菜鸟学习apk-----Android studio之Button点击事件的实现方法(具体代码，实际效果，遇到问题)

activity_main.xml 布局文件

PS：==要设置为RelativeLayout，否则 UI 所有控件都在堆积在左上角！==

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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/btn_1"
        android:layout_width="80dp"
        android:layout_height="40dp"
        android:layout_marginLeft="20dp"
        android:layout_marginTop="50dp"
        android:text="click"
        android:visibility="visible" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="192dp"
        android:layout_height="27dp"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="118dp"
        tools:layout_editor_absoluteX="33dp"
        tools:layout_editor_absoluteY="113dp" />

</RelativeLayout>

对应的Java代码

package com.example.dahyzhu.apk_jni_test;

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

public class MainActivity extends AppCompatActivity {
    private TextView textView1 = null;
    private Button test_btn = null;
    String textString;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);//加载活动页面
        textView1 = (TextView)findViewById(R.id.textView1);
        textString = "我是 TextView";
        test_btn = (Button) findViewById(R.id.btn_1); //绑定Button资源
        test_btn.setOnClickListener(new MyButtonListener());//设置Button监听
    }

    // 实现OnClickListener接口
    private class MyButtonListener implements View.OnClickListener {

        @Override
        public void onClick(View view) {
            textView1.setText(textString);
        }
    }
}

实际效果如下