Question

我不明白这个问题，请帮忙...。新machinemessage（）。commit（）中的问题

package com.example.ashraf.myapplication;

import android.support.annotation.NonNull;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.MenuItem;




public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
    private DrawerLayout drawer;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        drawer = findViewById(R.id.drawer_layout);
        NavigationView navigationView = findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);

        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, drawer, toolbar,
                R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.addDrawerListener(toggle);
        toggle.syncState();


    }

    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
        switch (item.getItemId()) {
            case R.id.nav_liste:
                getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                        new listemessage()).commit();
                break;
            case R.id.nav_machine:
                getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                        new machinemessage()).commit();
                break;
            case R.id.nav_Listepannes:
                getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                        new listedespannesmessage()).commit();
                break;


        }

        drawer.closeDrawer(GravityCompat.START);
        return true;
    }

this is the class machinemessage that i want to put in it a tabeLayout but its not working

package com.example.ashraf.myapplication;


import android.support.annotation.Nullable;
import android.support.design.widget.TabLayout;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.widget.TextView;


public class machinemessage extends AppCompatActivity {


    /**
     * The {@link android.support.v4.view.PagerAdapter} that will provide
     * fragments for each of the sections. We use a
     * {@link FragmentPagerAdapter} derivative, which will keep every
     * loaded fragment in memory. If this becomes too memory intensive, it
     * may be best to switch to a
     * {@link android.support.v4.app.FragmentStatePagerAdapter}.
     */
    private SectionsPagerAdapter mSectionsPagerAdapter;

    /**
     * The {@link ViewPager} that will host the section contents.
     */
    private ViewPager mViewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_tab);

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        // Create the adapter that will return a fragment for each of the three
        // primary sections of the activity.
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());






        // Set up the ViewPager with the sections adapter.
        mViewPager = (ViewPager) findViewById(R.id.container);
        mViewPager.setAdapter(mSectionsPagerAdapter);

        TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);

        mViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
        tabLayout.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(mViewPager));

        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();
            }
        });

    }


    @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_tab, menu);
        return true;
    }
    @Override

    // public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    //   return inflater.inflate(R.layout.fragment_tab, container, false);

    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);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {
        /**
         * The fragment argument representing the section number for this
         * fragment.
         */
        private static final String ARG_SECTION_NUMBER = "section_number";

        public PlaceholderFragment() {
        }

        /**
         * Returns a new instance of this fragment for the given section
         * number.
         */
        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 = inflater.inflate(R.layout.fragment_tab, container, false);
            TextView textView = (TextView) rootView.findViewById(R.id.section_label);
            textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
            return rootView;
        }
    }

    /**
     * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
     * one of the sections/tabs/pages.
     */
    public class SectionsPagerAdapter extends FragmentStatePagerAdapter {

        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            Fragment fragment = null;
            switch (position){
                case 0 :

                   fragment  = new frag1();
                    break;
                    case 1:

                   fragment  = new frag2();
                    break;
                 case 2 :

                  fragment   = new frag3();
                    break;
            }
            return fragment;
        }

        @Override
        public int getCount() {
            // Show 3 total pages.
            return 3;
        }
    }
}




the problem in new machinemessage()
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Answer 1

只能使用Fragment进行FragmentTransaction（Center( child: GestureDetector( onTap: () { _gotoEvent(item); }, child: new AspectRatio( aspectRatio: 4.0 / 3.0, child: new Container( decoration: new BoxDecoration( image: new DecorationImage( fit: BoxFit.fitWidth, alignment: FractionalOffset.topCenter, image: new NetworkImage(item.photo), ) ), ), ) ), ) ...）。请查看片段documentation，以获取有关片段的更多信息。现在，您正在尝试将活动（机器消息）作为片段添加到MainActivity。

片段的示例代码：

getSupportFragmentManager.beginTransaction

如果您只想从第一个活动开始一个新的活动，请使用以下代码：public class ExampleFragment extends Fragment { public ExampleFragment() { //empty public constructor is necessary } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_example, container, false); //Reference for a TextView in fragment_example.xml layout TextView textView = rootView.findViewById(R.id.textView); return rootView; } }

Answer 2

不要像这样放东西...

getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
new listedespannesmessage()).commit();

我是这样做的，而且像冠军一样...

Intent mlistedespannesmessage = new Intent(getApplicationContext(), listedespannesmessage.class);
startActivity(mlistedespannesmessage);

错误：类型不兼容：机器消息无法转换为片段

2 个答案: