第一次运行应用程序时崩溃（logcat上没有任何内容）。然后你可以看到权限请求，并在你给予权限后，你可以打开应用程序，它工作正常。
public class MainActivity extends AppCompatActivity {
String [] PERMISSIONS = {Manifest.permission.RECORD_AUDIO, Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.READ_EXTERNAL_STORAGE};
int PERMISSION_ALL = 1;
Button record;
Button play;
Button stop;
MediaPlayer mediaPlayer;
MediaRecorder mediaRecorder;
String outPutFile;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//---------------------
//asking for permission
//---------------------
if(!hasPermissions(this, PERMISSIONS)){
ActivityCompat.requestPermissions(this, PERMISSIONS, PERMISSION_ALL);
}
record = (Button) findViewById(R.id.recordbutton);
play = (Button) findViewById(R.id.playbutton);
stop = (Button) findViewById(R.id.stopbutton);
if (outPutFile==null){
play.setEnabled(false);
}
stop.setEnabled(false);
outPutFile = Environment.getExternalStorageDirectory().getAbsolutePath() + "/recording.3gp";
mediaRecorder = new MediaRecorder();
mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
mediaRecorder.setOutputFile(outPutFile);
//---------------------
//recording
//---------------------
record.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
try {
mediaRecorder.prepare();
} catch (IOException e) {
e.printStackTrace();
//Toast.makeText(getApplicationContext(),"error", Toast.LENGTH_LONG).show();
}
mediaRecorder.start();
record.setEnabled(false);
stop.setEnabled(true);
Toast.makeText(getApplicationContext(),"recording", Toast.LENGTH_LONG).show();
}
});
stop.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mediaRecorder.stop();
mediaRecorder.release();
mediaRecorder = null;
stop.setEnabled(false);
play.setEnabled(true);
Toast.makeText(getApplicationContext(), "Audio recorded", Toast.LENGTH_LONG).show();
}
});
//---------------------
//playing the record
//---------------------
play.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mediaPlayer = new MediaPlayer();
try {
mediaPlayer.setDataSource(outPutFile);
mediaPlayer.prepare();
Toast.makeText(getApplicationContext(), "Audio Playing", Toast.LENGTH_LONG).show();
} catch (Exception e) {
}
mediaPlayer.start();
record.setEnabled(true);
}
});
}
public static boolean hasPermissions(Context context, String... permissions) {
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && context != null && permissions != null) {
for (String permission : permissions) {
if (ActivityCompat.checkSelfPermission(context, permission) != PackageManager.PERMISSION_GRANTED) {
return false;
}
}
}
return true;
}
}
为什么？
的logcat -
07-30 19:03:03.812 4491-4491/com.example.tsuryohananov.voicerecorder E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.tsuryohananov.voicerecorder, PID: 4491
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.tsuryohananov.voicerecorder/com.example.tsuryohananov.voicerecorder.MainActivity}: java.lang.RuntimeException: setAudioSource failed.
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2817)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6540)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
Caused by: java.lang.RuntimeException: setAudioSource failed.
at android.media.MediaRecorder.setAudioSource(Native Method)
at com.example.tsuryohananov.voicerecorder.MainActivity.onCreate(MainActivity.java:64)
at android.app.Activity.performCreate(Activity.java:6980)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1213)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2770)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6540)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
答案 0 :(得分：0)
我移动了那些代码：
mediaRecorder = new MediaRecorder();
mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
mediaRecorder.setOutputFile(outPutFile);
到
record.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mediaRecorder = new MediaRecorder();
mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
mediaRecorder.setOutputFile(outPutFile);
try {
mediaRecorder.prepare();
} catch (IOException e) {
e.printStackTrace();
}
record.setEnabled(false);
stop.setEnabled(true);
mediaRecorder.start();
Toast.makeText(getApplicationContext(),"recording", Toast.LENGTH_LONG).show();
}
});
问题是，首先运行mediaRecorder.setAudioSource（MediaRecorder.AudioSource.MIC）;
在用户授予权限之前运行。
我认为还有其他方法，例如：
if (hasPermissions(this, PERMISSIONS)) {
mediaRecorder = new MediaRecorder();
mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
mediaRecorder.setOutputFile(outPutFile);
}