我是Android开发的新手所以请耐心等待我帮助我提前解决这个问题...
当我在模拟器上运行我的应用程序时，启动画面工作正常，但在此之后，当显示下一个布局时会弹出一条消息“应用程序意外停止” 每次我运行应用程序时，相同的结果都会完美地运行，但就在错误消息之后。
我删除了＆amp;重新创建了AVD，清理了项目，重启了日食，机器却什么都没有......
如果有帮助的其他信息
在第一天，我创建了一个针对Google API 14＆amp; min SDK 8但是我在运行模拟器时遇到了麻烦，它只有一个黑屏，因此后来重新创建了AVD并将目标SDK更改为Google API 8（projrct-＆gt; properties-＆gt; Android-＆gt; Google API 8-＆gt; apply - ＆gt; ok）和min SDK 4。
这是MainActivity（启动画面）
package com.example.GPS;
import android.app.Activity;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Bundle;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.kclogo);
MediaPlayer mpsplash = MediaPlayer.create(this, R.raw.startup_tone);
mpsplash.start();
Thread logoTimer=new Thread()
{
public void run()
{
try
{
int logoTimer=0;
while(logoTimer<3499)
{
sleep(100);
logoTimer= logoTimer +100;
}
startActivity(new Intent("com.example.GPS.KCLOGO"));
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally
{
finish();
}
}
};
logoTimer.start();
}
}
这是MenuActivity
package com.example.GPS;
import android.app.Activity;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MenuActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.menu);
final MediaPlayer mpButtonClick = MediaPlayer.create(this,R.raw.buttonclick);
Button btn1 = (Button) findViewById(R.id.btnlogin);
btn1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
startActivity(new Intent("com.example.GPS.LOGIN"));
mpButtonClick.start();
}
});
}
}
清单
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.GPS"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="4"
android:targetSdkVersion="8" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.GPS.MainActivity"
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="com.example.GPS.MenuActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="com.example.GPS.KCLOGO" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
//sorry didn't include it to the question at first
<activity
android:name="com.example.GPS.LoginActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="com.example.GPS.LOGIN" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
</manifest>
02-27 22:29:14.031:E/AndroidRuntime(307): FATAL EXCEPTION: main
02-27 22:29:14.031:E/AndroidRuntime(307): java.lang.**RuntimeException**:Unable to start activity ComponentInfo{com.example.GPS/com.example.GPS.MenuActivity}: java.lang.**NullPointerException**
02-27 22:29:14.031:E/AndroidRuntime(307):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
02-27 22:29:14.031:E/AndroidRuntime(307):at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
02-27 22:29:14.031:E/AndroidRuntime(307):at android.app.ActivityThread.access$2300(ActivityThread.java:125)
02-27 22:29:14.031:E/AndroidRuntime(307):at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
02-27 22:29:14.031:E/AndroidRuntime(307):at android.os.Handler.dispatchMessage(Handler.java:99)
02-27 22:29:14.031:E/AndroidRuntime(307):at android.os.Looper.loop(Looper.java:123)
02-27 22:29:14.031:E/AndroidRuntime(307):at android.app.ActivityThread.main(ActivityThread.java:4627)
02-27 22:29:14.031:E/AndroidRuntime(307):at java.lang.reflect.Method.invokeNative(Native Method)
02-27 22:29:14.031:E/AndroidRuntime(307):at java.lang.reflect.Method.invoke(Method.java:521)
02-27 22:29:14.031:E/AndroidRuntime(307):at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
02-27 22:29:14.031:E/AndroidRuntime(307):at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
02-27 22:29:14.031:E/AndroidRuntime(307):at dalvik.system.NativeStart.main(Native Method)
02-27 22:29:14.031:E/AndroidRuntime(307): Caused by: java.lang.**NullPointerException**
02-27 22:29:14.031:E/AndroidRuntime(307):at com.example.GPS.MenuActivity.onCreate(MenuActivity.java:21)
02-27 22:29:14.031:E/AndroidRuntime(307):at android.app.Instrumentation.**callActivityOnCreate**(Instrumentation.java:1047)
02-27 22:29:14.031:E/AndroidRuntime(307):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
[2013-02-27 22:28:25 - GPSTracker] Android Launch!
[2013-02-27 22:28:25 - GPSTracker] adb is running normally.
