hasSystemFeature()判断是否有特定的功能模块

getPackageManager().hasSystemFeature(String name);
//例如
getPackageManager().hasSystemFeature(PackageManager.FEATURE_WIFI);
getPackageManager().hasSystemFe(PackageManager.FEATURE_BLUETOOTH);

范例：

PackageManager pm = context.getPackageManager();

FeatureInfo[] features = pm.getSystemAvailableFeatures(); //得到所有支援的硬件种类
for (FeatureInfo feature : features) Log.v(TAG, feature.name);

boolean hasFlashlight = pm.hsaSystemFeature(PackageManager.FEATURE_CAMERA_FLASH); //是否支援閃光燈

boolean hasCamera = pm.hsaSystemFeature(PackageManager.FEATURE_CAMERA); //是否支援相機

boolean hasBt = pm.hsaSystemFeature(PackageManager.FEATURE_BLUETOOTH); //是否支援藍牙

hasSystemFeature 這個接口參考信息是

/system/etc/permissions/android.hardware*.xml 文件中定義的feature的信息

/frameworks/base/data/etc/android.hardware.camera.flash-autofocus.xml

< ?xml version="1.0" encoding="utf-8"?>
 <permissions>
     <feature name="android.hardware.camera" />
     <feature name="android.hardware.camera.autofocus" />
     <feature name="android.hardware.camera.flash" />
  </permissions>

如果想增加Feature配置，可以再framework/base/data/etc/目录下增加xml文件

1. 获取当前设备支持的所有features

   FeatureInfo[] f = getPackageManager().getSystemAvailableFeatures();

2. 判断当前设备是否支持某项feature

   boolean b = getPackageManager().hasSystemFeature(featureName);

3. 获取当前设备上已经安装的其他app的uses-feature配置，获取其他app的uses-feature配置不需要特别的权限，设备上已安装的任意一个app都可以获取。

    try {
            String packageName = getPackageName();
            PackageInfo p = getPackageManager().getPackageInfo(packageName, PackageManager.GET_CONFIGURATIONS);
            FeatureInfo[] f = p.reqFeatures;
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }