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

如果你正在使用格莱德图书馆,这将是有帮助的:

Glide.with(getApplicationContext())
     .load(image_url)
     .asBitmap()
     .centerCrop()
     .into(new BitmapImageViewTarget(imageView) {
        @Override
        protected void setResource(Bitmap resource) {
          RoundedBitmapDrawable circularBitmapDrawable =
                       RoundedBitmapDrawableFactory.create(getApplicationContext().getResources(), resource);
          circularBitmapDrawable.setCornerRadius(dpToPx(10));
          circularBitmapDrawable.setAntiAlias(true);
          imageView.setImageDrawable(circularBitmapDrawable);
        }
     });


public int dpToPx(int dp) {
  DisplayMetrics displayMetrics = getApplicationContext().getResources().getDisplayMetrics();
  return Math.round(dp * (displayMetrics.xdpi / DisplayMetrics.DENSITY_DEFAULT));
}

其他回答

您应该扩展ImageView并绘制自己的圆角矩形。

如果你想在图像周围添加一个框架,你也可以在布局中将圆形框架叠加在图像视图的顶部。

例如,通过使用FrameLayout将帧叠加到原始图像上。FrameLayout的第一个元素将是你想要显示的图像。然后添加另一个ImageView与框架。第二个ImageView将显示在原始ImageView的顶部,因此Android将在原始ImageView上方绘制它的内容。

使用这个得到圆形图像与边界

    public static Bitmap getCircularBitmapWithBorder(Bitmap bitmap, int bordercolor) {
    if (bitmap == null || bitmap.isRecycled()) {
        return null;
    }
    int borderWidth=(int)(bitmap.getWidth()/40);
    final int width = bitmap.getWidth() + borderWidth;
    final int height = bitmap.getHeight() + borderWidth;

    Bitmap canvasBitmap = Bitmap.createBitmap(width, height,
            Bitmap.Config.ARGB_8888);
    BitmapShader shader = new BitmapShader(bitmap, TileMode.CLAMP,
            TileMode.CLAMP);
    Paint paint = new Paint();
    paint.setAntiAlias(true);
    paint.setShader(shader);

    Canvas canvas = new Canvas(canvasBitmap);
    float radius = width > height ? ((float) height) / 2f
            : ((float) width) / 2f;
    canvas.drawCircle(width / 2, height / 2, radius, paint);
    paint.setShader(null);
    paint.setStyle(Paint.Style.STROKE);
    paint.setColor(bordercolor);
    paint.setStrokeWidth(borderWidth);
    canvas.drawCircle(width / 2, height / 2, radius - borderWidth / 2,
            paint);
    return canvasBitmap;
}

如果你不希望边框影响图像,使用这个类。不幸的是,我没有找到任何方法来绘制画布上的透明区域来到onDraw()。这里创建了一个新的位图它是画在一个真实的画布上的。

如果您想要创建一个消失的边界,该视图非常有用。如果你将borderWidth设置为0,边框将会消失,图像仍然保持圆角,就像边界一样。也就是说,它看起来就像边界完全由图像边缘绘制。

import android.annotation.SuppressLint
import android.content.Context
import android.graphics.Bitmap
import android.graphics.Canvas
import android.graphics.Color
import android.graphics.Paint
import android.graphics.PorterDuff
import android.graphics.PorterDuffXfermode
import android.graphics.RectF
import android.util.AttributeSet
import androidx.appcompat.widget.AppCompatImageView


class RoundedImageViewWithBorder @JvmOverloads constructor(
        context: Context,
        attrs: AttributeSet? = null,
        defStyleAttr: Int = 0) : AppCompatImageView(context, attrs, defStyleAttr) {

    var borderColor: Int = 0
        set(value) {
            invalidate()
            field = value
        }
    var borderWidth: Int = 0
        set(value) {
            invalidate()
            field = value
        }
    var cornerRadius: Float = 0f
        set(value) {
            invalidate()
            field = value
        }

    private var bitmapForDraw: Bitmap? = null
    private var canvasForDraw: Canvas? = null
    private val transparentPaint = Paint().apply {
        isAntiAlias = true
        color = Color.TRANSPARENT
        style = Paint.Style.STROKE
        xfermode = PorterDuffXfermode(PorterDuff.Mode.SRC)
    }

    private val borderPaint = Paint().apply {
        isAntiAlias = true
        style = Paint.Style.STROKE
    }

    private val transparentAreaRect = RectF()
    private val borderRect = RectF()

    init {
        val typedArray = context.obtainStyledAttributes(attrs, R.styleable.RoundedImageViewWithBorder)

        try {
            borderWidth = typedArray.getDimensionPixelSize(R.styleable.RoundedImageViewWithBorder_border_width, 0)
            borderColor = typedArray.getColor(R.styleable.RoundedImageViewWithBorder_border_color, 0)
            cornerRadius = typedArray.getDimensionPixelSize(R.styleable.RoundedImageViewWithBorder_corner_radius, 0).toFloat()

        } finally {
            typedArray.recycle()
        }
    }

    @SuppressLint("CanvasSize", "DrawAllocation")
    override fun onDraw(canvas: Canvas) {
        if (canvas.height <=0 || canvas.width <=0) {
            return
        }

        if (canvasForDraw?.height != canvas.height || canvasForDraw?.width != canvas.width) {
            val newBitmap = Bitmap.createBitmap(canvas.width, canvas.height, Bitmap.Config.ARGB_8888)
            bitmapForDraw = newBitmap
            canvasForDraw = Canvas(newBitmap)
        }
        
        bitmapForDraw?.eraseColor(Color.TRANSPARENT)

        // Draw existing content
        super.onDraw(canvasForDraw)

        if (borderWidth > 0) {
            canvasForDraw?.let { drawWithBorder(it) }
        } else {
            canvasForDraw?.let { drawWithoutBorder(it) }
        }

        // Draw everything on real canvas
        bitmapForDraw?.let { canvas.drawBitmap(it, 0f, 0f, null) }
    }

    private fun drawWithBorder(canvas: Canvas) {
        // Draw transparent area
        transparentPaint.strokeWidth = borderWidth.toFloat() * 4
        transparentAreaRect.apply {
            left = -borderWidth.toFloat() * 1.5f
            top = -borderWidth.toFloat() * 1.5f
            right = canvas.width.toFloat() + borderWidth.toFloat() * 1.5f
            bottom = canvas.height.toFloat() + borderWidth.toFloat() * 1.5f
        }
        canvasForDraw?.drawRoundRect(transparentAreaRect, borderWidth.toFloat() * 2 + cornerRadius, borderWidth.toFloat() * 2 + cornerRadius, transparentPaint)

        // Draw border
        borderPaint.color = borderColor
        borderPaint.strokeWidth = borderWidth.toFloat()
        borderRect.apply {
            left = borderWidth.toFloat() / 2
            top = borderWidth.toFloat() / 2
            right = canvas.width.toFloat() - borderWidth.toFloat() / 2
            bottom = canvas.height.toFloat() - borderWidth.toFloat() / 2
        }
        canvas.drawRoundRect(borderRect, cornerRadius - borderWidth.toFloat() / 2, cornerRadius - borderWidth.toFloat() / 2, borderPaint)
    }

    private fun drawWithoutBorder(canvas: Canvas) {
        // Draw transparent area
        transparentPaint.strokeWidth = cornerRadius * 4
        transparentAreaRect.apply {
            left = -cornerRadius * 2
            top = -cornerRadius * 2
            right = canvas.width.toFloat() + cornerRadius * 2
            bottom = canvas.height.toFloat() + cornerRadius * 2
        }
        canvasForDraw?.drawRoundRect(transparentAreaRect, cornerRadius * 3, cornerRadius * 3, transparentPaint)
    }

}

值:

<declare-styleable name="RoundedImageViewWithBorder">
    <attr name="corner_radius" format="dimension|string" />
    <attr name="border_width" format="dimension|reference" />
    <attr name="border_color" format="color|reference" />
</declare-styleable>

我的ImageView圆角小部件的实现,(下||上)大小图像到所需的尺寸。它利用了CaspNZ的代码形式。

public class ImageViewRounded extends ImageView {

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

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

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

    @Override
    protected void onDraw(Canvas canvas) {
        BitmapDrawable drawable = (BitmapDrawable) getDrawable();

        if (drawable == null) {
            return;
        }

        if (getWidth() == 0 || getHeight() == 0) {
            return; 
        }

        Bitmap fullSizeBitmap = drawable.getBitmap();

        int scaledWidth = getMeasuredWidth();
        int scaledHeight = getMeasuredHeight();

        Bitmap mScaledBitmap;
        if (scaledWidth == fullSizeBitmap.getWidth() && scaledHeight == fullSizeBitmap.getHeight()) {
            mScaledBitmap = fullSizeBitmap;
        } else {
            mScaledBitmap = Bitmap.createScaledBitmap(fullSizeBitmap, scaledWidth, scaledHeight, true /* filter */);
        }

        Bitmap roundBitmap = ImageUtilities.getRoundedCornerBitmap(getContext(), mScaledBitmap, 5, scaledWidth, scaledHeight,
                false, false, false, false);
        canvas.drawBitmap(roundBitmap, 0, 0, null);

    }

}

如果你们中有人面临这个问题

大多数情况下,你使用的是Android Studio。由于图像大小的调整和所有在Android工作室,你可能会遇到这个问题。解决这个问题的一个简单方法是减小drawCircle()中的圆的半径。在我的情况下,我使用这个修复

使用画布。drawCircle(100,100,90, paint);而不是帆布。drawCircle(100,100,100, paint);这绝对能解决你的问题。

下面是最终编辑的代码:-

  public class Profile extends ActionBarActivity {


    TextView username;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.profile);


        username= (TextView) findViewById(R.id.txt);

        String recievedusername=getIntent().getExtras().getString("toname");
        username.setText(recievedusername);


        Bitmap bm = BitmapFactory.decodeResource(getResources(),
                R.mipmap.gomez);

        Bitmap resizedBitmap = Bitmap.createScaledBitmap(bm, 200,200, false);
        Bitmap conv_bm=getCircleBitmap(resizedBitmap,100);
        // set circle bitmap
        ImageView mImage = (ImageView) findViewById(R.id.profile_image);
        mImage.setImageBitmap(conv_bm);
        // TODO Auto-generated method stub
    }
    private Bitmap getCircleBitmap(Bitmap bitmap , int pixels) {
        final Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
                bitmap.getHeight(), Bitmap.Config.ARGB_8888);
        final Canvas canvas = new Canvas(output);
        final int color = 0xff424242;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, bitmap.getWidth(),bitmap.getHeight());
        final RectF rectF = new RectF(rect);
        paint.setAntiAlias(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(color);
        canvas.drawCircle(100,100, 90, paint);
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(bitmap, rect, rect, paint);
        bitmap.recycle();
        return output;
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu_apploud, menu);
        return super.onCreateOptionsMenu(menu);
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        //noinspection SimplifiableIfStatement
        if (id == R.id.action_addnew) {
            Intent i;
            i=new Intent(Profile.this,ApplaudSomeone.class);
            startActivity(i);
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}