将图像调整到ImageView中,保持纵横比,然后将ImageView调整为图像尺寸？

Question

如何将随机大小的图像拟合到ImageView？
什么时候:

• 最初ImageView尺寸为250dp*250dp
• 图像的较大尺寸应按比例放大/缩小至250dp
• 图像应保持其纵横比
• ImageView缩放后,尺寸应与缩放图像的尺寸相匹配

例如,对于100*150的图像,图像ImageView应为166*250.
例如,对于150*100的图像,图像ImageView应为250*166.

如果我将界限设置为

<ImageView
    android:id="@+id/picture"
    android:layout_width="250dp"
    android:layout_height="250dp"
    android:layout_gravity="center_horizontal"
    android:layout_marginTop="20dp"
    android:adjustViewBounds="true" />

图像适合在ImageView,但ImageView总是250dp*250dp.

Answer 1

对于这个具体问题可能无法回答,但是如果有人像我一样,在maxWidth保留纵横比的同时搜索如何在ImageView中使用有界大小(例如)来匹配图像,然后摆脱ImageView占用的过多空间,那么最简单的解决方案是在XML中使用以下属性:

    android:scaleType="centerInside"
    android:adjustViewBounds="true"

Answer 2

(在澄清原始问题后,答案被大量修改)

澄清之后:
这不能仅在xml中完成.无法对图像进行缩放,ImageView因此图像的一维尺寸始终为250dp,并且ImageView尺寸与图像的尺寸相同.

这个代码缩放 Drawable为一个ImageView像250dp x 250dp的正方形,一维正好250dp并保持纵横比.然后ImageView调整大小以匹配缩放图像的尺寸.代码用于活动.我通过按钮点击处理程序测试了它.

请享用.:)

private void scaleImage(ImageView view) throws NoSuchElementException  {
    // Get bitmap from the the ImageView.
    Bitmap bitmap = null;

    try {
        Drawable drawing = view.getDrawable();
        bitmap = ((BitmapDrawable) drawing).getBitmap();
    } catch (NullPointerException e) {
        throw new NoSuchElementException("No drawable on given view");
    } catch (ClassCastException e) {
        // Check bitmap is Ion drawable
        bitmap = Ion.with(view).getBitmap();
    }

    // Get current dimensions AND the desired bounding box
    int width = 0;

    try {
        width = bitmap.getWidth();
    } catch (NullPointerException e) {
        throw new NoSuchElementException("Can't find bitmap on given view/drawable");
    }

    int height = bitmap.getHeight();
    int bounding = dpToPx(250);
    Log.i("Test", "original width = " + Integer.toString(width));
    Log.i("Test", "original height = " + Integer.toString(height));
    Log.i("Test", "bounding = " + Integer.toString(bounding));

    // Determine how much to scale: the dimension requiring less scaling is
    // closer to the its side. This way the image always stays inside your
    // bounding box AND either x/y axis touches it.  
    float xScale = ((float) bounding) / width;
    float yScale = ((float) bounding) / height;
    float scale = (xScale <= yScale) ? xScale : yScale;
    Log.i("Test", "xScale = " + Float.toString(xScale));
    Log.i("Test", "yScale = " + Float.toString(yScale));
    Log.i("Test", "scale = " + Float.toString(scale));

    // Create a matrix for the scaling and add the scaling data
    Matrix matrix = new Matrix();
    matrix.postScale(scale, scale);

    // Create a new bitmap and convert it to a format understood by the ImageView 
    Bitmap scaledBitmap = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
    width = scaledBitmap.getWidth(); // re-use
    height = scaledBitmap.getHeight(); // re-use
    BitmapDrawable result = new BitmapDrawable(scaledBitmap);
    Log.i("Test", "scaled width = " + Integer.toString(width));
    Log.i("Test", "scaled height = " + Integer.toString(height));

    // Apply the scaled bitmap
    view.setImageDrawable(result);

    // Now change ImageView's dimensions to match the scaled image
    LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) view.getLayoutParams(); 
    params.width = width;
    params.height = height;
    view.setLayoutParams(params);

    Log.i("Test", "done");
}

private int dpToPx(int dp) {
    float density = getApplicationContext().getResources().getDisplayMetrics().density;
    return Math.round((float)dp * density);
}

xml代码ImageView:

