录音应用

要实现一个录音应用，你可以使用Android中提供的MediaRecorder类来录制音频。以下是一个简单的示例代码：

import android.Manifest;
import android.content.pm.PackageManager;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import java.io.IOException;

public class MainActivity extends AppCompatActivity {

    private static final int PERMISSION_REQUEST_CODE = 200;
    private boolean isRecording = false;
    private MediaRecorder mediaRecorder;
    private String audioFilePath;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button recordButton = findViewById(R.id.record_button);
        recordButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (isRecording) {
                    stopRecording();
                    recordButton.setText("Start Recording");
                } else {
                    if (checkPermissions()) {
                        startRecording();
                        recordButton.setText("Stop Recording");
                    }
                }
                isRecording = !isRecording;
            }
        });

        audioFilePath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/record.3gp";
    }

    private boolean checkPermissions() {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED ||
                ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.RECORD_AUDIO, Manifest.permission.WRITE_EXTERNAL_STORAGE}, PERMISSION_REQUEST_CODE);
            return false;
        }
        return true;
    }

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

        try {
            mediaRecorder.prepare();
            mediaRecorder.start();
            Toast.makeText(this, "Recording started", Toast.LENGTH_SHORT).show();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void stopRecording() {
        mediaRecorder.stop();
        mediaRecorder.release();
        mediaRecorder = null;
        Toast.makeText(this, "Recording stopped. File saved at: " + audioFilePath, Toast.LENGTH_LONG).show();
    }
}

上述代码假设你的布局文件中有一个id为record_button的按钮，用于开始/停止录音。你还需要在AndroidManifest.xml文件中添加相应的权限：

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

这样，当你点击录音按钮时，它将开始录制音频，并在停止录音时保存到指定的文件路径。请记得在使用此代码之前，确保你的应用已获得录音和写入外部存储的权限。