为什么选择mediaPlayer.stop();在这里不起作用

Question

[AS] 我已经加载了两个可以毫无问题地播放和重叠的声音，但是我似乎无法停止或暂停它们。

在当前状态下，停止按钮只写入日志，但我似乎无法让mediaplayer.stop((或mediaplayer.pause((工作。

需要明确的是，我希望 stopSound 结束当前播放的所有声音，并在再次调用时让每个声音从头开始。

音量控制是否会产生冲突？我错过了什么吗？任何帮助将不胜感激。

主活动.java

public class MainActivity extends AppCompatActivity {
    public MediaPlayer mediaPlayer;
    AudioManager audioManager;
    public void playSound(View view) {
        Button soundButton = (Button) view;
        Log.i("INFO", soundButton.getTag().toString() + " button pressed.");
        MediaPlayer mediaPlayer = MediaPlayer.create(this, getResources().getIdentifier(soundButton.getTag().toString(), "raw", getPackageName()));
        mediaPlayer.start();
    }
    public void stopSound(View view) {
        Log.i("INFO", "stop button pressed.");   
        mediaPlayer.stop();
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        audioManager = (AudioManager) getSystemService(AUDIO_SERVICE);
        int maxVolume = audioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC);
        int currentVolume = audioManager.getStreamVolume(AudioManager.STREAM_MUSIC);
        mediaPlayer = MediaPlayer.create(this, R.raw.sound_01);
        mediaPlayer = MediaPlayer.create(this, R.raw.sound_02);
        SeekBar volumeControl = (SeekBar) findViewById(R.id.seekBar);
        volumeControl.setMax(maxVolume);
        volumeControl.setProgress(currentVolume);
        volumeControl.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
                Log.i("Seekbar changed", Integer.toString(i));
                audioManager.setStreamVolume(AudioManager.STREAM_MUSIC, i, 0);
            }
            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {
            }
            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
            }
        });
    }

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/background_light"
    tools:context="com.example.company.app.MainActivity">
    <android.support.constraint.ConstraintLayout
        android:id="@+id/constraintLayout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">
        <ScrollView
            android:id="@+id/scrollView"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_marginBottom="128dp"
            android:layout_marginTop="64dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent">
            <GridLayout
                android:id="@+id/gridLayout"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="@android:color/black"
                android:columnCount="2"
                android:paddingBottom="4dp"
                android:paddingTop="4dp"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent">
                <Button
                    android:id="@+id/buttonL1"
                    android:layout_columnWeight="1"
                    android:layout_gravity="center_vertical"
                    android:layout_marginLeft="6dp"
                    android:layout_marginRight="1dp"
                    android:layout_rowWeight="1"
                    android:onClick="playSound"
                    android:tag="sound_01"
                    android:text="Sound One" />
                <Button
                    android:id="@+id/buttonR1"
                    android:layout_columnWeight="1"
                    android:layout_gravity="center_vertical"
                    android:layout_marginLeft="1dp"
                    android:layout_marginRight="6dp"
                    android:layout_rowWeight="1"
                    android:onClick="playSound"
                    android:tag="sound_02"
                    android:text="Sound Two" />

            </GridLayout>
        </ScrollView>
        <SeekBar
            android:id="@+id/seekBar"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginEnd="24dp"
            android:layout_marginStart="24dp"
            android:layout_marginTop="16dp"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/scrollView" />
        <Button
            android:id="@+id/stopButton"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:layout_marginTop="16dp"
            android:onClick="stopSound"
            android:text="stop"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@id/seekBar" />
    </android.support.constraint.ConstraintLayout>
</android.support.constraint.ConstraintLayout>

Answer 1

请像下面这样更改您的代码：-

媒体播放器

媒体播放器一;媒体播放器媒体播放器二;

public void playSound(View view) {
        Button soundButton = (Button) view;

        mediaPlayerOne.start();
        mediaPlayerTwo.start();
    }

您正在尝试停止尚未启动的媒体播放器实例。您正在播放该方法本地的媒体播放器实例。

在创建方法中，如下所示：-

mediaPlayerOne = MediaPlayer.create(this, R.raw.sound_01);
mediaPlayerTwo = MediaPlayer.create(this, R.raw.sound_02);

停止时：-

 mediaPlayerOne.stop();
 mediaPlayerTwo.stop();