带有图像错误的 Android 抽屉导航

Question

我根据这个教程写了一个简单的抽屉导航应用程序:https://www.youtube.com/watch?v=tZ2DNC3FIic
但是当我运行应用程序时出现问题。

错误是我在启动应用程序时有一个空白或空的抽屉列表，而不是我在应用程序启动时得到了列表。

喜欢这张图片:

这是 main_activity 布局:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:id="@+id/drawer_layout"
    android:layout_height="match_parent"
    tools:context="com.subhi.tabhost.MainActivity">

   <RelativeLayout
       android:layout_width="match_parent"
       android:id="@+id/main_content"
       android:layout_height="match_parent"></RelativeLayout>


    <RelativeLayout
        android:layout_width="match_parent"
        android:id="@+id/drawer_pane"
        android:layout_gravity="start"
        android:background="#FF4081"
        android:layout_height="match_parent"></RelativeLayout>

    <RelativeLayout
        android:layout_width="match_parent"
        android:id="@+id/profile_box"
        android:padding="8dp"
        android:gravity="center_vertical"
        android:layout_height="100dp">


        <ImageView
            android:id="@+id/icon"
            android:layout_margin="5dp"
            android:layout_width="50dp"
            android:background="@drawable/ic_launcher"
            android:layout_height="50dp" />


        <LinearLayout
            android:layout_width="match_parent"
            android:orientation="vertical"
            android:layout_toRightOf="@+id/icon"
            android:layout_height="match_parent">

            <TextView
                android:layout_width="wrap_content"
                android:textSize="18sp"
                android:textStyle="bold"
                android:textColor="#000000"
                android:text="Subhi"
                android:layout_height="wrap_content" />
            <TextView
                android:layout_width="wrap_content"
                android:textSize="18sp"
                android:textStyle="bold"
                android:textColor="#000000"
                android:text="Subhi"
                android:layout_height="wrap_content" />

        </LinearLayout>
    </RelativeLayout>

    <ListView
        android:layout_width="match_parent"
        android:id="@+id/nav_list"
        android:layout_below="@id/profile_box"
        android:choiceMode="singleChoice"
        android:background="#ffffff"
        android:layout_height="match_parent"></ListView>
</android.support.v4.widget.DrawerLayout>

这是 MainActivity 类:

package com.subhi.tabhost;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.RelativeLayout;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    DrawerLayout drawerLayout;
    RelativeLayout drawerPane;
    ListView lvNav;

    List<NavItem> listNavItems;
    List<Fragment> listFragments;

    ActionBarDrawerToggle actionBarDrawerToggle;


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

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        drawerLayout=(DrawerLayout)findViewById(R.id.drawer_layout);
        drawerPane= (RelativeLayout) findViewById(R.id.drawer_pane);
        lvNav =(ListView)findViewById(R.id.nav_list);

        listNavItems=new ArrayList<NavItem>();
        listNavItems.add(new NavItem("sHome", "HomePage", R.drawable.ic_launcher));
        listNavItems.add(new NavItem("Setting", "HomePage", R.drawable.ic_launcher));
        listNavItems.add(new NavItem("Setting", "HomePage", R.drawable.ic_launcher));

        NavListAdapter navListAdapter=new NavListAdapter(getApplicationContext(),R.id.nav_list,listNavItems);

        lvNav.setAdapter(navListAdapter);

        listFragments=new ArrayList<Fragment>();
        listFragments.add(new MyHome());
        listFragments.add(new MySettings());
        listFragments.add(new MyAbout());

        FragmentManager fragmentManager=getSupportFragmentManager();
        fragmentManager.beginTransaction().replace(R.id.main_content,listFragments.get(0)).commit();


        setTitle(listNavItems.get(0).getTitle());
        lvNav.setItemChecked(0, true);

        drawerLayout.closeDrawer(drawerPane);

        lvNav.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                FragmentManager fragmentManager = getSupportFragmentManager();
                fragmentManager.beginTransaction().replace(R.id.main_content, listFragments.get(position)).commit();


                setTitle(listNavItems.get(position).getTitle());
                lvNav.setItemChecked(position, true);

                drawerLayout.closeDrawer(drawerPane);
            }
        });


        actionBarDrawerToggle=new ActionBarDrawerToggle(this,drawerLayout,R.string.drawer_opened,R.string.drawer_closed){

