MainActivity进行分段，然后按返回按钮返回MainActivity [英] MainActivity to fragment and back to MainActivity on pressing back button

问题描述

我有一个Mainactivity，其中包含一个布局，该布局是4个子布局的父级.在单击子布局时，我将转到一个替换主布局的新片段.但是按下返回"按钮后我无法返回MainActivity

I have a Mainactivity which contains a Layout which is parent of 4 sub layout. on clicking on sub layout i am going to a new fragment replacing main layout. But i cant go back to MainActivity after pressing Back button

MainActivity.java

MainActivity.java

public class MainActivity extends AppCompatActivity {

    RelativeLayout aboutUs;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        aboutUs = (RelativeLayout) findViewById(R.id.aboutUs);

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });
    }


    //click methods goes here

    public void clickAboutUs(View view){

        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        FragmentAboutUs fragmentAboutUs = new FragmentAboutUs();
        fragmentTransaction.replace(R.id.fragment_container,fragmentAboutUs);
        fragmentTransaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
        fragmentTransaction.addToBackStack(null);

        fragmentTransaction.commit();



    }




    @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) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }


}

FragmentAboutUs.java

FragmentAboutUs.java

public class FragmentAboutUs extends Fragment
{

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.about_us, container,false);
        return view;
    }
}

如何从片段按返回按钮后再次返回主页.

How to go back to main page again after pressing back button from fragment.

推荐答案

像这样尝试

    public boolean popFragment() {
    boolean isPop = false;

    Fragment currentFragment = getSupportFragmentManager()
            .findFragmentById(R.id.flContent);

        if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
            isPop = true;
            getSupportFragmentManager().popBackStackImmediate();
        }

    return isPop;
}

@Override
public void onBackPressed() {
    if (!popFragment()) {
        finish();
    }
}

public void replaceFragment(Fragment fragment, boolean addToBackStack) {

    FragmentTransaction transaction = getSupportFragmentManager()
            .beginTransaction();

    if (addToBackStack) {
        transaction.addToBackStack(null);

    } else {
        getSupportFragmentManager().popBackStack(null,
                FragmentManager.POP_BACK_STACK_INCLUSIVE);

    }
    transaction.replace(R.id.fragment_container, fragment);
    transaction.commit();
    getSupportFragmentManager().executePendingTransactions();

}

添加上述方法在您的父活动中 并使用

add above method is in your parent Activity And Use like

 FragmentAboutUs fragmentAboutUs = new FragmentAboutUs();
 replaceFragment(fragmentAboutUs , true);

这篇关于MainActivity进行分段，然后按返回按钮返回MainActivity的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！