Android 圆角图片的实现

Android 圆角图片

效果图：

快速开始

1. activity_main.xml文件。

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/iv_img"
        android:layout_width="300dp"
        android:layout_height="200dp"
        android:layout_marginTop="30dp"
        android:src="@mipmap/image_bg"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent"/>

    <ImageView
        android:id="@+id/iv_rect_img"
        android:layout_width="300dp"
        android:layout_height="200dp"
        android:layout_marginTop="30dp"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toBottomOf="@id/iv_img"/>

    <ImageView
        android:id="@+id/iv_circle_img"
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:layout_marginTop="30dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@id/iv_rect_img"/>

</android.support.constraint.ConstraintLayout>

2. MainActivity.class文件。

public class MainActivity extends AppCompatActivity {

    private ImageView ivRectImg, ivCircleImg;

    private Bitmap bitmap;
    private int width;
    private int height;

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

        ivRectImg = findViewById(R.id.iv_rect_img);
        ivCircleImg = findViewById(R.id.iv_circle_img);

        bitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.image_bg);
        width = bitmap.getWidth();
        height = bitmap.getHeight();

        rectRoundBitmap();
        circleBitmap();
    }

	// 圆角矩形
    private void rectRoundBitmap() {
        RoundedBitmapDrawable bitmapDrawable = RoundedBitmapDrawableFactory.create(getResources(), bitmap);
        bitmapDrawable.setAntiAlias(true);
        bitmapDrawable.setCornerRadius(50);
        ivRectImg.setImageDrawable(bitmapDrawable);
    }

    // 把bitmap图片进行剪切成正方形， 然后再设置圆角半径为正方形边长的一半即可
    private void circleBitmap() {
        Bitmap circle = null;
        int min = Math.min(width, height);
        int max = Math.max(width, height);
        if (width == height) {
            circle = Bitmap.createBitmap(bitmap, 0, 0, width, height);
        } else {
            // 居中裁剪
            if (width > height) {
                circle = Bitmap.createBitmap(bitmap, (max - min) / 2, 0, min, min);
            } else {
                circle = Bitmap.createBitmap(bitmap, 0, (max - min) / 2, min, min);
            }
        }
        RoundedBitmapDrawable bitmapDrawable = RoundedBitmapDrawableFactory.create(getResources(), circle);
        bitmapDrawable.setCornerRadius(min / 2);
        bitmapDrawable.setAntiAlias(true);
        ivCircleImg.setImageDrawable(bitmapDrawable);
    }
}