如何解决OnClick方法单击问题，不起作用

Question

我已将onclick定义为clickFunction。我是编码和Android Studio的新手。

为什么下面的代码不起作用？

package com.example.learnerapp;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;
import android.view.View;

public class MainActivity extends AppCompatActivity {
    public void clickFunction(View view){
        Log.i( tag: "info", msg: "booyaa");
    }


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

Answer 1

JAVA FILE

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

public class MainTestActivity extends Activity {
    Context context;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        context = this;
        setContentView(R.layout.activity_main);
    }

    public void clickFunction(View view){
        Log.i("info","booyaa");
        Toast.makeText(context, "Button Clicked", Toast.LENGTH_SHORT).show();
    }
}

XML FILE

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="28dp"
        android:onClick="clickFunction"
        android:text="Sign In"/>

</androidx.constraintlayout.widget.ConstraintLayout>

我认为您忘记了在[[Button属性中以上述XML编写android:onClick="clickFunction"。

在此处检查解决方案：Click me

更多详细信息：Click me

Answer 2

我认为最好遵循一个按钮示例，因为当您单击按钮时，它将执行某些操作。

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import org.w3c.dom.Text;
public class yourActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.your_activity);
    Button yourbutton=(Button)findViewById(R.id.yourbutton);
    yourbutton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            //do something here
         } 
    });
}

并将其添加到yourActivity.xml
 <Button
        android:id="@+id/yourbutton"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:text="what you want to do?"            
 />