双击电源按钮时闪光灯应打开

Question

我有一个应用程序，其中只有一个切换按钮。这个切换按钮的功能是当我按下它时打开闪光灯，当我再次按下它时关闭闪光灯。但我希望即使我的设备被锁定、睡眠或工作时也能发生这种情况。每当我双击电源按钮时，应用程序功能应该在服务中运行，并通过广播它应该打开闪光灯。请让我知道如何做到这一点。

Answer 1

MainActivity

package com.example.salal_khan.flashlightservices;

import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;

public class MainActivity extends AppCompatActivity {


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);



        Context context = this;
        PackageManager pm = context.getPackageManager();
        // if device support camera?
        if (!pm.hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
            Log.e("err", "Device has no camera!");
            return;
        }
        startService();
    }


    public void startService() {
        startService(new Intent(getBaseContext(), MyService.class));
    }

    // Method to stop the service
    public void stopService() {
        stopService(new Intent(getBaseContext(), MyService.class));
    }
}

服务

package com.example.salal_khan.flashlightservices;

import android.app.Service;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.os.Binder;
import android.os.IBinder;
import android.support.annotation.Nullable;
import android.util.Log;
import android.widget.Toast;

/**
 * Created by salal-khan on 12/1/2017.
 */
public class MyService extends Service {


    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        // Let it continue running until it is stopped.
        Toast.makeText(this, "Service Started", Toast.LENGTH_LONG).show();

        final IntentFilter filter = new 
        IntentFilter(Intent.ACTION_SCREEN_ON);
        filter.addAction(Intent.ACTION_SCREEN_OFF);
        filter.addAction(Intent.ACTION_USER_PRESENT);
        final BroadcastReceiver mReceiver = new ScreenReceiver();
        registerReceiver(mReceiver, filter);
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Toast.makeText(this, "Service Destroyed", Toast.LENGTH_LONG).show();



    }




    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();
    }


}

广播接收器

package com.example.salal_khan.flashlightservices;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.hardware.Camera;
import android.util.Log;
import android.hardware.Camera.Parameters;

/**
 * Created by salal-khan on 12/1/2017.
 */

public class ScreenReceiver extends BroadcastReceiver {

    public static boolean wasScreenOn = true;


    Camera camera;
    boolean isON = false;

    int number_of_clicks = 0;
    boolean thread_started = false;
    final int DELAY_BETWEEN_CLICKS_IN_MILLISECONDS = 550;


    @Override
    public void onReceive(final Context context, final Intent intent) {
        ++number_of_clicks;
        if (!thread_started) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    thread_started = true;
                    try {
                        Thread.sleep(DELAY_BETWEEN_CLICKS_IN_MILLISECONDS);
                        if (number_of_clicks == 1) {

                        } else if (number_of_clicks == 2) {

                            if (isON) {

                                if (camera == null) {
                                    camera = Camera.open();
                                }

                                Parameters p = camera.getParameters();
                                p.setFlashMode(Parameters.FLASH_MODE_OFF);
                                camera.setParameters(p);
                                camera.stopPreview();
                                isON = false;
                            } else {
                                if (camera == null) {
                                    camera = Camera.open();
                                }
                                Parameters p = camera.getParameters();
                                p.setFlashMode(Parameters.FLASH_MODE_TORCH);
                                camera.setParameters(p);
                                camera.startPreview();
                                isON = true;
                            }
                        }
                        number_of_clicks = 0;
                        thread_started = false;
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }).start();

            Log.e("LOB", "onReceive");
            if (intent.getAction().equals(Intent.ACTION_SCREEN_OFF)) {
                wasScreenOn = false;
            }
            } else if (intent.getAction().equals(Intent.ACTION_SCREEN_ON))
            {
                wasScreenOn = true;
            }
            else if (intent.getAction().equals(Intent.ACTION_USER_PRESENT)) {
                Log.e("LOB", "userpresent");
                Log.e("LOB", "wasScreenOn" + wasScreenOn);
            }
    }
}

清单

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.salal_khan.flashlightservices">
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-feature android:name="android.hardware.camera" />
    <uses-permission android:name="android.permission.PREVENT_POWER_KEY" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <service android:name=".MyService" />
    </application>

</manifest>

Answer 2

捕获图像

package com.example.salal_khan.SecuriteCameraServices;

import android.content.BroadcastReceiver;
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.net.Uri;
import android.os.Handler;
import android.os.Looper;
import android.provider.MediaStore;
import android.util.Log;
import android.hardware.Camera.Parameters;
import android.view.SurfaceView;
import android.widget.Toast;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;

/**
 * Created by salal-khan on 12/1/2017.
 */

public class ScreenReceiver extends BroadcastReceiver {

    public static boolean wasScreenOn = true;


    Camera camera = null;
    boolean isON = false;

    int number_of_clicks = 0;
    boolean thread_started = false;
    final int DELAY_BETWEEN_CLICKS_IN_MILLISECONDS = 550;
    Context contexts;

    @Override
    public void onReceive(final Context context, final Intent intent) {
        contexts = context;
        ++number_of_clicks;
        final SurfaceView mview = new SurfaceView(context);
        if (camera==null) {
            camera = Camera.open(Camera.CameraInfo.CAMERA_FACING_BACK);
        }
        if (!thread_started) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    thread_started = true;
                    try {
                        Thread.sleep(DELAY_BETWEEN_CLICKS_IN_MILLISECONDS);
                        if (number_of_clicks == 1) {

                        } else if (number_of_clicks == 2) {

                            if (isON) {

                                Camera.Parameters parameters = camera.getParameters();
                                parameters.setPictureFormat(PixelFormat.JPEG);
                                camera.setParameters(parameters);


                                Handler h = new Handler(Looper.getMainLooper());
                                h.post(new Runnable() {
                                    public void run() {

                                        try {
                                            camera.setPreviewDisplay(mview.getHolder());
                                            camera.startPreview();
                                            camera.takePicture(null, null, photoCallback);

                                        } catch (IOException e) {
                                            // TODO Auto-generated catch block
                                            e.printStackTrace();
                                        }
                                    }
                                });


                            } else {


                                Camera.Parameters parameters = camera.getParameters();
                                parameters.setPictureFormat(PixelFormat.JPEG);
                                camera.setParameters(parameters);


                                Handler h = new Handler(Looper.getMainLooper());
                                h.post(new Runnable() {
                                    public void run() {

                                        try {

                                            camera.setPreviewDisplay(mview.getHolder());
                                            camera.startPreview();
                                            camera.takePicture(null, null, photoCallback);

                                        } catch (IOException e) {
                                            // TODO Auto-generated catch block
                                            e.printStackTrace();
                                        }
                                    }
                                });
                            }
                        }
                        number_of_clicks = 0;
                        thread_started = false;
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }).start();


            Log.e("LOB", "onReceive");
            if (intent.getAction().equals(Intent.ACTION_SCREEN_OFF)) {
                wasScreenOn = false;
            }
        } else if (intent.getAction().equals(Intent.ACTION_SCREEN_ON)) {
            wasScreenOn = true;
        } else if (intent.getAction().equals(Intent.ACTION_USER_PRESENT)) {
            Log.e("LOB", "userpresent");
            Log.e("LOB", "wasScreenOn" + wasScreenOn);
        }
    }


    Camera.PictureCallback photoCallback = new Camera.PictureCallback() {
        public void onPictureTaken(byte[] data, Camera camera) {

            Uri uriTarget = contexts.getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, new ContentValues());
            OutputStream imageFileOS;

            try {

                imageFileOS = contexts.getContentResolver().openOutputStream(uriTarget);
                imageFileOS.write(data);
                imageFileOS.flush();
                imageFileOS.close();

//                Toast.makeText(contexts.getApplicationContext(), "Image saved: " + uriTarget.toString(), Toast.LENGTH_LONG).show();

            } catch (FileNotFoundException e) {
                e.printStackTrace();

            } catch (IOException e) {
                e.printStackTrace();

            }

        }
    };
}

清单

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.salal_khan.SecuriteCameraServices">
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-feature android:name="android.hardware.camera" />
    <uses-permission android:name="android.permission.PREVENT_POWER_KEY" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.CAMERA" />

    <uses-feature android:name="android.hardware.camera.autofocus" />

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

    <application
        android:allowBackup="true"
        android:name=".MyApplication"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name="com.example.salal_khan.SecuriteCameraServices.MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <service android:name="com.example.salal_khan.SecuriteCameraServices.MyService" />
    </application>

</manifest>