1先上圖
第二思路
- 在定義View 的onMeasure()方法裏設置View的寬高相等,應該取寬高中的最小值。
- 在自定義View的onDraw()裏面使用畫筆paint結合BitmapShaper畫出一個圓形區域。
- 上述兩步已經可以實現一個圓形圖片,但是如果圖片大於View的設定的寬高,則只會繪製左上角的局域,內容顯示不完全(如下圖)。因此,還應該做好圖片的縮放。
public class CircleImageView extends ImageView {
private Paint mPaint; //畫筆
private int mRadius; //圓形圖片的半徑
private float mScale; //圖片的縮放比例
public CircleImageView(Context context) {
super(context);
}
public CircleImageView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public CircleImageView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
//因爲是圓形圖片,所以應該讓寬高保持一致
int size = Math.min(getMeasuredWidth(), getMeasuredHeight());
mRadius = size / 2;
setMeasuredDimension(size, size);
}
@Override
protected void onDraw(Canvas canvas) {
mPaint = new Paint();
Bitmap bitmap = drawableToBitmap(getDrawable());
//初始化BitmapShader,傳入bitmap對象
BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
//計算縮放比例
mScale = (mRadius * 2.0f) / Math.min(bitmap.getHeight(), bitmap.getWidth());
Matrix matrix = new Matrix();
matrix.setScale(mScale, mScale);
bitmapShader.setLocalMatrix(matrix);
mPaint.setShader(bitmapShader);
//畫圓形,指定好中心點座標、半徑、畫筆
canvas.drawCircle(mRadius, mRadius, mRadius, mPaint);
}
//寫一個drawble轉BitMap的方法
private Bitmap drawableToBitmap(Drawable drawable) {
if (drawable instanceof BitmapDrawable) {
BitmapDrawable bd = (BitmapDrawable) drawable;
return bd.getBitmap();
}
int w = drawable.getIntrinsicWidth();
int h = drawable.getIntrinsicHeight();
Bitmap bitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, w, h);
drawable.draw(canvas);
return bitmap;
}
}
第四使用
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.roundimage.MainActivity"
>
<com.roundimage.CircleImageView
android:id="@+id/image1"
android:layout_width="200dp"
android:layout_height="200dp"
android:layout_centerInParent="true"
android:scaleType="centerCrop"
android:src="@drawable/beauty"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/image1"
android:layout_centerHorizontal="true"
android:layout_marginTop="10dp"
android:text="斯嘉麗·約翰遜"
android:textColor="#333333"
android:textSize="17sp"
/>
</RelativeLayout>