<ImageView a:id="@+id/image_box"
    a:background="#ff0000"
    a:src="@drawable/star"
    a:layout_width="wrap_content"
    a:layout_height="wrap_content"
    a:layout_marginTop="20dp"
    a:layout_gravity="center_horizontal"/>

感谢有关扩展代码的讨论:http:
//www.anddev.org/resize_and_rotate_image_-_example-t621.html

2012年11月7日更新:
添加空指针检查,如评论中所示

Answer 3

<ImageView android:layout_width="match_parent"
           android:layout_height="wrap_content"
           android:scaleType="centerCrop"
           android:adjustViewBounds="true"/>

Answer 4

下面的代码使位图与imageview的大小完全相同.获取位图图像的高度和宽度,然后借助imageview的参数计算新的高度和宽度.这为您提供了最佳纵横比所需的图像.

int currentBitmapWidth = bitMap.getWidth();
int currentBitmapHeight = bitMap.getHeight();

int ivWidth = imageView.getWidth();
int ivHeight = imageView.getHeight();
int newWidth = ivWidth;

newHeight = (int) Math.floor((double) currentBitmapHeight *( (double) new_width / (double) currentBitmapWidth));

Bitmap newbitMap = Bitmap.createScaledBitmap(bitMap, newWidth, newHeight, true);

imageView.setImageBitmap(newbitMap)

请享用.

Answer 5

尝试添加android:scaleType="fitXY"到您的ImageView.

Answer 6

搜索一天后,我认为这是最简单的解决方案:

imageView.getLayoutParams().width = 250;
imageView.getLayoutParams().height = 250;
imageView.setAdjustViewBounds(true);

Answer 7

在大多数情况下有效的最佳解决方案是

这是一个例子:

<ImageView android:id="@+id/avatar"
           android:layout_width="match_parent"
           android:layout_height="match_parent"
           android:scaleType="fitXY"/>

Answer 8

如果它不适合你，那么用 android:src 替换 android:background

android:src 将发挥主要作用

    <ImageView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:adjustViewBounds="true"
    android:scaleType="fitCenter"
    android:src="@drawable/bg_hc" />

它像魅力一样工作正常

Answer 9

已编辑的Jarno Argillanders回答：

如何使图像适合您的宽度和高度：

1) 初始化 ImageView 并设置图像：

iv = (ImageView) findViewById(R.id.iv_image);
iv.setImageBitmap(image);

2）现在调整大小：

scaleImage(iv);

编辑scaleImage方法：（您可以替换 EXPECTED 边界值）

private void scaleImage(ImageView view) {
    Drawable drawing = view.getDrawable();
    if (drawing == null) {
        return;
    }
    Bitmap bitmap = ((BitmapDrawable) drawing).getBitmap();

    int width = bitmap.getWidth();
    int height = bitmap.getHeight();
    int xBounding = ((View) view.getParent()).getWidth();//EXPECTED WIDTH
    int yBounding = ((View) view.getParent()).getHeight();//EXPECTED HEIGHT

    float xScale = ((float) xBounding) / width;
    float yScale = ((float) yBounding) / height;

    Matrix matrix = new Matrix();
    matrix.postScale(xScale, yScale);

    Bitmap scaledBitmap = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
    width = scaledBitmap.getWidth();
    height = scaledBitmap.getHeight();
    BitmapDrawable result = new BitmapDrawable(context.getResources(), scaledBitmap);

    view.setImageDrawable(result);

    LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) view.getLayoutParams(); 
    params.width = width;
    params.height = height;
    view.setLayoutParams(params);
}

和.xml：

<ImageView
    android:id="@+id/iv_image"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal" />

Answer 10

所有这些都可以使用XML完成...其他方法似乎非常复杂。无论如何，您只需将高度设置为dp中所需的高度，然后设置宽度即可包装内容，反之亦然。使用scaleType fitCenter调整图像的大小。

<ImageView
    android:layout_height="200dp"
    android:layout_width="wrap_content"
    android:scaleType="fitCenter"
    android:adjustViewBounds="true"
    android:src="@mipmap/ic_launcher"
    android:layout_below="@+id/title"
    android:layout_margin="5dip"
    android:id="@+id/imageView1">