左右划动的箭头

     
     /**
         * 初始化悬浮按钮
         */
        private void initImageButtonView(){
            //获取WindowManager
            wm=(WindowManager)getApplicationContext().getSystemService("window");
            
            //设置LayoutParams相关参数
            wmParams = new WindowManager.LayoutParams();
            
            //设置window type
            wmParams.type=LayoutParams.TYPE_PHONE;   
            
            //设置图片格式，效果为背景透明
            wmParams.format=PixelFormat.RGBA_8888;   
            
            //设置Window flag参数
             wmParams.flags=LayoutParams.FLAG_NOT_TOUCH_MODAL | LayoutParams.FLAG_NOT_FOCUSABLE;

            //设置x、y初始值
            wmParams.x=0;
            wmParams.y=-25;
            
            //设置窗口长宽数据
            wmParams.width=50;
            wmParams.height=50;
            
            //创建左右按钮
            createLeftButtonView();
            createRightButtonView();
            
            
            
        }
        
        /**
         * 设置左边按钮
         */
        private void createLeftButtonView(){
            if(btnLeft==null){
                 btnLeft=new ImageView(this);
                    btnLeft.setImageResource(R.drawable.left_icon);
                   
//                  btnLeft.setAlpha(0); //为隐藏图标
                    btnLeft.setOnClickListener(new View.OnClickListener() {    
                        public void onClick(View arg0) {
                            if(progressDialog==null){
                                if(picturelist.size()>1){
                                    if(showing!=0){
                                        showi(false);
                                        tonext=2;
                                        setimg(showing,0);
                                        changing=true;
                                        if(showing==0){
                                            btnLeft.setVisibility(View.GONE);
                                        }else{
                                            btnLeft.setVisibility(View.VISIBLE);
                                        }
                                        if(showing == picturelist.size()-1){
                                            btnRight.setVisibility(View.GONE);
                                        }else{
                                            btnRight.setVisibility(View.VISIBLE);
                                        }
                                    }
                                }
                            }
                            
                        }
                    });
                    
                    //调整窗口
                    wmParams.gravity=Gravity.LEFT|Gravity.CENTER_VERTICAL;
                    
                    //显示图像
                    wm.addView(btnLeft, wmParams);
            }
           
            if (showing == 0) {
                btnLeft.setVisibility(View.GONE);
            } else {
                btnLeft.setVisibility(View.VISIBLE);
            }
            
        }
        
        /**
         * 设置右边按钮
         */
        private void createRightButtonView(){
            if(btnRight==null){
                 btnRight=new ImageView(this);
                    btnRight.setImageResource(R.drawable.right_icon);
                   
//                    btnRight.setAlpha(0); //为隐藏图标
                    btnRight.setOnClickListener(new View.OnClickListener() {    
                        public void onClick(View arg0) {
                            if(progressDialog==null){
                                if(picturelist.size()>1){
                                    if((picturelist.size()-1)!=showing){
                                        showi(true);
                                        tonext=1;
                                        setimg(showing,0);
                                        changing=true;
                                        if(showing==0){
                                            btnLeft.setVisibility(View.GONE);
                                        }else{
                                            btnLeft.setVisibility(View.VISIBLE);
                                        }
                                        if(showing == picturelist.size()-1){
                                            btnRight.setVisibility(View.GONE);
                                        }else{
                                            btnRight.setVisibility(View.VISIBLE);
                                        }
                                    }
                                    
                                }
                            }
                        }
                    });
                    
                    //调整窗口
                    wmParams.gravity=Gravity.RIGHT|Gravity.CENTER_VERTICAL;
                    
                    //显示图像
                    wm.addView(btnRight, wmParams);
            }
           
            try {
                if (picturelist.size()-1 == showing) {
                    btnRight.setVisibility(View.GONE);
                } else {
                    btnRight.setVisibility(View.VISIBLE);
                }
            } catch (Exception e) {
            }
        }
        @Override
        protected void onPause() {
            if(btnLeft!=null){
            btnLeft.setVisibility(View.GONE);
            btnRight.setVisibility(View.GONE);
            }
            super.onPause();
        }