我正在为Android制作应用程序，我已经制作了三个按钮来播放，暂停和停止。
我的播放和暂停按钮已设置，因此当我单击播放按钮时，它将变为不可见，并且将显示暂停按钮，反之亦然。
单击播放按钮时效果很好，但点击暂停按钮后，它会给我一个错误。
代码如下。
package com.mpIlango;
import java.io.IOException;
import java.util.ArrayList;
import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioGroup;
import android.widget.RadioGroup.OnCheckedChangeListener;
public class MpIlangoActivity extends Activity implements OnCheckedChangeListener {
/** Called when the activity is first created. */
MediaPlayer song1,song2,song3;
int whatsong = 0;
private ArrayList<Integer> songIds;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
RadioGroup rgMusic = (RadioGroup) findViewById(R.id.rgMusic);
songIds = new ArrayList<Integer>();
songIds.add(R.raw.fluet);
songIds.add(R.raw.airtel);
songIds.add(R.raw.titanic);
final Button bPlay = (Button) findViewById(R.id.bPlay);
final Button bStop = (Button) findViewById(R.id.bStop);
final Button bPause = (Button) findViewById(R.id.bPause);
bPause.setVisibility(View.GONE);
rgMusic.setOnCheckedChangeListener(this);
bPlay.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(song1!=null) {
song1.release();
}
if(song2!=null) {
song2.release();
}
if(song3!=null) {
song3.release();
}
switch (whatsong) {
case 1:
try {
song1 = MediaPlayer.create(MpIlangoActivity.this, songIds.get(0));
song1.prepare();
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
song1.start();
bPlay.setVisibility(View.GONE);
bPause.setVisibility(View.VISIBLE);
break;
case 2:
try {
song2 = MediaPlayer.create(MpIlangoActivity.this, songIds.get(1));
song2.prepare();
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
song2.start();
bPlay.setVisibility(View.GONE);
bPause.setVisibility(View.VISIBLE);
break;
case 3:
try {
song3 = MediaPlayer.create(MpIlangoActivity.this, songIds.get(2));
song3.prepare();
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
song3.start();
bPlay.setVisibility(View.GONE);
bPause.setVisibility(View.VISIBLE);
break;
}
}
});
bPause.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
bPlay.setVisibility(View.VISIBLE);
bPause.setVisibility(View.GONE);
if(song1.isPlaying()){
song1.pause();
}
if(song2.isPlaying()){
song2.pause();
}
if(song3.isPlaying()){
song3.pause();
}
}
});
bStop.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(song1!=null){
song1.release();
}
if(song2!=null){
song2.release();
}
if(song3!=null){
song3.release();
}
}
});;
}
@Override
public void onCheckedChanged(RadioGroup group, int rbId) {
switch (rbId) {
case R.id.rbMusic1:
whatsong = 1;
break;
case R.id.rbMusic2:
whatsong = 2;
break;
case R.id.rbMusic3:
whatsong = 3;
break;
}
}
}
答案 0 :(得分：2)
暂停我使用的媒体播放器...
Mediaplayer.pause();
length=Mediaplayer.getCurrentPosition();
并且从最近停止的位置恢复玩家是......
Mediaplayer.seekTo(length);
Mediaplayer.start();
答案 1 :(得分：1)
我猜你在这里得到一个NullPointerException！？
if(song1.isPlaying()){
song1.pause();
}
if(song2.isPlaying()){
song2.pause();
}
if(song3.isPlaying()){
song3.pause();
}
这也是你在这里使用开关的问题。
switch (whatsong) {
case 1:
if(song1.isPlaying()){
song1.pause();
}
或在其他地方初始化你的歌曲以确保它们永远不会为空
我还建议只使用一个MediaPlayer。
MediaPlayer song;
bPlay代码：
if(song!=null) {
song.release();
}
switch (whatsong) {
case 1:
try {
song = MediaPlayer.create(MpIlangoActivity.this, songIds.get(0));
song.prepare();
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
song.start();
bPlay.setVisibility(View.GONE);
bPause.setVisibility(View.VISIBLE);
b暂停代码：
bPlay.setVisibility(View.VISIBLE);
bPause.setVisibility(View.GONE);
if(song != null && song.isPlaying()){
song.pause();
}
本规范的所有内容均未经过测试！
答案 2 :(得分：0)
这是一个soundmanager / audiomanager类，希望它可以帮助或指出你正确的方向;）
import java.util.HashMap;
import java.util.Random;
import android.content.Context;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.SoundPool;
public class SoundManager {
public boolean audio;
public boolean audioSoundFX;
public boolean audioMusic;
private SoundPool mSoundPool;
private HashMap<Integer, Integer> mSoundPoolMap;
private AudioManager mAudioManager;
private Context mContext;
private Random random = new Random();
private MediaPlayer menuMusic;
private MediaPlayer gameMusic;
private int menuMusicCurrentPos = 0;
private int gameMusicCurrentPos = 0;
public static final SoundManager INSTANCE = new SoundManager();
private SoundManager() {
}
public void setAudio(boolean audioOn){
if(audioOn){
audio = true;
}
if(!audioOn) {
audio = false;
}
}
public void setSoundFX(boolean soundFX){
if(soundFX){
audioSoundFX = true;
}
if(!soundFX) {
audioSoundFX = false;
}
}
public void setMusic(boolean music){
if(music){
audioMusic = true;
}
if(!music) {
audioMusic = false;
}
}
public void initSounds(Context theContext) {
if (mSoundPool == null){
mContext = theContext;
mSoundPool = new SoundPool(4, AudioManager.STREAM_MUSIC, 0);
mSoundPoolMap = new HashMap<Integer, Integer>();
mAudioManager = (AudioManager)mContext.getSystemService(Context.AUDIO_SERVICE);
mSoundPoolMap.put(1, mSoundPool.load(mContext, R.raw.ufo_laser, 1));
mSoundPoolMap.put(2, mSoundPool.load(mContext, R.raw.enemy_hunter_one_laser, 1));
mSoundPoolMap.put(3, mSoundPool.load(mContext, R.raw.enemyhuntertwomissile, 1));
mSoundPoolMap.put(4, mSoundPool.load(mContext, R.raw.enemy_hunter_three_laser, 1));
mSoundPoolMap.put(5, mSoundPool.load(mContext, R.raw.enemy_drone, 1));
mSoundPoolMap.put(6, mSoundPool.load(mContext, R.raw.kamikaze, 1));
mSoundPoolMap.put(14, mSoundPool.load(mContext, R.raw.exploastroidshard, 1));
mSoundPoolMap.put(11, mSoundPool.load(mContext, R.raw.health, 1));
mSoundPoolMap.put(12, mSoundPool.load(mContext, R.raw.energy, 1));
mSoundPoolMap.put(13, mSoundPool.load(mContext, R.raw.shield, 1));
mSoundPoolMap.put(15, mSoundPool.load(mContext, R.raw.gameover, 1));
mSoundPoolMap.put(16, mSoundPool.load(mContext, R.raw.gameoverexplo, 1));
mSoundPoolMap.put(17, mSoundPool.load(mContext, R.raw.menu_beep, 1));
mSoundPoolMap.put(20, mSoundPool.load(mContext, R.raw.menu_beep, 1));
menuMusic = MediaPlayer.create(mContext, R.raw.musicmenu);
}
}
public void playSound(int index, boolean pitching, int loop){
if(audioSoundFX == true && audio == true){
float randomPitch;
if (pitching){
randomPitch = (float)(random.nextInt(3) + 9) / 10;
}else{
randomPitch = 1;
}
float streamVolume = mAudioManager.getStreamVolume(AudioManager.STREAM_MUSIC);
streamVolume = streamVolume / mAudioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC);
mSoundPool.play((Integer) mSoundPoolMap.get(index), streamVolume, streamVolume, 1, loop, randomPitch);
}
}
public void playMenuMusic(){
if(audioMusic == true && audio == true){
if (menuMusic == null){
if(MediaPlayer.create(mContext, R.raw.musicmenu) != null) {
menuMusic = MediaPlayer.create(mContext, R.raw.musicmenu);
if(menuMusicCurrentPos != 0){
menuMusic.seekTo(menuMusicCurrentPos);
}
menuMusic.start();
menuMusic.setVolume(1f , 1f);
menuMusic.setLooping(true);
}
}
}
}
public void releaseMenuMusic(){
if(menuMusic != null){
this.menuMusicCurrentPos = menuMusic.getCurrentPosition();
menuMusic.release();
menuMusic = null;
}
}
public void playGameMusic(){
if(audioMusic == true && audio == true){
if (gameMusic == null){
gameMusic = MediaPlayer.create(mContext, R.raw.music_game);
if(menuMusicCurrentPos != 0){
gameMusic.seekTo(gameMusicCurrentPos);
}
gameMusic.start();
gameMusic.setVolume(1f , 1f);
gameMusic.setLooping(true);
}
}
}
public void releaseGameMusic(){
if(gameMusic != null){
this.gameMusicCurrentPos = gameMusic.getCurrentPosition();
gameMusic.release();
gameMusic = null;
}
}
}