如何让Android TextView全屏显示，顶部没有间隙，底部不丢失文字

Question

我尝试将长文本上传到我的应用程序

任何实验都失败了，我无法删除顶部的间隙并显示所有文本而不丢失底部的文本结尾。

<?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="fill_parent"
    android:layout_height="fill_parent"
    android:layout_marginLeft="0dp"
    android:layout_marginTop="0dp"
    android:visibility="visible"
    tools:context=".ui.answer.AnswerFragment"
    tools:visibility="visible">

    <TextView
        android:id="@+id/text_answer"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:gravity="top"
        android:scrollbars="vertical"
        android:textColor="@color/white"
        android:textSize="20sp"
        android:visibility="visible"
        tools:text="Hello World"
        tools:visibility="visible"
        tools:ignore="MissingConstraints" />

</androidx.constraintlayout.widget.ConstraintLayout>

目前我正在滚动

    textView.setText(readTextFile(answerFile));
    String tst = "JAVA IS A TECHNOLOGY OF CHOICE FOR BUILDING APPLICATIONS" ...
    textView.setMovementMethod(new ScrollingMovementMethod());

但尝试了很多其他变体，但差距仍然没有消失。我的选项卡导航菜单定义为

<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:id="@+id/container"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#1F1F1F"
    android:paddingTop="?attr/actionBarSize">

    <fragment
        android:id="@+id/nav_host_fragment_activity_main"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_marginTop="0dp"
        app:defaultNavHost="true"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/mobile_navigation" />

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/nav_view"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:background="?android:attr/windowBackground"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:menu="@menu/bottom_nav_menu" />

</androidx.constraintlayout.widget.ConstraintLayout>

正确的解决方案是什么？

Answer 1

1. 从父 ConstraintLayout 中删除

   paddingTop

   。
2. 将您的片段放在 BottomNavigationView 上方。

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#1F1F1F">

    <fragment
        android:id="@+id/nav_host_fragment_activity_main"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:defaultNavHost="true"
        app:layout_constraintBottom_toTopOf="@id/nav_view"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/mobile_navigation" />

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/nav_view"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:background="?android:attr/windowBackground"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:menu="@menu/bottom_nav_menu" />

</androidx.constraintlayout.widget.ConstraintLayout>