方法解析：增大／降低音量值public void adjustStreamVolume(int streamType, int direction, int flags)设置音量值public void setStreamVolume(int streamType, int index, int flags)参数介绍
streamType是需要调整音量的类型,可以是: STREAM_ALARM 警报 STREAM_MUSIC 音乐回放即媒体音量 STREAM_NOTIFICATION 窗口顶部状态栏Notification, STREAM_RING 铃声 STREAM_SYSTEM 系统 STREAM_VOICE_CALL 通话 STREAM_DTMF 双音多频
direction是调整的方向,增加或减少,可以是: ADJUST_LOWER 降低音量 ADJUST_RAISE 升高音量 ADJUST_SAME 保持不变,这个主要用于向用户展示当前的音量
flags是一些附加参数,只介绍两个常用的 FLAG_PLAY_SOUND 调整音量时播放声音 FLAG_SHOW_UI 调整时显示音量条
index是要设置的音量值，类型为int
示例代码public class SunActivity extends AppCompatActivity implements SeekBar.OnSeekBarChangeListener {private int VOICE_TYPE;private SeekBar sb_media, sb_calling, sb_system, sb_clock;private AudioManager audioManager;private int startPoint;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_sun);audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);sb_media = (SeekBar) findViewById(R.id.sb_media);sb_calling = (SeekBar) findViewById(R.id.sb_ring);sb_system = (SeekBar) findViewById(R.id.sb_system);sb_clock = (SeekBar) findViewById(R.id.sb_alarm);//为了SeekBar的效果明显，将音量值乘以10显示sb_media.setProgress(audioManager.getStreamVolume(AudioManager.STREAM_MUSIC) * 10);sb_calling.setProgress(audioManager.getStreamVolume(AudioManager.STREAM_RING) * 10);sb_system.setProgress(audioManager.getStreamVolume(AudioManager.STREAM_SYSTEM) * 10);sb_clock.setProgress(audioManager.getStreamVolume(AudioManager.STREAM_ALARM) * 10);sb_media.setOnSeekBarChangeListener(this);sb_calling.setOnSeekBarChangeListener(this);sb_system.setOnSeekBarChangeListener(this);sb_clock.setOnSeekBarChangeListener(this);}@Overridepublic void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {}@Overridepublic void onStartTrackingTouch(SeekBar seekBar) {startPoint = seekBar.getProgress();}@Overridepublic void onStopTrackingTouch(SeekBar seekBar) {switch (seekBar.getId()) {case R.id.sb_media:VOICE_TYPE = AudioManager.STREAM_MUSIC;break;case R.id.sb_ring:VOICE_TYPE = AudioManager.STREAM_RING;break;case R.id.sb_system:VOICE_TYPE = AudioManager.STREAM_SYSTEM;break;case R.id.sb_alarm:VOICE_TYPE = AudioManager.STREAM_ALARM;break;}//if (seekBar.getProgress() > startPoint) { //提升音量//audioManager.adjustStreamVolume(VOICE_TYPE, AudioManager.ADJUST_RAISE, 0);//} else {//降低音量//audioManager.adjustStreamVolume(VOICE_TYPE, AudioManager.ADJUST_LOWER, 0);//}audioManager.setStreamVolume(VOICE_TYPE, seekBar.getProgress() / 10, AudioManager.FLAG_SHOW_UI);}}部分布局代码 <LinearLayoutandroid:layout_width=”match_parent”android:layout_height=”wrap_content”android:gravity=”center_vertical”android:orientation=”horizontal”android:padding=”20dp”><TextViewandroid:layout_width=”wrap_content”android:layout_height=”wrap_content”android:layout_marginRight=”10dp”android:background=”@drawable/shape_text”android:padding=”3dp”android:text=”媒体”android:textColor=”#ffffff” /><SeekBarandroid:id=”@+id/sb_media”android:layout_width=”match_parent”android:layout_height=”wrap_content” /></LinearLayout>
我知道按攻略去旅行的人往往玩得过于按步就班，
