我得到了一些奇怪的错误列表，有些看起来毫不相关，但我无法判断，因为我甚至无法加载我的应用程序进行调试。这是一个非常简单的应用程序，在一个单选按钮组中有3个单选按钮，每个按钮将触发不同的歌曲播放。
我将从发布我的清单、活动文件和布局开始，然后发布错误日志。
清单：
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.cis298.lab2"
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:label = "@string/app_name"
android:name = ".LayoutActivity">
<intent-filter >
<action android:name = "android.intent.action.MAIN" />
<category android:name = "android.intent.category.LAUNCHER" />
</intent-filter>
></activity>
</application>
</manifest>
布局活动：
package com.cis298.lab2;
import java.io.IOException;
import com.cis298.lab2.R;
import android.app.Activity;
import android.os.Bundle;
import android.media.MediaPlayer;
import android.widget.RadioGroup;
public class LayoutActivity extends Activity {
int song;
MediaPlayer mediaplayer = MediaPlayer.create(this, song);
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.layout);
try {
mediaplayer.prepare();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
RadioGroup radgrp = (RadioGroup) findViewById(R.id.radiogroup);
radgrp.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
switch (checkedId){
case R.id.dance:
song = R.raw.redalert;
mediaplayer.start();
break;
case R.id.rap:
song = R.raw.cannedheat;
break;
case R.id.rock:
song = R.raw.movmou8105;
break;}
}
});
}
}
布局：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<RadioGroup
android:id="@+id/radiogroup"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:orientation="vertical" >
<RadioButton
android:id="@+id/rock"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Play Rock" />
<RadioButton
android:id="@+id/rap"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Play Rap"
android:checked="true"/>
<RadioButton
android:id="@+id/dance"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Play Dance"
android:textAlignment="center" />
</RadioGroup>
</RelativeLayout>
日志：
02-21 20:34:05.044: D/AndroidRuntime(322): 关闭虚拟机 02-21 20:34:05.044: W/dalvikvm(322): 线程1：带有未捕获异常退出的线程 02-21 20:34:05.094: E/AndroidRuntime(322): 致命错误：主要活动无法实例化 ComponentInfo{com.cis298.lab2/com.cis298.lab2.LayoutActivity}: java.lang.NullPointerException 02-21 20:34:05.094: E/AndroidRuntime(322): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585) 02-21 20:34:05.094: E/AndroidRuntime(322): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) 02-21 20:34:05.094: E/AndroidRuntime(322): at android.app.ActivityThread.access$2300(ActivityThread.java:125) 02-21 20:34:05.094: E/AndroidRuntime(322): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033) 02-21 20:34:05.094: E/AndroidRuntime(322): at android.os.Handler.dispatchMessage(Handler.java:99) 02-21 20:34:05.094: E/AndroidRuntime(322): at android.os.Looper.loop(Looper.java:123) 02-21 20:34:05.094: E/AndroidRuntime(322): at android.app.ActivityThread.main(ActivityThread.java:4627) 02-21 20:34:05.094: E/AndroidRuntime(322): at java.lang.reflect.Method.invokeNative(Native Method) 02-21 20:34:05.094: E/AndroidRuntime(322): at java.lang.reflect.Method.invoke(Method.java:521) 02-21 20:34:05.094: E/AndroidRuntime(322): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 02-21 20:34:05.094: E/AndroidRuntime(322): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 02-21 20:34:05.094: E/AndroidRuntime(322): at dalvik.system.NativeStart.main(Native Method) 02-21 20:34:05.094: E/AndroidRuntime(322): 错误原因：java.lang.NullPointerException 02-21 20:34:05.094: E/AndroidRuntime(322): at android.content.ContextWrapper.getResources(ContextWrapper.java:80) 02-21 20:34:05.094: E/AndroidRuntime(322): at android.media.MediaPlayer.create(MediaPlayer.java:641) 02-21 20:34:05.094: E/AndroidRuntime(322): at com.cis298.lab2.LayoutActivity.(LayoutActivity.java:15) 02-21 20:34:05.094: E/AndroidRuntime(322): at java.lang.Class.newInstanceImpl(Native Method) 02-21 20:34:05.094: E/AndroidRuntime(322): at java.lang.Class.newInstance(Class.java:1429) 02-21 20:34:05.094: E/AndroidRuntime(322): at android.app.Instrumentation.newActivity(Instrumentation.java:1021) 02-21 20:34:05.094: E/AndroidRuntime(322): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577) 02-21 20:34:05.094: E/AndroidRuntime(322): ... 还有11个任何帮助都将不胜感激。