ImageView的scaleType="fitXY"在Cardview内无法在5.0以下的设备上工作 | Android

Question

我有一个ImageView，它在我的代码中作为CardView的一部分。我的ImageView scaleType="fitXY" 在早期版本的Android系统设备上无法正常工作。但在Lollipop（棒棒糖）设备上看起来更好。请看下面的图片。
如上图所示，在图像周围有白色填充，我想要去除它，使其在早期和后期的Android系统设备上都显示相同。请帮我解决这个问题。谢谢 :)

 <android.support.v7.widget.CardView
                android:layout_width="match_parent"
                android:layout_height="160dp"
                android:layout_marginRight="10dp"
                android:layout_marginTop="6dp"
                app:cardCornerRadius="10dp"
                card_view:cardUseCompatPadding="false"
                >

                <ImageView
                    android:id="@+id/imgChat"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:scaleType="fitXY"
                    />
            </android.support.v7.widget.CardView>

- Ravindra Kushwaha

---

嘿，你可以检查版本代码，如果低于21，则使用带有圆角的矩形制作自定义ImageView，并在自定义ImageView中设置图像。 - Vaibhavi

@Vaibhavi 谢谢你的输入 :) - Ravindra Kushwaha

Answer 1

这个间隙是因为在Android 5.0以下的设备中，CardView内部填充导致的。由于在Api < 21中没有原生支持阴影和剪切，CardView通过后备解决方案重新创建这些效果。现在，如果您定义了一个cardCornerRadius，在Android 5.0以下的设备中，CardView将对您的内容应用内容填充（等于角半径值），以防止您的内容重叠在角落处。

要禁用此行为，您可以在XML中执行以下操作：

card_view:cardPreventCornerOverlap="false"

或者使用Java:

cardView.setPreventCornerOverlap(false)

禁用重叠角边距。

更新: 如果你真的想在Android 5.0之前的设备上实现相同的效果，你可以尝试使用类似于这个库的库来剪切你的图像：

https://github.com/vinc3m1/RoundedImageView

这样当你的内容与CardView重叠时，角落会重叠，并且你将得到与Android 5.0之后的设备相同的外观。

- Keivan Esbati

---

我更新了答案，请告诉我这是否适用于您。 - Keivan Esbati

我已经在cardview中使用了card_view:cardPreventCornerOverlap="false"，但现在出现了一个新问题：现在图像显示为矩形，没有任何圆角（所有图像的末端都是弧形）。 - Ravindra Kushwaha

尝试通过检查操作系统的版本来解决问题 :| 加油！ - Ravindra Kushwaha

谢谢，由于您努力实现了与早期版本相同的效果，我更新了我的答案。希望能对您有所帮助。 - Keivan Esbati

我使用Glide或Universal图像库完成了这个，你可以查看我的回答:P ......感谢您宝贵的评论朋友 :) - Ravindra Kushwaha

Answer 2

由于在 pre-lollipop 设备上问题没有得到解决，我们可以自定义 ImageView 以创建圆角图像视图（就像在 Lollipop 设备上一样）。我们可以检查操作系统（OS）并根据其进行自定义设置。

基本上，我们可以使用 Universal image loaderthis或Glide image loaderthis来创建应用程序。

Universal image loader提供了默认的RoundedCorners以创建ImageView的边角，如下所示：

 ImageLoader imageLoader = ImageLoader.getInstance();
        imageLoader.init(ImageLoaderConfiguration.createDefault(MainActivity.this));
        DisplayImageOptions options = new DisplayImageOptions.Builder()
                .displayer(new RoundedBitmapDisplayer(20))/// RoundedBitmapDisplayer IS THE CLASS BY  WHICH , WE CAN CREATE THE ROUNDED CORNER OF THE IMAGEVIEW
                .cacheInMemory(true)
                .cacheOnDisk(true)
                .build();
        imageLoader.displayImage("http://thedeveloperworldisyours.com/wp-content/uploads/scareface.jpeg", YOUR_IMAGEVIEW,options);

在 Glide 图像加载器中，我们需要创建自定义类来创建 ImageView 的弧形，在这个 链接 中，您可以找到自定义圆角类来创建 ImageView 周围的圆角弧线。

