Android（java）学习笔记63：Clock App 编写报错01
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" ><span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">uses-sdk </span><span style="color: rgba(255, 0, 0, 1)">android:minSdkVersion</span><span style="color: rgba(0, 0, 255, 1)">="15"</span><span style="color: rgba(255, 0, 0, 1)"> android:targetSdkVersion</span><span style="color: rgba(0, 0, 255, 1)">="17"</span> <span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">application </span><span style="color: rgba(255, 0, 0, 1)">android:allowBackup</span><span style="color: rgba(0, 0, 255, 1)">="true"</span><span style="color: rgba(255, 0, 0, 1)"> android:icon</span><span style="color: rgba(0, 0, 255, 1)">="@drawable/ic_launcher"</span><span style="color: rgba(255, 0, 0, 1)"> android:label</span><span style="color: rgba(0, 0, 255, 1)">="@string/app_name"</span><span style="color: rgba(255, 0, 0, 1)"> android:theme</span><span style="color: rgba(0, 0, 255, 1)">="@style/AppTheme"</span> <span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">activity </span><span style="color: rgba(255, 0, 0, 1)">android:name</span><span style="color: rgba(0, 0, 255, 1)">=".MainActivity"</span><span style="color: rgba(255, 0, 0, 1)"> android:label</span><span style="color: rgba(0, 0, 255, 1)">="@string/app_name"</span> <span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">intent-filter</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">action </span><span style="color: rgba(255, 0, 0, 1)">android:name</span><span style="color: rgba(0, 0, 255, 1)">="android.intent.action.MAIN"</span> <span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">category </span><span style="color: rgba(255, 0, 0, 1)">android:name</span><span style="color: rgba(0, 0, 255, 1)">="android.intent.category.LAUNCHER"</span> <span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">intent-filter</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">activity</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">activity </span><span style="color: rgba(255, 0, 0, 1)">android:name</span><span style="color: rgba(0, 0, 255, 1)">=".ClockActivity"</span> <span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">activity </span><span style="color: rgba(255, 0, 0, 1)">android:name</span><span style="color: rgba(0, 0, 255, 1)">=".StopwatchActivity"</span> <span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">activity </span><span style="color: rgba(255, 0, 0, 1)">android:name</span><span style="color: rgba(0, 0, 255, 1)">=".TimerActivity"</span> <span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">application</span><span style="color: rgba(0, 0, 255, 1)">></span></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。