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example,您必须在循环中调用fadeIn()/ fadeOut(),以在一段时间内增加/减少音量. deltaTime将是循环的每次迭代之间的时间.

您必须在主UI线程的单独线程中执行此操作,因此您不会阻止它并导致应用程序崩溃.您可以通过将此循环放在新的Thread / Runnable / Timer中来实现.

这是我淡入的例子(你可以做一个类似的事情淡出)：

float volume = 0;

private void startFadeIn(){

final int FADE_DURATION = 3000; //The duration of the fade

//The amount of time between volume changes. The smaller this is, the smoother the fade

final int FADE_INTERVAL = 250;

final int MAX_VOLUME = 1; //The volume will increase from 0 to 1

int numberOfSteps = FADE_DURATION/FADE_INTERVAL; //Calculate the number of fade steps

//Calculate by how much the volume changes each step

final float deltaVolume = MAX_VOLUME / (float)numberOfSteps;

//Create a new Timer and Timer task to run the fading outside the main UI thread

final Timer timer = new Timer(true);

TimerTask timerTask = new TimerTask() {

@Override

public void run() {

fadeInStep(deltaVolume); //Do a fade step

//Cancel and Purge the Timer if the desired volume has been reached

if(volume>=1f){

timer.cancel();

timer.purge();

}

}

};

timer.schedule(timerTask,FADE_INTERVAL,FADE_INTERVAL);

}

private void fadeInStep(float deltaVolume){

mediaPlayer.setVolume(volume, volume);

volume += deltaVolume;

}

在你的情况下,我会使用一个并在渐变之间交换轨道,而不是使用两个单独的MediaPlayer对象.

例：

**Audio track #1 is playing but coming to the end**

startFadeOut();

mediaPlayer.stop();

mediaPlayer.reset();

mediaPlayer.setDataSource(context,audiofileUri);

mediaPlayer.prepare();

mediaPlayer.start();

startFadeIn();

**Audio track #2 has faded in and is now playing**

希望这能解决你的问题.