Glide.with(this)
                .load("http://thedeveloperworldisyours.com/wp-content/uploads/scareface.jpeg")
                .bitmapTransform(new RoundedCornersTransformation( MainActivity.this,15, 2)) ///RoundedCornersTransformation IS THE CLASS, WHICH YOU NEED TO COPY INSIDE YOURS PROJECT, PLEASE FIND THIS CLASS ON ABOVE LINK AND I AM ALSO PROVIDING THE CLASS FOR IT
                .into(YOUR_IMAGEVIEW);

要在Glide中创建圆角，我们需要将以下类复制到我们的项目中，我从这个link获取了这个类。

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.RectF;
import android.graphics.Shader;

import com.bumptech.glide.Glide;
import com.bumptech.glide.load.Transformation;
import com.bumptech.glide.load.engine.Resource;
import com.bumptech.glide.load.engine.bitmap_recycle.BitmapPool;
import com.bumptech.glide.load.resource.bitmap.BitmapResource;

/**
 * Created by javiergonzalezcabezas on 2/4/16.
 */
public class RoundedCornersTransformation implements Transformation<Bitmap> {

    public enum CornerType {
        ALL,
        TOP_LEFT, TOP_RIGHT, BOTTOM_LEFT, BOTTOM_RIGHT,
        TOP, BOTTOM, LEFT, RIGHT,
        OTHER_TOP_LEFT, OTHER_TOP_RIGHT, OTHER_BOTTOM_LEFT, OTHER_BOTTOM_RIGHT,
        DIAGONAL_FROM_TOP_LEFT, DIAGONAL_FROM_TOP_RIGHT
    }

    private BitmapPool mBitmapPool;
    private int mRadius;
    private int mDiameter;
    private int mMargin;
    private CornerType mCornerType;

    public RoundedCornersTransformation(Context context, int radius, int margin) {
        this(context, radius, margin, CornerType.ALL);
    }

    public RoundedCornersTransformation(BitmapPool pool, int radius, int margin) {
        this(pool, radius, margin, CornerType.ALL);
    }

    public RoundedCornersTransformation(Context context, int radius, int margin,
                                        CornerType cornerType) {
        this(Glide.get(context).getBitmapPool(), radius, margin, cornerType);
    }

    public RoundedCornersTransformation(BitmapPool pool, int radius, int margin,
                                        CornerType cornerType) {
        mBitmapPool = pool;
        mRadius = radius;
        mDiameter = mRadius * 2;
        mMargin = margin;
        mCornerType = cornerType;
    }

    @Override
    public Resource<Bitmap> transform(Resource<Bitmap> resource, int outWidth, int outHeight) {
        Bitmap source = resource.get();

        int width = source.getWidth();
        int height = source.getHeight();

        Bitmap bitmap = mBitmapPool.get(width, height, Bitmap.Config.ARGB_8888);
        if (bitmap == null) {
            bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        }

        Canvas canvas = new Canvas(bitmap);
        Paint paint = new Paint();
        paint.setAntiAlias(true);
        paint.setShader(new BitmapShader(source, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP));
        drawRoundRect(canvas, paint, width, height);
        return BitmapResource.obtain(bitmap, mBitmapPool);
    }

    private void drawRoundRect(Canvas canvas, Paint paint, float width, float height) {
        float right = width - mMargin;
        float bottom = height - mMargin;

