Android：java.lang.RuntimeException：无法实例化活动 ComponentInfo：java.lang.NullPointerException
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【中文标题】Android：java.lang.RuntimeException：无法实例化活动 ComponentInfo：java.lang.NullPointerException【英文标题】：Android : java.lang.RuntimeException: Unable to instantiate activity ComponentInfo: java.lang.NullPointerException 【发布时间】：2012-05-16 13:32:45 【问题描述】：我正在尝试录制音频，之后应该立即播放录音。我要去哪里错了。请帮帮我。我没有得到。显示空指针异常...
这里是代码
import android.app.Activity;
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioRecord;
import android.media.AudioTrack;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.LinearLayout;
public class Audio_testActivity extends Activity
private String LOG_TAG = null;
/* variables which are required to generate and manage the UI of the App */
// private RecordButton mRecordButton = null;
private Button recordBtn, stopBtn, playBtn;
/*
* variables which are required for the actual functioning of the recording
* and playing
*/
private AudioRecord recorder = null;
private AudioTrack player = null;
private AudioManager audioManager = null;
private int recorderBufSize, recordingSampleRate;
private int trackBufSize;
private short[] audioData;
private boolean isRecording = false, isPlaying = false;
private Thread startRecThread;
private AudioRecord.OnRecordPositionUpdateListener posUpdateListener;
/**
* constructor method for initializing the variables
*/
public Audio_testActivity()
super();
LOG_TAG = "Constructor";
recorderBufSize = recordingSampleRate = trackBufSize = 0;
// init function will initialize all the necessary variables ...
init();
if (recorder != null && player != null)
Log.e(LOG_TAG, "recorder and player initialized");
audioData = new short[recorderBufSize / 2]; // since we r reading
// shorts
else
Log.e(LOG_TAG, "Problem inside init function ");
posUpdateListener = new AudioRecord.OnRecordPositionUpdateListener()
int numShortsRead = 0;
@Override
public void onPeriodicNotification(AudioRecord rec)
// TODO Auto-generated method stub
// String LOG_TAG = Thread.currentThread().getName();
// Log.e(LOG_TAG, "inside position listener");
audioData = new short[recorderBufSize / 2]; // divide by 2 since
// now we are
// reading shorts
numShortsRead = rec.read(audioData, 0, audioData.length);
player.write(audioData, 0, numShortsRead);
@Override
public void onMarkerReached(AudioRecord recorder)
// TODO Auto-generated method stub
Log.e(LOG_TAG, "Marker Reached");
;
// listener will be called every time 160 frames are reached
recorder.setPositionNotificationPeriod(160);
recorder.setRecordPositionUpdateListener(posUpdateListener);
Log.e(LOG_TAG, "inside constructor");
private void init()
LOG_TAG = "initFunc";
// int[] mSampleRates = new int[] 8000, 11025, 22050, 44100 ;
short audioFormat = AudioFormat.ENCODING_PCM_16BIT;
// for (int rate : mSampleRates)
this.recordingSampleRate = AudioTrack
.getNativeOutputSampleRate(AudioManager.STREAM_MUSIC);
try
// Log.d(LOG_TAG, "Attempting rate " + rate + "Hz, bits: " +
// audioFormat);
int bufrSize = AudioRecord.getMinBufferSize(
this.recordingSampleRate, AudioFormat.CHANNEL_IN_MONO,
audioFormat);
// lets find out the minimum required size for AudioTrack
int audioTrackBufSize = AudioTrack.getMinBufferSize(
this.recordingSampleRate, AudioFormat.CHANNEL_OUT_MONO,
audioFormat);
if (bufrSize != AudioRecord.ERROR_BAD_VALUE
&& bufrSize != AudioRecord.ERROR)
// check if we can instantiate and have a success
if (audioTrackBufSize >= bufrSize)
this.recorderBufSize = audioTrackBufSize;
else
this.recorderBufSize = bufrSize;
AudioRecord rec = new AudioRecord(
MediaRecorder.Audiosource.DEFAULT,
this.recordingSampleRate, AudioFormat.CHANNEL_IN_MONO,
audioFormat, this.recorderBufSize);
if (rec != null
&& rec.getState() == AudioRecord.STATE_INITIALIZED)
// storing variables for future use . . .
// this.recordingSampleRate = rate;
// this.recorderBufSize = bufrSize;
Log.e(LOG_TAG,
"Returning..(rate:channelConfig:audioFormat:recorderBufSize)"
+ this.recordingSampleRate + ":"
+ AudioFormat.CHANNEL_IN_MONO + ":"
+ audioFormat + ":" + this.recorderBufSize);
// Now create an instance of the AudioTrack
// int audioTrackBufSize = AudioTrack.getMinBufferSize(rate,
// AudioFormat.CHANNEL_OUT_MONO, audioFormat);
Log.e(LOG_TAG, "Audio Record / Track / Final buf size :"
+ bufrSize + "/ " + audioTrackBufSize + "/ "
+ this.recorderBufSize);
this.player = new AudioTrack(AudioManager.STREAM_MUSIC,
this.recordingSampleRate,
AudioFormat.CHANNEL_OUT_MONO, audioFormat,
this.recorderBufSize, AudioTrack.MODE_STREAM);
this.recorder = rec;
this.player.stop();
this.player.flush();
this.player.setPlaybackRate(this.recordingSampleRate);
return;
catch (IllegalArgumentException e)
Log.d(LOG_TAG,
this.recordingSampleRate + "Exception, keep trying.", e);
catch (Exception e)
Log.e(LOG_TAG, this.recordingSampleRate + "Some Exception!!", e);
// for loop for channel config ended here. . . .
// for loop for audioFormat ended here. . .
// // for loop for sampleRate
return;
private void startPlaying()
LOG_TAG = "startPlaying";
Log.e(LOG_TAG, "start Playing");
private void stopPlaying()
LOG_TAG = "stopPlaying";
Log.e(LOG_TAG, "stop Playing");
private void startRecording()
LOG_TAG = "startRecording";
/* start a separate recording thread from here . . . */
startRecThread = new Thread()
@Override
public void run()
// TODO Auto-generated method stub
android.os.Process
.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);
// String LOG_TAG = Thread.currentThread().getName();
if (recorder.getRecordingState() != AudioRecord.RECORDSTATE_RECORDING)
recorder.startRecording();
// Log.e(LOG_TAG, "running" +recorder.getRecordingState());
while (recorder.getRecordingState() == AudioRecord.RECORDSTATE_RECORDING)
recorder.read(audioData, 0, audioData.length);
try
Thread.sleep(1000); // sleep for 2s
catch (InterruptedException e)
// TODO Auto-generated catch block
Log.e("run Method", "recorder thread is interrupted");
e.printStackTrace();
;
setVolumeControlStream(AudioManager.STREAM_MUSIC);
audioManager.setSpeakerphoneOn(false);
player.flush();
player.play();
startRecThread.start();
Log.e(LOG_TAG, "start Recording");
private void stopRecording()
LOG_TAG = "stopRecording";
recorder.stop();
if (startRecThread != null && startRecThread.isAlive())
startRecThread.destroy();
startRecThread = null;
player.stop();
player.flush();
Log.e(LOG_TAG, "stop Recording");
private void stop()
if (isRecording)
isRecording = false;
stopRecording();
if (isPlaying)
isPlaying = false;
stopPlaying();
recordBtn.setEnabled(true);
playBtn.setEnabled(true);
@Override
public void onCreate(Bundle icicle)
super.onCreate(icicle);
LOG_TAG = "onCreate";
// Log.e(LOG_TAG, "Create Called");
// getting the audio service
audioManager = (AudioManager) getSystemService(AUDIO_SERVICE);
LinearLayout ll = new LinearLayout(this);
// creating Buttons one by one . . . .
// button to start the recording process
recordBtn = new Button(this);
recordBtn.setText("Record");
recordBtn.setOnClickListener(new OnClickListener()
public void onClick(View v)
// TODO Auto-generated method stub
recordBtn.setEnabled(false);
playBtn.setEnabled(false);
isRecording = true;
startRecording();
);
// single button to stop recording and playing as applicable
stopBtn = new Button(this);
stopBtn.setText("Stop");
stopBtn.setOnClickListener(new OnClickListener()
public void onClick(View v)
// TODO Auto-generated method stub
stop();
);
// button to play the recorded sound
playBtn = new Button(this);
playBtn.setText("Play");
playBtn.setOnClickListener(new OnClickListener()
public void onClick(View v)
// TODO Auto-generated method stub
// reverse the isPlaying
isPlaying = true;
recordBtn.setEnabled(false);
playBtn.setEnabled(false);
startPlaying();
);
ll.addView(recordBtn, new LinearLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT, 1));
ll.addView(playBtn, new LinearLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT, 1));
ll.addView(stopBtn, new LinearLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT, 1));
setContentView(ll);
@Override
protected void onDestroy()
// Clean up code . ..
super.onDestroy();
if (recorder != null)
recorder.release();
if (startRecThread != null && startRecThread.isAlive())
startRecThread.destroy();
if (recorder != null)
recorder.release();
if (player != null)
player.release();
startRecThread = null;
recorder = null;
player = null;
recordBtn = null;
stopBtn = null;
playBtn = null;
audioData = null;
System.gc();
这是错误的LOGCAT文件.....
05-17 09:53:01.402: E/AndroidRuntime(367): FATAL EXCEPTION: main
05-17 09:53:01.402: E/AndroidRuntime(367): java.lang.NullPointerException
05-17 09:53:01.402: E/AndroidRuntime(367): at audio.xxx.com.Audio_testActivity.startRecording(Audio_testActivity.java:232)
05-17 09:53:01.402: E/AndroidRuntime(367): at audio.xxx.com.Audio_testActivity.access$9(Audio_testActivity.java:194)
05-17 09:53:01.402: E/AndroidRuntime(367): at audio.xxx.com.Audio_testActivity$3.onClick(Audio_testActivity.java:291)
05-17 09:53:01.402: E/AndroidRuntime(367): at android.view.View.performClick(View.java:2485)
05-17 09:53:01.402: E/AndroidRuntime(367): at android.view.View$PerformClick.run(View.java:9080)
05-17 09:53:01.402: E/AndroidRuntime(367): at android.os.Handler.handleCallback(Handler.java:587)
05-17 09:53:01.402: E/AndroidRuntime(367): at android.os.Handler.dispatchMessage(Handler.java:92)
05-17 09:53:01.402: E/AndroidRuntime(367): at android.os.Looper.loop(Looper.java:123)
05-17 09:53:01.402: E/AndroidRuntime(367): at android.app.ActivityThread.main(ActivityThread.java:3683)
05-17 09:53:01.402: E/AndroidRuntime(367): at java.lang.reflect.Method.invokeNative(Native Method)
05-17 09:53:01.402: E/AndroidRuntime(367): at java.lang.reflect.Method.invoke(Method.java:507)
05-17 09:53:01.402: E/AndroidRuntime(367): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
05-17 09:53:01.402: E/AndroidRuntime(367): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
05-17 09:53:01.402: E/AndroidRuntime(367): at dalvik.system.NativeStart.main(Native Method)
让我知道我错在哪里..请帮助我.!!!!!!!!!
【问题讨论】：
Audio_testActivity.java 中的第 81 行？ 请让我们知道 Audio_testActivity.java 中的第 81 号，因为您的文件中缺少导入语句，因此我们无法获取。 @DheereshSingh -- 使用 IMPORT 更新 .. 请让我知道解决方案。谢谢 谢谢 rahul，但我的意思是，当您遇到错误时，请让我们知道您的 IDE 中 Audio_testActivity.java 中的第 81 行... 在“初始化函数内部出现问题”错误之前，您是否在日志中收到此语句？ 【参考方案1】：如果您从代码中得到“初始化函数内部的问题”
if (recorder != null && player != null)
Log.e(LOG_TAG, "recorder and player initialized");
audioData = new short[recorderBufSize / 2]; // since we r reading
// shorts
else
Log.e(LOG_TAG, "Problem inside init function ");
recorder 可能为空。请检查一下。
【讨论】：
这个日志“初始化函数内部出现问题”来了？ 不，它没有出现在 INIT() 中。我在 startrecording 函数中添加了 81 行代码。现在开始录制功能出错。 对不起，你为什么这样做“我在 startrecording 函数中添加了 81 行代码。现在 startrecording 函数出错。” ?我们只想知道第 81 行代码。 似乎您最好在尝试调用其任何方法之前检查 recorder 是否为非空。如果为 null，则需要对其进行初始化或酌情放弃当前操作。 @ChrisStratton 我试过了.. 录音机不为空.. 请你帮帮我.. 谢谢以上是关于Android：java.lang.RuntimeException：无法实例化活动 ComponentInfo：java.lang.NullPointerException的主要内容，如果未能解决你的问题，请参考以下文章
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