Android：将录音机代码与获取和显示用户位置集成时出现问题

Question

我一直在尝试将我非常简单的录音机应用程序与获取当前用户位置并将其显示在屏幕上的功能集成。我希望它在应用程序启动后立即开始搜索位置，但我的代码存在逻辑问题。我仍在学习，但我已经阅读了大量文档和许多不同的教程/示例代码，但似乎没有任何效果。我认为我非常接近我的解决方案，我的录音机应用程序可以工作，但是它与获取用户位置的配合不太好......你们能帮助我吗？非常感谢任何帮助！

这是我的代码（请注意，它可能看起来有点长，但这只是由于额外的间距）：

public class AndroidPOIActivity extends Activity implements LocationListener
{
    EditText textBoxMessage = null;

    private static final String LOG_TAG = "AudioRecordTest";
    private static String mFileName = null;

    private RecordButton mRecordButton = null;
    private MediaRecorder mRecorder = null;

    private PlayButton   mPlayButton = null;
    private MediaPlayer   mPlayer = null;

    /***************** Record Button ********************/
    private void onRecord(boolean start) {
        if (start) {
            startRecording();
        } else {
            stopRecording();
        }
    }

    private void startRecording() 
    {
        mRecorder = new MediaRecorder();
        mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        mRecorder.setOutputFile(mFileName);
        mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);

        try {
            mRecorder.prepare();
        } catch (IOException e) {
            Log.e(LOG_TAG, "prepare() failed");
        }

        mRecorder.start();
    }

    private void stopRecording() {
        mRecorder.stop();
        mRecorder.release();
        mRecorder = null;
    }

    class RecordButton extends Button {
        boolean mStartRecording = true;

        OnClickListener clicker = new OnClickListener() {
            public void onClick(View v) {
                onRecord(mStartRecording);
                if (mStartRecording) {
                    setText("Stop recording");
                } else {
                    setText("Start recording");
                }
                mStartRecording = !mStartRecording;
            }
        };

        public RecordButton(Context ctx) {
            super(ctx);
            setText("Start recording");
            setOnClickListener(clicker);
        }
    }

    /***************** Play Button ********************/
    private void startPlaying() {
        mPlayer = new MediaPlayer();
        try {
            mPlayer.setDataSource(mFileName);
            mPlayer.prepare();
            mPlayer.start();
        } catch (IOException e) {
            Log.e(LOG_TAG, "prepare() failed");
        }
    }

    private void stopPlaying() {
        mPlayer.release();
        mPlayer = null;
    }

    private void onPlay(boolean start) {
        if (start) {
            startPlaying();
        } else {
            stopPlaying();
        }
    }

    class PlayButton extends Button {
        boolean mStartPlaying = true;

        OnClickListener clicker = new OnClickListener() {
            public void onClick(View v) {
                onPlay(mStartPlaying);
                if (mStartPlaying) {
                    setText("Stop playing");
                } else {
                    setText("Start playing");
                }
                mStartPlaying = !mStartPlaying;
            }
        };

        public PlayButton(Context ctx) {
            super(ctx);
            setText("Start playing");
            setOnClickListener(clicker);
        }
    }
   /***************** File Saver ********************/

    public AndroidPOIActivity() {
        mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
        mFileName += "/audiorecordtest.3gp";
    }

    /***************** On Create ********************/
    @Override
    public void onCreate(Bundle icicle) 
    {
        super.onCreate(icicle);
        //preparing linear layout
        LinearLayout ll = new LinearLayout(this);

        //record button
        mRecordButton = new RecordButton(this);
        ll.addView(mRecordButton,
            new LinearLayout.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT,
                0));

        //play button
        mPlayButton = new PlayButton(this);
        ll.addView(mPlayButton,
            new LinearLayout.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT,
                0));

        TextView locationText = (TextView)this.findViewById(R.id.lblLocationInfo);

        ll.addView(locationText, 
                new LinearLayout.LayoutParams(
                        ViewGroup.LayoutParams.WRAP_CONTENT,
                        ViewGroup.LayoutParams.WRAP_CONTENT,
                        0));

        //getSystemService(LOCATION_SERVICE);           

        //setting linear layout
        setContentView(ll);

        //getting a reference to the system location manager
        LocationManager locationManager = (LocationManager)this.getSystemService(LOCATION_SERVICE);

