app--Activity--Custom Dialog:演示如何编写一个类似弹出菜单的Activity.
com.example.android.apis.app.CustomDialogActivity
提醒了需要以下包
import con.example.android.apis.R
android:gravity="center_vertical|center_horizontal"

app--Activty--Custom Title:演示如何制作有左右标题的标题栏
而且注释就得向如下这样写
/**
* Example of how to use a custom title {@link android.view.Window#FEATURE_CUSTOM_TITLE}.
*

CustomTitle

This demonstrates how a custom title can be used.

Demo

Source files

com.example.android.apis.app.CustomTitle
Example of how to use a custom title android.view.Window.FEATURE_CUSTOM_TITLE.

CustomTitle
This demonstrates how a custom title can be used.

Demo
App/Title/Custom Title
Source files
src/com.example.android.apis/app/CustomTitle.java The Custom Title implementation
/res/any/layout/custom_title.xml Defines contents of the screen

app--Activity--Dialog:演示如何使用theme,对话框风格使你的activity看起来像一个对话框.
com.example.android.apis.app.DialogActivity

app--Activity--Forwarding:使某个Activity在task堆栈中终止,即按back按钮不能返回到这个Activity.
finish();
com.example.android.apis.app.Forwarding

app--Activity--hello World:

app--Activity--Persistent State:演示如何使用persistent preferences来保留切屏时原Activity的一些值,方便在切回时复原.
com.example.android.apis.app.PersistentState
/**
* Upon being resumed we can retrieve the current state. This allows us
* to update the state if it was changed at any time while paused.
*/
@Override
protected void onResume() {
super.onResume();

SharedPreferences prefs = getPreferences(0);
String restoredText = prefs.getString("text", null);
if (restoredText != null) {
mSaved.setText(restoredText, TextView.BufferType.EDITABLE);

int selectionStart = prefs.getInt("selection-start", -1);
int selectionEnd = prefs.getInt("selection-end", -1);
if (selectionStart != -1 && selectionEnd != -1) {
mSaved.setSelection(selectionStart, selectionEnd);
}
}
}

/**
* Any time we are paused we need to save away the current state, so it
* will be restored correctly when we are resumed.
*/
@Override
protected void onPause() {
super.onPause();

SharedPreferences.Editor editor = getPreferences(0).edit();
editor.putString("text", mSaved.getText().toString());
editor.putInt("selection-start", mSaved.getSelectionStart());
editor.putInt("selection-end", mSaved.getSelectionEnd());
editor.commit();
}
app--Activity--QuickContactDemo:也许是演示一个快速启动电话拨号的Activity.但在模拟器上不能显示效果.
com.example.android.apis.app.QuickContactsDemo

app--Activity--Receive Result:演示如何让第二个Activity向第一个activity返回时返回值.
com.example.android.apis.app.ReceiveResult
这个例子由两个Activity组成:ReceiveResult运行pick activity且接收结果;SendResult可以让用户选择和发送回调的结果.实现这个功能涉及setResult()发送结果 onActivityResult()接收结果