Question

在生命周期中搜索后，我发现我的应用程序需要使用destroy();方法。但是，当我实现这个时，应用程序不会关闭。我正在尝试将其应用于按钮exitButton。如果有人能指引我朝着正确的方向前进，那就太棒了。

MainActivity.java

package com.webcraftbd.radio;

import android.os.Bundle;
import android.os.IBinder;
import android.app.Activity;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.ServiceConnection;
import android.support.v4.app.NotificationCompat;
import android.support.v4.app.TaskStackBuilder;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity {        

    static String radioTitle = "Android Live Radio";
    static String radioStreamURL = "http://stream.infowars.com:80"; 

    Button playButton;
    Button pauseButton;
    Button stopButton;  
    Button exitbutton;
    TextView statusTextView, bufferValueTextView;
    NotificationCompat.Builder notifyBuilder;

    private RadioUpdateReceiver radioUpdateReceiver;
    private RadioService radioServiceBinder;

    //Notification
     private static final int NOTIFY_ME_ID=12345;
     private NotificationManager notifyMgr=null;

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

        TextView titleTextView = (TextView) this.findViewById(R.id.titleTextView);
        titleTextView.setText(radioTitle);

        playButton = (Button) this.findViewById(R.id.PlayButton);
        pauseButton = (Button) this.findViewById(R.id.PauseButton);
        stopButton = (Button) this.findViewById(R.id.StopButton);
        playButton.setEnabled(true);
        pauseButton.setEnabled(false);
        stopButton.setEnabled(false);
        pauseButton.setVisibility(View.INVISIBLE);

        statusTextView = (TextView) this.findViewById(R.id.StatusDisplayTextView);

        notifyMgr=(NotificationManager)getSystemService(NOTIFICATION_SERVICE);
        showNotification();

        // Bind to the service
        Intent bindIntent = new Intent(this, RadioService.class);
        bindService(bindIntent, radioConnection, Context.BIND_AUTO_CREATE);
        startService(new Intent(this, RadioService.class));
    }


    public void onClickPlayButton(View view) {
        radioServiceBinder.play();
    }

    public void onClickPauseButton(View view) {
        radioServiceBinder.pause();
    }

    public void onClickStopButton(View view) {      
        radioServiceBinder.stop();
    }
    public void onClicexitbutton(View view) {       
        super.finish();
        super.onDestroy();
    radioServiceBinder.onDestroy();
    radioServiceBinder.stop();
    radioServiceBinder.stopService(getParentActivityIntent());

    }


    @Override
    protected void onPause() {
        super.onPause();
        if (radioUpdateReceiver != null) 
            unregisterReceiver(radioUpdateReceiver);
    }

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

        /* Register for receiving broadcast messages */
        if (radioUpdateReceiver == null) radioUpdateReceiver = new RadioUpdateReceiver();   
        registerReceiver(radioUpdateReceiver, new IntentFilter(RadioService.MODE_CREATED));
        registerReceiver(radioUpdateReceiver, new IntentFilter(RadioService.MODE_DESTROYED));
        registerReceiver(radioUpdateReceiver, new IntentFilter(RadioService.MODE_STARTED));
        registerReceiver(radioUpdateReceiver, new IntentFilter(RadioService.MODE_PREPARED));
        registerReceiver(radioUpdateReceiver, new IntentFilter(RadioService.MODE_PLAYING));
        registerReceiver(radioUpdateReceiver, new IntentFilter(RadioService.MODE_PAUSED));
        registerReceiver(radioUpdateReceiver, new IntentFilter(RadioService.MODE_STOPPED));
        registerReceiver(radioUpdateReceiver, new IntentFilter(RadioService.MODE_COMPLETED));
        registerReceiver(radioUpdateReceiver, new IntentFilter(RadioService.MODE_ERROR));
        registerReceiver(radioUpdateReceiver, new IntentFilter(RadioService.MODE_BUFFERING_START));
        registerReceiver(radioUpdateReceiver, new IntentFilter(RadioService.MODE_BUFFERING_END));
    }

    protected void onDestroy(){

        super.onDestroy();
    }
    /* Receive Broadcast Messages from RadioService */
    private class RadioUpdateReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {

