Android AudioTrack Error

Question

私は現在、AudioTrackを使用してAndroid上にマルチ波形オシレータを構築しようとしていますが、方形波を実装しようとしましたが、同じ致命的なエラーが発生します。ここに役立つことに私のコードです：

package com.example.jack.synthesiser; 

import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.EditText; 
import android.widget.TextView; 
import android.widget.ToggleButton; 

public class MainActivity extends AppCompatActivity implements  View.OnClickListener { 

EditText frequencyInput; 
TextView displayFrequency; 
ToggleButton startStop; 
ToggleButton startStopSquare; 
PlayWave wave = new PlayWave(); 
PlaySquare sWave = new PlaySquare(); 



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

private void initializeView() { 

    frequencyInput = (EditText) findViewById(R.id.editText); 
    startStop = (ToggleButton) findViewById(R.id.toggleButton); 
    startStopSquare = (ToggleButton) findViewById(R.id.toggleButton2); 
    displayFrequency = (TextView) findViewById(R.id.textView); 
    startStop.setOnClickListener(this); 
} 

@Override 
public void onClick(View v) { 
    // TODO Auto-generated method stub 
    int frequency = Integer.parseInt(frequencyInput.getText().toString()); 
    displayFrequency.setText(String.valueOf(frequency)); 
    wave.setWave(frequency); 
    sWave.setSquareWave(frequency); 
    boolean on = startStop.isChecked(); 
    boolean square = startStopSquare.isChecked(); 
    if (on) { 
     wave.start(); 
    } else if (!on){ 
     wave.stop(); 
    } 
    //if (square) { 
    // sWave.start(); 
    //} else if (!square) { 
    // sWave.stop(); 
    //} 





} 
} 

そして、私のプレイ波クラスは、次のようになります。

package com.example.jack.synthesiser; 

import android.media.AudioFormat; 
import android.media.AudioManager; 
import android.media.AudioTrack; 

/** 
    * Created by Jack on 16/01/2017. 
    */ 

public class PlayWave { 

private final int SAMPLE_RATE = 44100; //maximum sample rate Audiotrack can use 
private AudioTrack mAudio; 
int buffsize = AudioTrack.getMinBufferSize(SAMPLE_RATE, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT); 
private int sampleCount; 

public PlayWave() { 

    mAudio = new AudioTrack(AudioManager.STREAM_MUSIC, SAMPLE_RATE, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT, 
          buffsize, AudioTrack.MODE_STATIC); 
} 

public void setWave (int frequency) { 

    sampleCount = (int) ((float) SAMPLE_RATE/frequency); 
    short samples[] = new short[sampleCount]; //array to hold samples 
    int amplitude = 32767; //max amplitude can reach 
    double twoPi = 8. * Math.atan(1.); //twoPi calculated as the arctangent of 1 multiplied by 8 
    double phase = 0.0; 

    for (int i = 0; i < sampleCount; i++) { 
     samples[i] = (short) (amplitude * Math.sin(phase)); 
     phase += twoPi * frequency/SAMPLE_RATE; 
    } 
    mAudio.write(samples, 0, sampleCount); 
} 

public void setSquareWave (int frequency) { 
    sampleCount = (int) ((float) SAMPLE_RATE/frequency); 
    short samples[] = new short[sampleCount]; 
    int amplitude = 32767; 
    double phase = 0.0; 
    double twoPi = 8. * Math.atan(1.); 
    for (int i = 0; i < sampleCount; i++) { 
     samples[i] = (short) (amplitude * Math.sin(phase)); 
     if (samples[i] > (short) 0.0) { 
      samples[i] = 32767; 
     } 

     if (samples[i] < (short) 0.0) { 
      samples[i] = -32767; 
     } 
     phase += twoPi * frequency/SAMPLE_RATE; 
    } 
} 

public void start() { 
    mAudio.reloadStaticData(); 
    mAudio.setLoopPoints(0, sampleCount, -1); 
    mAudio.play(); 
} 

public void stop() { 
    mAudio.stop(); 

} 
} 

私が手にエラーがこれです：

E/AndroidRuntime: FATAL EXCEPTION: main 
       Process: com.example.jack.synthesiser, PID: 18957 
       java.lang.IllegalStateException: play() called on uninitialized AudioTrack. 
        at android.media.AudioTrack.play(AudioTrack.java:1141) 
        at com.example.jack.synthesiser.PlayWave.start(PlayWave.java:61) 
        at com.example.jack.synthesiser.MainActivity.onClick(MainActivity.java:47) 
        at android.view.View.performClick(View.java:4780) 
        at android.widget.CompoundButton.performClick(CompoundButton.java:120) 
        at android.view.View$PerformClick.run(View.java:19866) 
        at android.os.Handler.handleCallback(Handler.java:739) 
        at android.os.Handler.dispatchMessage(Handler.java:95) 
        at android.os.Looper.loop(Looper.java:135) 
        at android.app.ActivityThread.main(ActivityThread.java:5254) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at java.lang.reflect.Method.invoke(Method.java:372) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 

Answer 1

here

この回答を確認してくださいこれは、任意のwrite()メソッドを使用する前に、play()を呼び出すことをお勧めします。