片段中的 mPlayer

Question

你好，我在片段中添加 MdiaPlayer 时遇到了一些麻烦，但我想现在它会起作用，我需要 1 个 lats 东西，因为我的代码：private MediaPlayer mPlayer = null;是 "null" 并且我现在不需要在这一行的 () 中放入什么 mPlayer = new MediaPlayer();如果有人可以帮助我，非常感谢。

public class thekairi78 extends Fragment implements OnClickListener{

    View v;
    Button france2;
    private MediaPlayer mPlayer = null;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        v  = inflater.inflate(R.layout.thekairi78, container, false);

        france2 = (Button) v.findViewById(R.id.france2);
        france2.setOnClickListener(this);

        mPlayer = new MediaPlayer();


        return v;
        }





    private void playSound(int resId){
        if (mPlayer != null) {
            mPlayer.stop();
            mPlayer.release();

        }
        mPlayer = MediaPlayer.create(getActivity(), resId);
        mPlayer.start();
    }

    @Override
    public void onPause() {
        if(mPlayer != null && mPlayer.isPlaying()){
            mPlayer.pause();
        }
        super.onPause();

    }
    @Override
    public void onClick(View v) {

        switch (v.getId()) {
            case R.id.france2:
                playSound(R.raw.france1);
                break;



        }

    }
}

Answer 1

从

更改此行

mPlayer=new MediaPlayer()

至

mPlayer = MediaPlayer.create(getActivity(), R.raw.sample_song);

Answer 2

试试这个 class，它对我有用

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.media.MediaPlayer;
import android.os.Handler;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.SeekBar;
import android.widget.TextView;

import com.example.prolab2.learn_android.Activitys.Activity_Info;
import com.example.prolab2.learn_android.R;

import java.util.concurrent.TimeUnit;



public class Fragment_Audio extends Fragment implements View.OnClickListener 
{

public Fragment_Audio(){
}
private MediaPlayer mediaPlayer;
public TextView songName, duration;
ImageButton btn_play, btn_pause, btn_forward, btn_rewind;
Button btn_audio_player_show;
private double timeElapsed = 0, finalTime = 0;
private int forwardTime = 2000, backwardTime = 2000;
private Handler durationHandler = new Handler();
private SeekBar seekbar;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_audio, container, false);

    btn_audio_player_show = (Button) view.findViewById(R.id.btn_audio_player_show);
    btn_audio_player_show.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(getActivity(), Activity_Info.class);
            intent.putExtra("Buttons_id", v.getId());
            startActivity(intent);
        }
    });

    songName = (TextView) view.findViewById(R.id.songName);
    btn_forward = (ImageButton) view.findViewById(R.id.media_ff);
    btn_play = (ImageButton) view.findViewById(R.id.media_play);
    btn_pause = (ImageButton) view.findViewById(R.id.media_pause);
    btn_rewind = (ImageButton) view.findViewById(R.id.media_rew);

    btn_forward.setOnClickListener(this);
    btn_play.setOnClickListener(this);
    btn_pause.setOnClickListener(this);
    btn_rewind.setOnClickListener(this);

    mediaPlayer = MediaPlayer.create(getActivity(), R.raw.sample_song);
    finalTime = mediaPlayer.getDuration();
    duration = (TextView) view.findViewById(R.id.songDuration);
    seekbar = (SeekBar) view.findViewById(R.id.seekBar);
    songName.setText("Sample_Song.mp3");

    seekbar.setMax((int) finalTime);
    seekbar.setClickable(false);

    return view;
}

// play mp3 song
public void play() {
    mediaPlayer.start();
    timeElapsed = mediaPlayer.getCurrentPosition();
    seekbar.setProgress((int) timeElapsed);
    durationHandler.postDelayed(updateSeekBarTime, 100);
}

//handler to change seekBarTime
private Runnable updateSeekBarTime = new Runnable() {
    public void run() {
        //get current position
        timeElapsed = mediaPlayer.getCurrentPosition();
        //set seekbar progress
        seekbar.setProgress((int) timeElapsed);
        //set time remaing
        double timeRemaining = finalTime - timeElapsed;
        duration.setText(String.format("%d min, %d sec", TimeUnit.MILLISECONDS.toMinutes((long) timeRemaining), TimeUnit.MILLISECONDS.toSeconds((long) timeRemaining) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes((long) timeRemaining))));

        //repeat yourself that again in 100 miliseconds
        durationHandler.postDelayed(this, 100);
    }
};

// pause mp3 song
public void pause() {
    mediaPlayer.pause();
}

// go forward at forwardTime seconds
public void forward() {
    //check if we can go forward at forwardTime seconds before song endes
    if ((timeElapsed + forwardTime) <= finalTime) {
        timeElapsed = timeElapsed + forwardTime;

        //seek to the exact second of the track
        mediaPlayer.seekTo((int) timeElapsed);
    }
}

// go backwards at backwardTime seconds
public void rewind() {
    //check if we can go back at backwardTime seconds after song starts
    if ((timeElapsed - backwardTime) > 0) {
        timeElapsed = timeElapsed - backwardTime;

        //seek to the exact second of the track
        mediaPlayer.seekTo((int) timeElapsed);
    }
}

@Override
public void onClick(View v) {
    switch(v.getId()){
        case R.id.media_ff:
            forward();
            break;

        case R.id.media_play:
            play();
            break;
        case R.id.media_pause:
            pause();
            break;

        case R.id.media_rew:
            rewind();
            break;
    }
}
}

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