在多个片段类中使用一个 MediaPlayer 实例答案

【问题标题】：Use one instance of MediaPlayer throughout several fragment classes在多个片段类中使用一个 MediaPlayer 实例
【发布时间】：2015-06-06 20:13:42
【问题描述】：

我正在创建一个音板 Android 应用程序，该应用程序将使用多个片段来显示单击时会播放声音的按钮。到目前为止，我的代码使用了两个 MediaPlayer 实例。我不知道如何在仍然有两个片段的情况下使用单个 MediaPlayer 实例。

这是我的代码：

package com.davidreadiii.android.soundboardexample1;

import android.content.res.AssetFileDescriptor;
import android.content.res.Resources;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

import java.io.IOException;


public class MainFragment {

public static class Fragment1 extends Fragment {

    int selectedSoundId;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.page1, container, false);

        final MediaPlayer player = new MediaPlayer();
        final Resources res = getResources();

        final int[] buttonIds = { R.id.btn1, R.id.btn2, R.id.btn3 };
        final int[] soundIds = {R.raw.giggity_giggity_goo, R.raw.hey_baby, R.raw.hump_day };

        View.OnClickListener listener = new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                for (int i = 0; i < buttonIds.length; i++) {
                    if (v.getId() == buttonIds[i]) {
                        selectedSoundId = soundIds[i];
                        AssetFileDescriptor afd = res.openRawResourceFd(soundIds[i]);
                        player.reset();
                        try {
                            player.setDataSource(afd.getFileDescriptor(), afd.getStartOffset(), afd.getLength());
                        } catch (IllegalArgumentException e) {
                            e.printStackTrace();
                        } catch (IllegalStateException e) {
                            e.printStackTrace();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        try {
                            player.prepare();
                        } catch (IllegalStateException e) {
                            e.printStackTrace();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        player.start();
                        break;
                    }
                }
            }
        };

        for (int i = 0; i < buttonIds.length; i++) {
            Button soundButton = (Button) rootView.findViewById(buttonIds[i]);
            registerForContextMenu(soundButton);
            soundButton.setOnClickListener(listener);
        }
        return rootView;
    }
}

public static class Fragment2 extends Fragment {

    int selectedSoundId;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.page2, container, false);

        final MediaPlayer player = new MediaPlayer();
        final Resources res = getResources();

        final int[] buttonIds = { R.id.btn4, R.id.btn5, R.id.btn6 };
        final int[] soundIds = { R.raw.ios_note, R.raw.old_spice, R.raw.you_suck };

        View.OnClickListener listener = new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                for (int i = 0; i < buttonIds.length; i++) {
                    if (v.getId() == buttonIds[i]) {
                        selectedSoundId = soundIds[i];
                        AssetFileDescriptor afd = res.openRawResourceFd(soundIds[i]);
                        player.reset();
                        try {
                            player.setDataSource(afd.getFileDescriptor(), afd.getStartOffset(), afd.getLength());
                        } catch (IllegalArgumentException e) {
                            e.printStackTrace();
                        } catch (IllegalStateException e) {
                            e.printStackTrace();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        try {
                            player.prepare();
                        } catch (IllegalStateException e) {
                            e.printStackTrace();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        player.start();
                        break;
                    }
                }
            }
        };

        for (int i = 0; i < buttonIds.length; i++) {
            Button soundButton = (Button) rootView.findViewById(buttonIds[i]);
            registerForContextMenu(soundButton);
            soundButton.setOnClickListener(listener);
        }
        return rootView;
    }
}
}

据我所知，我可能需要将片段更改为公共类而不是公共静态类。有人可以帮我找到解决方案吗？？？谢谢。

【问题讨论】：

我建议创建一个 MediaPlayer 实例或 Fragment1 之一。我不喜欢将 Fragment1 声明为静态的。一般来说，片段并不意味着在内存中是静态的。我明天可能会发布示例代码。

标签： java android android-intent android-fragments android-mediaplayer

【解决方案1】：

您可以使用单例模式：

    public class Singleton {
    private static Singleton mInstance = null;

    private String mString;

    private Singleton(){
        mString = "Hello";
    }

    public static Singleton getInstance(){
        if(mInstance == null)
        {
            mInstance = new Singleton();
        }
        return mInstance;
    }

    public String getString(){
        return this.mString;
    }

    public void setString(String value){
        mString = value;
    }
}

将此模式用于您的 MediaPlayer，并在需要您的 MediaPlayer 实例时调用 getInstance()。

【讨论】：