为什么我的吐司不工作？ （机器人）

Question

我想弄清楚为什么每当按下按钮时我的toast消息都没有弹出。无论何时按下按钮，都没有任何反应。我做了一些研究，无法弄清楚这一点。我对此很新。我是一名学生，正在努力学习如何成为一名Android开发人员。有人可以帮忙吗？

这是我的java：

package com.example.mymusicplaylist;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class NationActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_nation);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
    }

    public void nClickHandler(View v) {
        Button nBut = (Button) findViewById(R.id.nationButton);
        nBut.isClickable();
        switch (v.getId()) {
            case R.id.nationButton:
                if (nBut.isPressed()) {
                    Toast nToast = Toast.makeText(this, "Just imagine listening to the song", Toast.LENGTH_LONG);
                    nToast.show();

                }


        }
    }
}



And here is my xml:

<?xml version="1.0" encoding="utf-8"?>

<android.support.design.widget.CoordinatorLayout
    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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.example.mymusicplaylist.NationActivity"
    android:background="@drawable/nation"
    >

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_nation" />
    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:text="@string/nation"
        android:layout_gravity="center"
        android:textStyle="bold"
        android:textColor="@android:color/white"
        android:textSize="22sp"
        android:layout_weight="1"
        android:layout_marginTop="62dp"/></LinearLayout>



    <Button
        android:id="@+id/nationButton"
        android:onClick="nClickHandler"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:text="Press to Play 7 Nation Army"
        android:layout_marginBottom="16dp"
        />

</android.support.design.widget.CoordinatorLayout>

Answer 1

nClickHandler已经处理了按钮的单击事件，这意味着它已被按下。您在该方法中所需要的只是实例化toast并显示它：

public void nClickHandler(View v) {
    switch (v.getId()) {
        case R.id.nationButton:
            Toast.makeText(this, "Just imagine listening to the song", Toast.LENGTH_LONG).show();
    }
}

Answer 2

您的代码不对。重新安排你的代码如下。

public class NationActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_nation);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        Button nBut = (Button) findViewById(R.id.nationButton);
        nBut.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                nClickHandler();
            }
        });
    }

    public void nClickHandler() {
        Toast nToast = Toast.makeText(this, "Just imagine listening to the song", Toast.LENGTH_LONG);
        nToast.show();
    }
}