            @Override
            public void onDrawerOpened(View drawerView) {
                invalidateOptionsMenu();
                super.onDrawerOpened(drawerView);
            }

            @Override
            public void onDrawerClosed(View drawerView) {
                invalidateOptionsMenu();
                super.onDrawerClosed(drawerView);
            }
        };

        drawerLayout.setDrawerListener(actionBarDrawerToggle);



    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        actionBarDrawerToggle.syncState();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        if(actionBarDrawerToggle.onOptionsItemSelected(item))
            return true;
        return super.onOptionsItemSelected(item);
    }
}

这是 Navlist 适配器类:

package com.subhi.tabhost;

import android.annotation.SuppressLint;
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.List;

/**
 * Created by subhi on 2/9/2016.
 */
public class NavListAdapter extends ArrayAdapter<NavItem> {

    Context context;
    int reslayout;
    List<NavItem> listNavItem;


    public NavListAdapter(Context context, int reslayout,  List<NavItem> listNavItem) {
        super(context, reslayout,  listNavItem);

        this.context=context;
        this.reslayout=reslayout;
        this.listNavItem=listNavItem;
    }


    @SuppressLint("ViewHolder") @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        View v=View.inflate(context, reslayout, null);

        TextView tvtitle= (TextView) v.findViewById(R.id.titlemain);
        TextView tvsubtitle=(TextView)v.findViewById(R.id.subtitle);
        ImageView navicon= (ImageView) v.findViewById(R.id.nav_icon);

        NavItem navItem=listNavItem.get(position);
        tvtitle.setText(navItem.getTitle());
        tvsubtitle.setText(navItem.getSubtitle());
        navicon.setImageResource(navItem.getResicon());



        return v;
    }
}

这是 NavItem 类:

package com.subhi.tabhost;

/**
 * Created by subhi on 2/9/2016.
 */
public class NavItem {

    private String title;
    private String subtitle;
    private int resicon;

    public NavItem(String title,String subtitle, int resicon ) {
        this.subtitle = subtitle;
        this.resicon = resicon;
        this.title = title;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getSubtitle() {
        return subtitle;
    }

    public void setSubtitle(String subtitle) {
        this.subtitle = subtitle;
    }

    public int getResicon() {
        return resicon;
    }

    public void setResicon(int resicon) {
        this.resicon = resicon;
    }
}

这是我在单击该项目时使用的 fragment 之一:

package com.subhi.tabhost;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

/**
 * Created by subhi on 2/9/2016.
 */
public class MyHome extends Fragment {

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

        View v=inflater.inflate(R.layout.fragment_home,container,false);

        return super.onCreateView(inflater, container, savedInstanceState);
    }
}

这是 item_nav_list.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal" android:layout_width="match_parent"
    android:padding="10dp"
    android:layout_height="match_parent">

    <ImageView
        android:layout_width="40dp"
        android:layout_height="40dp"
        android:src="@drawable/ic_launcher"
        android:id="@+id/nav_icon" />

    <LinearLayout
        android:layout_width="wrap_content"
        android:orientation="vertical"
        android:gravity="center_vertical"
        android:layout_margin="10dp"
        android:layout_height="40dp">


        <TextView
            android:layout_width="wrap_content"
            android:id="@+id/titlemain"
            android:textStyle="bold"
            android:textSize="18sp"
            android:text="Titile"
            android:textColor="#000"
            android:layout_height="wrap_content" />
        <TextView
            android:layout_width="wrap_content"
            android:text="title2"
            android:textSize="18sp"
            android:id="@+id/subtitle"
            android:textColor="#000"
            android:layout_height="wrap_content" />
    </LinearLayout>

</LinearLayout>

Answer 1

错误来自这一行

new NavListAdapter(getApplicationContext(),R.id.nav_list,listNavItems)

R.id.nav_list 的参数应该是 R.layout.nav_item，其中 nav_item.xml 是布局NavListAdapter 中的一行。