首先，由于Android的更改或我的问题完全不同，因此stackoverflow上提供的所有解决方案都无法使用。
我想实现的目标-我想检测我的视图（例如-ThirdFragment）何时成为焦点并变为用户可见。另外，它应该检测用户何时从当前视图滑动到下一个视图或上一个视图。
我为什么要这样做？ -好吧，我正在其中一个视图中创建媒体播放器，如示例片段代码所示，并且用户可以通过点击列表中的音乐来播放视图中列出的任何音乐，但是当用户滑动到下一个屏幕时，停止。
有什么问题？ -问题是媒体播放器从视图切换后并没有立即停止播放，但是[***]如果我滑动两步，它会停止播放但不能干净地播放，它会在后台抖动。
我之前尝试过的内容-我已经尝试过此[[setUserVisibleHint，但由于已被废弃，因此无法正常工作。 onPause，onDetach，onStop均无法正常运行，如此处所述[***]]/*------Home ViewPager----- */
public class HomeFragment extends Fragment {
private ViewPager viewPager;
private String[] titles = {"First","Second","Third","Fourth"};
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
TextView subtitle = getActivity().findViewById(R.id.toolbar_right_subtitle);
subtitle.setText(titles[0]);
return inflater.inflate(R.layout.fragment_home, container, false);
}
@Override
public void onViewCreated(@NonNull final View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
/* pages */
viewPager = view.findViewById(R.id.interfaces);
InterfaceAdapter interfacePagerAdapter = new InterfaceAdapter(getActivity().getSupportFragmentManager(),0);
viewPager.setAdapter(interfacePagerAdapter);
viewPager.setCurrentItem(0);
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
TextView subtitle = getActivity().findViewById(R.id.toolbar_right_subtitle);
subtitle.setText(titles[position]);
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
}
}
/*---------- My Fragment Adapter --------- */
public class InterfaceAdapter extends FragmentStatePagerAdapter {
public InterfaceAdapter(@NonNull FragmentManager fm, int behavior) {
super(fm, behavior);
}
@NonNull
@Override
public Fragment getItem(int position) {
switch (position){
case 0:
return new FirstFragment();
case 1:
return new SecondFragment();
case 2:
return new ThirdFragment();
case 3:
return new FourthFragment();
default:
return null;
}
}
@Override
public int getCount() {
return 4;
}
}
/*---------- One of my Fragment --------- */
public class ThirdFragment extends Fragment {
//------Media Player ----------
private MusicAdapter musicAdapter;
private List<SongData> songsList;
private ListView listView;
private static MediaPlayer mediaPlayer;
private Handler handler = new Handler();
private Runnable runnable;
private ImageView playButton, prevButton, nextButton;
private SeekBar seekbarPayer;
private TextView playerTime,songTitle;
private int pos = 0;
public ThirdFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
mediaPlayer = new MediaPlayer();
getAllSongs();
return inflater.inflate(R.layout.fragment_focus, container, false);
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
//--------Music Player---------------
mediaPlayer = new MediaPlayer();
playButton = view.findViewById(R.id.playpause_player);
prevButton = view.findViewById(R.id.prev_player);
nextButton = view.findViewById(R.id.next_player);
seekbarPayer = view.findViewById(R.id.seekbar_player);
playerTime = view.findViewById(R.id.playertime);
songTitle = view.findViewById(R.id.songname);
songTitle.setSelected(true);
songsList = new ArrayList<>();
musicAdapter = new MusicAdapter(getActivity(), songsList);
listView = view.findViewById(R.id.songList);
listView.setAdapter(musicAdapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
pos = position;
playMusicFile(songsList.get(position).getUri(),songsList.get(position).getTitle());
}
});
//play or pause music
playButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
playPause();
}
});
//next music
nextButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (pos < songsList.size() - 1) {
pos++;
} else {
pos = 0;
}
playMusicFile(songsList.get(pos).getUri(),songsList.get(pos).getTitle());
}
});
//next music
prevButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (pos > 0) {
pos--;
} else {
pos = songsList.size() - 1;
}
playMusicFile(songsList.get(pos).getUri(),songsList.get(pos).getTitle());
}
});
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
@Override
public void onStart() {
super.onStart();
getAllSongs();
Log.d("SystemStatus","Start");
}
@Override
public void onResume() {
super.onResume();
getAllSongs();
Log.d("SystemStatus","Resume");
}
@Override
public void onStop() {
super.onStop();
stopPlayer();
Log.d("SystemStatus","Stop");
}
@Override
public void onDetach() {
super.onDetach();
stopPlayer();
Log.d("SystemStatus","Detach");
}
@Override
public void onPause() {
super.onPause();
stopPlayer();
Log.d("SystemStatus","Pause");
}
//---Media Player-----
private void getAllSongs() {
/*
* get all songs and add it into songlist
*/
}
private void playMusicFile(String filePath,final String title){
if(mediaPlayer!=null) {
mediaPlayer.reset();
try {
mediaPlayer.setDataSource(filePath);
mediaPlayer.prepareAsync();
mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
@Override
public void onPrepared(MediaPlayer mp) {
mp.start();
}
});
mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
stopPlayer();
}
});
} catch (IOException e) {
e.printStackTrace();
}
}
}
private void playPause() {
if (!mediaPlayer.isPlaying()) {
mediaPlayer.start();
}else {
mediaPlayer.pause();
}
}
private void stopPlayer() {
if(mediaPlayer.isPlaying()){
mediaPlayer.stop();
mediaPlayer.reset();
}
}
}
首先，由于Android的更改或我的问题完全不同，因此在stackoverflow上提供的所有解决方案都无法使用。我想实现的目标-我想检测我的视图何时（对于...
0作为行为，它对应于已弃用的BEHAVIOR_SET_USER_VISIBLE_HINT。通过使用该行为，当您的片段成为当前页面时，将用BEHAVIOR_SET_USER_VISIBLE_HINT调用setUserVisibleHint()，否则将不使用true来调用。如果切换到未弃用的false，则仅当前页面将获得BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT。当页面更改时，该Fragment将获得对BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT的回调，而新活动的fragment将获得对onResume()的调用。