该应用程序记录音频。每次执行检查时，如果要创建一个文件，它都不会用相同的名称替换以前的文件，而是创建一个新文件，而在文件名中添加“（number）”。
这是它的代码：
mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
int entryNumber = 1;
File mFile = new File(mFileName + "/Recording (" + String.valueOf(entryNumber) + ")" + ".mp3");
while (mFile.exists()) {
entryNumber++;
mFile = new File(mFileName + "/Recording (" + String.valueOf(entryNumber) + ")" + ".mp3");
}
this.mFileName = mFile.getAbsolutePath();
记录过程：
mRecorder = new MediaRecorder();
mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
mRecorder.setOutputFile(mFileName);
try {
mRecorder.prepare();
} catch (IOException e) {
Log.e(LOG_TAG, "prepare() failed");
}
mRecorder.start();
isRecording = true;
recordBtn.setText("Stop");
Toast.makeText(getApplicationContext(), "Recording Started", Toast.LENGTH_LONG).show();
我发现了一个错误。该应用仅在退出并重新启动时才会创建新文件。
如果用户继续录制声音，则该应用不会创建新文件，而是会覆盖之前的文件来替换它。应该总是在录制时创建一个新文件。
完整的项目代码：
package com.android.greg.garec;
import android.content.pm.PackageManager;
import android.media.MediaPlayer;
import android.media.MediaRecorder;
import android.os.Environment;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import java.io.File;
import java.io.IOException;
import static android.Manifest.permission.READ_EXTERNAL_STORAGE;
import static android.Manifest.permission.RECORD_AUDIO;
import static android.Manifest.permission.WRITE_EXTERNAL_STORAGE;
public class MainActivity extends AppCompatActivity {
private Button recordBtn, playBtn;
private MediaRecorder mRecorder;
private MediaPlayer mPlayer;
private static final String LOG_TAG = MainActivity.class.getSimpleName();
private static String mFileName = null;
public static final int REQUEST_AUDIO_PERMISSION_CODE = 1;
boolean isRecording = false;
boolean isPlaying = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
recordBtn = findViewById(R.id.btnRecord);
playBtn = findViewById(R.id.btnPlay);
playBtn.setEnabled(false);
playBtn.setVisibility(View.INVISIBLE);
////////////////////////////////////////////////////////////////////////////////////////////////////////
mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
int entryNumber = 1;
File mFile = new File(mFileName + "/Recording_" + String.valueOf(entryNumber) + ".mp3");
while (mFile.exists()) {
// File exists, just increment number
entryNumber++;
}
// Only create the file when it does not exist
mFile = new File(mFileName + "/Recording_" + String.valueOf(entryNumber) + ".mp3");
try {
mFile.createNewFile();
}
catch (IOException e) {
e.printStackTrace();
}
this.mFileName = mFile.getAbsolutePath();
////////////////////////////////////////////////////////////////////////////////////////////////////////
//Record button actions
recordBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (isRecording) {
playBtn.setEnabled(true);
playBtn.setVisibility(View.VISIBLE);
mRecorder.stop();
mRecorder.release();
mRecorder = null;
// Toast.makeText(getApplicationContext(), "Recording Stopped", Toast.LENGTH_LONG).show();
isRecording = false;
recordBtn.setText("Record");
} else {
if (CheckPermissions()) {
playBtn.setEnabled(false);
playBtn.setVisibility(View.INVISIBLE);
mRecorder = new MediaRecorder();
mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
mRecorder.setOutputFile(mFileName);
try {
mRecorder.prepare();
} catch (IOException e) {
Log.e(LOG_TAG, "prepare() failed");
}
mRecorder.start();
isRecording = true;
recordBtn.setText("Stop");
// Toast.makeText(getApplicationContext(), "Recording Started", Toast.LENGTH_LONG).show();
} else {
RequestPermissions();
}
}
}
});
//Play button actions
playBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(isPlaying) {
mPlayer.release();
mPlayer = null;
recordBtn.setEnabled(true);
playBtn.setEnabled(true);
