Android应用Toolbar菜单项点击Toast不生效问题求助

问题描述 #

开发Android Studio Java项目时，为Toolbar添加了菜单项，但运行后点击菜单项，Toast无法正常显示。

相关代码 #

activity_main.xml #

<?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/main"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#000"
    tools:context=".MainActivity">
    <androidx.appcompat.widget.Toolbar
        android:id="@+id/main_toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="@color/colorPrimary"
        android:elevation="4dp"
        app:title="@string/app_name"
        app:menu="@menu/main_menu"
        android:theme="@style/Theme.AppCompat.DayNight"
        />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:id="@+id/firstRowLinearLayout"
        >

        <Button
            android:id="@+id/btn1"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="0.5"
            android:lines="2"
            android:layout_margin="5dp"

            >

        </Button>
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="0.5"
            android:lines="2"
            android:layout_margin="5dp"

            >

        </Button>

    </LinearLayout>


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:id="@+id/secondRowLinearLayout"
        >

        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="0.5"
            android:lines="2"
            android:layout_margin="5dp"

            >

        </Button>
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="0.5"
            android:lines="2"
            android:layout_margin="5dp"

            >

        </Button>

    </LinearLayout>


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:id="@+id/thirdRowLinearLayout"
        >

        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="0.5"
            android:lines="2"
            android:layout_margin="5dp"

            >

        </Button>
        <Button
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="0.5"
            android:lines="2"
            android:layout_margin="5dp"

            >

        </Button>

    </LinearLayout>


    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="@string/question_text"
        android:id="@+id/txtQuestionNumber"
        android:layout_gravity="center_horizontal"
        android:layout_marginBottom="@dimen/margin_value"
        android:textColor="#fff"
        >

    </TextView>

    <ImageView
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:layout_gravity="center"
        android:id="@+id/imgAnimal"
        android:layout_marginBottom="@dimen/margin_value"
        android:layout_marginLeft="@dimen/margin_value_left"
        android:layout_marginRight="@dimen/margin_value_right"
        android:scaleType="fitCenter"
        >

    </ImageView>

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/txtAnswer"
        android:id="@+id/txtAnswer"
        android:layout_gravity="center_horizontal|bottom"
        android:gravity="center_horizontal"
        android:layout_marginBottom="@dimen/margin_value"
        android:textStyle="italic"
        android:textSize="@dimen/answer_font_size"
        android:textColor="#fff"
        >

    </TextView>


</LinearLayout>

main_menu.xml #

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <item android:id="@+id/new_settings"
        android:icon="@drawable/baseline_build_24"
        android:title="settings"
        app:showAsAction="ifRoom"
        />
</menu>

MainActivity.java #

package com.example.dontknow;

import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.Toast;

import androidx.activity.EdgeToEdge;
import androidx.annotation.NonNull;
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;

public class MainActivity extends AppCompatActivity {

//    @Override
//    public boolean onCreateOptionsMenu(Menu menu) {
//        MenuInflater inflater = getMenuInflater();
//        inflater.inflate(R.menu.main_menu, menu);
//        return true;
//    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        new MenuInflater(this).inflate(R.menu.main_menu, menu);
        return super.onCreateOptionsMenu(menu);
    }



    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
       int id = item.getItemId();
       if (id==R.id.new_settings){
           Toast.makeText(this, "clicked dfsssssssssssssssss ewrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr", Toast.LENGTH_SHORT).show();
       }else {
           Toast.makeText(this, "Nothing has happend", Toast.LENGTH_SHORT).show();
       }

        return super.onOptionsItemSelected(item);

    }







    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Toolbar toolbar = findViewById(R.id.main_toolbar);
        setSupportActionBar(toolbar);



    //    ActionBar actionBar = getSupportActionBar();
        if(getSupportActionBar()!=null){
            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        }




        EdgeToEdge.enable(this);
        setContentView(R.layout.activity_main);












        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main), (v, insets) -> {
            Insets systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars());
            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom);
            return insets;
        });
    }
}

问题分析及修复方案 #

1. 核心问题：Toolbar初始化顺序错误 #

在onCreate方法中，你先调用了findViewById(R.id.main_toolbar)，然后才调用setContentView(R.layout.activity_main)。此时布局还未加载，toolbar对象为null，导致setSupportActionBar(toolbar)无效，Toolbar的点击事件无法被正确处理。

2. 次要问题：菜单重复加载 #

你同时在Toolbar的xml中设置了app:menu="@menu/main_menu"，又在onCreateOptionsMenu中再次inflate了同一个菜单，可能导致菜单事件冲突。

3. 次要问题：菜单点击事件返回值错误 #

onOptionsItemSelected中处理完自定义菜单项后，返回了super.onOptionsItemSelected(item)，这会让系统继续处理该事件，可能覆盖你的Toast逻辑。

修复后的MainActivity.java代码 #

package com.example.dontknow;

import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;

import androidx.activity.EdgeToEdge;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EdgeToEdge.enable(this);
        // 先加载布局，再获取Toolbar
        setContentView(R.layout.activity_main);
        
        Toolbar toolbar = findViewById(R.id.main_toolbar);
        setSupportActionBar(toolbar);

        if(getSupportActionBar()!=null){
            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        }

        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main), (v, insets) -> {
            Insets systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars());
            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom);
            return insets;
        });
    }

    // 移除重复的菜单加载，保留其中一种方式即可，这里选择通过代码加载（也可以保留xml的app:menu并删除此方法）
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main_menu, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
        int id = item.getItemId();
        if (id == R.id.new_settings) {
            Toast.makeText(this, "设置项已点击", Toast.LENGTH_SHORT).show();
            // 处理完自定义事件后返回true，告知系统已处理
            return true;
        } else if (id == android.R.id.home) {
            // 处理返回按钮事件（可选）
            finish();
            return true;
        }
        // 其他事件交给系统处理
        return super.onOptionsItemSelected(item);
    }
}

额外优化建议 #

• 把Toast中的超长文本改为简洁提示，避免显示异常
• 如果选择保留xml中的app:menu，可以删除onCreateOptionsMenu方法，减少冗余代码

内容的提问来源于stack exchange，提问作者Arafat Hossain