我对安卓系统还比较新手。当我尝试使用addToBackStack()
时,遇到了一个问题。
当我在第二个Fragment中按下返回按钮时,它没有返回到第一个Fragment,而是回到了主页。
这是为什么?我的代码有什么问题吗? 谢谢!
MaiinActivity.java
public class MainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FragmentManager mFragmentManager = getFragmentManager();
FragmentTransaction mFragmentTransaction = mFragmentManager.beginTransaction();
mFragmentTransaction.add(R.id.id_frame, new firstFrag(), "firstFrag");
mFragmentTransaction.commit();
}
}
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.myfragtest2.MainActivity" >
<FrameLayout
android:id="@+id/id_frame"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
></FrameLayout>
</RelativeLayout>
firstFrag.java
public class firstFrag extends Fragment {
private Button button1;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.first_frag, container, false);
button1 = (Button)view.findViewById(R.id.btn1);
button1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
FragmentManager myFragmentManager = getFragmentManager();
FragmentTransaction myFTransaction = myFragmentManager.beginTransaction();
myFTransaction.replace(R.id.id_frame, new secondFrag());
myFTransaction.addToBackStack(null);
myFTransaction.commit();
}
});
return view;
}
}
first_frag.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<EditText
android:id="@+id/et1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="this is frag 1!!"
/>
<Button
android:id="@+id/btn1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:text="move to frag 2"
/>
</LinearLayout>
myFTransaction.addToBackStack(null);
。 - Piyush