Java StartActivity上的NullPointerException（Android）

我知道也有人问过类似的问题，但通读这些问题后，似乎有很多事情可能会出错，从而导致这个问题。这是我第一个真正的Android和Java应用程序，我可能已经完成了其中的大部分。提前感谢您的帮助

出于某种原因，Stack Logcat决定在eclipse中随机停止工作

spiritplumber的输出代码[at]gmail.com

package com.greymatterrobotics.gmserial;

import android.app.Activity;
import android.os.Bundle;
import android.os.SystemClock;

public class Output extends Activity {

    static public final char cr = (char) 13; // because i don't want to type that in every time
    static public final char lf = (char) 10; // because i don't want to type that in every time
    public String datatosend = "";


    @Override
    public void onCreate(Bundle savedInstanceState) {
        AudioSerialOutMono.activate();
        try{
            Bundle bundle = getIntent().getExtras();
            if (bundle.containsKey("BAUD"))
                AudioSerialOutMono.new_baudRate = Integer.parseInt(bundle.getString("BAUD"));
            if (bundle.containsKey("CHD"))
                AudioSerialOutMono.new_characterdelay = Integer.parseInt(bundle.getString("CHD"));
            if (bundle.containsKey("DATA"))
                datatosend = (bundle.getString("DATA"));
            AudioSerialOutMono.UpdateParameters(true);
            AudioSerialOutMono.output(datatosend+cr+lf);

            while (AudioSerialOutMono.isPlaying())
            {
                SystemClock.sleep(50);
            }
        }catch(Exception e){e.printStackTrace();}


//      android.os.Process.killProcess(android.os.Process.myPid()); // NUKE
        super.onCreate(savedInstanceState);
        this.finish();
    }
}

AndroidManifest.xml

---

尽量不要在两个活动上都使用MAIN intent筛选器。

Android中活动的生命周期由系统自动处理。我的意思是，您不应该创建GMSerial_CleanActivity的新实例。您应该直接调用output方法。不要调用GMSerial.output

另外，在output方法中，我更喜欢使用下面的代码来启动新活动您的代码片段可能是正确的。我手头没有Eclipse，因此无法测试它

Intent serialout = new Intent();
    serialout.setClass(this, Output.Class);

package com.greymatterrobotics.gmserial;

import android.app.Activity;
import android.os.Bundle;
import android.os.SystemClock;

public class Output extends Activity {

    static public final char cr = (char) 13; // because i don't want to type that in every time
    static public final char lf = (char) 10; // because i don't want to type that in every time
    public String datatosend = "";


    @Override
    public void onCreate(Bundle savedInstanceState) {
        AudioSerialOutMono.activate();
        try{
            Bundle bundle = getIntent().getExtras();
            if (bundle.containsKey("BAUD"))
                AudioSerialOutMono.new_baudRate = Integer.parseInt(bundle.getString("BAUD"));
            if (bundle.containsKey("CHD"))
                AudioSerialOutMono.new_characterdelay = Integer.parseInt(bundle.getString("CHD"));
            if (bundle.containsKey("DATA"))
                datatosend = (bundle.getString("DATA"));
            AudioSerialOutMono.UpdateParameters(true);
            AudioSerialOutMono.output(datatosend+cr+lf);

            while (AudioSerialOutMono.isPlaying())
            {
                SystemClock.sleep(50);
            }
        }catch(Exception e){e.printStackTrace();}


//      android.os.Process.killProcess(android.os.Process.myPid()); // NUKE
        super.onCreate(savedInstanceState);
        this.finish();
    }
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.greymatterrobotics.gmserial"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="3" />
    <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:name=".GMSerial_CleanActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity android:name=".Output"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Intent serialout = new Intent();
    serialout.setClass(this, Output.Class);