8.【小萌伴Android】手电筒功能及其实现

前面三篇介绍了【小萌伴】百宝箱中的三款原生小游戏，这里说说百宝箱中另一功能模块--实用小应用...

【小萌伴】手电筒.gif

原理

【小萌伴】手电筒.jpg

实现

    /**
     * 是否支持手电筒功能
     * @param context
     * @return
     */
    public static boolean hasFlash(Context context) {
        PackageManager pm = context.getPackageManager();
        FeatureInfo[] featureInfos = pm.getSystemAvailableFeatures();
        for (FeatureInfo f : featureInfos) {
            if (PackageManager.FEATURE_CAMERA_FLASH.equals(f.name)) {
                return true;
            }
        }
        return false;
    }

    public static Camera getCamera(Context context) {
        if (!hasFlash(context)) return null;
        if (sCamera == null) {
            try {
                sCamera = Camera.open();
            } catch (Exception e) {
                try {
                    sCamera = Camera.open(Camera.getNumberOfCameras() - 1);
                } catch (Exception e1) {
                    TastyToastUtil.toast(E7App.mApp, R.string.flashlight_open_error);
                }
            }
        }
        return sCamera;
    }

    private static void ensureCamera(Context context) {
        getCamera(context);
    }
<span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title">openFlash</span><span class="hljs-params">(Context context)</span> </span>{
    ensureCamera(context);
    <span class="hljs-keyword">if</span> (sCamera == <span class="hljs-keyword">null</span>) <span class="hljs-keyword">return</span>;
    <span class="hljs-keyword">try</span> {
        Camera.Parameters parameters = sCamera.getParameters();
        parameters.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
        sCamera.setParameters(parameters);
        sCamera.cancelAutoFocus();
        sCamera.startPreview();
    } <span class="hljs-keyword">catch</span> (Exception e) {
    }
}

<span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title">closeFlash</span><span class="hljs-params">()</span> </span>{
    <span class="hljs-keyword">if</span> (sCamera == <span class="hljs-keyword">null</span>) <span class="hljs-keyword">return</span>;
    <span class="hljs-keyword">try</span> {
        Camera.Parameters parameters = sCamera.getParameters();
        parameters.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
        sCamera.setParameters(parameters);
    } <span class="hljs-keyword">catch</span> (Exception e) {
    }
}

通知及广播

public class NotificationControl {
<span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> final <span class="hljs-keyword">int</span> sNotificationId = <span class="hljs-number">318</span>;

<span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title">showNotification</span><span class="hljs-params">(Context context)</span> </span>{
    NotificationCompat.Builder builder = <span class="hljs-keyword">new</span> NotificationCompat.Builder(context)
            .setSmallIcon(R.drawable.ic_notify)
            .setContentTitle(context.getString(R.<span class="hljs-built_in">string</span>.app_name))
            .setContentText(context.getString(R.<span class="hljs-built_in">string</span>.notification_text));

    PendingIntent pendingIntent =
            PendingIntent.getBroadcast(context, <span class="hljs-number">0</span>, <span class="hljs-keyword">new</span> Intent(FlashLightWidget.ACTION_LED_OFF), <span class="hljs-number">0</span>);
    builder.setContentIntent(pendingIntent);
    NotificationManager manager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
    manager.notify(sNotificationId, builder.build());
}

<span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title">cancelNotification</span><span class="hljs-params">(Context context)</span> </span>{
    NotificationManager manager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
    manager.cancel(sNotificationId);
}

}

    BroadcastReceiver mReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            if (FlashLightWidget.ACTION_LED_ON.equals(intent.getAction())) {
                flashOpend();
            } else if (FlashLightWidget.ACTION_LED_OFF.equals(intent.getAction())) {
                flashClosed();
            }
        }
    };

【小萌伴】手电筒2.jpg

小组件

    @Override
    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
        // There may be multiple widgets active, so update all of them
        for (int widgetId : appWidgetIds) {
            updateAppWidget(context, appWidgetManager, widgetId);
        }
    }
<span class="hljs-function"><span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title">updateAppWidget</span><span class="hljs-params">(Context context, AppWidgetManager appWidgetManager,
                            <span class="hljs-keyword">int</span> appWidgetId)</span> </span>{
    RemoteViews views = <span class="hljs-keyword">new</span> RemoteViews(context.getPackageName(), R.layout.flash_light_widget);
    views.setImageViewResource(R.id.widget_led, R.drawable.widget_led);
    views.setInt(R.id.widget_led, <span class="hljs-string">"setBackgroundResource"</span>, R.drawable.widget_led_bg);
    views.setOnClickPendingIntent(R.id.widget_led, PendingIntent.getBroadcast(context, <span class="hljs-number">0</span>, <span class="hljs-keyword">new</span> Intent(ACTION_LED_ON), <span class="hljs-number">0</span>));
    appWidgetManager.updateAppWidget(appWidgetId, views);
}

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