Setting API

In PSLab android app, we have included sensor instruments which use either inbuilt sensor of smartphone or external sensor to record sensor data. For example, Lux Meter uses the light sensor to record lux data but the problem is that these instruments doesn’t contain settings option to configure the sensor record-setting like which sensor to use, change the update period etc. Therefore, we need to create a settings page for the Lux Meter instrument which allows the user to modify the properties of the sensor instrument. For that I will use Android Preference APIs to build a settings interface that is similar to setting activity in any other android app. The main building block of the settings activity is the Preference object. Each preference appears as a single setting item in an activity and it corresponds to key-value pair which stores the settings in default Shared Preferences file. Every time any setting is changed by the user the Android will store the updated value of the setting in the default shared preferences which we can read in any other activity across the app. In the following steps I will describe instruction on how to create the setting interface in Android app:  Step1 Include the dependency First, we need to include the dependency for v7 Preference Support Library by including the following code: dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) compile 'com.android.support:appcompat-v7:23.1.1' compile 'com.android.support:design:23.1.1' compile 'com.android.support:preference-v7:23.1.1' }  Step 2 Creating the preferences screen in XML For this step, I have created a preference screen which will be inflated when the settings fragment is being created. I created a file named  “lux_meter_settings.xml” and place it in the res/xml/ directory. The root node for the XML file must be a <PreferenceScreen> element. We have to add each Preference within this element. Each child I added within the <PreferenceScreen> element appears as a single item in the list of settings. The preference which I have used are: <EdittextPreference> This preference opens up a dialog box with edit text and stores whatever value is written by the user in the edit text. I have used this preference for inputting update period and high limit of data during recording. <CheckboxPreference> shows an item with a checkbox for a setting that is either enabled or disabled. The saved value is a boolean (true if it's checked). I have used this preference for enabling or disabling location data with the recorded data. <ListPreference> opens a dialog with a list of radio buttons. The saved value can be any one of the supported value types. I have used this preference to allow the user to choose between multiple sensor types. <?xml version="1.0" encoding="utf-8"?> <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"> <EditTextPreference android:key="setting_lux_update_period" android:title="@string/update_period" android:dialogTitle="@string/update_period" android:defaultValue="1000" android:dialogMessage="Please provide time interval(in ms) at which data will be updated" android:summary="Update period is 900ms"/> <EditTextPreference android:key="setting_lux_high_limit" android:title="High Limit" android:dialogTitle="High Limit" android:defaultValue="2000" android:dialogMessage="Please provide maximum limit of LUX value to be recorded" android:summary="High Limit is 2000 Lux"/> <CheckBoxPreference android:defaultValue="false" android:key="include_location_sensor_data" android:summary="Include the location data in the logged file" android:title="Include Location…