Android 实现切圆图作为头像使用实例

public class MyView extends View {

  Bitmap bmp;

  Paint paint = new Paint();


  public MyView(Context context) {
    super(context);
  }

  public MyView(Context context, AttributeSet attrs) {
    super(context, attrs);
    bmp = BitmapFactory.decodeResource(getResources(), R.mipmap.c);
    src = new RectF(bmp.getWidth() / 2 - 50, bmp.getHeight() / 2 - 50, bmp.getWidth() / 2 + 50, bmp.getHeight() / 2 + 50);
    dst = new Rect(200, 200, 400, 400);

    paint.setAntiAlias(true);
    paint.setDither(true);
    Shader shaer = new BitmapShader(bmp, Shader.TileMode.MIRROR, Shader.TileMode.REPEAT);
    paint.setShader(shaer);
  }


  private RectF src = null;
  private Rect dst = null;

  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    //绘制Bitmap

    Matrix m = new Matrix();

    //每次set都会重置矩形
    m.setRotate(90, bmp.getWidth() / 2, bmp.getHeight() / 2);

    m.postTranslate(100, 100);

    m.preScale(0.5f, 0.5f, bmp.getWidth() / 2, bmp.getHeight() / 2);

    //错切
    m.postSkew(0.3f, 0.3f);

    // canvas.drawBitmap(bmp, m, null);

    // canvas.drawBitmap(bmp, src, dst, null);

    //拿view的高宽
    canvas.drawArc(src, 100, 270, true, paint);

  }
}

public class MainActivity extends AppCompatActivity {

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
  }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
  android:orientation="vertical"
  tools:context="com.example.administrator.lesson12_drawbitmap.MainActivity">


  <com.example.administrator.lesson12_drawbitmap.MyView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />


</LinearLayout>