        Location location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);

        if (location != null) 
        {
          Log.d(LOG_TAG, location.toString());
          this.onLocationChanged(location);
        }

        //defining listener that responds to location updates

        LocationListener locationListener = new LocationListener()
        {
            public void onLocationChanged(Location location) 
            {
                // Called when a new location is found by the network location provider.
                makeUseOfNewLocation(location);
            }

            public void onStatusChanged(String provider, int status, Bundle extras) {}

            public void onProviderEnabled(String provider) {}

            public void onProviderDisabled(String provider) {}
        };        
        // Register the listener with the Location Manager to receive location updates
        locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);

    }

    @Override
    public void onPause() {
        super.onPause();
        if (mRecorder != null) {
            mRecorder.release();
            mRecorder = null;
        }

        if (mPlayer != null) {
            mPlayer.release();
            mPlayer = null;
        }
    }

    @Override
    public void onProviderDisabled(String arg0)
    {
        // TODO Auto-generated method stub              
    }
    @Override
    public void onProviderEnabled(String arg0)
    {
        // TODO Auto-generated method stub              
    }
    @Override
    public void onStatusChanged(String arg0, int arg1, Bundle arg2) 
    {
        // TODO Auto-generated method stub              
    }
    @Override
       public void onLocationChanged(Location location)
    {
        makeUseOfNewLocation(location);     
    }
    private void makeUseOfNewLocation(Location location)
    {       
        double lon = (double) (location.getLongitude() * 1E6);
        double lat = (double) (location.getLatitude() * 1E6);

        int lontitude = (int)lon;
        int latitude = (int)lat;
        Toast.makeText(getApplicationContext(), "New Lontitue = "+ lontitude +"\n New Latitute = "+ latitude, Toast.LENGTH_LONG).show();
    }
}

我的代码在清单中也具有权限：

这是我的 main.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <TextView android:id="@+id/lblLocationInfo"
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:text="Waiting for location..."/>

    <Button android:id="@+id/mRecordButton"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Start Recording"
        android:layout_gravity="center"></Button>

    <Button android:id="@+id/mPlayButton"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Start Playing"
        android:layout_gravity="center"></Button>
</LinearLayout>

Stacktrace： [2011-11-15 14:51:47 - AndroidPOI] ------------------------------------------

[2011-11-15 14:51:47 - AndroidPOI] Android Launch!
[2011-11-15 14:51:47 - AndroidPOI] adb is running normally.
[2011-11-15 14:51:47 - AndroidPOI] Performing org.me.androidpoi.AndroidPOIActivity activity launch
[2011-11-15 14:51:47 - AndroidPOI] Automatic Target Mode: launching new emulator with compatible AVD 'android_2-2'
[2011-11-15 14:51:47 - AndroidPOI] Launching a new emulator with Virtual Device 'android_2-2'
[2011-11-15 14:52:17 - Emulator] emulator: emulator window was out of view and was recentred
[2011-11-15 14:52:17 - Emulator] 
[2011-11-15 14:52:36 - AndroidPOI] New emulator found: emulator-5554
[2011-11-15 14:52:36 - AndroidPOI] Waiting for HOME ('android.process.acore') to be launched...
[2011-11-15 14:53:51 - AndroidPOI] HOME is up on device 'emulator-5554'
[2011-11-15 14:53:51 - AndroidPOI] Uploading AndroidPOI.apk onto device 'emulator-5554'
[2011-11-15 14:53:51 - AndroidPOI] Installing AndroidPOI.apk...
[2011-11-15 14:54:27 - AndroidPOI] Success!
[2011-11-15 14:54:27 - AndroidPOI] Starting activity org.me.androidpoi.AndroidPOIActivity on device emulator-5554
[2011-11-15 14:54:29 - AndroidPOI] ActivityManager: Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] cmp=org.me.androidpoi/.AndroidPOIActivity }

