100行代码 CircleImageView

IDE预览效果

手机截屏

100行代码实现圆形ImageView

package com.example.androidtest;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.Bitmap.Config;
import android.util.AttributeSet;
import android.widget.ImageView;

public class CircleView extends ImageView {

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

	public CircleView(Context context, AttributeSet attrs) {
		super(context, attrs);
	}

	public CircleView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
	}

	/**
	 * 布局预览时会调用该方法
	 */
	@Override
	public void setImageDrawable(Drawable drawable) {
		Bitmap bitmap1 = getBitmapFromDrawable(drawable);//获取到Bitmap
		//创建同样大小的Bitmap作为画布
		Bitmap bitmap2 = Bitmap.createBitmap(bitmap1.getWidth(), bitmap1.getHeight(), Config.ARGB_8888);
		
		//画在bitmap2上
		Canvas canvas = new Canvas(bitmap2);

		Paint paint = new Paint();
		paint.setAntiAlias(true);
		//找到短的边作为圆的直径
		int r;
		if (bitmap2.getHeight() > bitmap2.getWidth()) {
			r = bitmap2.getWidth() / 2;
		} else {
			r = bitmap2.getHeight() / 2;
		}

		//在bitmap2上画圆
		canvas.drawCircle(bitmap2.getWidth() / 2, bitmap2.getHeight() / 2, r, paint);
		//设置为SRC_IN，即显示重叠部分中后画的部分。   先画的部分为DST，后画的为SRC
		paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
		//把原来的bitmap1画到bitmap2上
		canvas.drawBitmap(bitmap1, 0, 0, paint);
		
		//上面执行完毕后bitmap2就是所要的圆形图片了
		super.setImageDrawable(new BitmapDrawable(bitmap2));
	}

	@Override
	public void setImageResource(int resId) {

		setImageDrawable(getResources().getDrawable(resId));
	}

	/**
	 * 获取Drawable对应的Bitmap
	 * @param drawable
	 * @return
	 */
	private Bitmap getBitmapFromDrawable(Drawable drawable) {
		if (drawable == null) {
			return null;
		}
		if (drawable instanceof BitmapDrawable) {
			return ((BitmapDrawable) drawable).getBitmap();
		}
		try {
			Bitmap bitmap;

			if (drawable instanceof ColorDrawable) {
				bitmap = Bitmap.createBitmap(1, 1, Config.ARGB_8888);
			} else {
				bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(),
						Config.ARGB_8888);
			}

			Canvas canvas = new Canvas(bitmap);
			drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
			drawable.draw(canvas);
			return bitmap;
		} catch (OutOfMemoryError e) {
			return null;
		}
	}
}

布局

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#888"
        android:orientation="vertical" >

                

        <com.example.androidtest.CircleView
            android:id="@+id/civ"
            android:scaleType="centerCrop"
            android:layout_width="100dp"
            android:layout_height="100dp"
            android:src="@drawable/pic"
           />

        <ImageView
            android:layout_marginTop="10dp"
            android:layout_width="100dp"
            android:layout_height="100dp"
            
            android:scaleType="centerCrop"
            android:background="#080"
            android:src="@drawable/pic" />
        
        
        
        
        <com.example.androidtest.CircleView
            android:id="@+id/civ2"
            android:scaleType="centerCrop"
            android:layout_width="100dp"
            android:layout_height="100dp"
            android:src="@drawable/iii"
              />

        <ImageView
            android:layout_marginTop="10dp"
            android:layout_width="100dp"
            android:layout_height="100dp"
            
            android:scaleType="centerCrop"
            android:background="#080"
            android:src="@drawable/iii" />
        
          <com.example.androidtest.CircleView
            android:id="@+id/civ3"
            android:scaleType="centerCrop"
            android:layout_width="100dp"
            android:layout_height="100dp"
            android:src="@drawable/pic"
              />

        <ImageView
            android:layout_marginTop="10dp"
            android:layout_width="100dp"
            android:layout_height="100dp"
            
            android:scaleType="centerCrop"
            android:background="#080"
            android:src="@drawable/pic" />
    </LinearLayout>

</ScrollView>

调用

package com.example.androidtest;

import android.os.Bundle;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuffXfermode;
import android.graphics.Bitmap.Config;
import android.graphics.PorterDuff.Mode;
import android.view.Menu;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        CircleView civ=(CircleView) findViewById(R.id.civ);
        Bitmap bitmap1=BitmapFactory.decodeResource(getResources(), R.drawable.pic);
        civ.setImageBitmap(bitmap1);
        
        
        CircleView civ2=(CircleView) findViewById(R.id.civ2);
        civ2.setImageResource(R.drawable.iii);
        
        
        CircleView civ3=(CircleView) findViewById(R.id.civ3);
        civ3.setImageDrawable(getResources().getDrawable(R.drawable.iii));;
        
        
    }

 
  

}