在Android中打开/关闭相机手电筒的小工具

Question

我正在开发一个用于打开/关闭手机摄像头的小部件.

我创建了一个可以像切换按钮(开/关)一样工作的小部件.

行为如下所示:当我启用小部件时,有时候led灯仍然亮着.但它不会打开/关闭相机,但它会改变图标.

我无法弄清楚实际问题是什么.

在Activity(火炬之光应用程序)中同样适用.

任何人都可以解释我如何解决我的问题？

我哪里错了？

你可以查看我到目前为止所做的代码

onUpdate 方法

@Override
    public void onUpdate(Context context, AppWidgetManager appWidgetManager,
            int[] appWidgetIds) {

         //super.onUpdate(context, appWidgetManager, appWidgetIds);

        remoteViews = new RemoteViews( context.getPackageName(), R.layout.widgetlayout);
        watchWidget = new ComponentName( context, FlashLightWidget.class );

        Intent intentClick = new Intent(context,FlashLightWidget.class);
        intentClick.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, ""+appWidgetIds[0]);

        PendingIntent pendingIntent = PendingIntent.getBroadcast(context, appWidgetIds[0],intentClick, 0);
        remoteViews.setOnClickPendingIntent(R.id.myToggleWidget, pendingIntent);
        appWidgetManager.updateAppWidget( watchWidget, remoteViews );
        ctx=context;      
    }

onReceive 方法如下:

@Override

    public void onReceive(Context context, Intent intent) {
        // TODO Auto-generated method stub

        remoteViews = new RemoteViews( context.getPackageName(), R.layout.widgetlayout);
        if (intent.getAction()==null) {
            Bundle extras = intent.getExtras();
            if(extras!=null) {
                 if(status)
                    {
                        status=false;
                        remoteViews.setImageViewResource(R.id.myToggleWidget, R.drawable.shutdown1);
                        processOnClick();
                        Toast.makeText(context,"Status==false-onclick",Toast.LENGTH_SHORT).show();
                    }
                    else
                    {
                        status = true;
                        remoteViews.setImageViewResource(R.id.myToggleWidget, R.drawable.shutdown2);
                        processOffClick();
                        Toast.makeText(context,"Status==true--Ofclick",Toast.LENGTH_SHORT).show();
                    }
                }

                watchWidget = new ComponentName( context, FlashLightWidget.class );

                (AppWidgetManager.getInstance(context)).updateAppWidget( watchWidget, remoteViews );
           }
        }
  }

processOffClick 方法

private void processOffClick() {

        if (mCamera != null) {
            mCamera.stopPreview();
            mCamera.setPreviewCallback(null);
            mCamera.release();      
            mCamera = null;
        }
    }

processOnClick 方法

private void processOnClick() {

    if(mCamera==null)
    {
        try {
            mCamera = Camera.open();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    if (mCamera != null) {

        Parameters params = mCamera.getParameters();
        List<String> flashModes = params.getSupportedFlashModes();

        if (flashModes == null) {
            return;
        } else {

                params.setFlashMode(Parameters.FLASH_MODE_OFF);
                mCamera.setParameters(params);
                mCamera.startPreview();

            String flashMode = params.getFlashMode();

            if (!Parameters.FLASH_MODE_TORCH.equals(flashMode)) {

                if (flashModes.contains(Parameters.FLASH_MODE_TORCH)) {
                    params.setFlashMode(Parameters.FLASH_MODE_TORCH);
                    mCamera.setParameters(params);

                } 

            }
        }
    } else if (mCamera == null) {
        //Toast.makeText(ctx, "Camera not found", Toast.LENGTH_LONG).show();
        return;
    }
}

Answer 1

很长一段时间后,我可以自由地解决这个问题.

这就是我做的.

