在Android模拟器中启动我的应用程序时，它崩溃并出现以下错误 我附上下面的代码文件.. 请检查代码并建议我寻求解决方案
错误日志
03-19 17:42:07.613: W/Trace(901): Unexpected value from nativeGetEnabledTags: 0
03-19 17:42:07.623: W/Trace(901): Unexpected value from nativeGetEnabledTags: 0
03-19 17:42:08.273: D/dalvikvm(901): GC_FOR_ALLOC freed 64K, 7% free 2514K/2696K, paused 44ms, total 47ms
03-19 17:42:08.294: I/dalvikvm-heap(901): Grow heap (frag case) to 3.569MB for 1050832-byte allocation
03-19 17:42:08.354: D/dalvikvm(901): GC_FOR_ALLOC freed 1K, 5% free 3539K/3724K, paused 57ms, total 57ms
03-19 17:42:08.454: D/dalvikvm(901): GC_CONCURRENT freed <1K, 5% free 3576K/3732K, paused 10ms+22ms, total 100ms
03-19 17:42:08.614: D/AndroidRuntime(901): Shutting down VM
03-19 17:42:08.614: W/dalvikvm(901): threadid=1: thread exiting with uncaught exception (group=0x40a70930)
03-19 17:42:08.624: E/AndroidRuntime(901): FATAL EXCEPTION: main
03-19 17:42:08.624: E/AndroidRuntime(901): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.mypiano/com.example.mypiano.Piano}: java.lang.NullPointerException
03-19 17:42:08.624: E/AndroidRuntime(901): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
03-19 17:42:08.624: E/AndroidRuntime(901): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
03-19 17:42:08.624: E/AndroidRuntime(901): at android.app.ActivityThread.access$600(ActivityThread.java:141)
03-19 17:42:08.624: E/AndroidRuntime(901): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
03-19 17:42:08.624: E/AndroidRuntime(901): at android.os.Handler.dispatchMessage(Handler.java:99)
03-19 17:42:08.624: E/AndroidRuntime(901): at android.os.Looper.loop(Looper.java:137)
03-19 17:42:08.624: E/AndroidRuntime(901): at android.app.ActivityThread.main(ActivityThread.java:5039)
03-19 17:42:08.624: E/AndroidRuntime(901): at java.lang.reflect.Method.invokeNative(Native Method)
03-19 17:42:08.624: E/AndroidRuntime(901): at java.lang.reflect.Method.invoke(Method.java:511)
03-19 17:42:08.624: E/AndroidRuntime(901): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
03-19 17:42:08.624: E/AndroidRuntime(901): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
03-19 17:42:08.624: E/AndroidRuntime(901): at dalvik.system.NativeStart.main(Native Method)
03-19 17:42:08.624: E/AndroidRuntime(901): Caused by: java.lang.NullPointerException
03-19 17:42:08.624: E/AndroidRuntime(901): at com.example.mypiano.Piano.onCreate(Piano.java:118)
03-19 17:42:08.624: E/AndroidRuntime(901): at android.app.Activity.performCreate(Activity.java:5104)
03-19 17:42:08.624: E/AndroidRuntime(901): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
03-19 17:42:08.624: E/AndroidRuntime(901): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
03-19 17:42:08.624: E/AndroidRuntime(901): ... 11 more
03-19 17:42:39.023: I/Process(901): Sending signal. PID: 901 SIG: 9
Piano.java
package com.example.mypiano;
import android.app.Activity;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.RadioButton;
public class Piano extends Activity {
MediaPlayer curSnd;
Button sa,ri,ga,ma,pa,da,ni;
RadioButton msc,ani,hrn,rb;
OnClickListener radioListener;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_piano);
System.out.print("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXxxx");
sa = (Button)findViewById(R.id.B1);
ri = (Button)findViewById(R.id.B2);
ga = (Button)findViewById(R.id.B3);
ma = (Button)findViewById(R.id.B4);
pa = (Button)findViewById(R.id.B5);
da = (Button)findViewById(R.id.B6);
AudioManager audioManager = (AudioManager) getSystemService(AUDIO_SERVICE);
audioManager.setStreamVolume(AudioManager.STREAM_MUSIC, 20, 0);
radioListener = new OnClickListener(){
@Override
public void onClick(View v) {
System.out.println("coming here 1");
// TODO Auto-generated method stub
