android中 怎么显示一直图片为圆形图片

Posted

tags:

篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了android中 怎么显示一直图片为圆形图片相关的知识,希望对你有一定的参考价值。

比如自己拍摄了一张图片,然后显示在android,但是显示的方式是圆形的 这个是怎么实现的
我上传一个效果图,登录界面的 头像 就是我现在所描述的需求
这个头像图片就是圆形的,那这个在android是怎么实现的

android中的imageview只能显示矩形的图片,这样一来不能满足我们其他的需求,比如要显示圆形的图片,这个时候,我们就需要自定义imageview了,其原理就是首先获取到图片的bitmap,然后进行裁剪圆形的bitmap,然后在ondraw()进行绘制圆形图片输出。 参考技术A 这个跟图片没关系,是你在android系统上设置的图标显示效果..android设置里的个性化窗口.很多外软件也可以设置样式. 参考技术B 这个貌似是应用程序功能导致的,你自己的照片是不能搞成圆形的。 参考技术C 自定义一个圆形的ImageView,然后在Xml里应用这个view,把图片放进去,就能有圆形效果了。

public class XCRoundImageView extends ImageView

private Paint paint ; public XCRoundImageView(Context context) this(context,null);


public XCRoundImageView(Context context, AttributeSet attrs)

this(context, attrs,0);


public XCRoundImageView(Context context, AttributeSet attrs, int defStyle)

super(context, attrs, defStyle);
paint = new Paint();

/** * 绘制圆形图片
* @author caizhiming */ @Override protected void onDraw(Canvas canvas)

Drawable drawable = getDrawable(); if (null != drawable)
Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();
Bitmap b = getCircleBitmap(bitmap, 14); final Rect rectSrc = new Rect(0, 0, b.getWidth(), b.getHeight()); final Rect rectDest = new Rect(0,0,getWidth(),getHeight());
paint.reset();
canvas.drawBitmap(b, rectSrc, rectDest, paint);

else super.onDraw(canvas);

/** * 获取圆形图片方法
* @param bitmap
* @param pixels
* @return Bitmap
* @author caizhiming */ private Bitmap getCircleBitmap(Bitmap bitmap, int pixels)
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
bitmap.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output); final int color = 0xff424242; final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color); int x = bitmap.getWidth();

canvas.drawCircle(x / 2, x / 2, x / 2, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint); return output;

本回答被提问者采纳
参考技术D   
  将图片变为圆形图片,可以将系统ImageView替换成如下自定义 的view RoundImageView :

  /**
  * 圆形ImageView,可设置最多两个宽度不同且颜色不同的圆形边框。
  *
  * @author Alan
  */
  public class RoundImageView extends ImageView
  private int mBorderThickness = 0;
  private Context mContext;
  private int defaultColor = 0xFFFFFFFF;
  // 如果只有其中一个有值,则只画一个圆形边框
  private int mBorderOutsideColor = 0;
  private int mBorderInsideColor = 0;
  // 控件默认长、宽
  private int defaultWidth = 0;
  private int defaultHeight = 0;
  
  public RoundImageView(Context context)
  super(context);
  mContext = context;
  
  
  public RoundImageView(Context context, AttributeSet attrs)
  super(context, attrs);
  mContext = context;
  setCustomAttributes(attrs);
  
  
  public RoundImageView(Context context, AttributeSet attrs, int defStyle)
  super(context, attrs, defStyle);
  mContext = context;
  setCustomAttributes(attrs);
  
  
  private void setCustomAttributes(AttributeSet attrs)
  TypedArray a = mContext.obtainStyledAttributes(attrs,
  R.styleable.roundedimageview);
  mBorderThickness = a.getDimensionPixelSize(
  R.styleable.roundedimageview_border_thickness, 0);
  mBorderOutsideColor = a
  .getColor(R.styleable.roundedimageview_border_outside_color,
  defaultColor);
  mBorderInsideColor = a.getColor(
  R.styleable.roundedimageview_border_inside_color, defaultColor);
  
  
  @Override
  protected void onDraw(Canvas canvas)
  Drawable drawable = getDrawable();
  if (drawable == null)
  return;
  
  
  if (getWidth() == 0 || getHeight() == 0)
  return;
  
  this.measure(0, 0);
  if (drawable.getClass() == NinePatchDrawable.class)
  return;
  Bitmap b = ((BitmapDrawable) drawable).getBitmap();
  Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);
  if (defaultWidth == 0)
  defaultWidth = getWidth();
  
  
  if (defaultHeight == 0)
  defaultHeight = getHeight();
  
