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1、按钮点击事件
当点击按钮后出现效果或结果就是点击事件,首先先看效果图,点击后吐司在屏幕上、
代码如下:
xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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/btn"
android:layout_width="100dp"
android:layout_height="40dp"
android:text="点击"
/>
</android.support.constraint.ConstraintLayout>
Java:
package com.example.zy.mystudy;
import android.app.Activity;
import android.content.DialogInterface;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity extends Activity {
private Button button;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button)findViewById(R.id.btn);
button.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View view) {
Toast.makeText(MainActivity.this, "匿名内部类方式", Toast.LENGTH_SHORT).show();
}
}
);
}
}
这样是通过了匿名内部类方式实现了点击按钮吐司
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同时,你也可以这样写:
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:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
android:orientation="vertical"
>
<Button
android:id="@+id/btn1"
android:layout_width="100dp"
android:layout_height="40dp"
android:text="点击1"
/>
<Button
android:id="@+id/btn2"
android:layout_width="100dp"
android:layout_height="40dp"
android:text="点击2"
/>
</LinearLayout>
Java:
package com.example.zy.mystudy;
import android.app.Activity;
import android.content.DialogInterface;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity extends Activity {
private Button button1;
private Button button2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button1 = (Button)findViewById(R.id.btn1);
button1.setOnClickListener(onClickListener);
button2 = (Button)findViewById(R.id.btn2);
button2.setOnClickListener(onClickListener);
}
View.OnClickListener onClickListener = new View.OnClickListener(){
@Override
public void onClick(View view) {
switch (view.getId()){
case R.id.btn1:
Toast.makeText(MainActivity.this,"点击事件1",Toast.LENGTH_SHORT).show();
break;
case R.id.btn2:
Toast.makeText(MainActivity.this,"点击事件2",Toast.LENGTH_SHORT).show();
break;
}
}
};
}
这样写可以避免在创建时多次占用资源