我使用以下代码在我的项目中创建圆形图像视图。
public class CircularImageView extends ImageView {
// Border & Selector configuration variables
private boolean hasBorder;
private boolean hasSelector;
private boolean isSelected;
private int borderWidth;
private int canvasSize;
private int selectorStrokeWidth;
// Objects used for the actual drawing
private BitmapShader shader;
private Bitmap image;
private Paint paint;
private Paint paintBorder;
private Paint paintSelectorBorder;
private ColorFilter selectorFilter;
public CircularImageView(Context context) {
this(context, null);
}
public CircularImageView(Context context, AttributeSet attrs)
{
this(context, attrs, R.attr.circularImageViewStyle);
}
public CircularImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init(context, attrs, defStyle);
}
/**
* Initializes paint objects and sets desired attributes.
*
* @param context
* @param attrs
* @param defStyle
*/
private void init(Context context, AttributeSet attrs, int defStyle) {
// Initialize paint objects
paint = new Paint();
paint.setAntiAlias(true);
paintBorder = new Paint();
paintBorder.setAntiAlias(true);
paintSelectorBorder = new Paint();
paintSelectorBorder.setAntiAlias(true);
// load the styled attributes and set their properties
TypedArray attributes = context.obtainStyledAttributes(attrs, R.styleable.CircularImageView, defStyle, 0);
// Check if border and/or border is enabled
hasBorder = attributes.getBoolean(R.styleable.CircularImageView_border, false);
hasSelector = attributes.getBoolean(R.styleable.CircularImageView_selector, false);
// Set border properties if enabled
if(hasBorder) {
int defaultBorderSize = (int) (2 * context.getResources().getDisplayMetrics().density + 0.5f);
setBorderWidth(attributes.getDimensionPixelOffset(R.styleable.CircularImageView_border_width, defaultBorderSize));
setBorderColor(attributes.getColor(R.styleable.CircularImageView_border_color, Color.WHITE));
}
// Set selector properties if enabled
if(hasSelector) {
int defaultSelectorSize = (int) (2 * context.getResources().getDisplayMetrics().density + 0.5f);
setSelectorColor(attributes.getColor(
R.styleable.CircularImageView_selector_color, Color.TRANSPARENT));
setSelectorStrokeWidth(attributes.getDimensionPixelOffset(R.styleable.CircularImageView_selector_stroke_width, defaultSelectorSize));
setSelectorStrokeColor(attributes.getColor(R.styleable.CircularImageView_selector_stroke_color, Color.BLUE));
}
// Add shadow if enabled
if(attributes.getBoolean(R.styleable.CircularImageView_shadow, false))
addShadow();
// We no longer need our attributes TypedArray, give it back to cache
attributes.recycle();
}
/**
* Sets the CircularImageView's border width in pixels.
*
* @param borderWidth
*/
public void setBorderWidth(int borderWidth) {
this.borderWidth = borderWidth;
this.requestLayout();
this.invalidate();
}
/**
* Sets the CircularImageView's basic border color.
*
* @param borderColor
*/
public void setBorderColor(int borderColor) {
if (paintBorder != null)
paintBorder.setColor(borderColor);
this.invalidate();
}
/**
* Sets the color of the selector to be draw over the
* CircularImageView. Be sure to provide some opacity.
*
* @param selectorColor
*/
public void setSelectorColor(int selectorColor) {
this.selectorFilter = new PorterDuffColorFilter(selectorColor, PorterDuff.Mode.SRC_ATOP);
this.invalidate();
}
/**
* Sets the stroke width to be drawn around the CircularImageView
* during click events when the selector is enabled.
*
* @param selectorStrokeWidth
*/
public void setSelectorStrokeWidth(int selectorStrokeWidth) {
this.selectorStrokeWidth = selectorStrokeWidth;
this.requestLayout();
this.invalidate();
}
/**
* Sets the stroke color to be drawn around the CircularImageView
* during click events when the selector is enabled.
*
* @param selectorStrokeColor
*/
public void setSelectorStrokeColor(int selectorStrokeColor) {
if (paintSelectorBorder != null)
paintSelectorBorder.setColor(selectorStrokeColor);
this.invalidate();
}
/**
* Adds a dark shadow to this CircularImageView.
