ImageView 缩放

 <ImageView                android:id="@+id/imageview"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                                android:src="@drawable/zixun"                android:scaleType="matrix"                />关键点：缩放的内容不能是图片的背景，一定要是图片的内容

public class HelpActivity extends Activity{    private static final int NONE = 0;    private static final int DRAG = 1;    private static final int ZOOM = 2;    private int mode = NONE;    private float oldDist;    private Matrix matrix = new Matrix();    private Matrix savedMatrix = new Matrix();    private PointF start = new PointF();    private PointF mid = new PointF();    protected void onCreate(Bundle savedInstanceState)    {        super.onCreate(savedInstanceState);        setContentView(R.layout.help);        ImageView view = (ImageView) findViewById(R.id.imageview);//        view.setImageResource(R.drawable.icon);        view.setOnTouchListener(mOnTouchListener);    }    OnTouchListener mOnTouchListener = new OnTouchListener()    {        public boolean onTouch(View v, MotionEvent event)        {            Trace.Log("------------------"+event.toString());            ImageView view = (ImageView) v;            switch (event.getAction() & MotionEvent.ACTION_MASK)            {            case MotionEvent.ACTION_DOWN:                savedMatrix.set(matrix);                start.set(event.getX(), event.getY());                mode = DRAG;                break;            case MotionEvent.ACTION_UP:            case MotionEvent.ACTION_POINTER_UP:                mode = NONE;                break;            // 多点触控            case MotionEvent.ACTION_POINTER_DOWN:                oldDist = spacing(event);                if (oldDist > 10f)                {                    savedMatrix.set(matrix);                    midPoint(mid, event);                    mode = ZOOM;                }                break;            case MotionEvent.ACTION_MOVE:                if (mode == DRAG)                {                    matrix.set(savedMatrix);                    matrix.postTranslate(event.getX() - start.x, event.getY() - start.y);                }                else if (mode == ZOOM)                {                    float newDist = spacing(event);                    if (newDist > 10f)                    {                        matrix.set(savedMatrix);                        float scale = newDist / oldDist;                        matrix.postScale(scale, scale, mid.x, mid.y);                        Trace.Log("------------------"+newDist);                    }                }                break;            }            view.setImageMatrix(matrix);//            view.invalidate();            return true;        }    };    private float spacing(MotionEvent event)    {        float x = event.getX(0) - event.getX(1);        float y = event.getY(0) - event.getY(1);        return FloatMath.sqrt(x * x + y * y);    }    private void midPoint(PointF point, MotionEvent event)    {        float x = event.getX(0) + event.getX(1);        float y = event.getY(0) + event.getY(1);        point.set(x / 2, y / 2);    }    public void onClickBack(View view)    {        backToCardSelect();    }    }

ImageVIew 需要在最上面一层，否则可能不会生效

更多相关文章

随机推荐