这期内容当中小编将会给大家带来有关怎么在Android中判断是否有悬浮窗权限，文章内容丰富且以专业的角度为大家分析和叙述，阅读完这篇文章希望大家可以有所收获。
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Android 原生有自带权限管理的，只是被隐藏了。看android源码在android.app下就有个AppOpsManager类。
类说明如下：
/** * API for interacting with "application operation" tracking. * *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 * {@link Context#getSystemService(String) Context.getSystemService} with * {@link Context#APP_OPS_SERVICE Context.APP_OPS_SERVICE}.
*/
上面说明了只对系统应用有用，rom厂商们应该就是利用这个AppOps机制开放一些权限控制。
我们要判断是否有权限该如何做呢？就只能通过反射去判断了。
AppOpsManager的checkOp方法，就是检测是否有某项权限的方法有这些返回值，分别是允许，忽略，错误和默认：
/**
* Result from {@link #checkOp}, {@link #noteOp}, {@link #startOp}: the given caller is
* allowed to perform the given operation.
*/
public static final int MODE_ALLOWED = 0;
/**
* Result from {@link #checkOp}, {@link #noteOp}, {@link #startOp}: the given caller is
* not allowed to perform the given operation, and this attempt should
* silently fail (it should not cause the app to crash).
*/
public static final int MODE_IGNORED = 1;
/**
* Result from {@link #checkOpNoThrow}, {@link #noteOpNoThrow}, {@link #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 {@link SecurityException}.
*/
public static final int MODE_ERRORED = 2;
/**
* Result from {@link #checkOp}, {@link #noteOp}, {@link #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;只有MODE_ALLOWED才是确定有权限的。
类里面checkOp方法如下，三个参数分别是操作id，uid和包名：
/**
* Do a quick check for whether an application might be able to perform an operation.
* This is not a security check; you must use {@link #noteOp(int, int, String)}
* or {@link #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 {@link #MODE_ALLOWED} if the operation is allowed, or
* {@link #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;
}操作id即op可以在该类中找到静态值定义，android23里面有62种权限，我们需要的是OP_SYSTEM_ALERT_WINDOW=24
知道这些就可以用反射把我们的方法写出了：
/**
* 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 {
Object object = context.getSystemService("appops");
if (object == null) {
return false;
}
Class localClass = object.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;
}
Object[] arrayOfObject1 = new Object[3];
arrayOfObject1[0] = Integer.valueOf(24);
arrayOfObject1[1] = Integer.valueOf(Binder.getCallingUid());
arrayOfObject1[2] = context.getPackageName();
int m = ((Integer) method.invoke(object, arrayOfObject1)).intValue();
return m == AppOpsManager.MODE_ALLOWED;
} catch (Exception ex) {
}
return false;
}上述就是小编为大家分享的怎么在Android中判断是否有悬浮窗权限了，如果刚好有类似的疑惑，不妨参照上述分析进行理解。如果想知道更多相关知识，欢迎关注创新互联行业资讯频道。