        switch (mCornerType) {
            case ALL:
                canvas.drawRoundRect(new RectF(mMargin, mMargin, right, bottom), mRadius, mRadius, paint);
                break;
            case TOP_LEFT:
                drawTopLeftRoundRect(canvas, paint, right, bottom);
                break;
            case TOP_RIGHT:
                drawTopRightRoundRect(canvas, paint, right, bottom);
                break;
            case BOTTOM_LEFT:
                drawBottomLeftRoundRect(canvas, paint, right, bottom);
                break;
            case BOTTOM_RIGHT:
                drawBottomRightRoundRect(canvas, paint, right, bottom);
                break;
            case TOP:
                drawTopRoundRect(canvas, paint, right, bottom);
                break;
            case BOTTOM:
                drawBottomRoundRect(canvas, paint, right, bottom);
                break;
            case LEFT:
                drawLeftRoundRect(canvas, paint, right, bottom);
                break;
            case RIGHT:
                drawRightRoundRect(canvas, paint, right, bottom);
                break;
            case OTHER_TOP_LEFT:
                drawOtherTopLeftRoundRect(canvas, paint, right, bottom);
                break;
            case OTHER_TOP_RIGHT:
                drawOtherTopRightRoundRect(canvas, paint, right, bottom);
                break;
            case OTHER_BOTTOM_LEFT:
                drawOtherBottomLeftRoundRect(canvas, paint, right, bottom);
                break;
            case OTHER_BOTTOM_RIGHT:
                drawOtherBottomRightRoundRect(canvas, paint, right, bottom);
                break;
            case DIAGONAL_FROM_TOP_LEFT:
                drawDiagonalFromTopLeftRoundRect(canvas, paint, right, bottom);
                break;
            case DIAGONAL_FROM_TOP_RIGHT:
                drawDiagonalFromTopRightRoundRect(canvas, paint, right, bottom);
                break;
            default:
                canvas.drawRoundRect(new RectF(mMargin, mMargin, right, bottom), mRadius, mRadius, paint);
                break;
        }
    }

    private void drawTopLeftRoundRect(Canvas canvas, Paint paint, float right, float bottom) {
        canvas.drawRoundRect(new RectF(mMargin, mMargin, mMargin + mDiameter, mMargin + mDiameter),
                mRadius, mRadius, paint);
        canvas.drawRect(new RectF(mMargin, mMargin + mRadius, mMargin + mRadius, bottom), paint);
        canvas.drawRect(new RectF(mMargin + mRadius, mMargin, right, bottom), paint);
    }

    private void drawTopRightRoundRect(Canvas canvas, Paint paint, float right, float bottom) {
        canvas.drawRoundRect(new RectF(right - mDiameter, mMargin, right, mMargin + mDiameter), mRadius,
                mRadius, paint);
        canvas.drawRect(new RectF(mMargin, mMargin, right - mRadius, bottom), paint);
        canvas.drawRect(new RectF(right - mRadius, mMargin + mRadius, right, bottom), paint);
    }

    private void drawBottomLeftRoundRect(Canvas canvas, Paint paint, float right, float bottom) {
        canvas.drawRoundRect(new RectF(mMargin, bottom - mDiameter, mMargin + mDiameter, bottom),
                mRadius, mRadius, paint);
        canvas.drawRect(new RectF(mMargin, mMargin, mMargin + mDiameter, bottom - mRadius), paint);
        canvas.drawRect(new RectF(mMargin + mRadius, mMargin, right, bottom), paint);
    }

    private void drawBottomRightRoundRect(Canvas canvas, Paint paint, float right, float bottom) {
        canvas.drawRoundRect(new RectF(right - mDiameter, bottom - mDiameter, right, bottom), mRadius,
                mRadius, paint);
        canvas.drawRect(new RectF(mMargin, mMargin, right - mRadius, bottom), paint);
        canvas.drawRect(new RectF(right - mRadius, mMargin, right, bottom - mRadius), paint);
    }

    private void drawTopRoundRect(Canvas canvas, Paint paint, float right, float bottom) {
        canvas.drawRoundRect(new RectF(mMargin, mMargin, right, mMargin + mDiameter), mRadius, mRadius,
                paint);
        canvas.drawRect(new RectF(mMargin, mMargin + mRadius, right, bottom), paint);
    }

    private void drawBottomRoundRect(Canvas canvas, Paint paint, float right, float bottom) {
        canvas.drawRoundRect(new RectF(mMargin, bottom - mDiameter, right, bottom), mRadius, mRadius,
                paint);
        canvas.drawRect(new RectF(mMargin, mMargin, right, bottom - mRadius), paint);
    }

    private void drawLeftRoundRect(Canvas canvas, Paint paint, float right, float bottom) {
        canvas.drawRoundRect(new RectF(mMargin, mMargin, mMargin + mDiameter, bottom), mRadius, mRadius,
                paint);
        canvas.drawRect(new RectF(mMargin + mRadius, mMargin, right, bottom), paint);
    }

    private void drawRightRoundRect(Canvas canvas, Paint paint, float right, float bottom) {
        canvas.drawRoundRect(new RectF(right - mDiameter, mMargin, right, bottom), mRadius, mRadius,
                paint);
        canvas.drawRect(new RectF(mMargin, mMargin, right - mRadius, bottom), paint);
    }

    private void drawOtherTopLeftRoundRect(Canvas canvas, Paint paint, float right, float bottom) {
        canvas.drawRoundRect(new RectF(mMargin, bottom - mDiameter, right, bottom), mRadius, mRadius,
                paint);
        canvas.drawRoundRect(new RectF(right - mDiameter, mMargin, right, bottom), mRadius, mRadius,
                paint);
        canvas.drawRect(new RectF(mMargin, mMargin, right - mRadius, bottom - mRadius), paint);
    }

    private void drawOtherTopRightRoundRect(Canvas canvas, Paint paint, float right, float bottom) {
        canvas.drawRoundRect(new RectF(mMargin, mMargin, mMargin + mDiameter, bottom), mRadius, mRadius,
                paint);
        canvas.drawRoundRect(new RectF(mMargin, bottom - mDiameter, right, bottom), mRadius, mRadius,
                paint);
        canvas.drawRect(new RectF(mMargin + mRadius, mMargin, right, bottom - mRadius), paint);
    }

    private void drawOtherBottomLeftRoundRect(Canvas canvas, Paint paint, float right, float bottom) {
        canvas.drawRoundRect(new RectF(mMargin, mMargin, right, mMargin + mDiameter), mRadius, mRadius,
                paint);
        canvas.drawRoundRect(new RectF(right - mDiameter, mMargin, right, bottom), mRadius, mRadius,
                paint);
        canvas.drawRect(new RectF(mMargin, mMargin + mRadius, right - mRadius, bottom), paint);
    }

    private void drawOtherBottomRightRoundRect(Canvas canvas, Paint paint, float right,
                                               float bottom) {
        canvas.drawRoundRect(new RectF(mMargin, mMargin, right, mMargin + mDiameter), mRadius, mRadius,
                paint);
        canvas.drawRoundRect(new RectF(mMargin, mMargin, mMargin + mDiameter, bottom), mRadius, mRadius,
                paint);
        canvas.drawRect(new RectF(mMargin + mRadius, mMargin + mRadius, right, bottom), paint);
    }

    private void drawDiagonalFromTopLeftRoundRect(Canvas canvas, Paint paint, float right,
                                                  float bottom) {
        canvas.drawRoundRect(new RectF(mMargin, mMargin, mMargin + mDiameter, mMargin + mDiameter),
                mRadius, mRadius, paint);
        canvas.drawRoundRect(new RectF(right - mDiameter, bottom - mDiameter, right, bottom), mRadius,
                mRadius, paint);
        canvas.drawRect(new RectF(mMargin, mMargin + mRadius, right - mDiameter, bottom), paint);
        canvas.drawRect(new RectF(mMargin + mDiameter, mMargin, right, bottom - mRadius), paint);
    }

    private void drawDiagonalFromTopRightRoundRect(Canvas canvas, Paint paint, float right,
                                                   float bottom) {
        canvas.drawRoundRect(new RectF(right - mDiameter, mMargin, right, mMargin + mDiameter), mRadius,
                mRadius, paint);
        canvas.drawRoundRect(new RectF(mMargin, bottom - mDiameter, mMargin + mDiameter, bottom),
                mRadius, mRadius, paint);
        canvas.drawRect(new RectF(mMargin, mMargin, right - mRadius, bottom - mRadius), paint);
        canvas.drawRect(new RectF(mMargin + mRadius, mMargin + mRadius, right, bottom), paint);
    }

    @Override public String getId() {
        return "RoundedTransformation(radius=" + mRadius + ", margin=" + mMargin + ", diameter="
                + mDiameter + ", cornerType=" + mCornerType.name() + ")";
    }
}

- Ravindra Kushwaha