Question

button按钮的点击事件怎么写

Answer 1

xml文件代码如下：

<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button1" />

<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button2" />

四种方法分述如下：
匿名内部类：

public class TestButtonActivity extends Activity {

Button btn1, btn2;
Toast tst;

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

btn1 = (Button) findViewById(R.id.button1);
btn2 = (Button) findViewById(R.id.button2);

btn1.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Toast tst = Toast.makeText(TestButtonActivity.this, "111111111", Toast.LENGTH_SHORT);
tst.show();

}
});

btn2.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Toast tst = Toast.makeText(TestButtonActivity.this, "222222222", Toast.LENGTH_SHORT);
tst.show();
}
});
}
}

自定义单击事件监听类：

public class TestButtonActivity extends Activity {

Button btn1, btn2;
Toast tst;

class MyClickListener implements OnClickListener {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.button1:
tst = Toast.makeText(TestButtonActivity.this, "111111111", Toast.LENGTH_SHORT);
tst.show();
break;
case R.id.button2:
tst = Toast.makeText(TestButtonActivity.this, "222222222", Toast.LENGTH_SHORT);
tst.show();
break;
default:
break;
}
}
}

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

btn1 = (Button) findViewById(R.id.button1);
btn2 = (Button) findViewById(R.id.button2);

btn1.setOnClickListener(new MyClickListener());
btn2.setOnClickListener(new MyClickListener());
}
}

Activity继承View.OnClickListener，由Activity实现OnClick(View view)方法，在OnClick(View view)方法中用switch-case对不同id代表的button进行相应的处理

public class TestButtonActivity extends Activity implements OnClickListener {

Button btn1, btn2;
Toast tst;

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

btn1 = (Button) findViewById(R.id.button1);
btn2 = (Button) findViewById(R.id.button2);

btn1.setOnClickListener(this);
btn2.setOnClickListener(this);
}

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.button1:
tst = Toast.makeText(this, "111111111", Toast.LENGTH_SHORT);
tst.show();
break;
case R.id.button2:
tst = Toast.makeText(this, "222222222", Toast.LENGTH_SHORT);
tst.show();
break;
default:
break;
}
}
}

最后一种是我今天看到的一种写法，在XML文件中“显示指定按钮的onClick属性，这样点击按钮时会利用反射的方式调用对应Activity中的click()方法”

<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="onClick"
android:text="Button1" />

<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="onClick"
android:text="Button2" />

这里在输完android:的时候按下 Alt+/ 会有 onClick 属性的提示， 但输入到 android:onClick=“ 的地方按下 Alt+/ 并没有提示 onClick 选项，让我突然觉得这里好像有点问题。

public class TestButtonActivity extends Activity {

Button btn1, btn2;
Toast tst;

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

// 注意 这里没有 @Override 标签
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.button1:
tst = Toast.makeText(this, "111111111", Toast.LENGTH_SHORT);
tst.show();
break;
case R.id.button2:
tst = Toast.makeText(this, "222222222", Toast.LENGTH_SHORT);
tst.show();
break;
default:
break;
}
}
}

这种写法整个代码中都不用声明button就可以实现button的单击事件。