Question

我的png图像宽度为200 x高度50像素。我需要围绕它的中心旋转一个角度。

enter image description here

我的onDraw方法

@Override
    public void onDraw(Canvas canvas){
        initDrawingTools();
        drawRect(canvas);
        drawBack(canvas);
        Matrix mat = new Matrix();
        Bitmap bMap = BitmapFactory.decodeResource(getResources(),R.drawable.needle);
        cX = getWidth()/2-bMap.getWidth()/2;
        cY = getHeight()/2-bMap.getHeight()/2;
        mat.setTranslate(cX, cY);
        mat.postRotate(angleSpeed,cX, cY);      
        Bitmap bMapRotate = Bitmap.createBitmap(bMap, 0, 0,bMap.getWidth(),bMap.getHeight(), mat, true);
        canvas.drawBitmap(bMapRotate, mat, null);
    }

这是我管理的最接近的。据我所知，图像中心在旋转时是浮动的。例如：0度 - 200x50,9度50x200等。在这种情况下，它不会围绕其中心旋转。有人可以给我一些提示或解释如何得到结果吗？

编辑Mikel Pascualc的建议：

动画后如何使箭头保持在倾斜位置

seekBar = (SeekBar)findViewById(R.id.seekBar1);
        seekBar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
               ROTATE_TO = speed;
               spin();}
            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {
                ROTATE_FROM = speed;}
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                speed = progress;
//            textView = (TextView)findViewById(R.id.textView1);
//            textView.setText(progress);
            //rodykle.onSpeedChanged((float)progress);
            }
        });
    }
    public void spin(){
        TextView textView1 = (TextView)findViewById(R.id.textView1);
        textView1.setText("From: " + ROTATE_FROM + "\nTo: " + ROTATE_TO + "\nProgress: " + speed);
        ImageView needle = (ImageView) findViewById(R.id.needle1);
        RotateAnimation r = new RotateAnimation(ROTATE_FROM, ROTATE_TO, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
        r.setDuration((long) 2*1000);
        r.setRepeatCount(0);
        r.setFillAfter(true); // <-- ADDED THIS TO STAY IMG IN ANGLE AFTER ANIMATION
        needle.startAnimation(r);
    }

Answer 1

您最好使用动画。示例：

public class NeedleRotateActivity extends Activity {
private static final float ROTATE_FROM = 0.0f;
private static final float ROTATE_TO = -10.0f * 360.0f;

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

    ImageView needle = (ImageView) findViewById(R.id.needle);

    RotateAnimation r = new RotateAnimation(ROTATE_FROM, ROTATE_TO, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
    r.setDuration((long) 2*1500);
    r.setRepeatCount(0);
    r.setFillAfter(true);
    needle.startAnimation(r);
}

Answer 2

我对此做了类似的事情。我将一个瓶子自己旋转，慢慢降低速度，直至停止。从中分享一段代码，希望对您有所帮助。

rotateAnimation = new RotateAnimation(0, 360,
                    Animation.RELATIVE_TO_SELF, 0.5f,
                    Animation.RELATIVE_TO_SELF, 0.5f);
            rotateAnimation.setInterpolator(new LinearInterpolator());
            rotateAnimation.setDuration(duration);
            rotateAnimation.setRepeatCount(0);
            imgBottle.startAnimation(rotateAnimation);

            rotateAnimation.setAnimationListener(new AnimationListener() {
                public void onAnimationStart(Animation anim) {
                };

                public void onAnimationRepeat(Animation anim) {
                };

                public void onAnimationEnd(Animation anim) {
                    duration = duration + 70;
                };
            });

imgBottle.startAnimation(rotateAnimation);

围绕其中心旋转自定义图像

2 个答案: