Question

我需要调整ImageView的大小以使其适合屏幕，保持相同的宽高比。以下条件成立：

图像是固定宽度（屏幕宽度的大小）
图像是从互联网上下载的，即尺寸只能在以后确定
每张图片的宽高比会有所不同;有些很高，有些是正方形，有些是扁平的
ImageView的 height 需要根据
裁剪多余的高度，默认情况下不能有很多空白区域。

例如，400像素宽屏幕上的小型50x50图像会将图像缩放到400x400像素。 800x200图像将缩放到400x100。

我已经查看了大多数其他线程，许多提议的解决方案，例如只更改adjustViewBounds和scaleType只会缩小图像，而不是缩放它。

Answer 1

我在这篇文章中借助Bob Lee的回答创建了它：Android: How to stretch an image to the screen width while maintaining aspect ratio?

package com.yourpackage.widgets;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.ImageView;

public class AspectRatioImageView extends ImageView {

    public AspectRatioImageView(Context context) {
        super(context);
    }

    public AspectRatioImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public AspectRatioImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int width = MeasureSpec.getSize(widthMeasureSpec);
        int height = width * getDrawable().getIntrinsicHeight() / getDrawable().getIntrinsicWidth();
        setMeasuredDimension(width, height);
    }
}

现在在XML中使用它：

<com.yourpackage.widgets.AspectRatioImageView android:layout_centerHorizontal="true"
    android:src="@drawable/yourdrawable" android:id="@+id/image"
    android:layout_alignParentTop="true" android:layout_height="wrap_content"
    android:layout_width="match_parent" android:adjustViewBounds="true" />

玩得开心！

Answer 2

ImageView mImageView; // This is the ImageView to change

// Use this in onWindowFocusChanged so that the ImageView is fully loaded, or the dimensions will end up 0.
public void onWindowFocusChanged(boolean hasFocus) 
{
    super.onWindowFocusChanged(hasFocus);

    // Abstracting out the process where you get the image from the internet
    Bitmap loadedImage = getImageFromInternet (url);

    // Gets the width you want it to be
    intendedWidth = mImageView.getWidth();

    // Gets the downloaded image dimensions
    int originalWidth = loadedImage.getWidth();
    int originalHeight = loadedImage.getHeight();

    // Calculates the new dimensions
    float scale = (float) intendedWidth / originalWidth;
    int newHeight = (int) Math.round(originalHeight * scale);

    // Resizes mImageView. Change "FrameLayout" to whatever layout mImageView is located in.
    mImageView.setLayoutParams(new FrameLayout.LayoutParams(
            FrameLayout.LayoutParams.WRAP_CONTENT,
            FrameLayout.LayoutParams.WRAP_CONTENT));
    mImageView.getLayoutParams().width = intendedWidth;
    mImageView.getLayoutParams().height = newHeight;
}

Answer 3

我更喜欢Agarwal的答案，因为它可以修复：

package com.yourpackage.widgets;

import android.content.Context;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.widget.ImageView;

public class AspectRatioImageView extends ImageView {

    public AspectRatioImageView(Context context) 
    {       
        super(context);
        this.setScaleType(ScaleType.FIT_XY);
    }

    public AspectRatioImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.setScaleType(ScaleType.FIT_XY);
    }

    public AspectRatioImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        this.setScaleType(ScaleType.FIT_XY);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) 
    {
        Drawable d = getDrawable();

        if (d != null && d.getIntrinsicWidth() > 0)
        {
            int width = MeasureSpec.getSize(widthMeasureSpec);
            if (width <= 0)
                width = getLayoutParams().width;

            int height = width * d.getIntrinsicHeight() / d.getIntrinsicWidth();
            setMeasuredDimension(width, height);
        }
        else
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);       
    }
}

现在在XML中使用它：

<com.yourpackage.widgets.AspectRatioImageView 
android:src="@drawable/yourdrawable"
android:layout_height="wrap_content"
android:layout_width="match_parent"/>

调整ImageView的大小以适应宽高比

3 个答案: