Add simplePio sample.

A simple sample that covers the basic usage for the PIO APIs.

Change-Id: I56789ce84b7f167be832b6e4a7ff4205d833837c

.gitignore

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+*.iml
+.gradle
+local.properties
+.idea
+.DS_Store
+build

README.md

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+Simple example of Brillo Peripheral I/O APIs
+============================================
+
+This Brillo app runs basic code that exercises the PIO APIs. There is a set of API samples that
+can be "browsed" and executed by clicking on onboard buttons.
+
+Pre-requisites
+--------------
+
+- Intel Edison
+- Brillo 2.0
+
+
+Build and install
+=================
+
+1. Plug your Intel Edison board to your computer via USB
+2. Click on "Run" in Android Studio or use the command line: `./gradlew installDebug`
+
+
+Run
+===
+
+Press the "RM" button on the Intel Edison to change from one task to another, and then press the
+"PWR" button to execute the selected task. The selected task will be printed on
+logcat (`adb logcat`).
+
+
+License
+-------
+
+Copyright 2016 The Android Open Source Project, Inc.
+
+Licensed to the Apache Software Foundation (ASF) under one or more contributor
+license agreements.  See the NOTICE file distributed with this work for
+additional information regarding copyright ownership.  The ASF licenses this
+file to you under the Apache License, Version 2.0 (the "License"); you may not
+use this file except in compliance with the License.  You may obtain a copy of
+the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+License for the specific language governing permissions and limitations under
+the License.

app/build.gradle

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+apply plugin: 'com.android.application'
+
+android {
+    compileSdkVersion 23
+    buildToolsVersion '24.0.0-rc4'
+
+    defaultConfig {
+        applicationId "com.google.samples.mysample"
+        minSdkVersion 21
+        targetSdkVersion 22
+        versionCode 1
+        versionName "1.0"
+        jackOptions {
+            enabled true
+        }
+    }
+    buildTypes {
+        debug {
+            multiDexEnabled true
+        }
+        release {
+            multiDexEnabled true
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+}
+
+dependencies {
+    compile fileTree(dir: 'libs', include: ['*.jar'])
+    testCompile 'junit:junit:4.12'
+}

app/proguard-rules.pro

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+# Add project specific ProGuard rules here.
+# By default, the flags in this file are appended to flags specified
+# in /usr/local/google/home/stammt/Android/Sdk/tools/proguard/proguard-android.txt
+# You can edit the include path and order by changing the proguardFiles
+# directive in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# Add any project specific keep options here:
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}

app/src/main/AndroidManifest.xml

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+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.google.samples.simplepio">
+
+    <application
+        android:allowBackup="true"
+        android:icon="@android:drawable/sym_def_app_icon"
+        android:label="@string/app_name">
+        <service
+            android:name="com.google.samples.simplepio.SimplePIOService"
+            android:exported="true"
+            android:permission="android.permission.BIND_HEADLESS_SERVICE"
+            >
+            <intent-filter>
+                <action android:name="android.service.headless.HomeService" />
+                <category android:name="android.intent.category.DEFAULT" />
+            </intent-filter>
+        </service>
+
+    </application>
+
+
+</manifest>

app/src/main/java/com/google/samples/simplepio/SimplePIOService.java

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+package com.google.samples.simplepio;
+
+import android.os.Handler;
+import android.os.HandlerThread;
+import android.service.headless.HomeService;
+import android.util.Log;
+import android.view.InputEvent;
+import android.view.KeyEvent;
+
+import com.google.samples.simplepio.task.GPIOTask;
+import com.google.samples.simplepio.task.LEDTask;
+
+/**
+ * Simple {@link HomeService} that executes {@link Runnable} in a separate thread.
+ *
+ * When certain input events (Intel Edison onboard PWR and RM buttons) are received,
+ * this class cycles through a list of tasks ({@link Runnable}) and schedules the selected task
+ * to execute in a separate thread.
+ */
+public class SimplePIOService extends HomeService {
+    public static final String TAG = "SimplePIOService";
+
+    private static final int BUTTON_EDISON_RM_KEYCODE = 148;
+    private static final int BUTTON_EDISON_PWR_KEYCODE = 116;
+
+    private HandlerThread mRunnerThread;
+    private Handler mRunnerThreadHandler;
+    private int mCurrentTask;
+    private Runnable[] mTasks;
+
+    @Override
+    public void onCreate() {
+        Log.d(TAG, "Headless service created");
+        mRunnerThread = new HandlerThread("runnerThread");
+        mRunnerThread.start();
+        mRunnerThreadHandler = new Handler(mRunnerThread.getLooper());
+
+        mCurrentTask = 0;
+        mTasks = new Runnable[] {
+                new GPIOTask(),
+                new LEDTask()
+        };
+
+        Log.i(TAG, mTasks.length + " tasks available. Current task is " +
+                getTaskName(mTasks[mCurrentTask]));
+        Log.i(TAG, "Press the RM onboard button to select another task.");
+        Log.i(TAG, "Press the PWR onboard button to execute the current task.");
+    }
+
+    private String getTaskName(Runnable r) {
+        return r.getClass().getSimpleName();
+    }
+
+    @Override
+    public void onInputEvent(InputEvent event) {
+        if (((KeyEvent) event).getAction() == KeyEvent.ACTION_DOWN) {
+            switch (((KeyEvent) event).getScanCode()) {
+                case BUTTON_EDISON_RM_KEYCODE:
+                    mCurrentTask = (mCurrentTask + 1) % mTasks.length;
+                    Log.d(TAG, "Button RM pressed. Changed current task to " + mCurrentTask +
+                            " (" + getTaskName(mTasks[mCurrentTask]) + "). Now press " +
+                            "PWR to execute it.");
+                    break;
+                case BUTTON_EDISON_PWR_KEYCODE:
+                    Log.d(TAG, "Button PWR pressed. Executing task " + mCurrentTask +
+                            " (" + getTaskName(mTasks[mCurrentTask]) + ")");
+                    executeCurrentTask();
+                    break;
+            }
+        }
+    }
+
+    @Override
+    public void onDestroy() {
+        if (mRunnerThread != null) {
+            mRunnerThread.quit();
+        }
+    }
+
+    private void executeCurrentTask() {
+        Log.d(TAG, "Executing task " + mCurrentTask +
+                " (" + getTaskName(mTasks[mCurrentTask]) + ")");
+        Runnable r = mTasks[mCurrentTask];
+
+        // It is a good practice to execute I/O code in a separate thread
+        mRunnerThreadHandler.post(r);
+    }
+
+}

