我有一个ViewPager与3片段,每个片段都有自己的独特布局。每个Fragment通过从保存ViewPager的FragmentActivity的newInstance()方法中获取布局ID作为参数来知道使用哪个布局。此ViewPager由FragmentStatePagerAdapter控制,名为MyPagerAdapter。保留查看寻呼机片段布局的变化
public class MainActivity extends FragmentActivity {
ViewPager pager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
pager = (ViewPager) findViewById(R.id.viewPager);
pager.setAdapter(new MyPagerAdapter(getSupportFragmentManager()));
}
private class MyPagerAdapter extends FragmentStatePagerAdapter {
SparseArray<Fragment> registeredFragments = new SparseArray<Fragment>();
public MyPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int pos) {
switch(pos) {
case 0: return FirstFragment.newInstance("FirstFragment, Instance 1");
case 1: return SecondFragment.newInstance("SecondFragment, Instance 1");
case 2: return ThirdFragment.newInstance("ThirdFragment, Instance 1");
}
}
@Override
public int getCount() {
return 3;
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
Fragment fragment = (Fragment) super.instantiateItem(container, position);
registeredFragments.put(position, fragment);
return fragment;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
registeredFragments.remove(position);
super.destroyItem(container, position, object);
}
public Fragment getRegisteredFragment(int position) {
return registeredFragments.get(position);
}
}
public void setBackgroundImage(View view){
int i = pager.getCurrentItem();
Fragment page = ((MyPagerAdapter)pager.getAdapter()).getRegisteredFragment(i);
page.getView().findViewById(R.id.first).findViewById(R.id.button1);
page.getView().findViewById(R.id.first).setBackgroundResource(R.drawable.ic_launcher);
}
}
activity_main.xml中:
<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"
tools:context=".MainActivity" >
<android.support.v4.view.ViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/viewPager"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
</RelativeLayout>
这里是FirstFragment:
public class FirstFragment extends Fragment{
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.first_frag, container, false);
TextView tv = (TextView) v.findViewById(R.id.tvFragFirst);
tv.setText(getArguments().getString("msg"));
return v;
}
public static FirstFragment newInstance(String text) {
FirstFragment f = new FirstFragment();
Bundle b = new Bundle();
b.putString("msg", text);
f.setArguments(b);
return f;
}}
first_frag.xml:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/holo_orange_dark"
android:id="@+id/first" >
<TextView
android:id="@+id/tvFragFirst"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:textSize="26dp"
android:text="TextView" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/tvFragFirst"
android:text="Button"
android:onClick="setBackgroundImage"/>
</RelativeLayout>
它有更多的按钮和imagebuttons与方法的onClick ,但它不是必需的除了需要知道我有许多类似于setBackgroundImage的onClick方法来改变布局的外观之外,这个问题是必须的。
SecondFragment和ThirdFragment与它们的布局类似。
您可以在MainActivity中看到setBackgroundImage方法,它会更改片段的背景图像。但是一旦它改变了,它就不是永久的,因为当我翻转碎片并返回到第一个碎片时,变化不会被保存,而是显示原始布局。我明白,一旦失去视觉,碎片的布局就会被破坏。有没有办法保留布局更改?
yeap。没有帮助。顺便说一句,它是“setRetainInstance(true);” – Nazerke