Question

我创建了一个简单的Android应用程序来显示吐司，但每当我尝试单击该按钮时，应用程序崩溃

我的xml代码

<?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:layout_width="match_parent"
                android:layout_height="match_parent"
                app:layout_behavior="@string/appbar_scrolling_view_behavior"
                tools:context="com.example.nsk.demoapp.add_layout"
                tools:showIn="@layout/add_layout"
                android:orientation="vertical">

                <RelativeLayout
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:layout_weight="1">

                    <TextView
                        android:layout_width="match_parent"
                        android:layout_height="match_parent"
                        android:text="Hi there"
                        android:textSize="60dp"
                        android:gravity="center" />


                </RelativeLayout>

                <RelativeLayout
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:layout_weight="1">

                    <Button
                        android:id="@+id/bt1"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:text="Confirm"
                        android:gravity="center"
                        android:onClick="toastNote"/>
                </RelativeLayout>

            </LinearLayout>

我的java代码

package com.example.nsk.demoapp;

            import android.os.Bundle;
            import android.support.design.widget.FloatingActionButton;
            import android.support.design.widget.Snackbar;
            import android.support.v7.app.AppCompatActivity;
            import android.support.v7.widget.Toolbar;
            import android.util.Log;
            import android.view.View;
            import android.widget.Toast;

            public class add_layout extends AppCompatActivity {

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

                    FloatingActionButton fab = (FloatingActionButton) 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();
                        }
                    });
                    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
                }

                public void toastNote(View v)
                {
                    Toast.makeText(this, "Hi there", Toast.LENGTH_LONG).show();
                }

            }

Android监视器错误

/AndroidRuntime: FATAL EXCEPTION: main
                                                                       Process: com.example.nsk.demoapp, PID: 3531
                                                                       java.lang.IllegalStateException: Could not find method toastNote(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatButton with id 'bt1'
                                                                           at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:327)
                                                                           at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:284)
                                                                           at android.view.View.performClick(View.java:5637)
                                                                           at android.view.View$PerformClick.run(View.java:22429)
                                                                           at android.os.Handler.handleCallback(Handler.java:751)
                                                                           at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                           at android.os.Looper.loop(Looper.java:154)
                                                                           at android.app.ActivityThread.main(ActivityThread.java:6119)
                                                                           at java.lang.reflect.Method.invoke(Native Method)
                                                                           at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
                                                                           at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

Answer 1

使用getApplicationContext()代替this。所以你的吐司应该是这样的：

Toast.makeText(getApplicationContext(), "Hi there", Toast.LENGTH_LONG).show();

而不是：

Toast.makeText(this, "Hi there", Toast.LENGTH_LONG).show();

希望这有帮助！

Answer 2

进行以下更改

public void toastNote(View bt1)<----- bt1 is important as u define onClick in xml
            {
                Toast.makeText(this, "Hi there", Toast.LENGTH_LONG).show();
            }

Answer 3

您可以使用YourClassName.this

Toast.makeText(YourClassName.this, "TEXT", Toast.LENGTH_SHORT).show();

或getApplicationContext()

Toast.makeText(getApplicationContext(), "TEXT", Toast.LENGTH_SHORT).show();

应用程序使用按钮在创建吐司时崩溃

3 个答案: