android圆形图片的获取与图片绕中心旋转

来源：互联网发布：淘宝店铺做淘宝客教程编辑：程序博客网时间：2024/06/09 21:46

这是我第一篇博客，写得比较简单，望大家见谅。这篇博客主要介绍如何对图片进行处理变为图形图片，并使得图片绕中心旋转。效果图如下

首先是图形图片的获取方法，代码如下：

private Bitmap getCircularBitmap(Bitmap bitmap, int radius) {
       Bitmap sbmp = Bitmap.createScaledBitmap(bitmap, radius, radius, false);

       Bitmap output = Bitmap.createBitmap(sbmp.getWidth(), sbmp.getHeight(),
               Config.ARGB_8888);
       Canvas canvas = new Canvas(output);

       Paint paint = new Paint();
       Rect rect = new Rect(0, 0, sbmp.getWidth(), sbmp.getHeight());

       paint.setAntiAlias(true);
       paint.setFilterBitmap(true);
       paint.setDither(true);
       canvas.drawARGB(0, 0, 0, 0);
       paint.setColor(Color.BLACK);
       canvas.drawCircle(sbmp.getWidth() / 2, sbmp.getHeight() / 2,
               sbmp.getWidth() / 2, paint);
       paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
       canvas.drawBitmap(sbmp, rect, rect, paint);
       return output;
   }

返回的是一张圆形的图片。下面是自定义的MyView类，对获取的图片进行处理，使图片绕中心旋转。代码如下：

public class MyView extends View {

   private Bitmap bitmap1;
   private Bitmap bitmap2;
   private int degree = 0;// 扳手图像的当前角度
   static boolean flag = false;
   Handler handler;
   // 视图的宽高
   WindowManager wm = (WindowManager) getContext().getSystemService(
           Context.WINDOW_SERVICE);

   int viewWidth = wm.getDefaultDisplay().getWidth();

   BitmapDrawable myImage;

   public MyView(Context context) {
       super(context);
       setBackgroundColor(Color.WHITE);
       bitmap1 = BitmapFactory.decodeResource(getResources(),
               R.drawable.music_play_people);
       bitmap2 = getCircularBitmap(bitmap1, 200);
       myImage = new BitmapDrawable(bitmap2);


       handler = new Handler();
       handler.post(runnable);
   }

   private Runnable runnable = new Runnable() {
       public void run() {
           if (flag) {
               postInvalidate();
           }
           handler.postDelayed(runnable, 50);
       }
   };

   @Override
   protected void onDraw(Canvas canvas) {
       int width = bitmap2.getWidth();
       int height = bitmap2.getHeight();
       // 控制旋转角度在0-360之间
       degree ++;
       if (degree > 360)
           degree = 0;
       // 设置扳手图像的旋转角度和旋转轴心坐标（后两个参数，注意这个坐标是相对于屏幕的），该轴心也是图像的正中心
       canvas.save();
       canvas.rotate(degree, viewWidth / 3 - 45, 200);
       myImage.setBounds(viewWidth / 3 - width - 45, 200 - height, viewWidth
               / 3 + width - 45, 200 + height);

       myImage.draw(canvas);
       canvas.restore();

   }

}

在MainActivity中加载MyView对象，主activity代码如下：

public class MainActivity extends Activity {

   private Button start, stop;
   private RelativeLayout re;
   private MyView view;

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

       re = (RelativeLayout) findViewById(R.id.my_image);
       RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(
               RelativeLayout.LayoutParams.MATCH_PARENT,
               RelativeLayout.LayoutParams.WRAP_CONTENT);
       layoutParams.addRule(RelativeLayout.CENTER_IN_PARENT);
       view = new MyView(this);
       view.setLayoutParams(layoutParams);
       re.addView(view);

       start = (Button) findViewById(R.id.start);
       stop = (Button) findViewById(R.id.end);

       start.setOnClickListener(new OnClickListener() {

           @Override
           public void onClick(View v) {
               MyView.flag = true;
           }
       });

       stop.setOnClickListener(new OnClickListener() {
           @Override
           public void onClick(View v) {
               MyView.flag = false;
           }
       });

   }
}

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