为什么我的播放器每次打开都会崩溃？

Question

我正在尝试Android中的音乐播放器，但它每次都会崩溃。我首先使用列表视图从哪里通过意图将数据发送到玩家活动。然后我和midea假设要播放音乐，但是出了什么问题呢？它甚至不开放。当我点击mainactivity类的歌曲列表时。它表明您的应用没有响应。这是我的播放器活动的java文件

package com.smp.ravirathore.materialdesign;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Color;
import android.media.MediaMetadataRetriever;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.NavUtils;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.SeekBar;

import java.io.File;
import java.util.ArrayList;

/**
 * Created by Python on 9/28/2015.
 */
public class Player extends ActionBarActivity implements View.OnClickListener {

    SeekBar seekBar;
    Uri uri;
    int position;
    Button play, forward, backward, nxt, previous;
    MediaPlayer player;
    ArrayList<File> arrayList;
    Thread seekupdate;
    Toolbar toolbar;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.player);
        toolbar = (Toolbar) findViewById(R.id.app_bar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setDefaultDisplayHomeAsUpEnabled(true);
        Intent i = getIntent();
        Bundle b = i.getExtras();
        arrayList = (ArrayList) b.getParcelableArrayList("mysongs");
        seekBar = (SeekBar) findViewById(R.id.seekBar);
        seekupdate = new Thread() {
            @Override
            public void run() {
                int totalDuration = player.getDuration();
                int currentDuration = 0;
                if (currentDuration < totalDuration) {
                    try {
                        sleep(500);
                        currentDuration = player.getCurrentPosition();
                        seekBar.setProgress(currentDuration);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                }
                //super.run();
            }
        };

        play = (Button) findViewById(R.id.play);
        forward = (Button) findViewById(R.id.forward);
        backward = (Button) findViewById(R.id.backwrd);
        nxt = (Button) findViewById(R.id.next);
        previous = (Button) findViewById(R.id.previous);
        play.setOnClickListener(this);
        forward.setOnClickListener(this);
        backward.setOnClickListener(this);
        nxt.setOnClickListener(this);
        previous.setOnClickListener(this);
        position = b.getInt("pos");
        uri = Uri.parse(arrayList.get(position).toString());
        player = MediaPlayer.create(getApplicationContext(), uri);
        seekBar.setProgress(0);
        player.start();
        seekBar.setMax(player.getDuration());
        seekupdate.start();
        seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {

            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
                player.seekTo(seekBar.getProgress());
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();

        if (id == R.id.action_settings) {
            return true;
        }
        if (id == android.R.id.home) {
            NavUtils.navigateUpFromSameTask(this);
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.play:
                if (player.isPlaying()) {
                    player.pause();
                    play.setText("Play");
                } else {
                    player.start();
                    play.setText("Pause");
                }
                break;
            case R.id.forward:
                player.seekTo(player.getCurrentPosition() + 10000);
                break;
            case R.id.backwrd:
                player.seekTo(player.getCurrentPosition() - 5000);
                break;
            case R.id.next:
                player.stop();
                player.release();
                position = (position + 1) % arrayList.size();
                uri = Uri.parse(arrayList.get(position).toString());
                player = MediaPlayer.create(getApplicationContext(), uri);
                seekBar.setProgress(0);
                player.start();
                seekBar.setMax(player.getDuration());
                break;
            case R.id.previous:
                player.stop();
                player.release();
                position = (position - 1 < 0) ? (arrayList.size() - 1) : position - 1;
                uri = Uri.parse(arrayList.get(position).toString());
                player = MediaPlayer.create(getApplicationContext(), uri);
                seekBar.setProgress(0);
                player.start();
                seekBar.setMax(player.getDuration());
                break;

        }
    }


}