我正在努力通过ActionBarDrawerToggle将工具栏实现到我的App中。 我所做的是实现了NavigationActivity，并将Activites添加到了我的项目中，我也将其实现为NavigationActivities，但后来对其进行了编辑以适合情况。
解释此问题的最好方法是向您显示我认为的代码和错误。
我所拥有的基本上是未涉及的导航活动：
package edmt.dev.androidgridlayout;
import android.content.Intent;
import android.nfc.Tag;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.design.widget.TabLayout;
import android.util.Log;
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 java.util.ArrayList;
public class NavigationActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_navigation);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = 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 = findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
}
@Override
public void onBackPressed() {
DrawerLayout drawer = 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.navigation, 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();
switch (id) {
case R.id.drawerHeros:
Intent intentHeros = new Intent(this, heroActivity.class);
startActivity(intentHeros);
break;
case R.id.drawerSpells:
Intent intentSpells = new Intent (this, spellActivity.class);
startActivity(intentSpells);
break;
case R.id.drawerItems:
Intent intentItems = new Intent (this, itemActivity.class);
startActivity(intentItems);
break;
case R.id.drawerImprovements:
Intent intentImpr = new Intent (this, improvementActivity.class);
startActivity(intentImpr);
break;
case R.id.drawerCreeps:
Intent intentCreeps = new Intent (this, creepActivity.class);
startActivity(intentCreeps);
break;
}
DrawerLayout drawer = findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
比我向您展示我实现的一项活动（heroActivity）：
public class heroActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
private SwitchCompat switchHeros;
List<Heros> listHeros;
AppCompatSpinner spinnerHeros;
private xCustomSpinnerAdapater spinnerAdapter;
private String[] spinnerNames = {"All", "Black", "Blue", "Green", "Red"};
private int[] spinnerImages = {R.drawable.artifact, R.drawable.black, R.drawable.blue, R.drawable.green, R.drawable.red};
private Toast spinnerToast;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_hero);
Toolbar toolbar = (findViewById(R.id.toolbar)); // this is fine since there is only app_bar_navigation */
setSupportActionBar(toolbar);
FloatingActionButton fab = findViewById(R.id.fab); // that is the button for e-mail -> is fine -> app_bar_navigation */
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 = findViewById(R.id.drawer_layout_hero);
final ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view_hero);
navigationView.setNavigationItemSelectedListener(this);
/* Make ----------- Content_Hero ----------------*/
setContentView(R.layout.content_hero);
spinnerHeros = findViewById(R.id.heroSpinner);
switchHeros = findViewById(R.id.switchHeros);
/*Spinner: */
spinnerAdapter = new xCustomSpinnerAdapater(this, spinnerNames,spinnerImages);
spinnerHeros.setAdapter(spinnerAdapter);
spinnerHeros.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
if(spinnerToast != null){
spinnerToast.cancel();
}
spinnerToast.makeText(getApplicationContext(),"Category: " + spinnerNames[i] + " is shown.",Toast.LENGTH_SHORT).show();
getHeroList(spinnerHeros.getSelectedItem().toString(),switchHeros.isChecked());
RecyclerView rvHeros = findViewById(R.id.recycler_heros);
RecyclerViewAdapterHero newAdapterHeros = new RecyclerViewAdapterHero(heroActivity.this, listHeros);
rvHeros.setLayoutManager(new GridLayoutManager(heroActivity.this,3));
rvHeros.setAdapter(newAdapterHeros);
}
@Override
public void onNothingSelected(AdapterView<?> adapterView) {
getHeroList(spinnerHeros.getSelectedItem().toString(),switchHeros.isChecked());
RecyclerView rvHeros = findViewById(R.id.recycler_heros);
RecyclerViewAdapterHero newAdapterHeros = new RecyclerViewAdapterHero(heroActivity.this, listHeros);
rvHeros.setLayoutManager(new GridLayoutManager(heroActivity.this,3));
rvHeros.setAdapter(newAdapterHeros);
}
});
// Load everything ones.
