运行效果：
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;
@Override
public 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WindowManager
wm = (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() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent 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 stub
dataRefresh();
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);
}
@Override
public void onStart(Intent intent, int startId) {
Log.d("FloatService", "onStart");
setForeground(true);
super.onStart(intent, startId);
}
@Override
public void onDestroy() {
handler.removeCallbacks(task);
Log.d("FloatService", "onDestroy");
wm.removeView(view);
super.onDestroy();
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
}
其主要功能部分在creatView方法里：
private void createView() {
// 获取WindowManager
wm = (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() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent 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：
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();
}
}
}
// beginIndex
int begin = content.indexOf(':');
// endIndex
int 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。
