在Android中,ImageView默认是一个矩形。如何使它成为一个圆角矩形(剪辑我的位图的所有4个角为圆角矩形)在ImageView?


请注意,从2021年起,只需使用ShapeableImageView


当前回答

让你的ImageView像这样:

<com.example..CircularImageView
    android:id="@+id/profile_image_round_corner"
    android:layout_width="80dp"
    android:layout_height="80dp"
    android:scaleType="fitCenter"
    android:padding="2dp"
    android:background="@null"
    android:adjustViewBounds="true"
    android:layout_centerInParent="true"
    android:src="@drawable/dummy"
    />

并创建一个类:

package com.example;

import java.util.Formatter.BigDecimalLayoutForm;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.widget.ImageView;

public class CircularImageView extends ImageView {

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

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

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

    @Override
    protected void onDraw(Canvas canvas) {

        Drawable drawable = getDrawable();

        if (drawable == null) {
            return;
        }

        if (getWidth() == 0 || getHeight() == 0) {
            return;
        }
        Bitmap b = ((BitmapDrawable) drawable).getBitmap();
        Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);

        int w = getWidth(), h = getHeight();

        Bitmap roundBitmap = getRoundBitmap(bitmap, w);
        canvas.drawBitmap(roundBitmap, 0, 0, null);

    }

    public static Bitmap getRoundBitmap(Bitmap bmp, int radius) {
        Bitmap sBmp;

        if (bmp.getWidth() != radius || bmp.getHeight() != radius) {
            float smallest = Math.min(bmp.getWidth(), bmp.getHeight());
            float factor = smallest / radius;
            sBmp = Bitmap.createScaledBitmap(bmp, (int)(bmp.getWidth() / factor), (int)(bmp.getHeight() / factor), false);
        } else {
            sBmp = bmp;
        }

        Bitmap output = Bitmap.createBitmap(radius, radius, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(output);
        final int color = 0xffa19774;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, radius, radius);
        paint.setAntiAlias(true);
        paint.setFilterBitmap(true);
        paint.setDither(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(Color.parseColor("#BAB399"));
        canvas.drawCircle(radius / 2 + 0.7f,
                radius / 2 + 0.7f, radius / 2 + 0.1f, paint);
        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
        canvas.drawBitmap(sBmp, rect, rect, paint);

        return output;
    }

}

其他回答

为什么不在draw()中进行剪辑?

以下是我的解决方案:

用剪切扩展RelativeLayout 将ImageView(或其他视图)放入布局中:

代码:

public class RoundRelativeLayout extends RelativeLayout {

    private final float radius;

    public RoundRelativeLayout(Context context, AttributeSet attrs) {
        super(context, attrs);

        TypedArray attrArray = context.obtainStyledAttributes(attrs,
                R.styleable.RoundRelativeLayout);
        radius = attrArray.getDimension(
                R.styleable.RoundRelativeLayout_radius, 0);
    }

    private boolean isPathValid;
    private final Path path = new Path();

    private Path getRoundRectPath() {
        if (isPathValid) {
            return path;
        }

        path.reset();

        int width = getWidth();
        int height = getHeight();
        RectF bounds = new RectF(0, 0, width, height);

        path.addRoundRect(bounds, radius, radius, Direction.CCW);
        isPathValid = true;
        return path;
    }

    @Override
    protected void dispatchDraw(Canvas canvas) {
        canvas.clipPath(getRoundRectPath());
        super.dispatchDraw(canvas);
    }

    @Override
    public void draw(Canvas canvas) {
        canvas.clipPath(getRoundRectPath());
        super.draw(canvas);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

        int oldWidth = getMeasuredWidth();
        int oldHeight = getMeasuredHeight();
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        int newWidth = getMeasuredWidth();
        int newHeight = getMeasuredHeight();
        if (newWidth != oldWidth || newHeight != oldHeight) {
            isPathValid = false;
        }
    }

