版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/u010356768/article/details/83587469
概念
Android手机每按一次音量+/-,音量的增加/减小幅度,这个我们称为:系统的音量步进值
音量还有一定的范围,系统的是:0到Max,Max不确定,这个称为:系统的音量范围
在Android中,是有几种类型的音量可以调节:
- STREAM_ALARM 警报
- STREAM_MUSIC 音乐回放即媒体音量
- STREAM_RING 铃声
- STREAM_SYSTEM 系统
- STREAM_VOICE_CALL 通话
栗子:seekbar控制媒体音量
public class SoundActivity extends AppCompatActivity {
private SeekBar seekBar;
private TextView tv_sound;
private AudioManager mAudioManager;
private int maxVolume,currentVolume;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sound);
seekBar = findViewById(R.id.seekbar);
tv_sound = findViewById(R.id.tv_sound);
//获取系统的Audio管理者
mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
//最大音量
maxVolume = mAudioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC);
//当前音量
currentVolume = mAudioManager.getStreamVolume(AudioManager.STREAM_MUSIC);
//seekbar设置最大值为最大音量,这样设置当前进度时不用换算百分比了
seekBar.setMax(maxVolume);
//seekbar设置当前进度为当前音量
setView();
//seekbar设置拖动监听
seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener()
{
public void onProgressChanged(SeekBar arg0,int progress,boolean fromUser)
{
//设置媒体音量为当前seekbar进度
mAudioManager.setStreamVolume(AudioManager.STREAM_MUSIC, progress, 0);
currentVolume = mAudioManager.getStreamVolume(AudioManager.STREAM_MUSIC);
setView();
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
}
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
}
});
}
/*
* onkeydown 事件会在用户按下一个键盘按键时发生
*/
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
switch (keyCode) {
case KeyEvent.KEYCODE_VOLUME_DOWN:
if(--currentVolume>=0){
setView();
}else {
currentVolume = 0;
}
return true;
case KeyEvent.KEYCODE_VOLUME_UP:
if(++currentVolume<=maxVolume){
setView();
}else{
currentVolume = maxVolume;
}
return true;
case KeyEvent.KEYCODE_VOLUME_MUTE:
setView();
return true;
}
return super.onKeyDown(keyCode, event);
}
private void setView(){
tv_sound.setText(currentVolume+"");
seekBar.setProgress(currentVolume);
}
}