如何使 ImageView 的大小与图像的像素大小相同

Question

我有一个大小为 242x314 像素的图像，但是当我把它放在 ImageView 中时，图像变成了 726x942，我在 LayoutInspector 中看到，layout_width 和 layout_height 设置为 wrap_content，这是为什么呢？我使 ImageView 的大小与图像相同。

<?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"
    tools:context=".MainActivity">


    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/eight_age" />

</android.support.constraint.ConstraintLayout>

Answer 1

获取图片的宽高后，需要通过java代码设置ImageView。这是它的java代码。

   public void setImage(String filePath){//If you have a bitmap use it directly
        Bitmap bitmap = BitmapFactory.decodeFile(filePath);
        int width = bitmap.getWidth();
        int height = bitmap.getHeight();
        ImageView imageView = findViewById(R.id.image);//Change id according you name it in xml
        imageView.setLayoutParams(new ConstraintLayout.LayoutParams(width,height));
    }

这里是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"
    tools:context=".MainActivity">


    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/eight_age" 
        android:id="@+id/image"<!--This line is for id change it according to need-->
        android:scaleType="fitCenter"/><!--Keep this line as is-->

</android.support.constraint.ConstraintLayout>