应用程序关闭按钮单击

Question

我的应用程序给了我5个不同的错误在市场上，我无法弄清楚。它强制关闭按钮单击。

这是我得到的第一个错误。

java.lang.NullPointerException 
at com.yes.hotrod.main$1.onClick(main.java:25) 
at android.view.View.performClick(View.java:2408) 
at android.view.View$PerformClick.run(View.java:8818) 
at android.os.Handler.handleCallback(Handler.java:587) 
at android.os.Handler.dispatchMessage(Handler.java:92) 
at android.os.Looper.loop(Looper.java:123) 
at android.app.ActivityThread.main(ActivityThread.java:4627) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:521) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:871) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:629) 
at dalvik.system.NativeStart.main(Native Method) 

这里是我的main.java

package com.yes.hotrod; 

import android.app.Activity; 
import android.media.MediaPlayer; 
import android.os.Bundle; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 

public class main extends Activity {MediaPlayer FilmSound; 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    Button button1 = (Button)findViewById(R.id.button1); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.animalkingdom); 
    button1.setOnClickListener(new OnClickListener() { 
    public void onClick(View v) { 
    if (FilmSound.isPlaying()) 
    { 
    FilmSound.stop(); 
    FilmSound.reset(); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.animalkingdom); 
    FilmSound.start(); 
    } 
    else { 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.animalkingdom); 
    FilmSound.start(); }  
    }}); 


    Button button2 = (Button)findViewById(R.id.button2); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.bigassstunt); 
    button2.setOnClickListener(new OnClickListener() { 
    public void onClick(View v) { 
    if (FilmSound.isPlaying()) 
    { 
    FilmSound.stop(); 
    FilmSound.reset(); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.bigassstunt); 
    FilmSound.start(); 
    } 
    else { 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.bigassstunt); 
    FilmSound.start(); }  
    } 
    }); 
    Button button3 = (Button)findViewById(R.id.button3); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.godsofwar); 
    button3.setOnClickListener(new OnClickListener() { 
    public void onClick(View v) { 
    if (FilmSound.isPlaying()) 
    { 
    FilmSound.stop(); 
    FilmSound.reset(); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.godsofwar); 
    FilmSound.start(); 
    } 
    else { 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.godsofwar); 
    FilmSound.start(); }  
    } 
    }); 
    Button button4 = (Button)findViewById(R.id.button4); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.greentea); 
    button4.setOnClickListener(new OnClickListener() { 
    public void onClick(View v) { 
    if (FilmSound.isPlaying()) 
    { 
    FilmSound.stop(); 
    FilmSound.reset(); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.greentea); 
    FilmSound.start(); 
    } 
    else { 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.greentea); 
    FilmSound.start(); }  
    } 
    }); 
    Button button11 = (Button)findViewById(R.id.button11); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.havefun); 
    button11.setOnClickListener(new OnClickListener() { 
    public void onClick(View v) { 
    if (FilmSound.isPlaying()) 
    { 
    FilmSound.stop(); 
    FilmSound.reset(); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.havefun); 
    FilmSound.start(); 
    } 
    else { 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.havefun); 
    FilmSound.start(); }  
    } 
    }); 
    Button button6 = (Button)findViewById(R.id.button6); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.kisswashot); 
    button6.setOnClickListener(new OnClickListener() { 
    public void onClick(View v) { 
    if (FilmSound.isPlaying()) 
    { 
    FilmSound.stop(); 
    FilmSound.reset(); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.kisswashot); 
    FilmSound.start(); 
    } 
    else { 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.kisswashot); 
    FilmSound.start(); }  
    } 
    }); 
    Button button7 = (Button)findViewById(R.id.button7); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.ohshit); 
    button7.setOnClickListener(new OnClickListener() { 
    public void onClick(View v) { 
    if (FilmSound.isPlaying()) 
    { 
    FilmSound.stop(); 
    FilmSound.reset(); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.ohshit); 
    FilmSound.start(); 
    } 
    else { 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.ohshit); 
    FilmSound.start(); }  
    } 
    }); 
    Button button8 = (Button)findViewById(R.id.button8); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.throwingstar); 
    button8.setOnClickListener(new OnClickListener() { 
    public void onClick(View v) { 
    if (FilmSound.isPlaying()) 
    { 
    FilmSound.stop(); 
    FilmSound.reset(); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.throwingstar); 
    FilmSound.start(); 
    } 
    else { 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.throwingstar); 
    FilmSound.start(); }  
    } 
    }); 
    Button button9 = (Button)findViewById(R.id.button9); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.twolegittwoquit); 
    button9.setOnClickListener(new OnClickListener() { 
    public void onClick(View v) { 
    if (FilmSound.isPlaying()) 
    { 
    FilmSound.stop(); 
    FilmSound.reset(); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.twolegittwoquit); 
    FilmSound.start(); 
    } 
    else { 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.twolegittwoquit); 
    FilmSound.start(); }  
    } 
    }); 
    Button button10 = (Button)findViewById(R.id.button10); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.whiskey); 
    button10.setOnClickListener(new OnClickListener() { 
    public void onClick(View v) { 
    if (FilmSound.isPlaying()) 
    { 
    FilmSound.stop(); 
    FilmSound.reset(); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.whiskey); 
    FilmSound.start(); 
    } 
    else { 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.whiskey); 
    FilmSound.start(); }  
    } 
    }); 
    Button button5 = (Button)findViewById(R.id.button5); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.demons); 
    button5.setOnClickListener(new OnClickListener() { 
    public void onClick(View v) { 
    if (FilmSound.isPlaying()) 
    { 
    FilmSound.stop(); 
    FilmSound.reset(); 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.demons); 
    FilmSound.start(); 
    } 
    else { 
    FilmSound = MediaPlayer.create(getApplicationContext(), R.raw.demons); 
    FilmSound.start(); }  
    } 
    }); 
} 
} 

Answer 1

如果你看一下堆栈跟踪，你会看到错误的main.java的25行出现，OnClick方法为OnClickListener内为button1。

当您试图实例化FilmSound对象并且在该方法内为null时，很有可能出现错误。