头像和一些图片显示时我们需要显示成圆角或者圆形的图片,很多第三方库都是支持的。我们这里提供一种不需要任何第三方库的方法,很方便的获得圆角或者圆形图片。
首先,我们需要自定义控件的属性res/attrs.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="CircleImageView">
<attr name="radius" format="dimension"/>
<attr name="type">
<enum name="circle" value="0"/>
<enum name="round" value="1"/>
</attr>
</declare-styleable>
</resources>
接着我们需要一个自定义控件
public class CircleImageView extends ImageView {
private Paint mPaint;
private Xfermode mXfermode = new PorterDuffXfermode(PorterDuff.Mode.DST_IN);
private Bitmap mMaskBitmap;
private WeakReference<Bitmap> mWeakBitmap;
//图片相关的属性
private int type; //类型,圆形或者圆角
public static final int TYPE_CIRCLE = 0;
public static final int TYPE_ROUND = 1;
private static final int BODER_RADIUS_DEFAULT = 10; //圆角默认大小值
private int mBorderRadius; //圆角大小
public CircleImageView(Context context) {
this(context, null);
}
public CircleImageView(Context context, AttributeSet attrs) {
super(context, attrs);
mPaint = new Paint();
mPaint.setAntiAlias(true);
//取出attrs中我们为View设置的相关值
TypedArray tArray = context.obtainStyledAttributes(attrs, R.styleable.CircleImageView);
mBorderRadius = tArray.getDimensionPixelSize(R.styleable.CircleImageView_radius, BODER_RADIUS_DEFAULT);
type = tArray.getInt(R.styleable.CircleImageView_type, TYPE_CIRCLE);
tArray.recycle();
}
public CircleImageView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (type == TYPE_CIRCLE) {
int width = Math.min(getMeasuredWidth(), getMeasuredHeight());
setMeasuredDimension(width, width); //设置当前View的大小
}
}
@Override
protected void onDraw(Canvas canvas) {
//在缓存中取出bitmap
Bitmap bitmap = mWeakBitmap == null ? null : mWeakBitmap.get();
if (bitmap == null || bitmap.isRecycled()) {
//获取图片宽高
Drawable drawable = getDrawable();
int width = drawable.getIntrinsicWidth();
int height = drawable.getIntrinsicHeight();
if (drawable != null) {
bitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
Canvas drawCanvas = new Canvas(bitmap);
float scale = 1.0f;
if (type == TYPE_ROUND) {
scale = Math.max(getWidth() * 1.0f / width, getHeight()
* 1.0f / height);
} else {
scale = getWidth() * 1.0F / Math.min(width, height);
}
//根据缩放比例,设置bounds,相当于缩放图片了
drawable.setBounds(0, 0, (int) (scale * width),
(int) (scale * height));
drawable.draw(drawCanvas);
if (mMaskBitmap == null || mMaskBitmap.isRecycled()) {
mMaskBitmap = getBitmap();
}
mPaint.reset();
mPaint.setFilterBitmap(false);
mPaint.setXfermode(mXfermode);
//绘制形状
drawCanvas.drawBitmap(mMaskBitmap, 0, 0, mPaint);
//bitmap缓存起来,避免每次调用onDraw,分配内存
mWeakBitmap = new WeakReference<Bitmap>(bitmap);
//绘制图片
canvas.drawBitmap(bitmap, 0, 0, null);
mPaint.setXfermode(null);
}
}
if (bitmap != null) {
mPaint.setXfermode(null);
canvas.drawBitmap(bitmap, 0.0f, 0.0f, mPaint);
return;
}
}
//缓存Bitmap,避免每次OnDraw都重新分配内存与绘图
@Override
public void invalidate() {
mWeakBitmap = null;
if (mWeakBitmap != null) {
mMaskBitmap.recycle();
mMaskBitmap = null;
}
super.invalidate();
}
//定义一个绘制形状的方法
private Bitmap getBitmap() {
Bitmap bitmap = Bitmap.createBitmap(getWidth(), getHeight(),
Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); //抗锯齿
paint.setColor(Color.BLACK);
if (type == TYPE_ROUND) {
canvas.drawRoundRect(new RectF(0, 0, getWidth(), getHeight()),
mBorderRadius, mBorderRadius, paint);
} else {
canvas.drawCircle(getWidth() / 2, getWidth() / 2, getWidth() / 2, paint);
}
return bitmap;
}
}
最后我们将自定义控件引入我们的界面中
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.jay.xfermodedemo1.CircleImageView
android:layout_width="160dp"
android:layout_height="240dp"
android:layout_margin="10dp"
android:src="@mipmap/ic_bg_meizi2"
app:type="circle" />
<com.jay.xfermodedemo1.CircleImageView
android:layout_width="160dp"
android:layout_height="280dp"
android:layout_margin="10dp"
android:src="@mipmap/ic_bg_meizi1"
app:radius="30dp"
app:type="round" />
</LinearLayout>
这样一个圆角和一个圆形的图片我们就生成了。