}

下面的代码创建一个圆角矩形布局对象,该对象围绕放置在其中的任何子对象绘制圆角矩形。它还演示了如何在不使用布局xml文件的情况下以编程方式创建视图和布局。

package android.example;

import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.TypedValue;
import android.view.ViewGroup.LayoutParams;
import android.widget.LinearLayout;
import android.widget.TextView;

public class MessageScreen extends Activity {
 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  int mainBackgroundColor = Color.parseColor("#2E8B57");
  int labelTextColor = Color.parseColor("#FF4500");
  int messageBackgroundColor = Color.parseColor("#3300FF");
  int messageTextColor = Color.parseColor("#FFFF00");

  DisplayMetrics metrics = new DisplayMetrics();
  getWindowManager().getDefaultDisplay().getMetrics(metrics);
  float density = metrics.density;
  int minMarginSize = Math.round(density * 8);
  int paddingSize = minMarginSize * 2;
  int maxMarginSize = minMarginSize * 4;

  TextView label = new TextView(this);
  /*
   * The LayoutParams are instructions to the Layout that will contain the
   * View for laying out the View, so you need to use the LayoutParams of
   * the Layout that will contain the View.
   */
  LinearLayout.LayoutParams labelLayoutParams = new LinearLayout.LayoutParams(
    LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
  label.setLayoutParams(labelLayoutParams);
  label.setTextSize(TypedValue.COMPLEX_UNIT_SP, 18);
  label.setPadding(paddingSize, paddingSize, paddingSize, paddingSize);
  label.setText(R.string.title);
  label.setTextColor(labelTextColor);

  TextView message = new TextView(this);
  RoundedRectangle.LayoutParams messageLayoutParams = new RoundedRectangle.LayoutParams(
 LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
  /*
   * This is one of the calls must made to force a ViewGroup to call its
   * draw method instead of just calling the draw method of its children.
   * This tells the RoundedRectangle to put some extra space around the
   * View.
   */
  messageLayoutParams.setMargins(minMarginSize, paddingSize,
    minMarginSize, maxMarginSize);
  message.setLayoutParams(messageLayoutParams);
  message.setTextSize(TypedValue.COMPLEX_UNIT_SP, paddingSize);
  message.setText(R.string.message);
  message.setTextColor(messageTextColor);
  message.setBackgroundColor(messageBackgroundColor);

  RoundedRectangle messageContainer = new RoundedRectangle(this);
  LinearLayout.LayoutParams messageContainerLayoutParams = new LinearLayout.LayoutParams(
    LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
  messageContainerLayoutParams.setMargins(paddingSize, 0, paddingSize, 0);
  messageContainer.setLayoutParams(messageContainerLayoutParams);
  messageContainer.setOrientation(LinearLayout.VERTICAL);
  /*
   * This is one of the calls must made to force a ViewGroup to call its
   * draw method instead of just calling the draw method of its children.
   * This tells the RoundedRectangle to color the the exta space that was
   * put around the View as well as the View. This is exterior color of
   * the RoundedRectangle.
   */
  messageContainer.setBackgroundColor(mainBackgroundColor);
  /*
   * This is one of the calls must made to force a ViewGroup to call its
   * draw method instead of just calling the draw method of its children.
   * This is the interior color of the RoundedRectangle. It must be
   * different than the exterior color of the RoundedRectangle or the
   * RoundedRectangle will not call its draw method.
   */
  messageContainer.setInteriorColor(messageBackgroundColor);
  // Add the message to the RoundedRectangle.
  messageContainer.addView(message);

  //
  LinearLayout main = new LinearLayout(this);
  LinearLayout.LayoutParams mainLayoutParams = new LinearLayout.LayoutParams(
    LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
  main.setLayoutParams(mainLayoutParams);
  main.setOrientation(LinearLayout.VERTICAL);
  main.setBackgroundColor(mainBackgroundColor);
  main.addView(label);
  main.addView(messageContainer);

  setContentView(main);
 }
}

RoundedRectangle布局对象的类定义如下:

