Android中Glide加载圆形图片和圆角图片实例代码

一、简介：

介绍两种使用 bitmaptransformation 来实现 glide 加载圆形图片和圆角图片的方法。glide 并不能直接支持 round pictures ，需要使用 bitmaptransformation 来进行处理。

二、网上的实现方式

这里介绍下网上常见的方式和使用 roundedbitmapdrawable 两种方法，本质上是差不多的：

1. 使用 canvas 和 paint 来绘制
2. 使用 android.support.v4.graphics.drawable.roundedbitmapdrawable

实现圆形图片：

/**
 * 
 * glide 圆形图片 transform
 */

public class glidecircletransform extends bitmaptransformation {
  public glidecircletransform(context context) {
    super(context);
  }

  @override
  protected bitmap transform(bitmappool pool, bitmap totransform, int outwidth, int outheight) {
    return circlecrop(pool, totransform);
  }

  private static bitmap circlecrop(bitmappool pool, bitmap source) {
    if (source == null) return null;
    int size = math.min(source.getwidth(), source.getheight());
    int x = (source.getwidth() - size) / 2;
    int y = (source.getheight() - size) / 2;
    bitmap squared = bitmap.createbitmap(source, x, y, size, size);
    bitmap result = pool.get(size, size, bitmap.config.argb_8888);
    if (result == null) {
      result = bitmap.createbitmap(size, size, bitmap.config.argb_8888);
    }
    canvas canvas = new canvas(result);
    paint paint = new paint();
    paint.setshader(new bitmapshader(squared, bitmapshader.tilemode.clamp, bitmapshader.tilemode.clamp));
    paint.setantialias(true);
    float r = size / 2f;
    canvas.drawcircle(r, r, r, paint);
    return result;
  }

  @override
  public string getid() {
    return getclass().getname();
  }
}

实现圆角图片：

/**
 * glide 圆角 transform
 */

public class glideroundtransform extends bitmaptransformation {

  private static float radius = 0f;

  /**
 * 构造函数 默认圆角半径 4dp
 *
 * @param context context
 */
  public glideroundtransform(context context) {
    this(context, 4);
  }

  /**
 * 构造函数
 *
 * @param context context
 * @param dp 圆角半径
 */
  public glideroundtransform(context context, int dp) {
    super(context);
    radius = resources.getsystem().getdisplaymetrics().density * dp;
  }

  @override
  protected bitmap transform(bitmappool pool, bitmap totransform, int outwidth, int outheight) {
    return roundcrop(pool, totransform);
  }

  private static bitmap roundcrop(bitmappool pool, bitmap source) {
    if (source == null) return null;

    bitmap result = pool.get(source.getwidth(), source.getheight(), bitmap.config.argb_8888);
    if (result == null) {
      result = bitmap.createbitmap(source.getwidth(), source.getheight(), bitmap.config.argb_8888);
    }

    canvas canvas = new canvas(result);
    paint paint = new paint();
    paint.setshader(new bitmapshader(source, bitmapshader.tilemode.clamp, bitmapshader.tilemode.clamp));
    paint.setantialias(true);
    rectf rectf = new rectf(0f, 0f, source.getwidth(), source.getheight());
    canvas.drawroundrect(rectf, radius, radius, paint);
    return result;
  }

  @override
  public string getid() {
    return getclass().getname() + math.round(radius);
  }
}

三、笔者比较喜欢的简便的实现方式

//加载圆角图片
   public static void loadroundimage(final context context, string url,final imageview imageview){
     glide.with(context)
         .load(url)
         .asbitmap()
         .placeholder(placeholder)
         .error(placeholder)
         .diskcachestrategy(diskcachestrategy.all) //设置缓存
         .into(new bitmapimageviewtarget(imageview){
           @override
           protected void setresource(bitmap resource) {
             super.setresource(resource);
             roundedbitmapdrawable circularbitmapdrawable =
                 roundedbitmapdrawablefactory.create(context.getresources(), resource);
             circularbitmapdrawable.setcornerradius(10); //设置圆角弧度
             imageview.setimagedrawable(circularbitmapdrawable);
           }
         });
   }


  //加载圆形图片
  public static void loadcirclepic(final context context, string url, final imageview imageview) {
    glide.with(context)
        .load(url)
        .asbitmap()
        .placeholder(placeholder)
        .error(placeholder)
        .diskcachestrategy(diskcachestrategy.all) //设置缓存
        .into(new bitmapimageviewtarget(imageview) {
          @override
          protected void setresource(bitmap resource) {
            roundedbitmapdrawable circularbitmapdrawable =
                roundedbitmapdrawablefactory.create(context.getresources(), resource);
            circularbitmapdrawable.setcircular(true);
            imageview.setimagedrawable(circularbitmapdrawable);
          }
        });

  }

关于drawabletobitmap的源码的实现是这样的

public static bitmap drawabletobitmap(drawable drawable) {
    // 取 drawable 的长宽
    int w = drawable.getintrinsicwidth();
    int h = drawable.getintrinsicheight();

    // 取 drawable 的颜色格式
    bitmap.config config = drawable.getopacity() != pixelformat.opaque ? bitmap.config.argb_8888
        : bitmap.config.rgb_565;
    // 建立对应 bitmap
    bitmap bitmap = bitmap.createbitmap(w, h, config);
    // 建立对应 bitmap 的画布
    canvas canvas = new canvas(bitmap);
    drawable.setbounds(0, 0, w, h);
    // 把 drawable 内容画到画布中
    drawable.draw(canvas);
    return bitmap;
  }
/**
 * roundedbitmapdrawable 是 v4 下的一个类，不能简单的通过：强制转换成 bitmapdrawable
 * bitmap bitmap = ((bitmapdrawable)xxx).getbitmap();
 */

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。