getHeroList(spinnerHeros.getSelectedItem().toString(),switchHeros.isChecked());
RecyclerView rvHeros = findViewById(R.id.recycler_heros);
RecyclerViewAdapterHero newAdapterHeros = new RecyclerViewAdapterHero(heroActivity.this, listHeros);
rvHeros.setLayoutManager(new GridLayoutManager(heroActivity.this,3));
rvHeros.setAdapter(newAdapterHeros);
/*--- Switch ---*/
switchHeros.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
getHeroList(spinnerHeros.getSelectedItem().toString(),switchHeros.isChecked());
RecyclerView rvHeros = findViewById(R.id.recycler_heros);
RecyclerViewAdapterHero newAdapterHeros = new RecyclerViewAdapterHero(heroActivity.this, listHeros);
rvHeros.setLayoutManager(new GridLayoutManager(heroActivity.this,3));
rvHeros.setAdapter(newAdapterHeros);
}
});
}
private void getHeroList(String chosenCategory, Boolean switchStatus) {
listHeros = new ArrayList<>();
switch(chosenCategory){
case "All":
if(switchStatus != true){
listHeros.add(new Heros(R.drawable.bloodseeker,"Bloodseeker", "7", "0", "6", "<b>Blood Bath:</b> <br />Fully heal Bloodseeker after a unit blocking it dies.", "black", R.drawable.blood_rage, "Blood rage", "Silence a unit this round. Give that unit +4 Attack this round.", R.drawable.artifact_big, "", "This is boosters hero", "My homeland is a place of beauty and grace... of crystal streams and bountiful harvest... it is undeniably a gift from the gods. But when such a gift is bestowed upon you, it is right to give thanks... and there is only one way to show gratitude to the Flayed Twins. With blood.<br />— Strygwyr, the Bloodseeker", "Rare"));
[..many more..]
}
}
@Override
public void onBackPressed() {
setContentView(R.layout.activity_hero);
DrawerLayout drawer = findViewById(R.id.drawer_layout_hero);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
setContentView(R.layout.activity_hero);
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.navigation, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
setContentView(R.layout.activity_hero);
// 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) {
setContentView(R.layout.activity_hero);
// Handle navigation view item clicks here.
int id = item.getItemId();
switch (id) {
case R.id.drawerHeros:
Intent intentHeros = new Intent(this, heroActivity.class);
startActivity(intentHeros);
break;
case R.id.drawerSpells:
Intent intentSpells = new Intent (this, spellActivity.class);
startActivity(intentSpells);
break;
case R.id.drawerItems:
Intent intentItems = new Intent (this, itemActivity.class);
startActivity(intentItems);
break;
case R.id.drawerImprovements:
Intent intentImpr = new Intent (this, improvementActivity.class);
startActivity(intentImpr);
break;
case R.id.drawerCreeps:
Intent intentCreeps = new Intent (this, creepActivity.class);
startActivity(intentCreeps);
break;
}
DrawerLayout drawer = findViewById(R.id.drawer_layout_hero);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
我认为RecyclerView不会为帖子增加任何价值，所以我将其排除在外。
现在看看我的xml文件：
<?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_hero"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:openDrawer="start">
<include
layout="@layout/app_bar_navigation"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<include layout="@layout/content_hero" />
<android.support.design.widget.NavigationView
android:id="@+id/nav_view_hero"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
app:headerLayout="@layout/nav_header_navigation"
app:menu="@menu/activity_navigation_drawer" />
</android.support.v4.widget.DrawerLayout>
heroActivity基本上使用了我第一个实现的NavigationView。因此，我可以编辑一次我的导航工具（如NavigationDrawer），然后更改所有活动。
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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/constraintLayoutHeros"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context=".heroActivity"
android:padding="8dp"
android:background="@drawable/background"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<android.support.design.widget.AppBarLayout
android:id="@+id/heroAppbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fitsSystemWindows="true"
android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
>
<android.support.v7.widget.Toolbar
android:id="@+id/heroToolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="@style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<TextView
android:layout_width="wrap_content"
android:layout_height="30dp"
android:layout_marginTop="15dp"
android:layout_marginBottom="5dp"
android:text="Heros in Artifact"
android:textSize="22sp"
android:textStyle="bold"
android:layout_gravity="center"
android:textColor="#fff"
/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="20dp"
android:textColor="#fff"
android:textSize="15sp"
android:text="Here will be the introduction to the hero page.."
/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:weightSum="2"
android:background="#fff"
>
<android.support.v7.widget.AppCompatSpinner
android:id="@+id/heroSpinner"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:layout_marginStart="10dp"
android:layout_marginEnd="10dp"
android:dropDownWidth="match_parent"
android:spinnerMode="dropdown"
android:popupBackground="#fff"
android:background="#8A8A8A"
/>
<android.support.v7.widget.SwitchCompat
android:id="@+id/switchHeros"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:layout_marginStart="20dp"
android:layout_marginEnd="20dp"
android:layout_gravity="center"
android:background="#8A8A8A"
android:checked="false"
/>
</LinearLayout>
</LinearLayout>
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_heros"
android:layout_width="match_parent"
android:layout_height="match_parent">
</android.support.v7.widget.RecyclerView>
</LinearLayout>
这是contentHero.xml文件，正在我的heroActivity中进行编辑。基本上，我想在此视图中实现工具栏。 如您所见，我试图在这种情况下实现另一个工具栏，但是当我尝试将heroActivity中的heroToolbar设置为setSupportActionBar时，就会出现nullPointer错误。
是否可以通过使用初始的NavigationView或正确实现工具栏来实现此目的？
致以最诚挚的问候 CG