ImageGetter 显示 Html 中的图片_html/css_WEB-ITnose

ImageGetter

在 TextView 中显示 html ，需要使用 ImageGetter 解析标签。ImageGetter 是一个接口，需要实现里面的方法。

public DrawablegetDrawable(String source);

简单的 ImageGetter 实现

创建一个 Drawable 对象，保留引用并返回，异步请求网络，获取图片，获取到图片后，转换为 Bitmap ，交给 Drawable 对象进行绘制。– 自定义 Drawable 对象

static class MyDrawable extends BitmapDrawable{    BitmapmBitmap;     public MyDrawable()    {      super();    }     @Override    public void draw(Canvascanvas)    {      super.draw(canvas);      if(mBitmap != null)      {        canvas.drawBitmap(mBitmap,0,0,getPaint());      }    }     public void setBitmap(Bitmapbitmap)    {      mBitmap = bitmap;    }}

• 实现 getDrawable() 方法

  MyImageGetter 有一个 TextView 成员，用于保存用于图片显示的 TextView ，加载完成后，调用 TextView 的 invalidate() 方法刷新视图。

public MyImageGetter(TextViewview){  mContainer = view;}  @Overridepublic DrawablegetDrawable(String s){  // 初始化占位 Drawable  final MyDrawabledrawable = new MyDrawable();   // 初始化请求对象  LocalHostModelmodel = new LocalHostModel();   // 设置回调函数  model.setImageListener(new LocalHostModel.OnRequestImageListener()  {    @Override    public void onSuccess(Bitmapbitmap)    {      // 处理 bitmap 刷新视图      drawable.setBitmap(bitmap);       int height = bitmap.getHeight();      int width = bitmap.getWidth();       drawable.setBounds(0, 0, width, height);       mContainer.invalidate();    }     @Override    public void onFailed(String msg)    {      Log.i(TAG, "onFailed: " + msg);    }  });   // 请求图片  model.requestImage(s);   return drawable;}

图片的显示

• Drawable.setBounds(Rect) 方法

  The setBounds(Rect) method must be called to tell the Drawable where it is drawn and how large it should be. All Drawables should respect the requested size, often simply by scaling their imagery. A client can find the preferred size for some Drawables with the getIntrinsicHeight() and getIntrinsicWidth() methods.

  Drawable.setBounds(Rect) 用于设置绘图的位置，和绘图的区域。

• Canvas.drawBitmap()bitmap 要通过 Drawable.draw(Canvas) 函数绘制，可以通过 Canvas.drawBitmap() 控制 bitmap 在Drawable 中的显示位置。

• 控制图片居中显示
• 首先获取 TextView 的宽度，减去 paddingLeft paddingRight 即为 Drawable 可用的显示宽度；
• 通过上面的两个方法配合，控制图片居中显示。

private void handleBitmap(MyDrawabledrawable, BitmapsrcBitmap){  // 获取原 bitmap 的大小  int srcHeight = srcBitmap.getHeight();  int srcWidth = srcBitmap.getWidth();   // drawable 可用的显示宽度  int containerPadding = mContainer.getPaddingLeft() + mContainer.getPaddingRight();  int drawableWidth = mContainer.getMeasuredWidth() - containerPadding;  int dstWidth = drawableWidth - mPadding * 2;   // 图片较小，不缩放  if (dstWidth >= srcWidth)  {    drawable.setBitmap(srcBitmap);     // 设置 drawable 区域    int drawableHeight = srcHeight + 2 * mPadding;    drawable.setBounds(0, 0, drawableWidth, drawableHeight);     // 设置 bitmap 绘制区域    int left = (drawableWidth - srcWidth) / 2;    int top = mPadding;    Rectrect = new Rect(left, top, left + srcWidth, top + srcHeight);    drawable.setDstRect(rect);   } else  {    // 图片缩放矩阵    Matrixmatrix = new Matrix();    float scale = (float) dstWidth / srcWidth;    matrix.postScale(scale, scale);     // 转换 bitmap 为适合 drawable 的大小    BitmapdstBitmap = Bitmap.createBitmap(srcBitmap, 0, 0, srcWidth, srcHeight, matrix, false);    drawable.setBitmap(dstBitmap);     // 设置 drawable 区域    int dstHeight = srcHeight * drawableWidth / srcWidth;    int drawableHeight = dstHeight + 2 * mPadding;    drawable.setBounds(0, 0, drawableWidth, drawableHeight);     // 设置 bitmap 绘制区域    int left = mPadding;    int top = mPadding;    Rectrect = new Rect(left, top, left + dstWidth, top + dstHeight);    drawable.setDstRect(rect);  }}static class MyDrawable extends BitmapDrawable{  BitmapmBitmap;  RectmSrcRect;  RectmDstRect;   public MyDrawable(Resourcesres, Bitmapbitmap)  {    super(res, bitmap);  }   public void setSrcRect(RectsrcRect)  {    mSrcRect = srcRect;  }   public void setDstRect(RectdstRect)  {    mDstRect = dstRect;  }   @Override  public void draw(Canvascanvas)  {    super.draw(canvas);     // 绘制 bitmap    if (mBitmap != null)    {      if (mSrcRect != null && mDstRect != null)      {        canvas.drawBitmap(mBitmap, mSrcRect, mDstRect, getPaint());      } else if (mDstRect != null)      {        int width = mBitmap.getWidth();        int height = mBitmap.getHeight();         RectsrcRect = new Rect(0, 0, width, height);        canvas.drawBitmap(mBitmap, srcRect, mDstRect, getPaint());      } else      {        canvas.drawBitmap(mBitmap, 0, 0, getPaint());      }    }  }   public void setBitmap(Bitmapbitmap)  {    mBitmap = bitmap;  }}

参考链接

• Drawable