  // 保证重新读取图片后不会因为图片大小而改变控件宽、高的大小(针对宽、高为wrap_content布局的imageview,但会导致margin无效)
  // if (defaultWidth != 0 && defaultHeight != 0)
  // LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(
  // defaultWidth, defaultHeight);
  // setLayoutParams(params);
  //
  int radius = 0;
  if (mBorderInsideColor != defaultColor
  && mBorderOutsideColor != defaultColor) // 定义画两个边框,分别为外圆边框和内圆边框
  radius = (defaultWidth < defaultHeight ? defaultWidth
  : defaultHeight) / 2 - 2 * mBorderThickness;
  // 画内圆
  drawCircleBorder(canvas, radius + mBorderThickness / 2,
  mBorderInsideColor);
  // 画外圆
  drawCircleBorder(canvas, radius + mBorderThickness
  + mBorderThickness / 2, mBorderOutsideColor);
   else if (mBorderInsideColor != defaultColor
  && mBorderOutsideColor == defaultColor) // 定义画一个边框
  radius = (defaultWidth < defaultHeight ? defaultWidth
  : defaultHeight) / 2 - mBorderThickness;
  drawCircleBorder(canvas, radius + mBorderThickness / 2,
  mBorderInsideColor);
   else if (mBorderInsideColor == defaultColor
  && mBorderOutsideColor != defaultColor) // 定义画一个边框
  radius = (defaultWidth < defaultHeight ? defaultWidth
  : defaultHeight) / 2 - mBorderThickness;
  drawCircleBorder(canvas, radius + mBorderThickness / 2,
  mBorderOutsideColor);
   else // 没有边框
  radius = (defaultWidth < defaultHeight ? defaultWidth
  : defaultHeight) / 2;
  
  Bitmap roundBitmap = getCroppedRoundBitmap(bitmap, radius);
  canvas.drawBitmap(roundBitmap, defaultWidth / 2 - radius, defaultHeight
  / 2 - radius, null);
  
  
  /**
  * 获取裁剪后的圆形图片
  *
  * @param radius
  * 半径
  */
  public Bitmap getCroppedRoundBitmap(Bitmap bmp, int radius)
  Bitmap scaledSrcBmp;
  int diameter = radius * 2;
  
  // 为了防止宽高不相等,造成圆形图片变形,因此截取长方形中处于中间位置最大的正方形图片
  int bmpWidth = bmp.getWidth();
  int bmpHeight = bmp.getHeight();
  int squareWidth = 0, squareHeight = 0;
  int x = 0, y = 0;
  Bitmap squareBitmap;
  if (bmpHeight > bmpWidth) // 高大于宽
  squareWidth = squareHeight = bmpWidth;
  x = 0;
  y = (bmpHeight - bmpWidth) / 2;
  // 截取正方形图片
  squareBitmap = Bitmap.createBitmap(bmp, x, y, squareWidth,
  squareHeight);
   else if (bmpHeight < bmpWidth) // 宽大于高
  squareWidth = squareHeight = bmpHeight;
  x = (bmpWidth - bmpHeight) / 2;
  y = 0;
  squareBitmap = Bitmap.createBitmap(bmp, x, y, squareWidth,
  squareHeight);
   else
  squareBitmap = bmp;
  
  
  if (squareBitmap.getWidth() != diameter
  || squareBitmap.getHeight() != diameter)
  scaledSrcBmp = Bitmap.createScaledBitmap(squareBitmap, diameter,
  diameter, true);
  
   else
  scaledSrcBmp = squareBitmap;
  
  Bitmap output = Bitmap.createBitmap(scaledSrcBmp.getWidth(),
  scaledSrcBmp.getHeight(), Config.ARGB_8888);
  Canvas canvas = new Canvas(output);
  
  Paint paint = new Paint();
  Rect rect = new Rect(0, 0, scaledSrcBmp.getWidth(),
  scaledSrcBmp.getHeight());
  
  paint.setAntiAlias(true);
  paint.setFilterBitmap(true);
  paint.setDither(true);
  canvas.drawARGB(0, 0, 0, 0);
  canvas.drawCircle(scaledSrcBmp.getWidth() / 2,
  scaledSrcBmp.getHeight() / 2, scaledSrcBmp.getWidth() / 2,
  paint);
  paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
  canvas.drawBitmap(scaledSrcBmp, rect, rect, paint);
  // bitmap回收(recycle导致在布局文件XML看不到效果)
  // bmp.recycle();
  // squareBitmap.recycle();
  // scaledSrcBmp.recycle();
  bmp = null;
  squareBitmap = null;
  scaledSrcBmp = null;
  return output;
  
  
  /**
  * 边缘画圆
  */
  private void drawCircleBorder(Canvas canvas, int radius, int color)
  Paint paint = new Paint();
  /* 去锯齿 */
  paint.setAntiAlias(true);
  paint.setFilterBitmap(true);
  paint.setDither(true);
  paint.setColor(color);
  /* 设置paint的 style 为STROKE:空心 */
  paint.setStyle(Paint.Style.STROKE);
  /* 设置paint的外框宽度 */
  paint.setStrokeWidth(mBorderThickness);
  canvas.drawCircle(defaultWidth / 2, defaultHeight / 2, radius, paint);
  
  
  

以上是关于android中 怎么显示一直图片为圆形图片的主要内容,如果未能解决你的问题,请参考以下文章

android圆形头像怎么实现

Android实现本地上传图片并设置为圆形头像

[Android] 给图像加入相框圆形圆角显示图片图像合成知识

Android自定义ImageView实现图片圆形 ,椭圆和矩形圆角显示

Glide加载圆形图片第一次只显示默认图片

如何制作一款圆形的vb按钮?