Android 将数据从活动发送到选项卡片段
我的代码有一个lite问题,我在这个网站上搜索,但仍然没有找到最好的答案 我会将数据发送到我的标签片段,这是我的代码 我的活动课Android 将数据从活动发送到选项卡片段,android,android-fragments,tabs,Android,Android Fragments,Tabs,我的代码有一个lite问题,我在这个网站上搜索,但仍然没有找到最好的答案 我会将数据发送到我的标签片段,这是我的代码 我的活动课 public class MainActivity extends AppCompatActivity private ViewPager pager; private Toolbar toolbar; private TabLayout tabs; @Override protected void onCreate(Bu
public class MainActivity extends AppCompatActivity
private ViewPager pager;
private Toolbar toolbar;
private TabLayout tabs;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
pager=(ViewPager) findViewById(R.id.pager);
tabs=(TabLayout) findViewById(R.id.tabs);
pager.setAdapter(new TabFragmentPagerAdapter(getSupportFragmentManager()));
tabs.setupWithViewPager(pager);
tabs.setTabGravity(TabLayout.GRAVITY_FILL);
Bundle bundle = new Bundle();
bundle.putString("edttext", "data From Activity");
// set Fragmentclass Arguments
tab1Fragment fragobj = new tab1Fragment();
fragobj.setArguments(bundle);
}
}
public class tab1Fragment extends Fragment
public tab1Fragment() {
// 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_tab1, container, false);
TextView tes=(TextView) view.findViewById(R.id.testtab1);
String strtext = getArguments().getString("edttext");
tes.setText("tes :"+ strtext);
return view;
}
}
这是我的tab1类
public class MainActivity extends AppCompatActivity
private ViewPager pager;
private Toolbar toolbar;
private TabLayout tabs;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
pager=(ViewPager) findViewById(R.id.pager);
tabs=(TabLayout) findViewById(R.id.tabs);
pager.setAdapter(new TabFragmentPagerAdapter(getSupportFragmentManager()));
tabs.setupWithViewPager(pager);
tabs.setTabGravity(TabLayout.GRAVITY_FILL);
Bundle bundle = new Bundle();
bundle.putString("edttext", "data From Activity");
// set Fragmentclass Arguments
tab1Fragment fragobj = new tab1Fragment();
fragobj.setArguments(bundle);
}
}
public class tab1Fragment extends Fragment
public tab1Fragment() {
// 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_tab1, container, false);
TextView tes=(TextView) view.findViewById(R.id.testtab1);
String strtext = getArguments().getString("edttext");
tes.setText("tes :"+ strtext);
return view;
}
}
这是我的页面片段适配器
public class TabFragmentPagerAdapter extends FragmentPagerAdapter
String[] title = new String[]{
"Tab 1", "Tab 2", "Tab 3"
};
public TabFragmentPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position){
Fragment fragment=null;
switch (position){
case 0:
fragment=new tab1Fragment();
break;
case 1:
fragment=new tab2Fragment();
break;
case 2:
fragment=new tab3Fragment();
break;
default:
fragment=null;
break;
}
return fragment;
}
@Override
public CharSequence getPageTitle(int position){
return title[position];
}
@Override
public int getCount(){
return title.length;
}
}
当我运行错误时
java.lang.NullPointerException
请在您发送的
AppCompatActivity
中提供帮助
tab1Fragment fragobj = new tab1Fragment();
fragobj.setArguments(bundle);
但是在您的选项卡FragmentPageRadapter
fragment=new tab1Fragment();
break;
它有空参数
内部开关
switch (position){
case 0:
fragment=new tab1Fragment();
Bundle bundle = new Bundle();
bundle.putString("edttext", "data From Activity");
fragment.setArguments(bundle);
break;
我想你可以先通过调用你的活动来启动Tab1Frame(),然后你可以这样做 用这个 而不是
可能是因为您的片段在
getItem
中再次初始化而没有参数,所以您得到的是NullPointerException
这样试试
@Override
public Fragment getItem(int position){
Fragment fragment=null;
Bundle bundle = new Bundle();
bundle.putString("edttext", "data From Activity");
switch (position){
case 0:
fragment=new tab1Fragment();
fragment.setArguments(bundle);
break;
case 1:
fragment=new tab2Fragment();
break;
case 2:
fragment=new tab3Fragment();
break;
default:
fragment=null;
break;
}
return fragment;
}
注意:确保在MainActivity和tab1Fragment中导入相同版本的片段。在片段中创建一个函数,以便从活动中传入数据,就像在对象类的
getters
和setters
中所做的那样:
// Fragment
class TabFragment extends Fragment{
public String myDataString;
...
public void setTabInfo(String myActivityString){
this.myDataString = myActivityString;
}
}
// Activity
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
...
TabFragment frag = new TabFragment();
frag.setTabInfo("data From Activity");
}
我更喜欢这种方法,因为在对象的情况下使用
Bundle
时,您不必序列化对象,直接传递数据可能是最晚的答案,但有一点对我有效:
将包发送到适配器:
Bundle bundle = new Bundle();
bundle.putString("edttext", "data From Activity");
pager.setAdapter(new TabFragmentPagerAdapter(getSupportFragmentManager(), bundle));
在适配器中扩展构造函数:
Bundle bundle;
public TabFragmentPagerAdapter(FragmentManager fm, Bundle bundle) {
super(fm);
this.bundle=bundle;
}
并将其发送到片段:
switch (position){
case 0:
fragment=new tab1Fragment();
fragment.setArguments(bundle);
break;
希望它能有所帮助。
}你从哪里得到的NullPointerException,在哪一行号上,post log catpost你的错误登录我看到了,如果我把bundle放到tabframentpageadapter,数据就会输出到我的第一个选项卡。但问题是数据来自另一个活动,比如说来自cutomer活动,我很难将数据发送到我的选项卡FragmentPageRadapterCustomerActivity(将数据发送到)->MainActivity(我通过getinten获取数据)->发送到tab1fragment(这是我的问题)在MainActivity中写入TabFragmentPagerAdapter您可以使用bundle从fragment发送任何数据,您无需创建单独的类尝试更新answeFATAL异常:主进程:com.kenjin.tabfragmentapp,PID:23716 java.lang.NullPointerException位于android.support.v4.app.fragment.performCreateView上的com.kenjin.tabfragmentapp.fragment.tab1Fragment.onCreateView(tab1Fragment.java:32)(Fragment.java:1)