1. 首先我们二话不说直接先看报错内容如下：
07-12 08:25:03.572: E/dalvikvm(3602): native fork pid:0 done.
07-12 08:25:03.582: E/dalvikvm(3602): threadid=6: created from interp,name=ReferenceQueueDaemon
07-12 08:25:03.582: E/dalvikvm(3602): threadid=6: calling run(),name=ReferenceQueueDaemon
07-12 08:25:03.582: E/dalvikvm(3602): threadid=7: created from interp,name=FinalizerDaemon
07-12 08:25:03.582: E/dalvikvm(3602): threadid=7: calling run(),name=FinalizerDaemon
07-12 08:25:03.592: E/dalvikvm(3602): threadid=8: created from interp,name=FinalizerWatchdogDaemon
07-12 08:25:03.592: E/dalvikvm(3602): threadid=8: calling run(),name=FinalizerWatchdogDaemon
07-12 08:25:03.642: D/ActivityThread(3602): setTargetHeapUtilization:0.25
07-12 08:25:03.642: D/ActivityThread(3602): setTargetHeapIdealFree:8388608
07-12 08:25:03.642: D/ActivityThread(3602): setTargetHeapConcurrentStart:2097152
07-12 08:25:03.662: I/System.out(3602): Sending WAIT chunk
07-12 08:25:03.662: W/ActivityThread(3602): Application com.himi.clock is waiting for the debugger on port 8100...
07-12 08:25:05.253: I/System.out(3602): Debugger has connected
07-12 08:25:05.253: I/System.out(3602): waiting for debugger to settle...
07-12 08:25:05.454: I/System.out(3602): waiting for debugger to settle...
07-12 08:25:05.654: I/System.out(3602): waiting for debugger to settle...
07-12 08:25:05.854: I/System.out(3602): waiting for debugger to settle...
07-12 08:25:06.054: I/System.out(3602): waiting for debugger to settle...
07-12 08:25:06.254: I/System.out(3602): waiting for debugger to settle...
07-12 08:25:06.455: I/System.out(3602): waiting for debugger to settle...
07-12 08:25:06.655: I/System.out(3602): waiting for debugger to settle...
07-12 08:25:06.855: I/System.out(3602): waiting for debugger to settle...
07-12 08:25:07.055: I/System.out(3602): waiting for debugger to settle...
07-12 08:25:07.256: I/System.out(3602): debugger has settled (1411)
07-12 08:26:55.171: D/ActivityThread(4159): setTargetHeapUtilization:0.25
07-12 08:26:55.171: D/ActivityThread(4159): setTargetHeapIdealFree:8388608
07-12 08:26:55.171: D/ActivityThread(4159): setTargetHeapConcurrentStart:2097152
07-12 08:26:55.391: W/dalvikvm(4159): threadid=1: thread exiting with uncaught exception (group=0x416cd498)
07-12 08:26:55.391: E/AndroidRuntime(4159): FATAL EXCEPTION: main
07-12 08:26:55.391: E/AndroidRuntime(4159): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.himi.clock/com.himi.clock.MainActivity}: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.himi.clock/com.himi.clock.ClockActivity}; have you declared this activity in your AndroidManifest.xml?
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2092)
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2117)
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.app.ActivityThread.access$600(ActivityThread.java:140)
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1213)
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.os.Handler.dispatchMessage(Handler.java:99)
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.os.Looper.loop(Looper.java:137)
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.app.ActivityThread.main(ActivityThread.java:4914)
07-12 08:26:55.391: E/AndroidRuntime(4159): at java.lang.reflect.Method.invokeNative(Native Method)
07-12 08:26:55.391: E/AndroidRuntime(4159): at java.lang.reflect.Method.invoke(Method.java:511)
07-12 08:26:55.391: E/AndroidRuntime(4159): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:808)
07-12 08:26:55.391: E/AndroidRuntime(4159): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:575)
07-12 08:26:55.391: E/AndroidRuntime(4159): at dalvik.system.NativeStart.main(Native Method)
07-12 08:26:55.391: E/AndroidRuntime(4159): Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.himi.clock/com.himi.clock.ClockActivity}; have you declared this activity in your AndroidManifest.xml?
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1541)
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.app.ActivityThread.resolveActivityInfo(ActivityThread.java:1903)
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:285)
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:694)
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.widget.TabHost.setCurrentTab(TabHost.java:358)
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.widget.TabHost.addTab(TabHost.java:236)
07-12 08:26:55.391: E/AndroidRuntime(4159): at com.himi.clock.MainActivity.addOneTab(MainActivity.java:32)
07-12 08:26:55.391: E/AndroidRuntime(4159): at com.himi.clock.MainActivity.onCreate(MainActivity.java:20)
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.app.Activity.performCreate(Activity.java:5086)
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
07-12 08:26:55.391: E/AndroidRuntime(4159): at com.lbe.security.service.core.client.b.x.callActivityOnCreate(Unknown Source)
07-12 08:26:55.391: E/AndroidRuntime(4159): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2056)
07-12 08:26:55.391: E/AndroidRuntime(4159): ... 11 more
07-12 08:34:04.128: D/ActivityThread(6074): setTargetHeapUtilization:0.25
07-12 08:34:04.128: D/ActivityThread(6074): setTargetHeapIdealFree:8388608
07-12 08:34:04.128: D/ActivityThread(6074): setTargetHeapConcurrentStart:2097152
07-12 08:34:04.379: W/dalvikvm(6074): threadid=1: thread exiting with uncaught exception (group=0x416cd498)
07-12 08:34:04.389: E/AndroidRuntime(6074): FATAL EXCEPTION: main
07-12 08:34:04.389: E/AndroidRuntime(6074): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.himi.clock/com.himi.clock.MainActivity}: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.himi.clock/com.himi.clock.ClockActivity}; have you declared this activity in your AndroidManifest.xml?
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2092)
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2117)
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.app.ActivityThread.access$600(ActivityThread.java:140)
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1213)
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.os.Handler.dispatchMessage(Handler.java:99)
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.os.Looper.loop(Looper.java:137)
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.app.ActivityThread.main(ActivityThread.java:4914)
07-12 08:34:04.389: E/AndroidRuntime(6074): at java.lang.reflect.Method.invokeNative(Native Method)
07-12 08:34:04.389: E/AndroidRuntime(6074): at java.lang.reflect.Method.invoke(Method.java:511)
07-12 08:34:04.389: E/AndroidRuntime(6074): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:808)
07-12 08:34:04.389: E/AndroidRuntime(6074): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:575)
07-12 08:34:04.389: E/AndroidRuntime(6074): at dalvik.system.NativeStart.main(Native Method)
07-12 08:34:04.389: E/AndroidRuntime(6074): Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.himi.clock/com.himi.clock.ClockActivity}; have you declared this activity in your AndroidManifest.xml?
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1541)
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.app.ActivityThread.resolveActivityInfo(ActivityThread.java:1903)
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:285)
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:694)
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.widget.TabHost.setCurrentTab(TabHost.java:358)
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.widget.TabHost.addTab(TabHost.java:236)
07-12 08:34:04.389: E/AndroidRuntime(6074): at com.himi.clock.MainActivity.addOneTab(MainActivity.java:32)
07-12 08:34:04.389: E/AndroidRuntime(6074): at com.himi.clock.MainActivity.onCreate(MainActivity.java:20)
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.app.Activity.performCreate(Activity.java:5086)
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
07-12 08:34:04.389: E/AndroidRuntime(6074): at com.lbe.security.service.core.client.b.x.callActivityOnCreate(Unknown Source)
07-12 08:34:04.389: E/AndroidRuntime(6074): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2056)
07-12 08:34:04.389: E/AndroidRuntime(6074): ... 11 more
仔细阅读红色字体处的报错信息知道：原来是我编写的APP中含有的多个Activity，必须要在AndroidManifest.xml中进行声明，声明如下：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.himi.clock"
android:versionCode="1"
android:versionName="1.0" > <uses-sdk
android:minSdkVersion="15"
android:targetSdkVersion="17" /> <application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".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=".ClockActivity" />
<activity android:name=".StopwatchActivity" />
<activity android:name=".TimerActivity" />
</application> </manifest>
再次加载程序到手机里面，发现这时候是可以运行的，没有报错了
那么为什么要这样在AndroidManifest.xml声明注册多个activity？？？
答：我们知道不同activity代表不同的窗口界面，Android系统只有先注册了不同的activity，系统内部才能对它操作，比如利用intent操作。