这是一个2片段的标签，在第一个片段点击button_save它将执行保存数据并保持在当前页面，但是当我选择第二页作为第二个片段时，数据不会更新然后我需要关闭我的应用程序并打开第二页片段，然后只有正在更新的数据，我怎么能解决这个问题，我不需要关闭我的应用程序当选项卡到第二页并获得自动更新第二页中的数据？使用Intent？
以下代码来自第一个片段
public class KeyInWeightF extends Fragment implements View.OnClickListener {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
contentView=inflater.inflate(R.layout.daily_weight_fragement, container, false);
btnSave = (Button) contentView.findViewById(R.id.button_save);
dbconnection = new SQLControlerWeight(getActivity());
dbconnection.openDatabase();
btnSave.setOnClickListener(this);
return contentView;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public void onClick(View v){
switch (v.getId()){
case R.id.button_save:
if (btnTime.getText().toString().equals("")||btnDate.getText().toString().equals("")
||kgnum.getText().toString().equals("")||bf.getText().toString().equals("")){
Toast.makeText(getActivity(), "Please insert all the detail!", Toast.LENGTH_LONG).show();
}
else{
String kgn = kgnum.getText().toString()+" kg";
String bodyfat = bf.getText().toString()+" %";
String date = btnDate.getText().toString();
String time = btnTime.getText().toString();
String comment = comm.getText().toString();
dbconnection.insertNote(kgn, bodyfat, date, time, comment);
Toast.makeText(getActivity(), "Suggest", Toast.LENGTH_LONG).show();
// Did i need add some code "Intent "here ??
}
break;
}
}
}
这是第二个片段
public class HistoryF extends Fragment implements YourFragmentInterface{
View contentView;
ListView list;
SQLControlerWeight dbconnection;
TextView weight_num, date_num, time_num, bf_num, comment,weight_ID;
private SimpleCursorAdapter adapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
contentView = inflater.inflate(R.layout.history_fragment, container, false);
dbconnection = new SQLControlerWeight(getActivity());
dbconnection.openDatabase();
list = (ListView) contentView.findViewById(R.id.listViewWeight);
list.setAdapter(adapter);
list.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView parent, View view, int position, long id) {
weight_ID = (TextView) view.findViewById(R.id.weight_id);
weight_num = (TextView) view.findViewById(R.id.weight_num);
bf_num = (TextView) view.findViewById(R.id.bf_num);
date_num = (TextView) view.findViewById(R.id.date_num);
time_num = (TextView) view.findViewById(R.id.time_num);
comment = (TextView) view.findViewById(R.id.comment_text);
String weightId = weight_ID.getText().toString();
String wn = weight_num.getText().toString();
String bfn = bf_num.getText().toString();
String dn = date_num.getText().toString();
String tn = time_num.getText().toString();
String cm = comment.getText().toString();
Intent modify_intent = new Intent(getActivity(), Update_detail_info.class);
modify_intent.putExtra("weightId", weightId);
modify_intent.putExtra("dateNum", dn);
modify_intent.putExtra("timeNum", tn);
modify_intent.putExtra("weightNum", wn);
modify_intent.putExtra("bodyFatNum", bfn);
modify_intent.putExtra("comment", cm);
startActivity(modify_intent);
}
});
return contentView;
}
@Override
public void fragmentBecameVisible() {
Cursor cursor = dbconnection.readNote();
String[] from = new String[]{
DBHelperNote.WEIGHT_ID,
DBHelperNote.WEIGHT_NUM,
DBHelperNote.BODY_FAT,
DBHelperNote.WEIGHT_DATE,
DBHelperNote.WEIGHT_TIME,
DBHelperNote.WEIGHT_COMMENTS
};
int[] to = new int[]{
R.id.weight_id,
R.id.weight_num,
R.id.bf_num,
R.id.date_num,
R.id.time_num,
R.id.comment_text
};
adapter = new SimpleCursorAdapter(
contentView.getContext(), R.layout.history, cursor, from, to,0);
adapter.notifyDataSetChanged();
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
}
这是我的主要活动：
