我只有1个活动,其中有2个片段。当开始活动时,片段A将启动。在用户键入某物并单击后,该按钮将定向到片段B。因此,我想做的是在左上角添加这样的“后退箭头”。
它与FragmentManager.popBackStack()有关吗?请指教 !谢谢
MainActivity.java
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FragmentManager manager=getSupportFragmentManager();
FragmentTransaction transaction=manager.beginTransaction();
first first=new first();
transaction.add(R.id.top,first);
transaction.commit();
}
}
第一.java
public class first extends Fragment implements View.OnClickListener{
Button get_button;
EditText get_input_name;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_first,container,false);
get_input_name=(EditText)rootView.findViewById(R.id.input_name);
get_button=(Button)rootView.findViewById(R.id.submit);
get_button.setOnClickListener(this);
return rootView;
}
public void onClick(View v){
FragmentManager manager=getFragmentManager();
FragmentTransaction transaction=manager.beginTransaction();
two Two=new two();
Bundle bundle = new Bundle();
bundle.putString("input_name_value",get_input_name.getText().toString());
Two.setArguments(bundle);
transaction.replace(R.id.top,Two);
transaction.commit();
}
}
二.java
public class two extends Fragment implements View.OnClickListener {
TextView get_display_input;
ImageView get_back_button;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_two, container, false);
}
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
get_display_input=(TextView)getActivity().findViewById(R.id.display_input);
get_back_button=(ImageView) getActivity().findViewById(R.id.back_button);
Bundle bundle = getArguments();
String get_name = bundle.getString("input_name_value");
//int store_get_input=Integer.parseInt(get_name);
get_display_input.setText("You have entered "+get_name);
}
public void onClick(View v){
// WHAT TO DO HERE IN ORDER TO RETURN TO PREVIOUS Fragment when clicking the button?
}
}
更精确地说,请参阅屏幕截图。
您可以使用的popBackStack()方法FragmentManager
将其放入onClickListener
后退按钮的内:
if (getFragmentManager().getBackStackEntryCount() != 0) {
getFragmentManager().popBackStack();
}
如果您使用工具栏的默认后退按钮(即主页按钮),则可以通过将以下代码放置在的onOptionsItemSelected()
方法中来做到这一点Activity
:
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == android.R.id.home) {
if (getFragmentManager().getBackStackEntryCount() != 0) {
getFragmentManager().popBackStack();
}
return true;
}
return super.onOptionsItemSelected(item);
}
或者,如果您希望在按下硬件后退按钮时具有相同的行为,则可以像下面这样重写类中的onBackPressed()
方法Activity
:
@Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() != 0) {
getFragmentManager().popBackStack();
} else {
super.onBackPressed();
}
}
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