app/src/main/java/com/google/samples/simplepio/task/GPIOTask.java

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+package com.google.samples.simplepio.task;
+
+import android.os.RemoteException;
+import android.pio.Gpio;
+import android.pio.PeripheralManagerService;
+import android.system.ErrnoException;
+import android.util.Log;
+
+import com.google.samples.simplepio.SimplePIOService;
+
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Simple GPIO port handling.
+ */
+
+public class GPIOTask implements Runnable {
+    private static final String TAG = SimplePIOService.TAG;
+
+    private PeripheralManagerService mService;
+
+    /**
+     * Preferred GPIO port to look for. For example, on Intel Edison Arduino-compatible boards,
+     * the port "IO13" has an onboard LED that turns on when the GPIO port is HIGH, and off
+     * otherwise, so it is easy to debug that GPIO port' state without any extra hardware.
+     */
+    private static final String PREFERRED_GPIO_PORT = "IO13";
+
+    private static final int NUMBER_OF_BLINKS = 30;
+    private static final int INTERVAL_BETWEEN_BLINKS_MS = 50;
+
+    public GPIOTask() {
+        mService = new PeripheralManagerService();
+    }
+
+    @Override
+    public void run() {
+        Log.i(TAG, "Executing task GPIOTask");
+        try {
+            List<String> gpios = listGpios();
+            if (gpios == null || gpios.isEmpty()) {
+                return;
+            }
+
+            String portName;
+            // if the preferred port exists, use it, otherwise use the first port identified.
+            int preferred = gpios.indexOf(PREFERRED_GPIO_PORT);
+            if (preferred >= 0) {
+                portName = gpios.get(preferred);
+            } else {
+                portName = gpios.get(0);
+            }
+
+            // GPIO ports are single-user resources, so make sure you close them when you're done.
+            // The "try with resources" syntax below is a good way of guaranteeing it.
+            try (Gpio gpio = mService.openGpio(portName)) {
+                gpio.setDirection(Gpio.DIRECTION_OUT_INITIALLY_LOW);
+                blink(gpio, NUMBER_OF_BLINKS, INTERVAL_BETWEEN_BLINKS_MS);
+            }
+            // Notice that the gpio resource will be closed anyway, either if the
+            // try(){} block finishes successfully or if an exception is thrown.
+            // If you do not use a try(resource){} block, make sure you close the gpio port
+            // in a finally clause, otherwise an ErrnoException will be thrown when
+            // openGpio is called again on this port.
+
+        } catch (RemoteException | ErrnoException e) {
+            Log.e(TAG, "Error on PeripheralIO API", e);
+        }
+    }
+
+    private List<String> listGpios() throws RemoteException {
+        // List available GPIOs:
+        List<String> gpios = mService.getGpioList();
+        if (gpios == null || gpios.isEmpty()) {
+            Log.i(TAG, "No GPIO port available on this device.");
+        } else {
+            Log.i(TAG, "List of available GPIO ports: " + gpios);
+        }
+        return gpios;
+    }
+
+    private void blink(Gpio gpio, int numberOfBlinks, int intervalBetweenBlinksMs)
+            throws RemoteException, ErrnoException {
+        // Alternate GPIO output in a loop. Connect an LED to the port to see it blinking.
+        for (int i=0; i < numberOfBlinks; i++) {
+
+            // Turn on when i is even, off otherwise
+            gpio.setValue( i % 2 == 0 );
+
+            // Sleep for a while
+            try {
+                TimeUnit.MILLISECONDS.sleep(intervalBetweenBlinksMs);
+            } catch (InterruptedException e) {
+                // Ignore sleep interruption.
+            }
+        }
+
+        // Turn off at the end
+        gpio.setValue(false);
+    }
+}