*/
public void addShadow() {
setLayerType(LAYER_TYPE_SOFTWARE, paintBorder);
paintBorder.setShadowLayer(4.0f, 0.0f, 2.0f, Color.BLACK);
}
@Override
public void onDraw(Canvas canvas) {
// Don't draw anything without an image
if(image == null)
return;
// Nothing to draw (Empty bounds)
if(image.getHeight() == 0 || image.getWidth() == 0)
return;
// Compare canvas sizes
int oldCanvasSize = canvasSize;
canvasSize = canvas.getWidth();
if(canvas.getHeight() < canvasSize)
canvasSize = canvas.getHeight();
// Reinitialize shader, if necessary
if(oldCanvasSize != canvasSize)
refreshBitmapShader();
// Apply shader to paint
paint.setShader(shader);
// Keep track of selectorStroke/border width
int outerWidth = 0;
// Get the exact X/Y axis of the view
int center = canvasSize / 2;
if(hasSelector && isSelected) { // Draw the selector stroke & apply the selector filter, if applicable
outerWidth = selectorStrokeWidth;
center = (canvasSize - (outerWidth * 2)) / 2;
paint.setColorFilter(selectorFilter);
canvas.drawCircle(center + outerWidth, center + outerWidth, ((canvasSize - (outerWidth * 2)) / 2) + outerWidth - 4.0f, paintSelectorBorder);
}
else if(hasBorder) { // If no selector was drawn, draw a border and clear the filter instead... if enabled
outerWidth = borderWidth;
center = (canvasSize - (outerWidth * 2)) / 2;
paint.setColorFilter(null);
canvas.drawCircle(center + outerWidth, center + outerWidth, ((canvasSize - (outerWidth * 2)) / 2) + outerWidth - 4.0f, paintBorder);
}
else // Clear the color filter if no selector nor border were drawn
paint.setColorFilter(null);
// Draw the circular image itself
canvas.drawCircle(center + outerWidth, center + outerWidth, ((canvasSize - (outerWidth * 2)) / 2) - 4.0f, paint);
}
@Override
public boolean dispatchTouchEvent(MotionEvent event) {
// Check for clickable state and do nothing if disabled
if(!this.isClickable()) {
this.isSelected = false;
return super.onTouchEvent(event);
}
// Set selected state based on Motion Event
switch(event.getAction()) {
case MotionEvent.ACTION_DOWN:
this.isSelected = true;
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_SCROLL:
case MotionEvent.ACTION_OUTSIDE:
case MotionEvent.ACTION_CANCEL:
this.isSelected = false;
break;
}
// Redraw image and return super type
this.invalidate();
return super.dispatchTouchEvent(event);
}
public void invalidate(Rect dirty) {
super.invalidate(dirty);
image = drawableToBitmap(getDrawable());
if(shader != null || canvasSize > 0)
refreshBitmapShader();
}
public void invalidate(int l, int t, int r, int b) {
super.invalidate(l, t, r, b);
image = drawableToBitmap(getDrawable());
if(shader != null || canvasSize > 0)
refreshBitmapShader();
}
@Override
public void invalidate() {
super.invalidate();
image = drawableToBitmap(getDrawable());
if(shader != null || canvasSize > 0)
refreshBitmapShader();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int width = measureWidth(widthMeasureSpec);
int height = measureHeight(heightMeasureSpec);
setMeasuredDimension(width, height);
}
private int measureWidth(int measureSpec) {
int result;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if (specMode == MeasureSpec.EXACTLY) {
// The parent has determined an exact size for the child.
result = specSize;
}
else if (specMode == MeasureSpec.AT_MOST) {
// The child can be as large as it wants up to the specified size.
result = specSize;
}
else {
// The parent has not imposed any constraint on the child.
result = canvasSize;
}
return result;
}
private int measureHeight(int measureSpecHeight) {
int result = 0;
int specMode = MeasureSpec.getMode(measureSpecHeight);
int specSize = MeasureSpec.getSize(measureSpecHeight);
if (specMode == MeasureSpec.EXACTLY) {
// We were told how big to be
result = specSize;
} else if (specMode == MeasureSpec.AT_MOST) {
// The child can be as large as it wants up to the specified size.
result = specSize;
} else {
// Measure the text (beware: ascent is a negative number)
result = canvasSize;
}
return (result + 2);
}
/**
* Convert a drawable object into a Bitmap
*
* @param drawable
* @return
*/
public Bitmap drawableToBitmap(Drawable drawable) {
if (drawable == null) { // Don't do anything without a proper drawable
return null;
}
else if (drawable instanceof BitmapDrawable) { // Use the getBitmap() method instead if BitmapDrawable
return ((BitmapDrawable) drawable).getBitmap();
}
// Create Bitmap object out of the drawable
Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),
drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
drawable.draw(canvas);
return bitmap;
}
/**
* Reinitializes the shader texture used to fill in
* the Circle upon drawing.
*/
public void refreshBitmapShader() {
shader = new BitmapShader(Bitmap.createScaledBitmap(image, canvasSize, canvasSize, false), Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
}
/**
* Returns whether or not this view is currently
* in its selected state.
*/
public boolean isSelected() {
return this.isSelected;
}
}
创建了圆形效果，但问题是我的所有图片都变窄了，因为图片太大而且它试图适合圆形图像视图。任何可能的解决方案？谢谢！
答案 0 :(得分：1)
假设圆形图像视图的大小是固定的，避免拉伸图像的唯一方法是将其裁剪为与图像视图相同的宽高比，或者在顶部或侧面引入边距。
由于您已经将位图缩放到refreshBitmapShader（）内的画布大小，因此可以使用Bitmap.createBitmap()将其裁剪为方便的位置：
public void refreshBitmapShader() {
int left = 0; y = 0; w = image.getWidth(), h = image.getHeight();
// decide whether we have to crop the sizes or the top and bottom:
if(w > h) // width is greater than height
{
x = (w - h) >> 1; // crop sides, half on each side
w = h;
}
else
{
y = (h - w) >> 1; // crop top and bottom
h = w;
}
Matrix m = new Matrix();
float scale = (float)canvasSize / (float)w;
m.preScale(scale, scale); // scale to canvas size
shader = new BitmapShader(Bitmap.createBitmap(image, x, y, w, h, m, false), Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
}