java - 服务内的((按钮) View )不起作用

Question

我正在尝试创建一个允许我通过服务录制音频的按钮，我希望该按钮具有文本:“开始录制”。在 OnClick 事件中，我希望按钮文本更改为:"Stop Recording"。

我在类里面使用此代码，但现在它在服务中不起作用，但是，由于我希望音频记录作为服务使用，我似乎无法更改按钮的文本。我对编码很陌生，所以非常感谢任何帮助!

我的代码如下:

类:

public class Test extends AppCompatActivity {       

    public void Record(View view) {
        Intent intent = new Intent(this, RecordService.class);
        startService(intent);
    }    

    public void Play(View view) {
        Intent intent = new Intent(this, RecordService.class);
        stopService(intent);    
    }
}

服务:

import android.app.Service;
import android.content.Intent;
import android.media.MediaRecorder;
import android.os.Environment;
import android.os.IBinder;
import android.widget.Button;
import android.view.View;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class RecordService extends Service {

    MediaRecorder mRecorder;
    public static String audioFilePath;
    public boolean isRecording = false;

    public RecordService() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        throw new UnsupportedOperationException("Not yet implemented");
    }

    public void onCreate () {

        if(mRecorder == null){

            SimpleDateFormat s = new SimpleDateFormat("ddMMyyyy_hhmmss");
            String format = s.format(new Date());

            audioFilePath = Environment.getExternalStorageDirectory().
                    getAbsolutePath() +  "/" + format + ".3gpp";

            mRecorder = new MediaRecorder();
            mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
            mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
            mRecorder.setOutputFile(audioFilePath);
            mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
        }

        if (isRecording) {
            try{
                stopRecording();
                isRecording = false;
                ((Button)view).setText("Start Recording");
            }catch(Exception e){
                e.printStackTrace();
            }
        } else {
            try{
                startRecording();
                isRecording = true;
                ((Button)view).setText("Stop Recording");
            }catch(Exception e){
                e.printStackTrace();
            }
        }
    }

    public void startRecording() throws IllegalStateException, IOException{
        mRecorder.prepare();
        mRecorder.start();
    }

    public void stopRecording() throws IllegalStateException, IOException{
        mRecorder.stop();
        mRecorder.release();
    }


    public void onStartCommand()
    {
        SimpleDateFormat s = new SimpleDateFormat("ddMMyyyy_hhmmss");
        String format = s.format(new Date());

        audioFilePath = Environment.getExternalStorageDirectory().
                getAbsolutePath() +  "/" + format + ".3gpp";

        mRecorder = new MediaRecorder();
        mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        mRecorder.setOutputFile(audioFilePath);
        mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
        try {
            mRecorder.prepare();
        } catch (IOException e) {
            e.printStackTrace();
        }
        mRecorder.start();

    }

    public void onDestroy()
    {
       super.onDestroy();
        mRecorder.stop();
        mRecorder.release();

    }


}

Activity :

<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:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context="kyr.com.knowyourrights.Test">

    <TextView android:text="@string/hello_world" android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <Button
        android:text="Record"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/RecordButton"
        android:layout_alignParentTop="true"
        android:onClick="Record">
    </Button>

</RelativeLayout>

Answer 1

这确实不能在这里工作，因为您的((按钮) View )没有在您的 onCreate() 中实例化。

我的建议是从服务中调用 Activity 中的一个函数来执行您想要执行的操作(此处，更改文本)。您可以使用 BroadcastReceiver 实现此目的。

为此，您可以执行以下操作:

在你的 Activity 中:

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

  // Register mMessageReceiver to receive messages.
  LocalBroadcastManager.getInstance(this).registerReceiver(mMessageReceiver,
      new IntentFilter("change-text"));
}

// handler for received Intents for the "change-text" event 
private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
  @Override
  public void onReceive(Context context, Intent intent) {
    // Extract data included in the Intent
    String message = intent.getStringExtra("message");
    button.setText(message); //Assuming you have instantiate properly your button inside your onCreate()
  }
};

@Override
protected void onPause() {
  // Unregister since the activity is not visible
  LocalBroadcastManager.getInstance(this).unregisterReceiver(mMessageReceiver);
  super.onPause();
} 

在你的服务中:

// Send an Intent with an action named "change-text". 
private void sendMessage(boolean startRecording) {
  Intent intent = new Intent("change-text");
  // add data
  if (startRecording) intent.putExtra("message", "Start Recording");
  else intent.putExtra("message","Stop Recording");
  LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
} 

要从您的服务更改文本按钮，您只需调用 sendMessage 函数，并根据您想要执行的操作将 true 或 false 作为参数!

您可以在此处查看我根据您的情况改编的代码源: http://www.vogella.com/tutorials/AndroidBroadcastReceiver/article.html#ownreceiver_localbroadcastmanager