再次單擊同一個ListView時如何暫停和恢復音頻？-有解無憂

我有一個 ListView 活動，顯示我的原始檔案中的歌曲串列，當我單擊其中一個 ListView 時，它將相應地播放歌曲，但如果我第二次單擊它只會再次重播同一首歌曲。如何在同一軌道上暫停和再次恢復？以下是我到目前為止所做的代碼。

MainActivity.java

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.media.MediaPlayer;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;

public class MainActivity extends AppCompatActivity {

private ListView musicListView;
private Trackmodel[] tracklist;
private TrackAdapter adapter;
private MediaPlayer mediaPlayer;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    musicListView = findViewById(R.id.musicListView);
    loadTracks();

    musicListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
            loadTracks();
            Trackmodel track = tracklist[i];

            if (mediaPlayer != null) {
                if (mediaPlayer.isPlaying()) {
                    mediaPlayer.stop();
                    mediaPlayer.reset();
                    track.setPlaying(false);
                }
            }

            try {
                mediaPlayer = MediaPlayer.create(MainActivity.this, track.getId());
                if (mediaPlayer.isPlaying()) {
                    mediaPlayer.stop();
                    mediaPlayer.reset();
                    track.setPlaying(false);
                } else {
                    mediaPlayer.start();
                    track.setPlaying(true);
                }

            } catch (Exception e) {
                Log.e("Exception", e.getMessage());
            }
        }
    });
}

public void loadTracks() {
    tracklist = new Trackmodel[]{
            new Trackmodel(R.raw.decode, "Paramore - Decode", false),
            new Trackmodel(R.raw.thats_what_you_get, "Paramore - That's What You Get", false),
            new Trackmodel(R.raw.starstrukk, "30H!3 - Starstrukk", false),
            new Trackmodel(R.raw.we_are_young, "30H!3 - We Are Young", false)
    };
    adapter = new TrackAdapter(MainActivity.this, tracklist);
    musicListView.setAdapter(adapter);
    adapter.notifyDataSetChanged();
}

@Override
protected void onDestroy() {
    super.onDestroy();

    if (mediaPlayer != null) {
        if (mediaPlayer.isPlaying()) {
            mediaPlayer.stop();
            mediaPlayer.reset();
        }
    }
}}

TrackModel.java

package com.example.myapplication;

public class Trackmodel {
private int id;
private String name;
private boolean isPlaying;

public Trackmodel(int id, String name, boolean isPlaying) {
    this.id = id;
    this.name = name;
    this.isPlaying = isPlaying;
}

public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public boolean isPlaying() {
    return isPlaying;
}

public void setPlaying(boolean playing) { isPlaying = playing; }
}

TrackAdapter.java

package com.example.myapplication;

import android.content.Context;
import android.view.ContentInfo;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

public class TrackAdapter extends BaseAdapter {

private Context context;
private Trackmodel[] tracks;

TrackAdapter(Context context, Trackmodel[] tracks) {
    this.context = context;
    this.tracks = tracks;
}

@Override
public int getCount() {
    return tracks.length;
}

@Override
public Object getItem(int i) {
    return tracks[i];
}

@Override
public long getItemId(int i) {
    return i;
}

@Override
public View getView(int i, View view, ViewGroup viewGroup) {
    Trackmodel track = (Trackmodel) getItem(i);
    ViewHolder holder;

    if (view == null) {
        view = LayoutInflater.from(context).inflate(R.layout.track_item, viewGroup, false);
        holder = new ViewHolder();
        holder.trackImage = view.findViewById(R.id.track_image);
        holder.titleText = view.findViewById(R.id.track_title);
        view.setTag(holder);
    } else {
        holder = (ViewHolder) view.getTag();
    }
    holder.titleText.setText(track.getName());

    if (track.isPlaying()) {
        holder.trackImage.setImageResource(R.drawable.ic_baseline_pause_circle);
    } else {
        holder.trackImage.setImageResource(R.drawable.ic_baseline_play_circle);
    }
    return view;
}

static class ViewHolder {
    ImageView trackImage;
    TextView titleText;
}
}

track_item.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@ id/sound_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:paddingLeft="16sp"
android:paddingTop="10dp"
android:paddingRight="16sp">

<ImageView
    android:id="@ id/track_image"
    android:layout_width="50dp"
    android:layout_height="50dp"
    android:layout_centerVertical="true"
    android:padding="5dp"
    app:tint="@android:color/black" />

<TextView
    android:id="@ id/track_title"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerVertical="true"
    android:layout_marginLeft="56dp"
    android:textAppearance="@style/TextAppearance.AppCompat.Body2" />
</RelativeLayout>

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">

<ListView
    android:id="@ id/musicListView"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />
</LinearLayout>

uj5u.com熱心網友回復：

在您的專案單擊中，您停止MediaPlayer但之后，您每次都創建一個新實體。你有一個 if 檢查，它檢查是否MediaPlayer正在播放并停止它。之后，您創建一個new MediaPlayer并再次執行相同的檢查。那么當你第一次點擊時會發生什么？第一個if檢查沒有執行，因為你的mediaplayer為空，它創建一個新的mediaplayer并開始播放。第二次單擊后，您的第一次if檢查正在執行，因為您的 MediaPlayer 不為空且isPlaying為真。您停止它，創建一個新實體MediaPlayer并再次播放它。這就是為什么在單擊所有下一次之后，您只需重播歌曲。因為單擊時您會停止歌曲，創建一個新實體并播放它。

所以你在這里需要什么，我假設你的串列中有不同的曲目，當你點擊另一個曲目時，你需要停止上一個曲目并開始新的曲目。但是，如果您單擊同一曲目，則要暫停它。

在這種情況下，您需要正在播放/播放的當前曲目 ID。下次點擊后，如果曲目ID與正在播放的曲目相同，則只需暫停即可。如果它是另一個軌道，停止它并開始新的軌道。這是下面的代碼，您可以進行相應的更改并將其應用于您的代碼。

int currentTrackId = -1;
    musicListView.setOnItemClickListener(
            (AdapterView.OnItemClickListener) (adapterView, view, i, l) -> {
        loadTracks();
        Trackmodel track = tracklist[i];
        if (currentTrackId != -1 && track.getId() == currentTrackId) {
            // That was the same song, just pause it.
            if (mediaPlayer != null) {
                if (mediaPlayer.isPlaying()) {
                    mediaPlayer.pause();
                    track.setPlaying(false);
                } else {
                    mediaPlayer.start();
                    track.setPlaying(true);
                }
            }
        } else {
            // That's another song, stop the previous one and start the new one
            currentTrackId = track.getId();
            if (mediaPlayer != null) {
                mediaPlayer.stop();
                mediaPlayer.reset();
            }

            try {
                mediaPlayer = MediaPlayer.create(MainActivity.this, track.getId());
                mediaPlayer.start();
                track.setPlaying(true);

            } catch (Exception e) {
                Log.e("Exception", e.getMessage());
            }  
        }
    });

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