Question

当按下主页按钮或屏幕熄灭时，媒体播放器会停止音乐....即使活动失去焦点，我也希望音乐继续播放....但我希望音乐暂停以接听来电以及用户是否暂停音乐......当通过后退按钮关闭活动时音乐应该停止

这是我的代码示例：

package com.example.acer.aartisangrah;

import android.content.Context;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.telephony.PhoneStateListener;
import android.telephony.TelephonyManager;
import android.text.Html;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.Toast;

public class ekdanta extends AppCompatActivity implements Runnable, View.OnClickListener,SeekBar.OnSeekBarChangeListener {
TextView tv4;
Button b9, b10,but19;
int count = 0;
MediaPlayer play;
SeekBar seek_bar;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_ekdanta);
    tv4 = (TextView) findViewById(R.id.textView9);
    tv4.setTextSize(18);
    tv4.setText(Html.fromHtml(getString(R.string.thirteen)));
    b9 = (Button) findViewById(R.id.b9);
    b10 = (Button) findViewById(R.id.b10);
    seek_bar = (SeekBar) findViewById(R.id.seekBar);
    seek_bar.setOnSeekBarChangeListener(this);
    seek_bar.setEnabled(false);
    but19 = (Button) findViewById(R.id.button19);
    but19.setOnClickListener(this);
    TelephonyManager mTelephonyManager = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
    mTelephonyManager.listen(mPhoneListener, PhoneStateListener.LISTEN_CALL_STATE);
}
private final PhoneStateListener mPhoneListener=new PhoneStateListener(){
    public void onCallStateChanged(int state, String incomingNumber) {
        super.onCallStateChanged(state, incomingNumber);

        // Call receive state
        if (state != TelephonyManager.CALL_STATE_IDLE) {
            if ((play!= null) && (play.isPlaying()))
            {
                play.pause();
                but19.setBackgroundResource(R.drawable.play);
            }
        }
    }
};

public void run() {
    int currentPosition = play.getCurrentPosition();
    final int total = play.getDuration();
    while (play != null && currentPosition < total) {
        try {
            Thread.sleep(1000);
            currentPosition = play.getCurrentPosition();
        } catch (InterruptedException e) {
            return;
        } catch (Exception e) {
            return;
        }
        seek_bar.setProgress(currentPosition);
    }
}
public void onClick(View v) {
    if (v.equals(but19)) {
        if (play == null) {
            play = MediaPlayer.create(getApplicationContext(), R.raw.ekadanta);
            seek_bar.setEnabled(true);
        }
        if (play.isPlaying()) {
            play.pause();
            but19.setBackgroundResource(R.drawable.play);
        } else {
            play.start();
            but19.setBackgroundResource(R.drawable.pause);
            seek_bar.setMax(play.getDuration());
            new Thread(this).start();
        }
    }
    play.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
        @Override
        public void onCompletion(MediaPlayer mp) {
            play.seekTo(0);
            but19.setBackgroundResource(R.drawable.play);
        }
    });
}

@Override
protected void onPause()
{
    super.onPause();
}

@Override
protected void onDestroy()
{
    super.onDestroy();
    play.release();
}

@Override
public void onProgressChanged(SeekBar seek_bar, int progress, boolean fromUser) {
    try{
        if(play.isPlaying()||play!=null){
            if (fromUser)
                play.seekTo(progress);
        }
        else if(play==null){
            Toast.makeText(getApplicationContext(),"First Play", Toast.LENGTH_SHORT).show();
            seek_bar.setProgress(0);
        }
    }
    catch(Exception e){
        Log.e("seek bar",""+e);
        seek_bar.setEnabled(false);
    }
}

@Override
public void onStartTrackingTouch(SeekBar seekBar) {

}

@Override
public void onStopTrackingTouch(SeekBar seekBar) {

}

public void increase(View inc) {
    count++;
    if (count == 1) {
        tv4.setTextSize(22);
    } else if (count == 2) {
        tv4.setTextSize(30);
    } else if (count >= 3) {
        count = 3;
        tv4.setTextSize(40);
    }
}

public void decrease(View dec) {
    count--;
    if (count <= 0) {
        tv4.setTextSize(18);
        count = 0;
    }
    if (count == 1) {
        tv4.setTextSize(22);
    } else if (count == 2) {
        tv4.setTextSize(30);
    } else if (count == 3) {
        tv4.setTextSize(40);
    }
}
}

编辑

使用此代码进行活动后...此活动无法在某些设备上打开...应用程序只是自行关闭....请帮助！没有此代码的其他活动也可以正常工作......

Answer 1

首先，您有以下代码

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

每次活动进入后台（失去焦点）或用户关闭时，都会执行

onPause方法。因此，您的第一步是从onPause方法中删除此代码，您可以在其中故意调用play.pause()。

您应该覆盖onBackPressed()方法并执行类似于您正在执行的操作，但调用play.stop()

检查here，特别是执行清理部分，其中显示以下内容

MediaPlayer对象可能占用大量系统资源，所以你应该只保留它，只要你需要和打电话完成后释放（）。这称之为重要显式清理方法而不是依赖系统垃圾收集因为垃圾可能需要一些时间收集器收回MediaPlayer

请务必查看该指南。

Answer 2

当应用到达后台时停止播放音乐。评论play.pause()如下：

@Override 
protected void onPause() 
{ 
    super.onPause(); 
    if ((play!= null) && (play.isPlaying())) 
    { 
        // play.pause(); 
    } 
}

播放本身应该在后退时停止播放（我几乎可以肯定）。确保在onDestroy()。

中丢弃mediaPlayer

在通话接收时停止。在您的活动中实例化以下接收者：

// Listens for phone state and pauses in an event of call
    private final PhoneStateListener mPhoneListener = new PhoneStateListener() {
        public void onCallStateChanged(int state, String incomingNumber) {
            super.onCallStateChanged(state, incomingNumber);

            // Call receive state
            if (state != TelephonyManager.CALL_STATE_IDLE) {
                if ((play!= null) && (play.isPlaying())) 
                { 
                    play.pause(); 
                }
            }
        }
    };

您需要注册（可能在onCreate()）：

// Make mTelephonyManager an instance variable
TelephonyManager mTelephonyManager = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
mTelephonyManager.listen(mPhoneListener, PhoneStateListener.LISTEN_CALL_STATE);

请勿忘记在onDestroy()中取消注册：

mTelephonyManager.listen(mPhoneListener, PhoneStateListener.LISTEN_NONE);

当活动失去焦点时（主页或屏幕熄灭时），媒体播放器会暂停音乐

2 个答案: