONOSPACE.style), 0, 24, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE) spanString.setSpan(ForegroundColorSpan(Color.BLUE), 536, spanString.length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE) spanString.setSpan(RelativeSizeSpan(2f), 536, spanString.length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE) spanString.setSpan(StyleSpan(Typeface.MONOSPACE.style), 536, spanString.length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE) charSequence = TextUtils.concat(htmlString, spanString) textView.viewTreeObserver.addOnGlobalLayoutListener(object : ViewTreeObserver.OnGlobalLayoutListener { override fun onGlobalLayout() { // Removing layout listener to avoid multiple calls textView.viewTreeObserver.removeOnGlobalLayoutListener(this) pagination = Pagination( charSequence, textView.width, textView.height, textView.paint, textView.lineSpacingMultiplier, textView.lineSpacingExtra, textView.includeFontPadding ) update() } }) buttonBack.setOnClickListener { currentIndex = if ((currentIndex > 0)) currentIndex - 1 else 0 update() } buttonForward.setOnClickListener { currentIndex = if ((currentIndex < pagination!!.size() - 1)) currentIndex + 1 else pagination!!.size() - 1 update() } } private fun update() { val text = pagination!![currentIndex] if (text != null) textView.text = text } }
步驟 5 − 將以下程式碼新增到 androidManifest.xml
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.q11"> <application 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/AppTheme"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>
讓我們嘗試執行您的應用程式。我假設您已將您的實際 Android 移動裝置連線到您的計算機。要從 Android Studio 執行應用程式,請開啟您專案中的一個活動檔案,然後單擊工具欄中的執行 圖示。選擇您的移動裝置作為選項,然後檢查您的移動裝置,它將顯示您的預設螢幕。
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