public class FragmentArguments extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.e("_____tag", "onCreate in main avtivity___1");
setContentView(R.layout.fragment_arguments);
Log.e("_____tag", "onCreate in main avtivity____2");
if (savedInstanceState != null) {
// First-time init; create fragment to embed in activity.
FragmentTransaction ft = getFragmentManager().beginTransaction();
Fragment newFragment = MyFragment.newInstance("From Arguments");
ft.add(R.id.created, newFragment);
ft.commit();
Log.e("_____tag", "onCreate in main avtivity____3");
}
}
public static class MyFragment extends Fragment {
CharSequence mLabel;
/**
* Create a new instance of MyFragment that will be initialized with the
* given arguments.
*/
static MyFragment newInstance(CharSequence label) {
MyFragment f = new MyFragment();
Bundle b = new Bundle();
b.putCharSequence("label", label);
f.setArguments(b);
return f;
}
/**
* Parse attributes during inflation from a view hierarchy into the
* arguments we handle.
*/
@SuppressLint("NewApi")
@Override
public void onInflate(Activity activity, AttributeSet attrs,
Bundle savedInstanceState) {
super.onInflate(activity, attrs, savedInstanceState);
Log.e("_____tag", "onInflate in MyFragment______1");
TypedArray a = activity.obtainStyledAttributes(attrs,
R.styleable.FragmentArguments);
mLabel = a.getText(R.styleable.FragmentArguments_android_label);
Log.e("_____tag", (String)mLabel + "in onInflate in MyFragment______2");
a.recycle();
}
/**
* During creation, if arguments have been supplied to the fragment then
* parse those out.
*/
@SuppressLint("NewApi")
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.e("_____tag", "onCreate in fragment");
Bundle args = getArguments();
Log.e("_____tag", (String)mLabel + "onCreate in MyFragment____1");
if (args != null) {
mLabel = args.getCharSequence("label", mLabel);
Log.e("_____tag", (String)mLabel + "in onCreate in MyFragment____2");
}
}
/**
* Create the view for this fragment, using the arguments given to it.
*/
@SuppressWarnings("deprecation")
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
Log.e("_____tag", "onCreateView in MyFragment____1");
View v = inflater.inflate(R.layout.hello_world, container, false);
View tv = v.findViewById(R.id.text);
Log.e("_____tag", (String)mLabel + "in onCreateView in MyFragment____2");
((TextView) tv).setText(mLabel != null ? mLabel : "(no label)");
tv.setBackgroundDrawable(getResources().getDrawable(
android.R.drawable.gallery_thumb));
return v;
}
}
}
好吧這是APIDemo的源碼,裏面加了點log用來分析的。
setContentView(R.layout.fragment_arguments);這個顯示用戶界面信息,來看看fragment_arguments.xml文件
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:padding="4dip"
android:gravity="center_horizontal"
android:layout_width="match_parent" android:layout_height="match_parent">
<TextView
android:id="@+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:padding="4dip"
android:layout_gravity="center_vertical|center_horizontal"
android:gravity="top|center_horizontal"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="@string/fragment_arguments_msg" />
<LinearLayout android:orientation="horizontal" android:padding="4dip"
android:layout_width="match_parent" android:layout_height="wrap_content">
<fragment class="com.example.android.apis.app.FragmentArguments$MyFragment"
android:id="@+id/embedded"
android:layout_width="0px" android:layout_height="wrap_content"
android:layout_weight="1"
android:label="@string/fragment_arguments_embedded" />
<FrameLayout
android:id="@+id/created"
android:layout_width="0px"
android:layout_height="wrap_content"
android:layout_weight="1" />
</LinearLayout>
</LinearLayout>
LinearLayout就不說了,主要是fragment 和FrameLayout這2個標籤. 第一個fragment指定了類MyFragment,就是在Activity裏面定義的內部類。指定了類那麼在setContentView的時候再內部調用了MyFragment類中複寫的一些方法就可以顯示一個fragment提供的UI 佈局(From Attributes這個框框)。
水平佈局layout_weight=1,在From Attributes普遍還有一個FrameLayout目前還是沒有UI界面顯示出來
if (savedInstanceState != null) {
// First-time init; create fragment to embed in activity.
FragmentTransaction ft = getFragmentManager().beginTransaction();
Fragment newFragment = MyFragment.newInstance("From Arguments");
ft.add(R.id.created, newFragment);
ft.commit();
Log.e("_____tag", "onCreate in main avtivity____3");
}
本來savedInstanceState == null是這樣的條件,在第一次初始化的時候savedInstanceState 這個值應該是空的!可以進入IF,一個MyFragment添加到了R.id.created,commit提交後,就可以顯示在屏幕上了。
每使用MyFragment創建一個對象用來顯示在屏幕上,MyFragment的生命週期就會執行,即MyFragment複寫的幾個函數會執行。
這裏發現了2類實用Fragment的不同方法。
1.直接在xml文件裏面添加自定義的fragment類的標籤實用,
2.在xml裏面佈局framelayout標籤,獲取ID後,將MyFragment使用FragmentTransaction對象的 add方法添加的指定的ID,commit提交後顯示界面
思考:自定義的MyFragment出現在xml裏面的時候只是可以使用例程中的方法指定類名嗎,直接使用類名作爲標籤可以嗎?
在xml裏面佈局的標籤不使用framelayout,使用其他標籤例如Linraelayout,可以在裏面commit自定義的fragment 嗎?
FragmentTransaction可以用來管理MyFragment,還有關於back stack的處理是和它相關的看看其他例子FragmentTransaction是怎麼管理Fragment的。。。