去设置里打开相机权限

function openCamera(){  
    var msg = "请在应用权限里设置允许使用相机权限";  
    mui.alert(msg,"开启相机权限","去开启",function(){          
        if (mui.os.ios) {  
            plus.runtime.openURL("app-settings:CAMERA");  
        } else {  
            var main = plus.android.runtimeMainActivity();  
            var Intent = plus.android.importClass("android.content.Intent");  
            var Build = plus.android.importClass("android.os.Build");  
            var Uri = plus.android.importClass("android.net.Uri");  
            var intent = new Intent();  
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);  
            if (Build.VERSION.SDK_INT >= 9) {//系统8.0以上的  
                intent.setAction("android.settings.APPLICATION_DETAILS_SETTINGS");  
                intent.setData(Uri.fromParts("package", main.getPackageName(), null));  
            } else if (Build.VERSION.SDK_INT <= 8) {//系统8.0以下的  
                intent.setAction(Intent.ACTION_VIEW);  
                intent.setClassName("com.android.settings", "com.android.setting.InstalledAppDetails");  
                intent.putExtra("com.android.settings.ApplicationPkgName", main.getPackageName());  
            }  
            main.startActivity(intent);  
            //  
        }  
    })  
};