为什么图标看起来很小？以及如何解决？

Question

我已经设计了登录页面和可绘制文件夹（drawable-xhdi，drawable-xxhdi等），并且图标看起来太小。每个屏幕尺寸的图标看起来都很小。 This is screen how it looks like

和xml代码：

    <?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
android:background="@drawable/back"
tools:context=".MainActivity">

<ImageView
    android:id="@+id/logo"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="60dp"
    android:src="@drawable/logo"/>
<EditText
    android:id="@+id/password"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_marginTop="24dp"
    android:background="@android:color/transparent"
    android:drawableLeft="@drawable/lock24"
    android:drawablePadding="6dp"
    android:ems="10"
    android:hint="@string/password"
    android:inputType="textPassword"
    android:maxLines="1"
    android:padding="8dp"
    android:textColor="#34ff8a"
    android:textColorHint="#BF34ff8a"
    app:layout_constraintEnd_toStartOf="@+id/guideline-right"
    app:layout_constraintHorizontal_bias="0.0"
    app:layout_constraintStart_toStartOf="@+id/guideline-left"
    app:layout_constraintTop_toTopOf="@+id/emailLine" />
<View
    android:id="@+id/passwordlLine"
    android:layout_width="0dp"
    android:layout_height="3dp"
    android:background="@drawable/linedesign"
    app:layout_constraintEnd_toStartOf="@+id/guideline-right"
    app:layout_constraintStart_toStartOf="@+id/guideline-left"
    app:layout_constraintTop_toBottomOf="@+id/password" />
</android.support.constraint.ConstraintLayout>

我该如何解决？