android可拖动的购物车效果(含点击放入购物车动画代码)

由于项目需要，做了一个可以移动的购物车控件，已经点击添加到购物车的动画效果.动画效果在列表中也是可以使用的(请无视我丑陋的UI...)

一.可以拖动的购物车

1.主要是通过WindowManager添加和删除自定义的LiearLayout实现，显示和隐藏购物车.

我这里使用的是FIRST_APPLICATION_WINDOW (应用程序窗口)，就是在程序里某个activity启动的时候可以显示出

来，跳转到application里其他activity不会主动消失，但是点击home回到桌面不会在桌面上显示

那么有人会问，为什么不用TYPE_APPLICATION(普通应用功能程序窗口),因为有时候点击过快，购物车还没显示，我

就跳到了下个界面，或者返回到了上个界面，这时候就会报错(Caused by: android.view.WindowManager$BadTokenException: Unable to add window -- token android.app.LocalActivityManager$LocalActivityRecord@45a58ee0 is not valid; is your activity running?)

其实WindowManager还可以实现很多功能，比如listview某一项的拖动重新排序，桌面的悬浮窗等功能.

2.然后是加入了拖动功能，无非就是重写了onTouchEvent. MotionEvent.ACTION_UP的时候改变windowmanagerParams的x和y坐标同时调用WindowManager.updateViewLayout

3.加入点击效果,MotionEvent.ACTION_UP的时候和Down的时候的X,Y坐标比较，如果都小于5(我这边设置的是5，有需要的可以自己改)则调用一个回调函数

public class DragView extends LinearLayout {private float mTouchX;private float mTouchY;private float x;private float y;private int startX;private int startY;private int imgId = R.drawable.ic_launcher;private int screenWidth;private int screenHeight;boolean isShow = false;private OnClickListener mClickListener;private WindowManager windowManager;private WindowManager.LayoutParams windowManagerParams = new WindowManager.LayoutParams();private ImageView iv;private TextView tv;private LinearLayout ly;SharedPreferences sharedPreferences;Editor editor;public WindowManager.LayoutParams getWindowManagerParams() {return windowManagerParams;}public DragView(Context context, AttributeSet attrs) {super(context, attrs);}public DragView(Context c) {super(c);sharedPreferences = c.getSharedPreferences("APPSET",Context.MODE_PRIVATE);editor = sharedPreferences.edit();initView(c);}@Overrideprotected void onDraw(Canvas canvas) {// TODO Auto-generated method stubsuper.onDraw(canvas);}// 初始化窗体public void initView(Context c) {windowManager = (WindowManager) c.getSystemService(Context.WINDOW_SERVICE);DisplayMetrics dm = getResources().getDisplayMetrics();screenWidth = dm.widthPixels;screenHeight = dm.heightPixels;View v = LayoutInflater.from(c).inflate(R.layout.dragview, null);iv = (ImageView) v.findViewById(R.id.iv);tv = (TextView) v.findViewById(R.id.tv_drag);ly = (LinearLayout) v.findViewById(R.id.ly_drag);this.addView(v);windowManagerParams.type = android.view.WindowManager.LayoutParams.FIRST_APPLICATION_WINDOW;windowManagerParams.format = PixelFormat.RGBA_8888; // 背景透明windowManagerParams.flags = android.view.WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL| android.view.WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;// 调整悬浮窗口至左上角，便于调整坐标windowManagerParams.gravity = Gravity.LEFT | Gravity.TOP;// 以屏幕左上角为原点，设置x、y初始值int x = screenWidth - v.getMeasuredWidth();int y = screenHeight >> 1;/** * 初始化之前保存的位置 */if (sharedPreferences.getInt("x", -1) != -1) {x = sharedPreferences.getInt("x", -1);}if (sharedPreferences.getInt("y", -1) != -1) {y = sharedPreferences.getInt("y", -1);}windowManagerParams.x = x;windowManagerParams.y = y;// 设置悬浮窗口长宽数据windowManagerParams.width = LayoutParams.WRAP_CONTENT;windowManagerParams.height = LayoutParams.WRAP_CONTENT;}public ImageView getImageView() {return iv;}public void setCount(String i) {if (TextUtils.isEmpty(i) || "0".equals(i)) {ly.setVisibility(View.GONE);} else {ly.setVisibility(View.VISIBLE);tv.setText(i + "");}}public void setImgResource(int id) {imgId = id;iv.setImageResource(id);}@Overridepublic boolean onTouchEvent(MotionEvent event) {Rect frame = new Rect();getWindowVisibleDisplayFrame(frame);int statusBarHeight = frame.top;// 获取相对屏幕的坐标，即以屏幕左上角为原点x = event.getRawX();y = event.getRawY() - statusBarHeight; // statusBarHeight是系统状态栏的高度Log.i("tag", "currX" + x + "====currY" + y);switch (event.getAction()) {case MotionEvent.ACTION_DOWN: // 捕获手指触摸按下动作// 获取相对View的坐标，即以此View左上角为原点mTouchX = event.getX();mTouchY = event.getY();startX = (int) x;startY = (int) y;Log.i("tag", "startX" + mTouchX + "====startY" + mTouchY);break;case MotionEvent.ACTION_MOVE: // 捕获手指触摸移动动作updateViewPosition();break;case MotionEvent.ACTION_UP: // 捕获手指触摸离开动作updateViewPosition();mTouchX = mTouchY = 0;if (Math.abs(x - startX) < 5 && Math.abs(y - startY) < 5) {// 如果的纵坐标和横坐标都<5，则为点击事件if (mClickListener != null) {mClickListener.onClick(this);}}break;}return super.onTouchEvent(event);}// 隐藏该窗体public void hide() {if (isShow) {windowManager.removeView(this);isShow = false;}}// 显示该窗体public void show() {if (isShow == false) {windowManager.addView(this, windowManagerParams);isShow = true;}}public void showAtLocation(int[] location) {show();windowManagerParams.x = location[0];windowManagerParams.y = location[1];windowManager.updateViewLayout(this, windowManagerParams); // 刷新显示}@Overridepublic void setOnClickListener(OnClickListener l) {this.mClickListener = l;}private void updateViewPosition() {// 更新浮动窗口位置参数windowManagerParams.x = (int) (x - mTouchX);windowManagerParams.y = (int) (y - mTouchY);editor.putInt("x", (int) (x - mTouchX));editor.putInt("y", (int) (y - mTouchY));editor.commit();windowManager.updateViewLayout(this, windowManagerParams); // 刷新显示}}

二.动画效果

1.其实就是一个组合动画,获取到点击的View然后通过view.getLocationOnScreen获取到view的x,y坐标作为其实坐标，然后把原本的view放大一点，然后渐渐缩小，结束坐标为购物车的x,y，本来还想加入旋转效果的，感觉不是很好看，就注释掉了

2.这里要注意了，我移动的view并不是这个view本身，而是另一个view,也是跟购物车一样也是一个windowmanager添加了一个自定义linearlayout(我这里直接使用了购物车那个自定义view)

第一次写博客，有任何错误的地方，请大家多多包涵，也欢迎大家多多指导

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