Android实现图片拖动效果

2024-02-28 03:05:03 53

publicclassMainActivityextendsActivityimplementsOnTouchListener{ privateImageViewiv_main; privateRelativeLayoutparentView; @Override protectedvoidonCreate(BundlesavedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); iv_main=(ImageView)findViewById(R.id.iv_main); parentView=(RelativeLayout)iv_main.getParent(); /* intright=parentView.getRight();//0 intbottom=parentView.getBottom();//0 Toast.makeText(this,right+"---"+bottom,1).show(); */ //设置touch监听 iv_main.setOnTouchListener(this); } privateintlastX; privateintlastY; privateintmaxRight; privateintmaxBottom; @Override publicbooleanonTouch(Viewv,MotionEventevent){ //得到事件的坐标 inteventX=(int)event.getRawX(); inteventY=(int)event.getRawY(); switch(event.getAction()){ caseMotionEvent.ACTION_DOWN: //得到父视图的right/bottom if(maxRight==0){//保证只赋一次值 maxRight=parentView.getRight(); maxBottom=parentView.getBottom(); } //第一次记录lastX/lastY lastX=eventX; lastY=eventY; break; caseMotionEvent.ACTION_MOVE: //计算事件的偏移 intdx=eventX-lastX; intdy=eventY-lastY; //根据事件的偏移来移动imageView intleft=iv_main.getLeft()+dx; inttop=iv_main.getTop()+dy; intright=iv_main.getRight()+dx; intbottom=iv_main.getBottom()+dy; //限制left>=0 if(left<0){ right+=-left; left=0; } //限制top if(top<0){ bottom+=-top; top=0; } //限制right<=maxRight if(right>maxRight){ left-=right-maxRight; right=maxRight; } //限制bottom<=maxBottom if(bottom>maxBottom){ top-=bottom-maxBottom; bottom=maxBottom; } iv_main.layout(left,top,right,bottom); //再次记录lastX/lastY lastX=eventX; lastY=eventY; break; default: break; } returntrue;//所有的motionEvent都交给imageView处理 } }

Android实现图片拖动效果

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