Android开发问题：ActivityNotFoundException: Unable to find explicit activity class

错误：android.content.ActivityNotFoundException: Unable to find explicit activity class {tt.test/tt.test.ViewActivity}; have you declared this activity in your AndroidManifest.xml? 

原因：AndroidManifest.xml未添加对应Activity配置。 

解决办法：在AndroidManifest.xml添加对应Activity配置内容。

    android:theme="@android:style/Theme.Dialog"
    android:screenOrientation="user" android:configChanges="orientation|keyboardHidden">
    <intent-filter>
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>

		<activity android:name=".Start" android:label="@string/app_name"
			android:theme="@android:style/Theme.Dialog"
			android:screenOrientation="user" android:configChanges="orientation|keyboardHidden">
			<intent-filter>
				<category android:name="android.intent.category.LAUNCHER" />
			</intent-filter>
		</activity>

 <activity
            android:name=".TestActivity"
            android:configChanges="orientation|keyboardHidden"
            android:label="@string/app_name" >

少了红色背景这句