            if (intent.getAction().equals(RadioService.MODE_CREATED)) {
                showNotification();
            }
            else if (intent.getAction().equals(RadioService.MODE_DESTROYED)) {
                clearNotification();
            }
            else if (intent.getAction().equals(RadioService.MODE_STARTED)) {
                playButton.setEnabled(false);
                pauseButton.setEnabled(false);
                stopButton.setEnabled(true);
                playButton.setVisibility(View.VISIBLE);
                pauseButton.setVisibility(View.INVISIBLE);
                updateStatus("Buffering...");
            }
            else if (intent.getAction().equals(RadioService.MODE_PREPARED)) {
                playButton.setEnabled(true);
                pauseButton.setEnabled(false);
                stopButton.setEnabled(false);
                playButton.setVisibility(View.VISIBLE);
                pauseButton.setVisibility(View.INVISIBLE);
                updateStatus("Rady");
            }
            else if (intent.getAction().equals(RadioService.MODE_BUFFERING_START)) {
                updateStatus("Buffering...");
            }
            else if (intent.getAction().equals(RadioService.MODE_BUFFERING_END)) {
                updateStatus("Playing");
            }
            else if (intent.getAction().equals(RadioService.MODE_PLAYING)) {
                playButton.setEnabled(false);
                pauseButton.setEnabled(true);
                stopButton.setEnabled(true);
                playButton.setVisibility(View.INVISIBLE);
                pauseButton.setVisibility(View.VISIBLE);
                showNotification();
                updateStatus("Playing");
            }
            else if(intent.getAction().equals(RadioService.MODE_PAUSED)) {
                playButton.setEnabled(true);
                pauseButton.setEnabled(false);
                stopButton.setEnabled(true);
                playButton.setVisibility(View.VISIBLE);
                pauseButton.setVisibility(View.INVISIBLE);
                updateStatus("Paused");
            }
            else if(intent.getAction().equals(RadioService.MODE_STOPPED)) {
                playButton.setEnabled(true);
                pauseButton.setEnabled(false);
                stopButton.setEnabled(false);
                playButton.setVisibility(View.VISIBLE);
                pauseButton.setVisibility(View.INVISIBLE);
                updateStatus("Stopped");
                clearNotification();
            }
            else if(intent.getAction().equals(RadioService.MODE_COMPLETED)) {
                playButton.setEnabled(true);
                pauseButton.setEnabled(false);
                stopButton.setEnabled(false);
                playButton.setVisibility(View.VISIBLE);
                pauseButton.setVisibility(View.INVISIBLE);
                updateStatus("Stopped");
            }
            else if(intent.getAction().equals(RadioService.MODE_ERROR)) {
                playButton.setEnabled(true);
                pauseButton.setEnabled(false);
                stopButton.setEnabled(false);
                playButton.setVisibility(View.VISIBLE);
                pauseButton.setVisibility(View.INVISIBLE);
                updateStatus("Error");
            }   
        }
    }

    public void updateStatus(String status) {       
        try {
                if(notifyBuilder!=null && notifyMgr!=null) {
                    notifyBuilder.setContentText(status).setWhen(0);
                    notifyMgr.notify(NOTIFY_ME_ID,notifyBuilder.build());
                }
                statusTextView.setText(status);
        }
        catch(Exception e) {
            e.printStackTrace();
        }
    }

    public void showNotification() {
        notifyBuilder = new NotificationCompat.Builder(this).setSmallIcon(R.drawable.ic_launcher).setContentTitle(radioTitle).setContentText("");
        Intent resultIntent = new Intent(this, MainActivity.class);
        resultIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        resultIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

        TaskStackBuilder stackBuilder = TaskStackBuilder.create(this);
        stackBuilder.addParentStack(MainActivity.class);
        stackBuilder.addNextIntent(resultIntent);