LogCat：

11-15 14:53:19.335: ERROR/Zygote(32): setreuid() failed. errno: 2
11-15 14:53:35.093: ERROR/Zygote(32): setreuid() failed. errno: 17
11-15 14:53:37.553: ERROR/BatteryService(67): usbOnlinePath not found
11-15 14:53:37.553: ERROR/BatteryService(67): batteryVoltagePath not found
11-15 14:53:37.553: ERROR/BatteryService(67): batteryTemperaturePath not found
11-15 14:53:37.603: ERROR/SurfaceFlinger(67): Couldn't open /sys/power/wait_for_fb_sleep or /sys/power/wait_for_fb_wake
11-15 14:53:47.964: ERROR/EventHub(67): could not get driver version for /dev/input/mouse0, Not a typewriter
11-15 14:53:47.964: ERROR/EventHub(67): could not get driver version for /dev/input/mice, Not a typewriter
11-15 14:53:48.414: ERROR/System(67): Failure starting core service
11-15 14:53:48.414: ERROR/System(67): java.lang.SecurityException
11-15 14:53:48.414: ERROR/System(67):     at android.os.BinderProxy.transact(Native Method)
11-15 14:53:48.414: ERROR/System(67):     at android.os.ServiceManagerProxy.addService(ServiceManagerNative.java:146)
11-15 14:53:48.414: ERROR/System(67):     at android.os.ServiceManager.addService(ServiceManager.java:72)
11-15 14:53:48.414: ERROR/System(67):     at com.android.server.ServerThread.run(SystemServer.java:184)
11-15 14:53:49.825: ERROR/SoundPool(67): error loading /system/media/audio/ui/Effect_Tick.ogg
11-15 14:53:49.845: ERROR/SoundPool(67): error loading /system/media/audio/ui/KeypressStandard.ogg
11-15 14:53:49.845: ERROR/SoundPool(67): error loading /system/media/audio/ui/KeypressSpacebar.ogg
11-15 14:53:49.857: ERROR/SoundPool(67): error loading /system/media/audio/ui/KeypressDelete.ogg
11-15 14:53:49.857: ERROR/SoundPool(67): error loading /system/media/audio/ui/KeypressReturn.ogg
11-15 14:53:52.643: ERROR/ThrottleService(67): Could not open GPS configuration file /etc/gps.conf
11-15 14:53:54.635: ERROR/logwrapper(149): executing /system/bin/tc failed: No such file or directory
11-15 14:53:54.786: ERROR/logwrapper(150): executing /system/bin/tc failed: No such file or directory
11-15 14:53:54.903: ERROR/logwrapper(151): executing /system/bin/tc failed: No such file or directory
11-15 14:54:10.153: ERROR/HierarchicalStateMachine(67): TetherMaster - unhandledMessage: msg.what=3
11-15 14:54:30.744: ERROR/AndroidRuntime(279): FATAL EXCEPTION: main
11-15 14:54:30.744: ERROR/AndroidRuntime(279): java.lang.RuntimeException: Unable to start activity ComponentInfo{org.me.androidpoi/org.me.androidpoi.AndroidPOIActivity}: java.lang.NullPointerException
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at android.os.Handler.dispatchMessage(Handler.java:99)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at android.os.Looper.loop(Looper.java:123)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at android.app.ActivityThread.main(ActivityThread.java:4627)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at java.lang.reflect.Method.invokeNative(Native Method)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at java.lang.reflect.Method.invoke(Method.java:521)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at dalvik.system.NativeStart.main(Native Method)
11-15 14:54:30.744: ERROR/AndroidRuntime(279): Caused by: java.lang.NullPointerException
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at android.view.ViewGroup.addViewInner(ViewGroup.java:1969)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at android.view.ViewGroup.addView(ViewGroup.java:1865)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at android.view.ViewGroup.addView(ViewGroup.java:1845)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at org.me.androidpoi.AndroidPOIActivity.onCreate(AndroidPOIActivity.java:169)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
11-15 14:54:30.744: ERROR/AndroidRuntime(279):     ... 11 more

Answer 1

您遇到空指针异常：

1-15 14:54:30.744: ERROR/AndroidRuntime(279): at org.me.androidpoi.AndroidPOIActivity.onCreate(AndroidPOIActivity.java:169)

我不知道第 169 行在代码中的位置，但请检查一下并确保那里的所有内容都正确。

Answer 2

哇，这真的很混乱，试试这个代码：

public class AndroidPOIActivity extends Activity 
{
    EditText textBoxMessage = null;

    private static final String LOG_TAG = "AudioRecordTest";
    private static String mFileName = null;

    private RecordButton mRecordButton = null;
    private MediaRecorder mRecorder = null;

    private PlayButton   mPlayButton = null;
    private MediaPlayer   mPlayer = null;

    /***************** Record Button ********************/
    private void onRecord(boolean start) {
        if (start) {
            startRecording();
        } else {
            stopRecording();
        }
    }

    private void startRecording() 
    {
        mRecorder = new MediaRecorder();
        mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        mRecorder.setOutputFile(mFileName);
        mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);

        try {
            mRecorder.prepare();
        } catch (IOException e) {
            Log.e(LOG_TAG, "prepare() failed");
        }

        mRecorder.start();
    }

    private void stopRecording() {
        mRecorder.stop();
        mRecorder.release();
        mRecorder = null;
    }

    class RecordButton extends Button {
        boolean mStartRecording = true;

        OnClickListener clicker = new OnClickListener() {
            public void onClick(View v) {
                onRecord(mStartRecording);
                if (mStartRecording) {
                    setText("Stop recording");
                } else {
                    setText("Start recording");
                }
                mStartRecording = !mStartRecording;
            }
        };

        public RecordButton(Context ctx) {
            super(ctx);
            setText("Start recording");
            setOnClickListener(clicker);
        }
    }

    /***************** Play Button ********************/
    private void startPlaying() {
        mPlayer = new MediaPlayer();
        try {
            mPlayer.setDataSource(mFileName);
            mPlayer.prepare();
            mPlayer.start();
        } catch (IOException e) {
            Log.e(LOG_TAG, "prepare() failed");
        }
    }

    private void stopPlaying() {
        mPlayer.release();
        mPlayer = null;
    }

    private void onPlay(boolean start) {
        if (start) {
            startPlaying();
        } else {
            stopPlaying();
        }
    }

    class PlayButton extends Button {
        boolean mStartPlaying = true;

        OnClickListener clicker = new OnClickListener() {
            public void onClick(View v) {
                onPlay(mStartPlaying);
                if (mStartPlaying) {
                    setText("Stop playing");
                } else {
                    setText("Start playing");
                }
                mStartPlaying = !mStartPlaying;
            }
        };

        public PlayButton(Context ctx) {
            super(ctx);
            setText("Start playing");
            setOnClickListener(clicker);
        }
    }
   /***************** File Saver ********************/

    public AndroidPOIActivity() {
        mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
        mFileName += "/audiorecordtest.3gp";
    }

    /***************** On Create ********************/
    @Override
    public void onCreate(Bundle icicle) 
    {
        super.onCreate(icicle);
        //preparing linear layout
        LinearLayout ll = new LinearLayout(this);

        //record button
        mRecordButton = new RecordButton(this);
        ll.addView(mRecordButton,
            new LinearLayout.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT,
                0));

        //play button
        mPlayButton = new PlayButton(this);
        ll.addView(mPlayButton,
            new LinearLayout.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT,
                0));

        TextView locationText = new TextView(this);

        ll.addView(locationText, 
                new LinearLayout.LayoutParams(
                        ViewGroup.LayoutParams.WRAP_CONTENT,
                        ViewGroup.LayoutParams.WRAP_CONTENT,
                        0));


        setContentView(ll);

    }

    private LocationListener locationListener = new LocationListener()
    {
        public void onLocationChanged(Location location) 
        {
            // Called when a new location is found by the network location provider.
            makeUseOfNewLocation(location);
        }

        public void onStatusChanged(String provider, int status, Bundle extras) {}

        public void onProviderEnabled(String provider) {}

        public void onProviderDisabled(String provider) {}
    };    

    @Override
    public void onPause() {
        super.onPause();
        if (mRecorder != null) {
            mRecorder.release();
            mRecorder = null;
        }

        if (mPlayer != null) {
            mPlayer.release();
            mPlayer = null;
        }
        LocationManager locationManager = (LocationManager)this.getSystemService(LOCATION_SERVICE);
        locationManager.removeUpdates(locationListener);
    }

    @Override
    protected void onResume() {
        LocationManager locationManager = (LocationManager)this.getSystemService(LOCATION_SERVICE);
        locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
        super.onResume();
    }


    private void makeUseOfNewLocation(Location location)
    {       
        double lon = (double) (location.getLongitude() * 1E6);
        double lat = (double) (location.getLatitude() * 1E6);

        int lontitude = (int)lon;
        int latitude = (int)lat;
        Toast.makeText(getApplicationContext(), "New Lontitue = "+ lontitude +"\n New Latitute = "+ latitude, Toast.LENGTH_LONG).show();
    }
}