Beginer在Android应用程序，请大家帮忙！ - 空指针异常 [英] Beginer at Android apps, please help! - NullPointerException
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问题描述
请帮我这一个。我喜欢这个网站，并不能告诉你，你有多少次给了我很好的建议，但似乎这个时候我无法找到答案。我有一个非常简单的应用程序，它是未正确启动。应用程序应加载一个启动画面，然后主要的应用程序。出于某种原因，它现在不工作 -
Please help me with this one. I love this site and can't tell you how many times you've given me great advice, but this time I can't seem to find an answer. I have a very simple app which isn't starting correctly. The app should load a splashscreen, and then the main app. For some reason its now not working -
logcat的：
02-08 13:30:41.846: E/AndroidRuntime(275): Uncaught handler: thread main exiting due to uncaught exception
02-08 13:30:41.865: E/AndroidRuntime(275): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.KES.GApps/com.KES.GApps.Splashscreen}: java.lang.NullPointerException
02-08 13:30:41.865: E/AndroidRuntime(275): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
02-08 13:30:41.865: E/AndroidRuntime(275): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
02-08 13:30:41.865: E/AndroidRuntime(275): at android.app.ActivityThread.access$2200(ActivityThread.java:119)
02-08 13:30:41.865: E/AndroidRuntime(275): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
02-08 13:30:41.865: E/AndroidRuntime(275): at android.os.Handler.dispatchMessage(Handler.java:99)
02-08 13:30:41.865: E/AndroidRuntime(275): at android.os.Looper.loop(Looper.java:123)
02-08 13:30:41.865: E/AndroidRuntime(275): at android.app.ActivityThread.main(ActivityThread.java:4363)
02-08 13:30:41.865: E/AndroidRuntime(275): at java.lang.reflect.Method.invokeNative(Native Method)
02-08 13:30:41.865: E/AndroidRuntime(275): at java.lang.reflect.Method.invoke(Method.java:521)
02-08 13:30:41.865: E/AndroidRuntime(275): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
02-08 13:30:41.865: E/AndroidRuntime(275): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
02-08 13:30:41.865: E/AndroidRuntime(275): at dalvik.system.NativeStart.main(Native Method)
02-08 13:30:41.865: E/AndroidRuntime(275): Caused by: java.lang.NullPointerException
02-08 13:30:41.865: E/AndroidRuntime(275): at android.view.ViewGroup.addViewInner(ViewGroup.java:1860)
02-08 13:30:41.865: E/AndroidRuntime(275): at android.view.ViewGroup.addView(ViewGroup.java:1756)
02-08 13:30:41.865: E/AndroidRuntime(275): at android.view.ViewGroup.addView(ViewGroup.java:1736)
02-08 13:30:41.865: E/AndroidRuntime(275): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:217)
02-08 13:30:41.865: E/AndroidRuntime(275): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:207)
02-08 13:30:41.865: E/AndroidRuntime(275): at android.app.Activity.setContentView(Activity.java:1633)
02-08 13:30:41.865: E/AndroidRuntime(275): at com.KES.GApps.Splashscreen.onCreate(Splashscreen.java:13)
02-08 13:30:41.865: E/AndroidRuntime(275): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-08 13:30:41.865: E/AndroidRuntime(275): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
02-08 13:30:41.865: E/AndroidRuntime(275): ... 11 more
02-08 13:30:41.884: I/dalvikvm(275): threadid=7: reacting to signal 3
02-08 13:30:41.884: E/dalvikvm(275): Unable to open stack trace file '/data/anr/traces.txt': Permission denied
XML的启动画面（的welcome.xml）：
xml for the splashscreen (welcome.xml):
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/img1"
android:orientation="vertical" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="200dp"
android:layout_gravity="fill_horizontal"
android:contentDescription="@string/crestinfo"
android:src="@drawable/logov2" />
<TextView
android:id="@+id/welcomescreen"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="right"
android:text="@string/welcomescreen"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textColor="#ffffff"
android:textStyle="bold" android:padding="5dp" android:textSize="15pt" />
</LinearLayout>
Java的：
package com.KES.GApps;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
public class Splashscreen extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.welcome);
Thread splashThread = new Thread() {
@Override
public void run() {
try {
int waited = 0;
while (waited < 2000) {
sleep(100);
waited += 100;
}
} catch (InterruptedException e) {
// do nothing
} finally {
finish();
Intent i = new Intent();
i.setClassName("com.KES.GApps",
"com.KES.GApps.KingEdwardVIISchoolActivity");
startActivity(i);
}
}
};
splashThread.start();
}
}
清单文件：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.KES.GApps"
android:versionCode="6"
android:versionName="1.5" >
<uses-sdk android:minSdkVersion="7" />
<uses-permission android:name="android.permission.INTERNET" />
<application
android:name="KingEdwardVIISchool"
android:debuggable="true"
android:icon="@drawable/icon"
android:label="@string/app_name"
android:launchMode="standard" >
<activity
android:name="KingEdwardVIISchoolActivity"
android:configChanges="orientation|keyboardHidden"
android:label="@string/app_name"
android:screenOrientation="portrait" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
</intent-filter>
</activity>
<activity
android:name="Splashscreen"
android:configChanges="orientation|keyboardHidden"
android:label="@string/app_name"
android:screenOrientation="portrait" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
就像我说的，我是一个初学者，因此任何意见将是AP preciated。
Like I say, I am a complete beginner so any advice would be appreciated.
推荐答案
我也从这个问题的痛苦一次。然后，我所做的就是我刚才复制的 ID 从我 R.java布局，并直接粘贴它的setContentView（）。 > 布局< - 也就是说，在这里，你的情况 ID 欢迎在 R.java / code>。然后我的应用程序成功运行，没有任何异常。因此，我意识到，它只是一个暂时性的问题。重新启动我的日食之后（有时你必须完全重新启动系统），我再次更换了标识由 R.layout.welcome 它工作得很好。
希望这有助于...
I was also suffering from this problem once. Then what i did was i just copied the id of the layout from my R.java and pasted it directly to setContentView(). ie, Here in your case the id of welcome in R.java->layout. then my app ran successfully without any exception. Thus i realized that its just a temporary problem. After restarting my eclipse (sometimes you have to restart your system fully) I replaced the id again by R.layout.welcome and it worked fine.
Hope this helps...
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