Android 获取判断是否有悬浮窗权限的方法

/**
 * API for interacting with "application operation" tracking.
 *
 * <p>This API is not generally intended for third party application developers; most
 * features are only available to system applications. Obtain an instance of it through
 * {@  Context#getSystemService(String) Context.getSystemService} with
 * {@  Context#APP_OPS_SERVICE Context.APP_OPS_SERVICE}.</p>
 */

/**
 * Result from {@  #checkOp}, {@  #noteOp}, {@  #startOp}: the given caller is
 * allowed to perform the given operation.
 */
public static final int MODE_ALLOWED = 0;

/**
 * Result from {@  #checkOp}, {@  #noteOp}, {@  #startOp}: the given caller is
 * not allowed to perform the given operation, and this attempt should
 * <em>silently fail</em> (it should not cause the app to crash).
 */
public static final int MODE_IGNORED = 1;

/**
 * Result from {@  #checkOpNoThrow}, {@  #noteOpNoThrow}, {@  #startOpNoThrow}: the
 * given caller is not allowed to perform the given operation, and this attempt should
 * cause it to have a fatal error, typically a {@  SecurityException}.
 */
public static final int MODE_ERRORED = 2;

/**
 * Result from {@  #checkOp}, {@  #noteOp}, {@  #startOp}: the given caller should
 * use its default security check. This mode is not normally used; it should only be used
 * with appop permissions, and callers must explicitly check for it and deal with it.
 */
public static final int MODE_DEFAULT = 3;

/**
 * Do a quick check for whether an application might be able to perform an operation.
 * This is <em>not</em> a security check; you must use {@  #noteOp(int, int, String)}
 * or {@  #startOp(int, int, String)} for your actual security checks, which also
 * ensure that the given uid and package name are consistent. This function can just be
 * used for a quick check to see if an operation has been disabled for the application,
 * as an early reject of some work. This does not modify the time stamp or other data
 * about the operation.
 * @param op The operation to check. One of the OP_* constants.
 * @param uid The user id of the application attempting to perform the operation.
 * @param packageName The name of the application attempting to perform the operation.
 * @return Returns {@  #MODE_ALLOWED} if the operation is allowed, or
 * {@  #MODE_IGNORED} if it is not allowed and should be silently ignored (without
 * causing the app to crash).
 * @throws SecurityException If the app has been configured to crash on this op.
 * @hide
 */
public int checkOp(int op, int uid, String packageName) {
 try {
  int mode = mService.checkOperation(op, uid, packageName);
  if (mode == MODE_ERRORED) {
   throw new SecurityException(buildSecurityExceptionMsg(op, uid, packageName));
  }
  return mode;
 } catch (RemoteException e) {
 }
 return MODE_IGNORED;
}

 /**
  * 判断 悬浮窗口权限是否打开
  *
  * @param context
  * @return true 允许 false禁止
  */
 public static boolean getAppOps(Context context) {
  try {
       = context.getSystemService("appops");
   if (  == null) {
    return false;
   }
   Class localClass =  .getClass();
   Class[] arrayOfClass = new Class[3];
   arrayOfClass[0] = Integer.TYPE;
   arrayOfClass[1] = Integer.TYPE;
   arrayOfClass[2] = String.class;
   Method method = localClass.getMethod("checkOp", arrayOfClass);
   if (method == null) {
    return false;
   }
    [] arrayOf 1 = new  [3];
   arrayOf 1[0] = Integer.valueOf(24);
   arrayOf 1[1] = Integer.valueOf(Binder.getCallingUid());
   arrayOf 1[2] = context.getPackageName();
   int m = ((Integer) method.invoke( , arrayOf 1)).intValue();
   return m == AppOpsManager.MODE_ALLOWED;
  } catch (Exception ex) {
 
  }
  return false;
 }