RadioButton rb= (RadioButton)v;
curSnd = MediaPlayer.create(Piano.this,R.raw.rb);
playSound(curSnd);
switch(rb.getId())
{
case R.id.music : System.out.print("MUSIC");break;
case R.id.animals:System.out.print("ABIMALS");break;
case R.id.horns: System.out.print("HORN");break;
}
}
};
msc = (RadioButton)findViewById(R.id.music);
msc.setOnClickListener(radioListener);
ani = (RadioButton)findViewById(R.id.animals);
ani.setOnClickListener(radioListener);
hrn = (RadioButton)findViewById(R.id.horns);
hrn.setOnClickListener(radioListener);
sa.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
System.out.print("SA playing");
// TODO Auto-generated method stub
curSnd = MediaPlayer.create(Piano.this,R.raw.sa);
curSnd.start();
}
});
ri.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
curSnd = MediaPlayer.create(Piano.this,R.raw.ri);
curSnd.start();
}
});
ga.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
curSnd = MediaPlayer.create(Piano.this,R.raw.ga);
curSnd.start();
}
});
ma.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
curSnd = MediaPlayer.create(Piano.this,R.raw.ma);
curSnd.start();
}
});
pa.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
curSnd = MediaPlayer.create(Piano.this,R.raw.pa);
curSnd.start();
}
});
da.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
curSnd = MediaPlayer.create(Piano.this,R.raw.da);
curSnd.start();
}
});
ni.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
curSnd = MediaPlayer.create(Piano.this,R.raw.ni);
curSnd.start();
}
});
}
private void playSound(MediaPlayer mediaPlayer) {
mediaPlayer.start();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_piano, menu);
return true;
}
}
的Manifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.mypiano"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.mypiano.Piano"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
activity.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:background="@drawable/piano"
tools:context=".Piano" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<LinearLayout
android:layout_width="128dp"
android:layout_height="wrap_content"
android:orientation="vertical" >
<Button
android:id="@+id/B1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="1" />
<Button
android:id="@+id/B2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="2" />
<Button
android:id="@+id/B3"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="3" />
</LinearLayout>
<LinearLayout
android:layout_width="128dp"
android:layout_height="wrap_content"
android:orientation="vertical" >
<Button
android:id="@+id/B4"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="4" />
<Button
android:id="@+id/B5"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="5" />
<Button
android:id="@+id/B6"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="6" />
</LinearLayout>
</LinearLayout>
<RadioGroup
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<RadioButton
android:id="@+id/music"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:checked="true"
android:gravity="center_vertical|start|fill_vertical"
android:text="MUSIC" />
<RadioButton
android:id="@+id/animals"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="ANIMALS" />
<RadioButton
android:id="@+id/horns"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="HORN" />
</RadioGroup>
</LinearLayout>
答案 0 :(得分：1)
您似乎忘了初始化ni
ni = (Button) findViewById (R.id.buttonName);
所以你在这里得到null
ni.setOnClickListener(new View.OnClickListener() {
另外，只是一个建议，但您可以通过在xml中为onClick定义Buttons来保存大量代码
<Button
...
android:onClick="functionName"/>
然后在你的代码中使用switch case或类似的来定义你的函数逻辑
public void functionName(View v)
{
switch (v.getId())
case R.id.button1
// do something
语法可能不完全正确，但这应该会给你一个想法。然后你没有所有的听众，因为他们都做同样的事情，除了设置resource。