[2013-02-27 22:28:25 - GPSTracker] Performing com.example.GPS.MainActivity activity launch
[2013-02-27 22:28:25 - GPSTracker] Automatic Target Mode: launching new emulator with compatible AVD 'GMD'
[2013-02-27 22:28:25 - GPSTracker] Launching a new emulator with Virtual Device 'GMD'
[2013-02-27 22:28:27 - GPSTracker] New emulator found: emulator-5554
[2013-02-27 22:28:27 - GPSTracker] Waiting for HOME ('android.process.acore') to be launched...
[2013-02-27 22:28:50 - GPSTracker] HOME is up on device 'emulator-5554'
[2013-02-27 22:28:50 - GPSTracker] Uploading GPSTracker.apk onto device 'emulator-5554'
[2013-02-27 22:28:52 - GPSTracker] Installing GPSTracker.apk...
[2013-02-27 22:29:07 - GPSTracker] Success!
[2013-02-27 22:29:07 - GPSTracker] Starting activity com.example.GPS.MainActivity on device emulator-5554
[2013-02-27 22:29:08 - GPSTracker] ActivityManager: Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] cmp=com.example.GPS/.MainActivity }
login.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="@color/layoutbg" >
<TableLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0.45" >
<TableRow
android:id="@+id/tableRow1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
</TableRow>
<TableRow
android:id="@+id/tableRow2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="10dp" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="match_parent"
android:layout_height="150dp"
android:layout_gravity="center"
android:layout_weight="1"
android:src="@drawable/login_pic" />
</TableRow>
<TableRow
android:id="@+id/tableRow3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="15dp"
android:layout_marginTop="15dp" >
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1" >
<TextView
android:id="@+id/tvuserid"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:text="User ID"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/etuserid"
android:layout_width="220dp"
android:layout_height="wrap_content"
android:layout_marginLeft="16dp"
android:ems="10"
android:background="@drawable/gradiant" >
<requestFocus />
</EditText>
</LinearLayout>
</TableRow>
<TableRow
android:id="@+id/tableRow4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="15dp"
android:layout_marginTop="15dp" >
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1" >
<TextView
android:id="@+id/tvpass"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:text="Password"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/etpass"
android:layout_width="220dp"
android:layout_height="wrap_content"
android:layout_marginRight="20dp"
android:layout_weight="0.42"
android:ems="10"
android:inputType="textPassword"
android:background="@drawable/gradiant" />
</LinearLayout>
</TableRow>
<TableRow
android:id="@+id/tableRow5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="15dp" >
<Button
android:id="@+id/btnlogin"
android:layout_width="200dp"
android:layout_height="wrap_content"
android:layout_marginLeft="25dp"
android:layout_marginRight="25dp"
android:layout_weight="1"
android:drawableLeft="@drawable/padlock"
android:text="Login" />
</TableRow>
<TableRow
android:id="@+id/tableRow6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="15dp" >
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1" >
<ImageView
android:id="@+id/imageView2"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_marginLeft="150dp"
android:layout_weight="0.04"
android:src="@drawable/exclamation" />
<Button
android:id="@+id/btnsignup"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="35dp"
android:layout_marginRight="25dp"
android:layout_weight="0.33"
android:background="@color/layoutbg"
android:text="Sign Up"
android:textSize="16dp" />
</LinearLayout>
</TableRow>
</TableLayout>
</LinearLayout>
kclogo.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="@color/layoutbg">
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="12dp"
android:src="@drawable/kclogo" />
</LinearLayout>
menu.xml文件
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_horizontal"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity"
android:background="@color/layoutbg" >
<ImageView
android:id="@+id/imageView1"
android:layout_width="fill_parent"
android:layout_height="200dp"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:src="@drawable/gpscollage" />
<LinearLayout
android:id="@+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/imageView1"
android:layout_below="@+id/imageView1"
android:layout_marginTop="5dp"
android:orientation="vertical" >
<Button
android:id="@+id/loginsignup"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="10dp"
android:drawableLeft="@drawable/thumb_up_icon"
android:text="Login/Sign Up" />
<Button
android:id="@+id/addnewtomap"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="10dp"
android:drawableLeft="@drawable/add_to_map"
android:text="Add Member/s To Map" />
<Button
android:id="@+id/addnewtocontacts"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:drawableLeft="@drawable/add_contact_list"
android:text="Add To Contact List" />
</LinearLayout>
</RelativeLayout>
答案 0 :(得分：3)
确保布局xml中存在按钮btnlogin。
您在MenuActivity中使用的布局是main.xml，您正在查找main.xml中的btnlogin，它不存在。 btn1为null，因为它在布局中不存在。