从片段选项卡布局启动活动

Question

我在从片段启动活动时遇到问题。

我的应用程序构建得像一个选项卡布局，背景中有一个活动，片段与选项卡一起。在此选项卡之一中，我想设置一个按钮，此按钮必须启动活动。我尝试了所有方法，但我想知道为什么它不起作用。

Logcat也什么也没显示。

这是带有按钮的片段

public class Freestyle extends Fragment {
public Freestyle() {
// 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_freestyle, container, false);
Button btnOpen;
btnOpen   =(Button)view.findViewById(R.id.btnOpenPlan);
btnOpen.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent=new Intent(getContext(),Plan.class);
startActivity(intent);
}
});
return view;
}
}

这是来自活动的代码，必须启动

public class Plan extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_plan);
}
}

这是后台活动中的代码

public class MainActivity extends AppCompatActivity {

private SectionsPagerAdapter mSectionsPagerAdapter;

private ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.container2);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
mViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(mViewPager));
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}

public static class PlaceholderFragment extends Fragment {
private static final String ARG_SECTION_NUMBER = "section_number";
public PlaceholderFragment() {
}

public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = null;
switch (getArguments().getInt(ARG_SECTION_NUMBER)) {
case 1:
//eine Serververbindung
rootView = inflater.inflate(R.layout.fragment_freestyle, container, false);
break;
case 2:
//eine weitere
rootView = inflater.inflate(R.layout.fragment_events, container, false);
break;
case 3:
//eine weitere
rootView = inflater.inflate(R.layout.fragment_map, container, false);
break;
case 4:
//eine weitere
rootView = inflater.inflate(R.layout.fragment_tipp, container, false);
break;
case 5:
//eine weitere
rootView = inflater.inflate(R.layout.fragment_person, container, false);
break;
}
return rootView;
}
}

public static class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
return PlaceholderFragment.newInstance(position + 1);
}
@Override
public int getCount() {
return 5;
}
}

Answer 1

使用这个，

btnOpen.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(getActivity(), Plan.class);
getActivity().startActivity(intent); 
}
});

Answer 2

试试这个

Intent intent=new Intent(getActivity(),Plan.class);
getActivity().startActivity(intent);

Answer 3

尝试使用 getActivity(类型转换为您的 Activity 实例(从片段启动新的活动

btn1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent intent = new Intent(((MainActivity) getActivity()), Plan.class);
((MainActivity) getActivity()).startActivity(intent);
}
});

希望这有帮助。

Answer 4

试试这样的事情

btnLaunchActivity.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//Check if getActivity() is actually not null, could be null if fragment detatched, you could also check if its an instance you expect to be
if(getActivity() != null && getActivity() instanceof MyActivity) {
Intent intent = new Intent(getActivity(), TargetActivity.class);
//Launch the intent from the activity reference
getActivity().startActivity(intent); 
}
}
});