本来想通过构造方法给fragment传值,不过后来知道,google是不予许给frament创建有参数的构造方法的。那么下面我们就来学习如何使用setArguments()和getArguments()来实现传值吧,同时学习怎样动态的创建frament。
首先我们需要做一些准备工作
1、创建一个fragment作为模板
public class BlankFragment extends Fragment {
private TextView textView;
public BlankFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_blank, container, false);
return view;
}
}
其对应的布局:
<LinearLayout 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:orientation="vertical"
tools:context="com.example.fragmentdemo.BlankFragment">
<TextView
android:id="@+id/fragment_tv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="50sp"
android:text="数字" />
</LinearLayout>
2、在MainActivity的布局文中添加viewpager
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.fragmentdemo.MainActivity">
<android.support.v4.view.ViewPager
android:id="@+id/main_vp"
android:layout_width="match_parent"
android:layout_height="match_parent">
</android.support.v4.view.ViewPager>
</LinearLayout>
3、创建viewpager的适配器:
public class MyPagerAdapter extends FragmentPagerAdapter{
private List<Fragment> fragmentList;
public MyPagerAdapter(FragmentManager fm,List<Fragment> fragmentList) {
super(fm);
this.fragmentList = fragmentList;
}
@Override
public Fragment getItem(int position) {
return fragmentList.get(position);
}
@Override
public int getCount() {
return fragmentList.size();
}
}
下面我们开始进入主题:修改MainActivity中的代码,实现创建fragment和发送值:
public class MainActivity extends AppCompatActivity {
private ViewPager viewPager;
private MyPagerAdapter pagerAdapter;
private List<Fragment> fragmentList = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager = findViewById(R.id.main_vp);
for(int i =0;i<3;i++){
//创建Fragment对象
BlankFragment blankFragment = new BlankFragment();
//创建Bundle对象
Bundle bundle = new Bundle();
//将想要传给fragment的值通过键值对放入Bundle对象中
bundle.putInt("number",i);
//通过setArguments()发送
blankFragment.setArguments(bundle);
//最后将Fragment对象放入集和中
fragmentList.add(blankFragment);
}
pagerAdapter = new MyPagerAdapter(getSupportFragmentManager(),fragmentList);
viewPager.setAdapter(pagerAdapter);
}
}
最后在fragment中接收:
public class BlankFragment extends Fragment {
private TextView textView;
public BlankFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_blank, container, false);
textView = view.findViewById(R.id.fragment_tv);
//通过getArguments()获得Bundle对象
Bundle bundle = getArguments();
//通过键获得值
int number = bundle.getInt("number");
textView.setText(number+"");
return view;
}
}