在MIUI系统，Dialog设置属性.getWindow().setType( WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);
调Dialog.show();的时候并没有显示Dialog，或者报错：
Android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application

应该是MIUI针对这个属性修改过，针对MIUI系统，可以

if (!MIUIUtils.isMIUI()) {   Dialog.getWindow().setType(     WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);  } else {  Dialog.getWindow().setType(     WindowManager.LayoutParams.TYPE_TOAST);  }

是否MIUI，可以根据这个获取

public class MIUIUtils {    private static final String KEY_MIUI_VERSION_CODE = "ro.miui.ui.version.code";    private static final String KEY_MIUI_VERSION_NAME = "ro.miui.ui.version.name";    private static final String KEY_MIUI_INTERNAL_STORAGE = "ro.miui.internal.storage";    public static boolean isMIUI() {        try {            final BuildProperties prop = BuildProperties.newInstance();            return prop.getProperty(KEY_MIUI_VERSION_CODE, null) != null                    || prop.getProperty(KEY_MIUI_VERSION_NAME, null) != null                    || prop.getProperty(KEY_MIUI_INTERNAL_STORAGE, null) != null;        } catch (final IOException e) {            return false;        }    }}

public class BuildProperties {    private final Properties properties;    private BuildProperties() throws IOException {        properties = new Properties();        properties.load(new FileInputStream(new File(Environment.getRootDirectory(), "build.prop")));    }    public boolean containsKey(final Object key) {        return properties.containsKey(key);    }    public boolean containsValue(final Object value) {        return properties.containsValue(value);    }    public Set<Map.Entry<Object, Object>> entrySet() {        return properties.entrySet();    }    public String getProperty(final String name) {        return properties.getProperty(name);    }    public String getProperty(final String name, final String defaultValue) {        return properties.getProperty(name, defaultValue);    }    public boolean isEmpty() {        return properties.isEmpty();    }    public Enumeration<Object> keys() {        return properties.keys();    }    public Set<Object> keySet() {        return properties.keySet();    }    public int size() {        return properties.size();    }    public Collection<Object> values() {        return properties.values();    }    public static BuildProperties newInstance() throws IOException {        return new BuildProperties();    }}