Java 如何使媒体播放器在按设备后退按钮从片段返回活动时停止
我的问题是,当我按下设备后退按钮时,媒体播放器一直在播放。当按下设备后退按钮时,如何完全销毁碎片、媒体播放器和其中的所有内容,使其在屏幕上不可见 我是编程新手,所以欢迎所有关于如何改进代码的建议和评论。多谢各位 活动:Java 如何使媒体播放器在按设备后退按钮从片段返回活动时停止,java,android,Java,Android,我的问题是,当我按下设备后退按钮时,媒体播放器一直在播放。当按下设备后退按钮时,如何完全销毁碎片、媒体播放器和其中的所有内容,使其在屏幕上不可见 我是编程新手,所以欢迎所有关于如何改进代码的建议和评论。多谢各位 活动: import androidx.appcompat.app.AppCompatActivity; import androidx.fragment.app.FragmentManager; import android.os.Bundle; import android.view
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentManager;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
Button button1;
Button button2;
Button button3;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button1 = findViewById(R.id.button1);
button2 = findViewById(R.id.button2);
button3 = findViewById(R.id.button3);
button1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
FragmentManager fm= getSupportFragmentManager();
fragment1 fragment = new fragment1();
fm.beginTransaction()
.replace(R.id.container,fragment)
.addToBackStack(null)
.commit();
}
});
button2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
FragmentManager fm= getSupportFragmentManager();
fragment2 fragment= new fragment2();
fm.beginTransaction()
.replace(R.id.container,fragment)
.addToBackStack(null)
.commit();
}
});
button3.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
FragmentManager fm= getSupportFragmentManager();
fragment3 fragment= new fragment3();
fm.beginTransaction()
.replace(R.id.container,fragment)
.addToBackStack(null)
.commit();
}
});
}
}
片段:
import androidx.fragment.app.Fragment;
import android.media.MediaPlayer;
import android.view.LayoutInflater;
import android.view.ViewGroup;
import android.widget.Button;
import android.os.Bundle;
import android.widget.SeekBar;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.TextView;
import java.io.IOException;
public class fragment1 extends Fragment {
MediaPlayer mp;
Button play;
SeekBar seekBar;
TextView elapsedTimeLabel;
TextView remainingTimeLabel;
int totalTime;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_fragment1, container, false);
final MediaPlayer mp = new MediaPlayer();
try {
mp.setDataSource("https://firebasestorage.googleapis.com...");
} catch (IOException e) {
e.printStackTrace();
}
try {
mp.prepare();
} catch (IOException e) {
e.printStackTrace();
}
final Button play = rootView.findViewById(R.id.play);
elapsedTimeLabel = rootView.findViewById(R.id.elapsedTimeLabel);
remainingTimeLabel = rootView.findViewById(R.id.remainingTimeLabel);
totalTime = mp.getDuration();
mp.seekTo(0);
seekBar = rootView.findViewById(R.id.seekBar);
seekBar.setMax(totalTime);
seekBar.setOnSeekBarChangeListener
(new SeekBar.OnSeekBarChangeListener() {
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
if (fromUser) {
mp.seekTo(progress);
seekBar.setProgress(progress);
}
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
}
}
);
new Thread(new Runnable() {
@Override
public void run() {
while (mp != null) {
try {
Message msg = new Message();
msg.what = mp.getCurrentPosition();
handler.sendMessage(msg);
Thread.sleep(1000);
} catch (InterruptedException ignored) {
}
}
}
}).start();
mp.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
public void onCompletion(MediaPlayer sound) {
play.setBackgroundResource(R.drawable.play);
}
});
play.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (mp.isPlaying()) {
mp.pause();
play.setBackgroundResource(R.drawable.play);
} else {
mp.start();
play.setBackgroundResource(R.drawable.pause);
}
}
});
return rootView;
}
private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
int currentPosition = msg.what;