        PendingIntent resultPendingIntent = stackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);

        notifyBuilder.setContentIntent(resultPendingIntent);
        notifyMgr = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        notifyMgr.notify(NOTIFY_ME_ID, notifyBuilder.build());
    }

    public void clearNotification() {
        notifyMgr.cancel(NOTIFY_ME_ID);
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main_menu, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
        case R.id.about:
            Intent i = new Intent(this, AboutActivity.class);
            startActivity(i);
            return true;
        }
        return super.onOptionsItemSelected(item);
    }



    // Handles the connection between the service and activity
    private ServiceConnection radioConnection = new ServiceConnection() {
        public void onServiceConnected(ComponentName className, IBinder service) {
            radioServiceBinder = ((RadioService.RadioBinder)service).getService();
        }
        public void onServiceDisconnected(ComponentName className) {
            radioServiceBinder = null;
        }
    };
}
enter code here

activity_main.xml中

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#4a4a4a"
    tools:context=".MainActivity" >

    <LinearLayout
        android:id="@+id/player_header_bg"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true" >

        <TextView
            android:id="@+id/titleTextView"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="48dp"
            android:gravity="center"
            android:text="Classic Christmas Radio"
            android:textAlignment="center"
            android:textAppearance="?android:attr/textAppearanceLarge"
            android:textColor="#c0413b"
            android:textSize="40sp" />
    </LinearLayout>

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_centerInParent="true"
        android:layout_marginBottom="120dp"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:layout_marginTop="110dp"
        android:src="@drawable/cover" />

    <TextView
        android:id="@+id/StatusDisplayTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/PauseButton"
        android:layout_alignLeft="@+id/imageView1"
        android:layout_alignRight="@+id/imageView1"
        android:gravity="center"
        android:text="Unknown" />

    <Button
        android:id="@+id/PauseButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@id/StatusDisplayTextView"
        android:layout_alignParentBottom="true"
        android:layout_marginBottom="0.0dip"
        android:background="@drawable/btn_pause"
        android:onClick="onClickPauseButton" />

    <Button
        android:id="@+id/PlayButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@id/StatusDisplayTextView"
        android:layout_alignParentBottom="true"
        android:layout_marginBottom="0.0dip"
        android:background="@drawable/btn_play"
        android:onClick="onClickPlayButton" />

    <Button
        android:id="@+id/StopButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignRight="@id/StatusDisplayTextView"
        android:layout_marginBottom="0.0dip"
        android:background="@drawable/btn_stop"
        android:onClick="onClickStopButton" />

    <Button
        android:id="@+id/exitbutton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/StatusDisplayTextView"
        android:layout_centerHorizontal="true"
        android:text="Button" />

</RelativeLayout>

RadioService.java

package com.webcraftbd.radio;

import java.io.IOException;

import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.media.MediaPlayer.OnErrorListener;
import android.media.MediaPlayer.OnInfoListener;
import android.media.MediaPlayer.OnPreparedListener;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;

public class RadioService extends Service implements OnErrorListener, OnCompletionListener, OnPreparedListener, OnInfoListener {

    private MediaPlayer mediaPlayer;
    private String radioStreamURL = MainActivity.radioStreamURL;

    public static final String MODE_CREATED = "CREATED";
    public static final String MODE_DESTROYED = "DESTROYED";
    public static final String MODE_PREPARED = "PREPARED";
    public static final String MODE_STARTED = "STARTED";
    public static final String MODE_PLAYING = "PLAYING";
    public static final String MODE_PAUSED = "PAUSED";
    public static final String MODE_STOPPED = "STOPPED";
    public static final String MODE_COMPLETED = "COMPLETED";
    public static final String MODE_ERROR = "ERROR";
    public static final String MODE_BUFFERING_START = "BUFFERING_START";
    public static final String MODE_BUFFERING_END = "BUFFERING_END";

    private boolean isPrepared = false;

    private final IBinder binder = new RadioBinder();

    @Override
    public void onCreate() {
        /* Create MediaPlayer when it starts for first time */
        mediaPlayer = new MediaPlayer();
        mediaPlayer.setOnCompletionListener(this);
        mediaPlayer.setOnErrorListener(this);
        mediaPlayer.setOnPreparedListener(this);
        mediaPlayer.setOnInfoListener(this);

        sendBroadcast(new Intent(MODE_CREATED));
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        mediaPlayer.stop();
        mediaPlayer.reset();
        isPrepared = false;
        sendBroadcast(new Intent(MODE_DESTROYED));
    }


