按下按鈕，這取決於微調選擇播放不同MP3播放

Question

package com.RaffDev.RaffApp;

import android.app.Activity; import android.media.MediaPlayer; import android.os.Bundle; import android.view.View; import android.widget.Toast; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.Spinner;

public class RaffAppActivity extends Activity implements View.OnClickListener,``AdapterView.OnItemSelectedListener{

/*Regular Variables*/ 
String copyright = "Raff App \n\nVersion: Alpha 0.0.1\n\n(c) Copyright Raff App contributors and others 2011. All rights reserverd"; 
public int soundSelection; 
MediaPlayer mp; 

/*Called at the beginning of the application*/ 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    Spinner spinner = (Spinner) findViewById(R.id.spinner1); 
    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.soundEntries, android.R.layout.simple_spinner_item); 
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); 
    spinner.setAdapter(adapter);   
} 

/*Button Functions*/ 
public void onClick(View v){} 

public void infoClick(View v){ 

    Toast.makeText(this, copyright, Toast.LENGTH_LONG).show(); 
} 

public void pressPlay(View v){ 
    switch(soundSelection){ 
    case 1: 
     if(mp.isPlaying()) 
     mp.reset(); 
     mp = MediaPlayer.create(getApplicationContext(), R.raw.pleaseprettyface); 
     mp.start(); 
     break; 
    case 2: 
     if(mp.isPlaying()) 
     mp.reset(); 
     mp = MediaPlayer.create(getApplicationContext(),R.raw.sheeesh); 
     mp.start(); 
     break; 
    case 3: 
     if(mp.isPlaying()) 
     mp.reset(); 
     mp = MediaPlayer.create(getApplicationContext(),R.raw.heaintdodat); 
     mp.start(); 
     break; 
    case 4: 
     if(mp.isPlaying()) 
     mp.reset(); 
     mp = MediaPlayer.create(getApplicationContext(),R.raw.thedousky); 
     mp.start(); 
     break; 
    case 5: 
     if(mp.isPlaying()) 
     mp.reset(); 
     mp = MediaPlayer.create(getApplicationContext(),R.raw.nmouth); 
     mp.start(); 
     break; 


    } 

} 



/*Spinner Functions*/ 
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) { 
    soundSelection = (Integer) parent.getItemAtPosition(pos); 
} 

public void onNothingSelected(AdapterView<?> parent) { 
     // Do nothing. 
} 

}

Answer 1

mp是空的第一次運行該代碼，然後從微調的東西。請在pressPlay之內添加一個空檢查，或者在您的onCreate()中創建一個mp實例。