seekBar.setProgress(currentPosition);
String elapsedTime = createTimeLabel(currentPosition);
elapsedTimeLabel.setText(elapsedTime);
String remainingTime;
remainingTime = createTimeLabel(totalTime - currentPosition);
remainingTimeLabel.setText("-" + remainingTime);
}
};
public String createTimeLabel(int time) {
String timelabel;
int min = time / 1000 / 60;
int sec = time / 1000 % 60;
timelabel = min + ":";
if (sec < 10) timelabel += "0";
timelabel += sec;
return timelabel;
}
public void play(View view) {
if (mp == null) {
mp.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
stopPlayer();
}
});
}
mp.start();
}
public void pause(View view) {
if (mp != null) {
mp.pause();
}
}
private void stopPlayer() {
if (mp != null) {
mp.release();
mp = null;
}
}
}
导入androidx.fragment.app.fragment;
导入android.media.MediaPlayer;
导入android.view.LayoutInflater;
导入android.view.ViewGroup;
导入android.widget.Button;
导入android.os.Bundle;
导入android.widget.SeekBar;
导入android.os.Handler;
导入android.os.Message;
导入android.view.view;
导入android.widget.TextView;
导入java.io.IOException;
公共类fragment1扩展了Fragment{
MediaPlayer mp;
按钮播放;
SeekBar-SeekBar;
TextView elapsedTimeLabel;
文本视图保留时间标签;
整数总时间;
@凌驾
CreateView上的公共视图(布局、充气机、视图组容器、捆绑包保存状态){
视图根视图=充气机。充气(R.layout.fragment\u fragment1,容器,false);
最终MediaPlayer mp=新MediaPlayer();
试一试{
mp.setDataSource(“https://firebasestorage.googleapis.com...");
}捕获(IOE异常){
e、 printStackTrace();
}
试一试{
mp.prepare();
}捕获(IOE异常){
e、 printStackTrace();
}
最终按钮播放=rootView.findviewbyd(R.id.play);
elapsedtimelab=rootView.findviewbyd(R.id.elapsedtimelab);
remainingTimeLabel=rootView.findviewbyd(R.id.remainingTimeLabel);
totalTime=mp.getDuration();
希克托议员(0);
seekBar=rootView.findviewbyd(R.id.seekBar);
seekBar.setMax(总时间);
seekBar.setonseekbarchaneglistener
(新SeekBar.onseekbarchaneglistener(){
@凌驾
public void onProgressChanged(SeekBar-SeekBar、int-progress、boolean-fromUser){
如果(来自用户){
希克托议员(进步党);
seekBar.setProgress(进度);
}
}
@凌驾
开始跟踪触摸时的公共无效(SeekBar SeekBar){
}
@凌驾
TopTrackingTouch(SeekBar SeekBar)上的公共无效{
}
}
);
新线程(newrunnable()){
@凌驾
公开募捐{
while(mp!=null){
试一试{
Message msg=新消息();
msg.what=mp.getCurrentPosition();
handler.sendMessage(msg);
睡眠(1000);
}捕获(InterruptedException被忽略){
}
}
}
}).start();
mp.setOnCompletionListener(新的MediaPlayer.OnCompletionListener(){
公共空间完成(MediaPlayer声音){
play.setBackgroundResource(R.drawable.play);
}
});
play.setOnClickListener(新视图.OnClickListener(){
@凌驾
公共void onClick(视图){
if(mp.isPlaying()){
mp.pause();
play.setBackgroundResource(R.drawable.play);
}否则{
mp.start();
play.setBackgroundResource(R.drawable.pause);
}
}
});
返回rootView;
}
私有处理程序=新处理程序(){
@凌驾
公共无效handleMessage(消息消息消息){
int currentPosition=msg.what;
seekBar.setProgress(当前位置);
字符串elapsedTime=createTimeLabel(当前位置);
elapsedtimelab.setText(elapsedTime);
字符串剩余时间;
remainingTime=createTimeLabel(总时间-当前位置);
remainingTimeLabel.setText(“-”+remainingTime);
}
};
公共字符串createTimeLabel(整数时间){
字符串时间标签;
int min=时间/1000/60;
整数秒=时间/1000%60;
timelabel=min+“:”;
如果(秒<10)时间标签+=“0”;
时间标签+=秒;
返回时间标签;
}
公共无效播放(视图){
if(mp==null){
mp.setOnCompletionListener(新的MediaPlayer.OnCompletionListener(){
@凌驾
完成时的公共作废(MediaPlayer mp){
停止层();
}
});
}
mp.start();
}
公共无效暂停(视图){
如果(mp!=null){
mp.pause();
}
}
私有层(){
如果(mp!=null){
mp.release();
mp=null;
}
}
}
编辑:
我尝试了提供的解决方案,但不知何故,片段中的mediaplayer没有被破坏。当我回到片段时,其中的seekbar被重置,但音频文件仍在播放。当我再次按play键时,它会在前一个键的基础上再次开始播放,因此有两个文件同时播放不幸的是,由于片段没有
onBackPressed()
方法,因此您必须进行回调并在片段中实现它才能使其正常工作
首先,您需要创建一个实现其接口的接口和类,以拥有一个泛型方法
公共接口
@Override
public void onDestroy() {
super.onDestroy();
stopPlayer();
}
@Override
public void onDestroy() {
stopPlayer();
super.onDestroy();
}