    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {  
        sendBroadcast(new Intent(MODE_STARTED));

        /* Starts playback at first time or resumes if it is restarted */
        if(mediaPlayer.isPlaying())
            sendBroadcast(new Intent(MODE_PLAYING));
        else if(isPrepared) {
            sendBroadcast(new Intent(MODE_PAUSED));
        }
        else
            prepare();

        return Service.START_STICKY;
    }


    @Override
    public void onPrepared(MediaPlayer _mediaPlayer) {
        /* If radio is prepared then start playback */
        sendBroadcast(new Intent(MODE_PREPARED));
        isPrepared = true;
        play();
    }

    @Override
    public void onCompletion(MediaPlayer mediaPlayer) { 
        /* When no stream found then complete the playback */
        mediaPlayer.stop();
        mediaPlayer.reset();
        isPrepared = false;
        sendBroadcast(new Intent(MODE_COMPLETED));
    }

    public void prepare() {     
        /* Prepare Async Task - starts buffering */
        try {           
            mediaPlayer.setDataSource(radioStreamURL);
            mediaPlayer.prepareAsync();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (IllegalStateException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void play() {
        if(isPrepared) {
            mediaPlayer.start();
            System.out.println("RadioService: play");
            sendBroadcast(new Intent(MODE_PLAYING));
        }
        else
        {
            sendBroadcast(new Intent(MODE_STARTED));
            prepare();
        }
    }

    public void pause() {
        mediaPlayer.pause();
        System.out.println("RadioService: pause");
        sendBroadcast(new Intent(MODE_PAUSED));
    }

    public void stop() {
        mediaPlayer.stop();
        mediaPlayer.reset();
        isPrepared = false;
        System.out.println("RadioService: stop");
        sendBroadcast(new Intent(MODE_STOPPED));
    }

    @Override
    public boolean onInfo(MediaPlayer mp, int what, int extra) {
        /* Check when buffering is started or ended */
        if(what == MediaPlayer.MEDIA_INFO_BUFFERING_START) {
            sendBroadcast(new Intent(MODE_BUFFERING_START));
        }
        else if(what == MediaPlayer.MEDIA_INFO_BUFFERING_END) {
            sendBroadcast(new Intent(MODE_BUFFERING_END));
        }

        return false;
    }


    @Override
    public boolean onError(MediaPlayer mp, int what, int extra) {
        sendBroadcast(new Intent(MODE_ERROR));
        switch (what) {
            case MediaPlayer.MEDIA_ERROR_NOT_VALID_FOR_PROGRESSIVE_PLAYBACK:
                Log.v("ERROR","MEDIA ERROR NOT VALID FOR PROGRESSIVE PLAYBACK " + extra);
                break;
            case MediaPlayer.MEDIA_ERROR_SERVER_DIED:
                Log.v("ERROR","MEDIA ERROR SERVER DIED " + extra);
                break;
            case MediaPlayer.MEDIA_ERROR_UNKNOWN:
                Log.v("ERROR","MEDIA ERROR UNKNOWN " + extra);
                break;
        }
        return false;
    }


    @Override
    public IBinder onBind(Intent intent) {
        return binder;
    }

    /* Allowing activity to access all methods of RadioService */
    public class RadioBinder extends Binder {
        RadioService getService() {
            return RadioService.this;
        }
    }

}

Answer 1

好的，在开发了一些伪和一些逻辑之后，我注意到Andorid没有像你希望的方式那样的exit方法。当我第一次阅读这个问题时，我没有意识到它是Android，因为我是多任务的。正如您可能注意到的，几乎每个Android应用程序都没有退出按钮，这是有原因的。原因是Android应该通过操作系统加载和卸载应用程序，因此你不这样做。如果用户想要退出应用程序，他们将完成他们对彼此的操作，进入多任务菜单并将其滑动。请阅读以下内容以获取更多信息：http://android.nextapp.com/site/fx/doc/exit

如何销毁JFrame窗口？

1 个答案: