自定义圆放大缩小

来源：互联网发布：手机图片尺寸标注软件编辑：程序博客网时间：2024/05/01 21:14

/**
* Created by Zhangdake on 2017/4/16.
*/
public class ZhangYiFanView extends View{

private float XR = 400;
private float YR = 400;
private float R = 100;

private int width;
private int height;

private final float increment = 10;
private final float min = 50;

private final float sensitivity = 5;

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

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

public ZhangYiFanView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
width = getWidth();
height = getHeight();
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);

Paint paint = new Paint();

paint.setColor(Color.RED);
paint.setAntiAlias(true);
paint.setStyle(Paint.Style.FILL);

canvas.drawCircle(XR, YR, R, paint);

}

private float distance;

@Override
public boolean onTouchEvent(MotionEvent event) {

int pointer = event.getPointerCount();

float x = event.getX();
float y = event.getY();

int k = event.getAction();

if(k == MotionEvent.ACTION_POINTER_DOWN){
distance = getDistance(event);
}

if(pointer==1){
if(k == MotionEvent.ACTION_UP||k == MotionEvent.ACTION_MOVE){
if(x>width-R){
XR = width - R;
}else if(x<R){
XR = R;
}else{
XR = x;
}

if(y>height-R){
YR = height - R;
}else if(y<R){
YR = R;
}else{
YR = y;
}
postInvalidate();
}

}else if(pointer==2&&k == MotionEvent.ACTION_MOVE){

float maxR = 0;

if(XR<YR){
maxR = XR;
}else{
maxR = YR;
}

//判断手指方向
if(distance>getDistance(event)){
R -= increment;
if(R<min){
R = min;
}
}else if(distance<getDistance(event)){
R += increment;
if(R>maxR){
R = maxR;
}else if(R>width/2){
R = width/2;
}
}
distance = getDistance(event);
postInvalidate();
}
return true;
}

private float getDistance(MotionEvent event){

float xOne = event.getX(0);
float yOne = event.getY(0);
float xTwo = event.getX(1);
float yTwo = event.getY(1);

return (xOne - xTwo)*(xOne - xTwo)+(yOne - yTwo)*(yOne - yTwo);
}

}

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