public class MainActivity extends AppCompatActivity {
Toolbar toolbar;
TabLayout tabLayout;
ViewPager viewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tablayout);
tabLayout.setupWithViewPager(viewPager);
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFragment(new KeyInWeightF(), "TRACK");
adapter.addFragment(new HistoryF(), "HISTORY");
adapter.addFragment(new AnalysisF(), "GRAPH");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
@Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
@Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
@Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
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);
}
}
接口：
public interface YourFragmentInterface {
void fragmentBecameVisible();
}
答案 0 :(得分：0)
抱歉onResume（）可能无法正常使用tab.In认为您可以实现此问题中解释的answer。
创建界面，如下所示：
public interface YourFragmentInterface {
void fragmentBecameVisible();
}
在第二个fragmnet中实现上面的界面，如下所示：
public class HistoryF extends Fragment implements YourFragmentInterface {
View contentView;
ListView list;
SQLControlerWeight dbconnection;
TextView weight_num, date_num, time_num, bf_num, comment,weight_ID;
private SimpleCursorAdapter adapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
contentView = inflater.inflate(R.layout.history_fragment, container, false);
dbconnection = new SQLControlerWeight(getActivity());
dbconnection.openDatabase();
list = (ListView) contentView.findViewById(R.id.listViewWeight);
list.setAdapter(adapter);
list.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView parent, View view, int position, long id) {
weight_ID = (TextView) view.findViewById(R.id.weight_id);
weight_num = (TextView) view.findViewById(R.id.weight_num);
bf_num = (TextView) view.findViewById(R.id.bf_num);
date_num = (TextView) view.findViewById(R.id.date_num);
time_num = (TextView) view.findViewById(R.id.time_num);
comment = (TextView) view.findViewById(R.id.comment_text);
String weightId = weight_ID.getText().toString();
String wn = weight_num.getText().toString();
String bfn = bf_num.getText().toString();
String dn = date_num.getText().toString();
String tn = time_num.getText().toString();
String cm = comment.getText().toString();
Intent modify_intent = new Intent(getActivity(), Update_detail_info.class);
modify_intent.putExtra("weightId", weightId);
modify_intent.putExtra("dateNum", dn);
modify_intent.putExtra("timeNum", tn);
modify_intent.putExtra("weightNum", wn);
modify_intent.putExtra("bodyFatNum", bfn);
modify_intent.putExtra("comment", cm);
startActivity(modify_intent);
}
});
return contentView;
}
@Override
public void fragmentBecameVisible() {
Cursor cursor = dbconnection.readNote();
String[] from = new String[]{
DBHelperNote.WEIGHT_ID,
DBHelperNote.WEIGHT_NUM,
DBHelperNote.BODY_FAT,
DBHelperNote.WEIGHT_DATE,
DBHelperNote.WEIGHT_TIME,
DBHelperNote.WEIGHT_COMMENTS
};
int[] to = new int[]{
R.id.weight_id,
R.id.weight_num,
R.id.bf_num,
R.id.date_num,
R.id.time_num,
R.id.comment_text
};
adapter = new SimpleCursorAdapter(
contentView.getContext(), R.layout.history, cursor, from, to,0);
adapter.notifyDataSetChanged();
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
并在 onCreate（）的 MainActivity 中执行以下操作：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tablayout);
tabLayout.setupWithViewPager(viewPager);
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
YourFragmentInterface fragment = (YourFragmentInterface) mPagerAdapter.instantiateItem(mViewPager, position);
if (fragment != null) {
fragment.fragmentBecameVisible();
}
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
}
在实现界面时，您将拥有功能fragmentBecameVisible（）。
所以只要你的片段处于活动状态，它就会调用函数fragmentBecameVisible（）。这将更新您的标签。我认为这解决了你的问题