FlashlightWidgetProvider 课程:

public class FlashlightWidgetProvider extends AppWidgetProvider {

        @Override
        public void onUpdate(Context context, AppWidgetManager appWidgetManager,
                        int[] appWidgetIds) {

                Intent receiver = new Intent(context, FlashlightWidgetReceiver.class);
                receiver.setAction("COM_FLASHLIGHT");
                receiver.putExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS, appWidgetIds);
                PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, receiver, 0);

                RemoteViews views = new RemoteViews(context.getPackageName(),
                                R.layout.widget_layout);
                views.setOnClickPendingIntent(R.id.button, pendingIntent);

                appWidgetManager.updateAppWidget(appWidgetIds, views);

        }
}

和BroadcastReceiver for FlashlightWidgetReceiver:

public class FlashlightWidgetReceiver extends BroadcastReceiver {
            private static boolean isLightOn = false;
            private static Camera camera;

            @Override
            public void onReceive(Context context, Intent intent) {
                    RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget_layout);

                    if(isLightOn) {
                            views.setImageViewResource(R.id.button, R.drawable.off);
                    } else {
                            views.setImageViewResource(R.id.button, R.drawable.on);
                    }

                    AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
                    appWidgetManager.updateAppWidget(new ComponentName(context,     FlashlightWidgetProvider.class),
                                                                                     views);

                    if (isLightOn) {
                            if (camera != null) {
                                    camera.stopPreview();
                                    camera.release();
                                    camera = null;
                                    isLightOn = false;
                            }

                    } else {
                            // Open the default i.e. the first rear facing camera.
                            camera = Camera.open();

                            if(camera == null) {
                                    Toast.makeText(context, R.string.no_camera, Toast.LENGTH_SHORT).show();
                            } else {
                                    // Set the torch flash mode
                                    Parameters param = camera.getParameters();
                                    param.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
                                    try {
                                            camera.setParameters(param);
                                            camera.startPreview();
                                            isLightOn = true;
                                    } catch (Exception e) {
                                            Toast.makeText(context, R.string.no_flash, Toast.LENGTH_SHORT).show();
                                    }
                            }
                    }
            }
    }

Manifest.xml文件中要求的权限:

<uses-permission android:name="android.permission.CAMERA"></uses-permission>

还在Manifest.xml文件中注册接收器:

<receiver android:name=".FlashlightWidgetProvider" android:icon="@drawable/on" android:label="@string/app_name">
         <intent-filter>
            <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
         </intent-filter>

         <meta-data android:name="android.appwidget.provider"
                        android:resource="@xml/flashlight_appwidget_info" />
</receiver>

<receiver android:name="FlashlightWidgetReceiver">
        <intent-filter>
               <action android:name="COM_FLASHLIGHT"></action>
        </intent-filter>
 </receiver>

重要说明:如果您的手机FLASH_MODE_TORCH支持,此代码非常有用.

我已在三星Galaxy Ace 2.2.1和2.3.3中测试过.代码无法正常工作,因为该设备没有FLASH_MODE_TORCH.

适用于HTC Salsa,Wildfire ..

如果有人可以在这里测试和发布结果,那将是最好的.

Answer 2

处理来自a的点击的最佳方法RemoteViews是创建一个PendingIntent调用服务,并在服务中执行所需的"东西",包括RemoteViews小部件的任何其他更新.您可以在意图附加内容中发送相关数据.服务stopSelf()在最后调用,因此关闭.

你不能维持任何状态BroadcastReceiver; 系统在任何可用线程上运行那些,并且在调用后不保持对您的实例的任何引用onReceive().您的mCamera变量不能保证在您的调用之间保持不变BroadcastReceiver.

如果您确实需要维护状态,则必须在服务中执行此操作,并且不要使用stopSelf()(直到适当的时间).

您不需要UI线程来使用Camera该类,除非您正在进行图像预览,这需要SurfaceHolder(并暗示UI).但是,您必须激活一个事件循环,或者Camera不会向您发回回调,这是一个问题,因为Camera它主要是异步的.您可以在服务中执行此操作(请参阅参考资料HandlerThread)并保持服务正常运行,直到完成release()所有操作.无论哪个线程调用Camera.open()都会收到回调.

大家是否真的阅读过App Widgets的部分？ http://developer.android.com/guide/topics/appwidgets/index.html

使用AppWidgetProvider类部分说明了我在这里说的内容.