Question

我对Coding相对较新，但请耐心等待。我正在尝试将Google地图放在导航抽屉中。我认为最好的方法是使用片段但是尽管我尝试了各种各样的尝试但我仍然收到此错误：“错误：（35,62）错误：不兼容的类型：MapsActivity无法转换为片段”。

我有两项活动 1. MainActiyity：出现错误的地方。 2. MapsActivity：当选择在Android studio新项目创建时创建谷歌地图应用时，这是默认活动。

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.view.View;
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.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;

import android.support.v4.app.FragmentActivity;


public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {    

NavigationView navigationView = null;
Toolbar toolbar = null;

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

    // Set to start with fragment
    MapsActivity fragment = new MapsActivity();
    android.support.v4.app.FragmentTransaction fragmentTransaction =
            getSupportFragmentManager().beginTransaction();
    fragmentTransaction.replace(R.id.fragment_container, fragment);
    fragmentTransaction.commit();


    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();
        }
    });

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.setDrawerListener(toggle);
    toggle.syncState();

    navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);
}

@Override
public void onBackPressed() {
    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        super.onBackPressed();
    }
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.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();
    return super.onOptionsItemSelected(item);
}

@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
    // Handle navigation view item clicks here.
    int id = item.getItemId();

    if (id == R.id.nav_building) {
        MapsActivity fragment = new MapsActivity();
        android.support.v4.app.FragmentTransaction fragmentTransaction =
                getSupportFragmentManager().beginTransaction();
        fragmentTransaction.replace(R.id.fragment_container, fragment);
        fragmentTransaction.commit();

    } else if (id == R.id.nav_map) {

    } else if (id == R.id.nav_timetable) {

    } else if (id == R.id.nav_noticeboard) {

    } else if (id == R.id.nav_settings) {

    } else if (id == R.id.nav_placeholder) {

    }

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    drawer.closeDrawer(GravityCompat.START);
    return true;
}
}

此外，fragmentTransaction.replace中的'fragment'一词（R.id.fragment_container，fragment）; 红色下划线。我试图找到不同的教程和指南，但没有解决我的问题。

Answer 1

您无法使用活动执行FragmentTransaction。

要在NavigationDrawer中使用Google Map，请使用扩展SupportMapFragment的Fragment，并添加MapsActivity类当前具有的所有功能。

使用此字母开头：

public class MapsFragment extends SupportMapFragment
        implements OnMapReadyCallback {

    GoogleMap mGoogleMap;

    @Override
    public void onResume() {
        super.onResume();

        setUpMapIfNeeded();
    }

    private void setUpMapIfNeeded() {

        if (mGoogleMap == null) {
            getMapAsync(this);
        }
    }

    @Override
    public void onMapReady(GoogleMap googleMap)
    {
        mGoogleMap=googleMap;
        mGoogleMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
    }

}

然后在Activity中，将其更改为使用片段：

// Set to start with fragment
MapsFragment fragment = new MapsFragment();
android.support.v4.app.FragmentTransaction fragmentTransaction =
        getSupportFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.fragment_container, fragment);
fragmentTransaction.commit();

如何在NavigationDrawer中使用Google地图？

1 个答案: