android悬浮窗--获取内存

首先，得先说明，这个例子并不是我写的，是从eoeAndroid的一个帖子上面看到的，下载了他的源代码，然后分析一下，供学习共享。（另外，对于其代码有所修改，以便于更好的说明问题，另：同时把源代码上传，下载地址：http://download.csdn.net/detail/aomandeshangxiao/3880055）

一开始，我们先看一下运行效果：

其中，

这一块就是悬浮窗，可以随意拖动，动态显示当前内存使用量。

下面看一下代码是如何实现的：

悬浮窗的实现是用了一个service，为什么要用service呢？了解service特点的大体就会明白。下面看一下：

public class FloatService extends Service {WindowManager wm = null;WindowManager.LayoutParams wmParams = null;View view;private float mTouchStartX;private float mTouchStartY;private float x;private float y;int state;TextView tx1;TextView tx;ImageView iv;private float StartX;private float StartY;int delaytime=1000;@Overridepublic void onCreate() {Log.d("FloatService", "onCreate");super.onCreate();view = LayoutInflater.from(this).inflate(R.layout.floating, null);tx = (TextView) view.findViewById(R.id.memunused);tx1 = (TextView) view.findViewById(R.id.memtotal);tx.setText("" + memInfo.getmem_UNUSED(this) + "KB");tx1.setText("" + memInfo.getmem_TOLAL() + "KB");iv = (ImageView) view.findViewById(R.id.img2);iv.setVisibility(View.GONE);createView();handler.postDelayed(task, delaytime);}private void createView() {// 获取WindowManagerwm = (WindowManager) getApplicationContext().getSystemService("window");// 设置LayoutParams(全局变量）相关参数wmParams = new WindowManager.LayoutParams();wmParams.type = 2002;wmParams.flags |= 8;wmParams.gravity = Gravity.LEFT | Gravity.TOP; // 调整悬浮窗口至左上角// 以屏幕左上角为原点，设置x、y初始值wmParams.x = 0;wmParams.y = 0;// 设置悬浮窗口长宽数据wmParams.width = WindowManager.LayoutParams.WRAP_CONTENT;wmParams.height = WindowManager.LayoutParams.WRAP_CONTENT;wmParams.format = 1;wm.addView(view, wmParams);view.setOnTouchListener(new OnTouchListener() {public boolean onTouch(View v, MotionEvent event) {// 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() - 25; // 25是系统状态栏的高度Log.i("currP", "currX" + x + "====currY" + y);// 调试信息switch (event.getAction()) {case MotionEvent.ACTION_DOWN:state = MotionEvent.ACTION_DOWN;StartX = x;StartY = y;// 获取相对View的坐标，即以此View左上角为原点mTouchStartX = event.getX();mTouchStartY = event.getY();Log.i("startP", "startX" + mTouchStartX + "====startY"+ mTouchStartY);// 调试信息break;case MotionEvent.ACTION_MOVE:state = MotionEvent.ACTION_MOVE;updateViewPosition();break;case MotionEvent.ACTION_UP:state = MotionEvent.ACTION_UP;updateViewPosition();showImg();mTouchStartX = mTouchStartY = 0;break;}return true;}});iv.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubIntent serviceStop = new Intent();serviceStop.setClass(FloatService.this, FloatService.class);stopService(serviceStop);}});}public void showImg() {if (Math.abs(x - StartX) < 1.5 && Math.abs(y - StartY) < 1.5&& !iv.isShown()) {iv.setVisibility(View.VISIBLE);} else if (iv.isShown()) {iv.setVisibility(View.GONE);}}private Handler handler = new Handler();private Runnable task = new Runnable() {public void run() {// TODO Auto-generated method stubdataRefresh();handler.postDelayed(this, delaytime);wm.updateViewLayout(view, wmParams);}};public void dataRefresh() {tx.setText("" + memInfo.getmem_UNUSED(this) + "KB");tx1.setText("" + memInfo.getmem_TOLAL() + "KB");}private void updateViewPosition() {// 更新浮动窗口位置参数wmParams.x = (int) (x - mTouchStartX);wmParams.y = (int) (y - mTouchStartY);wm.updateViewLayout(view, wmParams);}@Overridepublic void onStart(Intent intent, int startId) {Log.d("FloatService", "onStart");setForeground(true);super.onStart(intent, startId);}@Overridepublic void onDestroy() {handler.removeCallbacks(task);Log.d("FloatService", "onDestroy");wm.removeView(view);super.onDestroy();}@Overridepublic IBinder onBind(Intent intent) {return null;}}

其主要功能部分在creatView方法里：

private void createView() {// 获取WindowManagerwm = (WindowManager) getApplicationContext().getSystemService("window");// 设置LayoutParams(全局变量）相关参数wmParams = new WindowManager.LayoutParams();wmParams.type = 2002;wmParams.flags |= 8;wmParams.gravity = Gravity.LEFT | Gravity.TOP; // 调整悬浮窗口至左上角// 以屏幕左上角为原点，设置x、y初始值wmParams.x = 0;wmParams.y = 0;// 设置悬浮窗口长宽数据wmParams.width = WindowManager.LayoutParams.WRAP_CONTENT;wmParams.height = WindowManager.LayoutParams.WRAP_CONTENT;wmParams.format = 1;wm.addView(view, wmParams);view.setOnTouchListener(new OnTouchListener() {public boolean onTouch(View v, MotionEvent event) {// 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() - 25; // 25是系统状态栏的高度Log.i("currP", "currX" + x + "====currY" + y);// 调试信息switch (event.getAction()) {case MotionEvent.ACTION_DOWN:state = MotionEvent.ACTION_DOWN;StartX = x;StartY = y;// 获取相对View的坐标，即以此View左上角为原点mTouchStartX = event.getX();mTouchStartY = event.getY();Log.i("startP", "startX" + mTouchStartX + "====startY"+ mTouchStartY);// 调试信息break;case MotionEvent.ACTION_MOVE:state = MotionEvent.ACTION_MOVE;updateViewPosition();break;case MotionEvent.ACTION_UP:state = MotionEvent.ACTION_UP;updateViewPosition();showImg();mTouchStartX = mTouchStartY = 0;break;}return true;}});iv.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubIntent serviceStop = new Intent();serviceStop.setClass(FloatService.this, FloatService.class);stopService(serviceStop);}});}

首先，代码里面用到了WindowManager借口，整个Android的窗口机制是基于一个叫做 WindowManager，这个接口可以添加view到屏幕，也可以从屏幕删除view。它面向的对象一端是屏幕，另一端就是View，直接忽略我们以前的Activity或者Dialog之类的东东。其实我们的Activity或者Diolog底层的实现也是通过WindowManager，这个 WindowManager是全局的，整个系统就是这个唯一的东东。它是显示View的最底层了。（该段文字来自网络）其方法很简单，基本用到的就三个addView，removeView，updateViewLayout。另：在设置View高度和宽度的时候一个错误，即在View的构造函数中获取getWidth()和getHeight()，当一个view对象创建时，android并不知道其大小，所以getWidth()和getHeight()返回的结果是0，真正大小是在计算布局时才会计算，所以会发现一个有趣的事，即在onDraw( ) 却能取得长宽的原因。使用一下方法即可：

width = activity.getWindowManager().getDefaultDisplay().getWidth();   height = activity.getWindowManager().getDefaultDisplay().getHeight();

下面是LayoutParams，设置他的属性：详情请看上一篇文章：

http://blog.csdn.net/aomandeshangxiao/article/details/7040486

在这里是设置成了所有应用程序之上，状态栏之下的形式，当移动的时候，会调用case MotionEvent.ACTION_MOVE:

下面的代码主要是：

private void updateViewPosition() {// 更新浮动窗口位置参数wmParams.x = (int) (x - mTouchStartX);wmParams.y = (int) (y - mTouchStartY);wm.updateViewLayout(view, wmParams);}

从新设置浮动栏的位置参数。这样就实现了拖动的功能。其内存数据是如何获取及及时更新的呢？

我们注意到了handler：

handler.postDelayed(task, delaytime);                                                                                                                                                                                                                                   private Runnable task = new Runnable() { public void run() { // TODO Auto-generated method stub dataRefresh(); handler.postDelayed(this, delaytime); wm.updateViewLayout(view, wmParams); } };

我们找到dataRefresh方法，delaytime是设置的1000，也就是每一秒钟更新一次数据。

public void dataRefresh() {tx.setText("" + memInfo.getmem_UNUSED(this) + "KB");tx1.setText("" + memInfo.getmem_TOLAL() + "KB");}

最后，看下memInfo的定义：

public class memInfo {public static long getmem_UNUSED(Context mContext) {long MEM_UNUSED;ActivityManager am = (ActivityManager) mContext.getSystemService(Context.ACTIVITY_SERVICE);ActivityManager.MemoryInfo mi = new ActivityManager.MemoryInfo();am.getMemoryInfo(mi);MEM_UNUSED = mi.availMem / 1024;return MEM_UNUSED;}public static long getmem_TOLAL() {long mTotal;// 系统内存String path = "/proc/meminfo";// 存储器内容String content = null;BufferedReader br = null;try {br = new BufferedReader(new FileReader(path), 8);String line;if ((line = br.readLine()) != null) {// 采集内存信息content = line;}} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} finally {if (br != null) {try {br.close();} catch (IOException e) {e.printStackTrace();}}}// beginIndexint begin = content.indexOf(':');// endIndexint end = content.indexOf('k');// 采集数量的内存content = content.substring(begin + 1, end).trim();// 转换为Int型mTotal = Integer.parseInt(content);return mTotal;}}

里面只定义了两个方法，获取总内存和使用内存。

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