导航抽屉打开一个新的片段

Question

我打开一个带有 Navigation Drawer Activity 的新 Android Studio 项目。所以layout-folder中有activty_main.xml、app_bar_main.xml、content_main.xml和一个nav_header_main.xml，还有一个Java-Class MainActivity。

当使用导航抽屉中的项目时，应该打开一个新片段。在片段中也必须是导航抽屉。我如何才能使用 API 8。我该怎么做？如何打开一个新的 Fragment？

activity_main：

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools" android:id="@+id/drawer_layout"
android:layout_width="match_parent" android:layout_height="match_parent"
android:fitsSystemWindows="true" tools:openDrawer="start">

<include layout="@layout/app_bar_main" android:layout_width="match_parent"
    android:layout_height="match_parent" />

<android.support.design.widget.NavigationView android:id="@+id/nav_view"
    android:layout_width="wrap_content" android:layout_height="match_parent"
    android:layout_gravity="start" android:fitsSystemWindows="true"
    app:headerLayout="@layout/nav_header_main" app:menu="@menu/activity_main_drawer" />

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <FrameLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />
</LinearLayout>

</android.support.v4.widget.DrawerLayout>

MainAcitvity：

package de.computerfreak.app.test;

import android.app.Fragment;
import android.app.FragmentTransaction;
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;

public class MainActivity extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener {

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

    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 = (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();

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

    return super.onOptionsItemSelected(item);
}

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

    if (id == R.id.nav_camara) {
        // Handle the camera action
        newFragment = new f1();
        transaction.replace(R.id.content_frame, newFragment);
        transaction.addToBackStack(null);
        transaction.commit();
    } else if (id == R.id.nav_gallery) {

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

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

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

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

    }

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

对不起我的英语，感谢您的帮助！

Answer 1

这是我在自己的一个解决方案中实现这一点的方法，只需在适当的地方切换值：

 mNavigationView = (NavigationView) (findViewById(R.id.nav_menu));
    mNavigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(MenuItem item) {
            switch(item.getItemId())
            {
                case R.id.menuEvents:
                {
                    mFragmentTransaction = getSupportFragmentManager().beginTransaction();
                    mFragmentTransaction.replace(R.id.main_fragment, new eventFragment());
                    mFragmentTransaction.commit();
                    getSupportActionBar().setTitle("Upcoming Events");
                    //item.setChecked(true);
                    mDrawerLayout.closeDrawers();
                    break;
                }

                case R.id.menuTechnique:
                {
                    mFragmentTransaction = getSupportFragmentManager().beginTransaction();
                    mFragmentTransaction.replace(R.id.main_fragment, new techniqueFragment());
                    mFragmentTransaction.commit();
                    getSupportActionBar().setTitle("Useful Techniques");
                    //item.setChecked(true);
                    mDrawerLayout.closeDrawers();
                    break;
                }

                case R.id.menuLink:
                {
                    mFragmentTransaction = getSupportFragmentManager().beginTransaction();
                    mFragmentTransaction.replace(R.id.main_fragment, new linkFragment());
                    mFragmentTransaction.commit();
                    getSupportActionBar().setTitle("Helpful Links");
                    //item.setChecked(true);
                    mDrawerLayout.closeDrawers();
                    break;
                }

                case R.id.menuSettings:
                {
                    mFragmentTransaction = getSupportFragmentManager().beginTransaction();
                    mFragmentTransaction.replace(R.id.main_fragment, new settingFragment());
                    mFragmentTransaction.commit();
                    getSupportActionBar().setTitle("Settings");
                    //item.setChecked(true);
                    mDrawerLayout.closeDrawers();
                    break;
                }
            }
            return true;
        }
    });