问题
I have a CardView with rounded corners, I want to have an ImageView at the top like shown in the example taken from the material design guidelines below.
<android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="@+id/card_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
card_view:cardCornerRadius="4dp">
<!-- ... -->
</android.support.v7.widget.CardView>
Then inside the CardView I have this ImageView
<ImageView
android:id="@+id/imageView"
android:layout_width="fill_parent"
android:layout_height="150dp"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:scaleType="centerCrop"
android:src="@drawable/default_cover" />
If I have the card_view:cardCornerRadius set to 0dp then the ImageView fits the card like how I want it to.
However, the material design guidelines state that cards should have rounded corners, and not square corners.
The problem I have is when I set the card_view:cardCornerRadius to something other than 0dp, e.g. 4dp, then the following happens:
As can be seen, the ImageView does not fit into the CardView.
My question is, how can I make this ImageView fit to the layout of the CardView when it has rounded corners.
回答1:
You need to do 2 things :
1) Call setPreventCornerOverlap(false) on your CardView.
2) Put rounded Imageview inside CardView
About rounding your imageview, I had the same problem so I made a library that you can set different radii on each corners. There is one good library(vinc3m1’s RoundedImageView) that supports rounded corners on ImageView, but it only supports the same radii on every corners. But I wanted it to be rounded only top left and top right corners.
Finally I got the result what I wanted like below.
https://github.com/pungrue26/SelectableRoundedImageView
回答2:
If your image size (width) is fixed with your ImageView width, you just only have to do is change your ImageView attribute to :
android:scaleType="fitXY"
That is. No additional image corner rounding, no busy work. Beside it efficient for app's performance.
Note : my suggestion may not appropriate for small image with large size ImageView.
回答3:
I got this to work by putting a RoundedImageView inside of a CardView. Also you need to set the appropriate CardView attributes.
https://medium.com/@etiennelawlor/layout-tips-for-pre-and-post-lollipop-bcb2e4cdd6b2#.kmb24wtkk
回答4:
EDIT 2015/09/29
https://github.com/vinc3m1/RoundedImageView added support of rounding of selected corners
You can also use makeramen RoundedImageView https://github.com/vinc3m1/RoundedImageView, and to remove auto padding in CardView for pre LolliPop use
yourCardView.setPreventCornerOverlap(false);
And then set padding you needded to show shadows of cardview
回答5:
Make a bck_rounded.xml in drawable folder. Give it a radius that is same as the card_view.
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
<corners android:radius="4dp" />
</shape>
Apply inside your imageView: android:background="@drawable/bck_rounded"
回答6:
I solved the problem with setting
1) app:cardUseCompatPadding="false"
2) setting a rounded imageView background
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
<corners android:radius="4dp" />
</shape>
回答7:
You have to Customize Your ImageView.
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
public class RoundedImageView extends android.support.v7.widget.AppCompatImageView {
private Paint mPaint;
private Path mPath;
private Bitmap mBitmap;
private Matrix mMatrix;
private int mRadius = convertDpToPixel(10);
private int mWidth;
private int mHeight;
private Drawable mDrawable;
public RoundedImageView(Context context) {
super(context);
init();
}
public RoundedImageView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public RoundedImageView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
mPaint = new Paint();
mPaint.setColor(Color.WHITE);
mPath = new Path();
}
public int convertDpToPixel(int dp) {
DisplayMetrics displayMetrics = Resources.getSystem().getDisplayMetrics();
return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, displayMetrics);
}
@Override
public void setImageDrawable(Drawable drawable) {
mDrawable = drawable;
if (drawable == null) {
return;
}
mBitmap = drawableToBitmap(drawable);
int bDIWidth = mBitmap.getWidth();
int bDIHeight = mBitmap.getHeight();
//Fit to screen.
float scale;
if ((mHeight / (float) bDIHeight) >= (mWidth / (float) bDIWidth)) {
scale = mHeight / (float) bDIHeight;
} else {
scale = mWidth / (float) bDIWidth;
}
float borderLeft = (mWidth - (bDIWidth * scale)) / 2;
float borderTop = (mHeight - (bDIHeight * scale)) / 2;
mMatrix = getImageMatrix();
RectF drawableRect = new RectF(0, 0, bDIWidth, bDIHeight);
RectF viewRect = new RectF(borderLeft, borderTop, (bDIWidth * scale) + borderLeft, (bDIHeight * scale) + borderTop);
mMatrix.setRectToRect(drawableRect, viewRect, Matrix.ScaleToFit.CENTER);
invalidate();
}
private Bitmap drawableToBitmap(Drawable drawable) {
Bitmap bitmap;
if (drawable instanceof BitmapDrawable) {
BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
if (bitmapDrawable.getBitmap() != null) {
return bitmapDrawable.getBitmap();
}
}
if (drawable.getIntrinsicWidth() <= 0 || drawable.getIntrinsicHeight() <= 0) {
bitmap = Bitmap.createBitmap(1, 1, Bitmap.Config.ARGB_8888); // Single color bitmap will be created of 1x1 pixel
} else {
bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
}
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
drawable.draw(canvas);
return bitmap;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
mWidth = MeasureSpec.getSize(widthMeasureSpec);
mHeight = MeasureSpec.getSize(heightMeasureSpec);
if ((mDrawable != null) && (mHeight > 0) && (mWidth > 0)) {
setImageDrawable(mDrawable);
}
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (mBitmap == null) {
return;
}
canvas.drawColor(Color.TRANSPARENT);
mPath.reset();
mPath.moveTo(0, mRadius);
mPath.lineTo(0, canvas.getHeight());
mPath.lineTo(canvas.getWidth(), canvas.getHeight());
mPath.lineTo(canvas.getWidth(), mRadius);
mPath.quadTo(canvas.getWidth(), 0, canvas.getWidth() - mRadius, 0);
mPath.lineTo(mRadius, 0);
mPath.quadTo(0, 0, 0, mRadius);
canvas.drawPath(mPath, mPaint);
canvas.clipPath(mPath);
canvas.drawBitmap(mBitmap, mMatrix, mPaint);
}
}
And in layout.xml
<com.example.widget.RoundedImageViewmageView
android:id="@+id/ivProductImg"
android:layout_width="match_parent"
android:layout_height="150dp"
android:scaleType="fitXY"
/>
回答8:
Sometimes using Glide instead of Picasso for loading images also helps.
回答9:
i try to using combination with cardview and imageview, so it will be like this :
android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="160dp"
android:layout_marginStart="16dp"
android:layout_marginLeft="16dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="16dp"
android:layout_marginRight="16dp"
app:cardCornerRadius="8dp"
android:elevation="10dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/kmp_warna1"
android:scaleType="centerCrop"/>
</android.support.v7.widget.CardView>
I just adding the corner radius and elevation attribute on cardview, and scaletype = centerCrop on image view
Hope it will help
来源：https://stackoverflow.com/questions/27394300/make-imageview-fit-width-of-cardview