如果定义的是前面两种normal或者dangerous,
我们自己的应用需要去访问其对应受保护的资源时只需要在androidManifest.xml中添加相同的uses-permission就行了。
如果是signature, 我们仅仅添加对权限的使用还不行， 必须同时具有相同的签名。
如果是signatureOrSystem（这种权限的应用第三方的应用无法单独访问）,
不仅要有相同的签名，而且签名必须是系统签名，此外可能还需要android:sharedUserId="android.uid.system"。
View Code/**
* A normal application value for {@link #protectionLevel}, corresponding
* to the <code>normal</code> value of
* {@link android.R.attr#protectionLevel}.
*/
public static final int PROTECTION_NORMAL = 0;
/**
* Dangerous value for {@link #protectionLevel}, corresponding
* to the <code>dangerous</code> value of
* {@link android.R.attr#protectionLevel}.
*/
public static final int PROTECTION_DANGEROUS = 1;
/**
* System-level value for {@link #protectionLevel}, corresponding
* to the <code>signature</code> value of
* {@link android.R.attr#protectionLevel}.
*/
public static final int PROTECTION_SIGNATURE = 2;
/**
* System-level value for {@link #protectionLevel}, corresponding
* to the <code>signatureOrSystem</code> value of
* {@link android.R.attr#protectionLevel}.
*/
public static final int PROTECTION_SIGNATURE_OR_SYSTEM = 3;
/**
* Additional flag for {@link #protectionLevel}, corresponding
* to the <code>system</code> value of
* {@link android.R.attr#protectionLevel}.
*/
public static final int PROTECTION_FLAG_SYSTEM = 0x10;
/**
* Additional flag for {@link #protectionLevel}, corresponding
* to the <code>development</code> value of
* {@link android.R.attr#protectionLevel}.
*/
public static final int PROTECTION_FLAG_DEVELOPMENT = 0x20;
/**
* Mask for {@link #protectionLevel}: the basic protection type.
*/
public static final int PROTECTION_MASK_BASE = 0xf;
/**
* Mask for {@link #protectionLevel}: additional flag bits.
*/
public static final int PROTECTION_MASK_FLAGS = 0xf0;
/** @hide */
public static int fixProtectionLevel(int level) {
if (level == PROTECTION_SIGNATURE_OR_SYSTEM) {
level = PROTECTION_SIGNATURE | PROTECTION_FLAG_SYSTEM;
}
return level;
}
/** @hide */
public static String protectionToString(int level) {
String protLevel = "????";
switch (level&PROTECTION_MASK_BASE) {
case PermissionInfo.PROTECTION_DANGEROUS:
protLevel = "dangerous";
break;
case PermissionInfo.PROTECTION_NORMAL:
protLevel = "normal";
break;
case PermissionInfo.PROTECTION_SIGNATURE:
protLevel = "signature";
break;
case PermissionInfo.PROTECTION_SIGNATURE_OR_SYSTEM:
protLevel = "signatureOrSystem";
break;
}
if ((level&PermissionInfo.PROTECTION_FLAG_SYSTEM) != 0) {
protLevel += "|system";
}
if ((level&PermissionInfo.PROTECTION_FLAG_DEVELOPMENT) != 0) {
protLevel += "|development";
}
return protLevel;
}
系统定义的这些permission来自两处：framework/base/core/res/AndroidManifest.xml和framework/base/data/etc/platform.xml，前者最主要，如android-4.4.2_r2。
