片段问题未解决

Question

我正在尝试更改我的代码以在 OnNavigationItemSelected 事件中使用片段

package com.example.xxxxx.myapplication;

import android.content.Intent;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.app.NavUtils;
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;

---

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

        if (id == R.id.nav_camera) {
            // Handle the camera action
        } 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;
    }
}

但我得到 Fragment is unresolved in my buld 但在我的应用程序的 build.gradle 中我添加了

  implementation 'com.android.support:support-v4:18.0.0'
  implementation "com.android.support:appcompat-v7:18.0.+"

下面的建议是这样的

Android Studio: Where is the Compiler Error Output Window?

Answer 1

第一： 在 build.gradle 中不建议使用“+”。

这些包的当前版本是：

    implementation 'com.android.support:support-v4:27.1.1'
    implementation 'com.android.support:appcompat-v7:27.1.1'

第二：

尝试添加这一行：

    implementation 'com.android.support:support-fragment:27.1.1'