java - 在 Android 中录制声音并读取 Amplitude

Question

我正在尝试制作一个应用程序来录制一秒钟的声音，然后从录制的声音中读取最大幅度。这是我目前所拥有的，但我的应用程序崩溃了，我不知道为什么。

这是我的第二个 Activity ，我在按下“记录”按钮后调用了第一个 Activity 。该应用程序在我的模拟器和手机上崩溃。

package radu.soundSampler;

import java.io.IOException;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;
import android.media.MediaRecorder;

public class DisplayMessageActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    //Intent intent = getIntent();
    //String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);

    MediaRecorder rec = new MediaRecorder();
    rec.setAudioSource(MediaRecorder.AudioSource.MIC);
    rec.setOutputFormat(MediaRecorder.OutputFormat.RAW_AMR);
    rec.setOutputFile("/newRecording");
    rec.setAudioEncoder(MediaRecorder.AudioEncoder.DEFAULT);

    try {
        rec.prepare();
    } catch (IllegalStateException e) {

    } catch (IOException o) {

    }
    rec.start();
            for(int i=0;i<100000;i++);
    rec.stop();
    int rezultat = rec.getMaxAmplitude();

    TextView textView = new TextView(this);
    textView.setTextSize(40);

    textView.setText(Integer.toString(rezultat));

    setContentView(textView);
}

}

我计算机上的(已更新)错误日志显示:

08-18 13:30:07.968: E/MediaRecorder(687): start called in an invalid state: 4
08-18 13:30:07.968: D/AndroidRuntime(687): Shutting down VM
08-18 13:30:07.968: W/dalvikvm(687): threadid=1: thread exiting with uncaught exception (group=0x40015560)
08-18 13:30:07.978: E/AndroidRuntime(687): FATAL EXCEPTION: main
08-18 13:30:07.978: E/AndroidRuntime(687): java.lang.RuntimeException: Unable to start activity ComponentInfo{radu.soundSampler/radu.soundSampler.DisplayMessageActivity}: java.lang.IllegalStateException
08-18 13:30:07.978: E/AndroidRuntime(687):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
08-18 13:30:07.978: E/AndroidRuntime(687):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
08-18 13:30:07.978: E/AndroidRuntime(687):  at android.app.ActivityThread.access$1500(ActivityThread.java:117)
08-18 13:30:07.978: E/AndroidRuntime(687):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
08-18 13:30:07.978: E/AndroidRuntime(687):  at android.os.Handler.dispatchMessage(Handler.java:99)
08-18 13:30:07.978: E/AndroidRuntime(687):  at android.os.Looper.loop(Looper.java:123)
08-18 13:30:07.978: E/AndroidRuntime(687):  at android.app.ActivityThread.main(ActivityThread.java:3683)
08-18 13:30:07.978: E/AndroidRuntime(687):  at java.lang.reflect.Method.invokeNative(Native Method)
08-18 13:30:07.978: E/AndroidRuntime(687):  at java.lang.reflect.Method.invoke(Method.java:507)
08-18 13:30:07.978: E/AndroidRuntime(687):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
08-18 13:30:07.978: E/AndroidRuntime(687):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
08-18 13:30:07.978: E/AndroidRuntime(687):  at dalvik.system.NativeStart.main(Native Method)
08-18 13:30:07.978: E/AndroidRuntime(687): Caused by: java.lang.IllegalStateException
08-18 13:30:07.978: E/AndroidRuntime(687):  at android.media.MediaRecorder.start(Native Method)
08-18 13:30:07.978: E/AndroidRuntime(687):  at radu.soundSampler.DisplayMessageActivity.onCreate(DisplayMessageActivity.java:29)
08-18 13:30:07.978: E/AndroidRuntime(687):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
08-18 13:30:07.978: E/AndroidRuntime(687):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
08-18 13:30:07.978: E/AndroidRuntime(687):  ... 11 more

所以我想模拟器可能无法“运行”麦克风，所以我在手机上安装了 .apk 但它也在那里崩溃了。我不知道可能是什么问题，所以你能帮助我，和/或给我任何提示吗？

提前致谢!

另一个堆栈跟踪，您请求的那个。我在 catch 语句中使用了 o.printStackTrace() 和 e.printStackTrace()，我希望这是你要求我做的:

08-18 14:06:11.908: W/System.err(811): java.io.FileNotFoundException: /newRecording (Read-only file system)
08-18 14:06:11.908: W/System.err(811):  at org.apache.harmony.luni.platform.OSFileSystem.open(Native Method)
08-18 14:06:11.908: W/System.err(811):  at dalvik.system.BlockGuard$WrappedFileSystem.open(BlockGuard.java:232)
08-18 14:06:11.918: W/System.err(811):  at java.io.FileOutputStream.<init>(FileOutputStream.java:94)
08-18 14:06:11.918: W/System.err(811):  at java.io.FileOutputStream.<init>(FileOutputStream.java:165)
08-18 14:06:11.918: W/System.err(811):  at java.io.FileOutputStream.<init>(FileOutputStream.java:144)
08-18 14:06:11.918: W/System.err(811):  at android.media.MediaRecorder.prepare(MediaRecorder.java:533)
08-18 14:06:11.918: W/System.err(811):  at radu.soundSampler.DisplayMessageActivity.onCreate(DisplayMessageActivity.java:23)
08-18 14:06:11.918: W/System.err(811):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
08-18 14:06:11.918: W/System.err(811):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
08-18 14:06:11.918: W/System.err(811):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
08-18 14:06:11.918: W/System.err(811):  at android.app.ActivityThread.access$1500(ActivityThread.java:117)
08-18 14:06:11.918: W/System.err(811):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
08-18 14:06:11.918: W/System.err(811):  at android.os.Handler.dispatchMessage(Handler.java:99)
08-18 14:06:11.918: W/System.err(811):  at android.os.Looper.loop(Looper.java:123)
08-18 14:06:11.918: W/System.err(811):  at android.app.ActivityThread.main(ActivityThread.java:3683)
08-18 14:06:11.918: W/System.err(811):  at java.lang.reflect.Method.invokeNative(Native Method)
08-18 14:06:11.928: W/System.err(811):  at java.lang.reflect.Method.invoke(Method.java:507)
08-18 14:06:11.928: W/System.err(811):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
08-18 14:06:11.928: W/System.err(811):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
08-18 14:06:11.928: W/System.err(811):  at dalvik.system.NativeStart.main(Native Method)
08-18 14:06:11.928: E/MediaRecorder(811): start called in an invalid state: 4
08-18 14:06:11.928: D/AndroidRuntime(811): Shutting down VM
08-18 14:06:11.928: W/dalvikvm(811): threadid=1: thread exiting with uncaught exception (group=0x40015560)
08-18 14:06:11.948: E/AndroidRuntime(811): FATAL EXCEPTION: main
08-18 14:06:11.948: E/AndroidRuntime(811): java.lang.RuntimeException: Unable to start activity ComponentInfo{radu.soundSampler/radu.soundSampler.DisplayMessageActivity}: java.lang.IllegalStateException
08-18 14:06:11.948: E/AndroidRuntime(811):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
08-18 14:06:11.948: E/AndroidRuntime(811):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
08-18 14:06:11.948: E/AndroidRuntime(811):  at android.app.ActivityThread.access$1500(ActivityThread.java:117)
08-18 14:06:11.948: E/AndroidRuntime(811):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
08-18 14:06:11.948: E/AndroidRuntime(811):  at android.os.Handler.dispatchMessage(Handler.java:99)
08-18 14:06:11.948: E/AndroidRuntime(811):  at android.os.Looper.loop(Looper.java:123)
08-18 14:06:11.948: E/AndroidRuntime(811):  at android.app.ActivityThread.main(ActivityThread.java:3683)
08-18 14:06:11.948: E/AndroidRuntime(811):  at java.lang.reflect.Method.invokeNative(Native Method)
08-18 14:06:11.948: E/AndroidRuntime(811):  at java.lang.reflect.Method.invoke(Method.java:507)
08-18 14:06:11.948: E/AndroidRuntime(811):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
08-18 14:06:11.948: E/AndroidRuntime(811):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
08-18 14:06:11.948: E/AndroidRuntime(811):  at dalvik.system.NativeStart.main(Native Method)
08-18 14:06:11.948: E/AndroidRuntime(811): Caused by: java.lang.IllegalStateException
08-18 14:06:11.948: E/AndroidRuntime(811):  at android.media.MediaRecorder.start(Native Method)
08-18 14:06:11.948: E/AndroidRuntime(811):  at radu.soundSampler.DisplayMessageActivity.onCreate(DisplayMessageActivity.java:30)
08-18 14:06:11.948: E/AndroidRuntime(811):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
08-18 14:06:11.948: E/AndroidRuntime(811):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
08-18 14:06:11.948: E/AndroidRuntime(811):  ... 11 more
08-18 14:06:14.181: I/Process(811): Sending signal. PID: 811 SIG: 9

Answer 1

使用 setOutoutFile(getExternalFilesDir().getAbsolutePath() + "/newRecording")

确保你的 list 中有这个权限

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

不要执行忙等待循环。使用计时器。

不要在准备过程中忽略异常。