/**
 *  A LinearLayout that draws a rounded rectangle around the child View that was added to it.
 */
package android.example;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.widget.LinearLayout;

/**
 * A LinearLayout that has rounded corners instead of square corners.
 * 
 * @author Danny Remington
 * 
 * @see LinearLayout
 * 
 */
public class RoundedRectangle extends LinearLayout {
 private int mInteriorColor;

 public RoundedRectangle(Context p_context) {
  super(p_context);
 }

 public RoundedRectangle(Context p_context, AttributeSet attributeSet) {
  super(p_context, attributeSet);
 }

 // Listener for the onDraw event that occurs when the Layout is drawn.
 protected void onDraw(Canvas canvas) {
  Rect rect = new Rect(0, 0, getWidth(), getHeight());
  RectF rectF = new RectF(rect);
  DisplayMetrics metrics = new DisplayMetrics();
  Activity activity = (Activity) getContext();
  activity.getWindowManager().getDefaultDisplay().getMetrics(metrics);
  float density = metrics.density;
  int arcSize = Math.round(density * 10);

  Paint paint = new Paint();
  paint.setColor(mInteriorColor);

  canvas.drawRoundRect(rectF, arcSize, arcSize, paint);
 }

 /**
  * Set the background color to use inside the RoundedRectangle.
  * 
  * @param Primitive int - The color inside the rounded rectangle.
  */
 public void setInteriorColor(int interiorColor) {
  mInteriorColor = interiorColor;
 }

 /**
  * Get the background color used inside the RoundedRectangle.
  * 
  * @return Primitive int - The color inside the rounded rectangle.
  */
 public int getInteriorColor() {
  return mInteriorColor;
 }

}

一个快速的xml解决方案-

<android.support.v7.widget.CardView
            android:layout_width="40dp"
            android:layout_height="40dp"
            app:cardElevation="0dp"
            app:cardCornerRadius="4dp">

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

</android.support.v7.widget.CardView>

你可以在CardView上设置你想要的宽度,高度和半径,在ImageView上设置scaleType。

对于AndroidX,使用< AndroidX .cardview.widget. cardview >

相当多的答案!

我遵循了一些人也建议的这个例子:http://www.techrepublic.com/article/pro-tip-round-corners-on-an-android-imageview-with-this-hack/

然而,我需要的是一个透明图像后面的彩色圆圈。对于任何有兴趣做同样事情的人…

1)设置FrameLayout的宽度和高度-在我的情况下,图像的大小(50dp)。 2)将带有src = "@drawable/…"的ImageView放在带有图像的ImageView之上。给它一个id,在我的例子中,我叫它iconShape 3) Drawable mask.xml应该是纯色的#ffffffff 4)如果你想在你的代码中动态地改变圆圈的颜色,可以这样做

ImageView iv2 = (ImageView) v.findViewById(R.id.iconShape);
Drawable shape = getResources().getDrawable(R.drawable.mask);
shape.setColorFilter(Color.BLUE, Mode.MULTIPLY);
iv2.setImageDrawable(shape);

我认为最简单的解决方法是这样的:-

步骤1 -创建一个形状绘图文件如下所示

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle" >

    <solid android:color="@color/white" />

    <corners android:radius="@dimen/dimen_10dp" />

    <stroke
        android:width="1dp"
        android:color="@color/white" />
</shape>

步骤2 -在代码中使用上述绘图。

Drawable drawable = ContextCompat.getDrawable(mActivity, R.drawable.photos_round_shape);
            drawable.mutate().setColorFilter(randomColor, PorterDuff.Mode.SRC_ATOP);
            imageView.setBackground(drawable);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
               imageView.setClipToOutline(true);
            }

Glide.with(mContext)
                .setDefaultRequestOptions(getNoAnimationOptions())
                .load(url)
                .into(imageView);

希望这能有所帮助。