Android之Activity
有两个方法大部分Activity子类都会实现:
OnCreate(Bundle)是用于初始化Activity,更为重要的是,在这里一般通过调用setContentView设置已经定义的layout资源和findViewById(int)初始化UI控件。
OnPause用于处理Avtivity将失去焦点动作,这时应该保存用户已经修改的数据。
所有的Activity必须在AndroidManifest.xml里面声明,否则在startActivity调用后,会crash.
实例:ActivityDemo
运行效果:
>adb shell dumpsys activity top
TASK com.rainsong.activitydemo id=90
ACTIVITY com.rainsong.activitydemo/.MainActivity 421bccb8 pid=7776
Local Activity 41e26278 State:
mResumed=true mStopped=false mFinished=false
mLoadersStarted=true
mChangingConfigurations=false
mCurrentConfig={1.0 460mcc2mnc zh_CN ldltr sw360dp w360dp h615dp 320dpi nrml long port finger -keyb/v/h -nav/h s.20 themeChanged=0 themeChangedFlags=0}
FragmentManager misc state:
mActivity=com.rainsong.activitydemo.MainActivity@41e26278
mContainer=android.app.Activity$1@41e263e8
mCurState=5 mStateSaved=false mDestroyed=false
ViewRoot:
mAdded=true mRemoved=false
mConsumeBatchedInputScheduled=false
mPendingInputEventCount=0
mProcessInputEventsScheduled=false
mTraversalScheduled=false
android.view.ViewRootImpl$NativePreImeInputStage: mQueueLength=0
android.view.ViewRootImpl$ImeInputStage: mQueueLength=0
android.view.ViewRootImpl$NativePostImeInputStage: mQueueLength=0
Choreographer:
mFrameScheduled=false
mLastFrameTime=152388770 (16254 ms ago)
View Hierarchy:
com.android.internal.policy.impl.PhoneWindow$DecorView{41e28790 V.E..... R....... 0,0-720,1280}
com.android.internal.widget.ActionBarOverlayLayout{41e2ab00 V.E..... ........ 0,0-720,1280 #102032b android:id/action_bar_overlay_layout}
android.widget.FrameLayout{41e2d250 V.E..... ........ 0,146-720,1280 #1020002 android:id/content}
android.widget.LinearLayout{41f5b7f8 V.E..... ........ 0,0-720,1134}
android.widget.TextView{41f5bb20 V.ED.... ........ 0,0-720,38}
com.android.internal.widget.ActionBarContainer{41e2d778 V.ED.... ........ 0,50-720,146 #102032c android:id/action_bar_container}
com.android.internal.widget.ActionBarView{41e32ea0 V.E..... ........ 0,0-720,96 #102032d android:id/action_bar}
android.widget.LinearLayout{41e33618 V.....C. ........ 32,0-342,96}
com.android.internal.widget.ActionBarView$HomeView{41e35100 V.E..... ........ 0,0-80,96}
android.widget.ImageView{41e355d8 G.ED.... ......I. 0,0-0,0 #102025a android:id/up}
android.widget.ImageView{41e359e0 V.ED.... ........ 8,16-72,80 #102002c android:id/home}
android.widget.LinearLayout{41e36db8 V.E..... ........ 80,23-310,72}
android.widget.TextView{41e37268 V.ED.... ........ 0,0-214,49 #1020265 android:id/action_bar_title}
android.widget.TextView{41e3fb68 G.ED.... ......I. 0,0-0,0 #1020266 android:id/action_bar_subtitle}
com.android.internal.view.menu.ActionMenuView{41f74db8 V.ED.... ......ID 720,0-720,96}
com.android.internal.widget.ActionBarContextView{41e40960 G.E..... ......ID 0,0-0,0 #102032e android:id/action_context_bar}
com.android.internal.widget.ActionBarContainer{41e413c8 G.ED.... ......I. 0,0-0,0 #102032f android:id/split_action_bar}
com.lbe.security.service.core.client.a.f{41f69ec8 V.E..... ........ 0,0-720,1280}
Looper (main, tid 1) {41d93b00}
Message 0: { when=+1s938ms what=1 obj=com.lbe.security.service.core.client.proxy.f@41debb08 target=com.lbe.security.service.core.client.proxy.bc }
(Total messages: 1, idling=false, quitting=false)
代码清单:
AndroidManifest.xml<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.rainsong.activitydemo" android:versionCode="1" android:versionName="1.0"> <uses-sdk android:minSdkVersion="11" android:targetSdkVersion="19" /> <application android:label="@string/app_name" android:icon="@drawable/ic_launcher"> <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> </application> </manifest>
布局文件:main.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Hello Android" /> </LinearLayout>
Java源代码文件:MainActivity.java
package com.rainsong.activitydemo; import android.app.Activity; import android.os.Bundle; public class MainActivity extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); } }
郑重声明:本站内容如果来自互联网及其他传播媒体,其版权均属原媒体及文章作者所有。转载目的在于传递更多信息及用于网络分享,并不代表本站赞同其观点和对其真实性负责,也不构成任何其他建议。