// Toast.makeText(getApplicationContext(), "Playing Audio Stopped", Toast.LENGTH_SHORT).show();
isPlaying=false;
playBtn.setText("Play");
} else {
recordBtn.setEnabled(true);
playBtn.setEnabled(true);
mPlayer = new MediaPlayer();
try {
mPlayer.setDataSource(mFileName);
mPlayer.prepare();
mPlayer.start();
// Toast.makeText(getApplicationContext(), "Recorded playback started", Toast.LENGTH_LONG).show();
mPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mediaPlayer) {
isPlaying = false;
// Toast.makeText(MainActivity.this, "Recorded playback finished", Toast.LENGTH_SHORT).show();
playBtn.setEnabled(true);
playBtn.setVisibility(View.VISIBLE);
playBtn.setText("Play");
}
});
} catch (IOException e) {
Log.e(LOG_TAG, "prepare() failed");
}
isPlaying=true;
playBtn.setText("Stop");
}
}
});
}
//Permission checks - requests
@Override
public void onRequestPermissionsResult ( int requestCode, String[] permissions, int[] grantResults){
switch (requestCode) {
case REQUEST_AUDIO_PERMISSION_CODE:
if (grantResults.length > 0) {
boolean permissionToRecord = grantResults[0] == PackageManager.PERMISSION_GRANTED;
boolean permissionToStore = grantResults[1] == PackageManager.PERMISSION_GRANTED;
boolean permissionToRead = grantResults[2] == PackageManager.PERMISSION_GRANTED;
if (permissionToRecord && permissionToStore && permissionToRead) {
Toast.makeText(getApplicationContext(), "Permission Granted", Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getApplicationContext(), "Permission Denied", Toast.LENGTH_LONG).show();
}
}
break;
}
}
public boolean CheckPermissions () {
int result = ContextCompat.checkSelfPermission(getApplicationContext(), WRITE_EXTERNAL_STORAGE);
int result1 = ContextCompat.checkSelfPermission(getApplicationContext(), RECORD_AUDIO);
int result2 = ContextCompat.checkSelfPermission(getApplicationContext(), READ_EXTERNAL_STORAGE);
return (result == PackageManager.PERMISSION_GRANTED) && (result1 == PackageManager.PERMISSION_GRANTED) && (result2 == PackageManager.PERMISSION_GRANTED);
}
private void RequestPermissions () {
ActivityCompat.requestPermissions(MainActivity.this, new String[]{RECORD_AUDIO, WRITE_EXTERNAL_STORAGE, READ_EXTERNAL_STORAGE}, REQUEST_AUDIO_PERMISSION_CODE);
}
}
XML：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:id="@+id/btnRecord"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentBottom="true"
android:layout_marginLeft="100dp"
android:layout_marginTop="120dp"
android:layout_marginEnd="135dp"
android:layout_marginBottom="160dp"
android:text="Record" />
<Button
android:id="@+id/btnPlay"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentBottom="true"
android:layout_marginLeft="100dp"
android:layout_marginEnd="135dp"
android:layout_marginBottom="100dp"
android:text="Play" />
</RelativeLayout>
清单文件：
<uses-permission android:name="android.permission.RECORD_AUDIO"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.STORAGE"/>
答案 0 :(得分：0)
new File()只是创建一个新对象，而不是文件系统上的实际文件。
使用createNewFile()创建一个空文件（documentation）：
File file = new File(mFileName + "/Recording (" + String.valueOf(entryNumber) + ")" + ".mp3");
if (!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
在不替换现有文件的情况下应该起作用的示例：
mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
int entryNumber = 1;
File mFile = new File(mFileName + "/Recording (" + String.valueOf(entryNumber) + ")" + ".mp3");
while (mFile.exists()) {
// File exists, just increment number
entryNumber++;
}
// Only create the file when it does not exists
mFile = new File(mFileName + "/Recording (" + String.valueOf(entryNumber) + ")" + ".mp3");
try {
mFile.createNewFile()
}
catch (IOException e) {
e.printStacjTrace();
}
this.mFileName = mFile.getAbsolutePath();
希望有帮助！