事件:
一般你点击一个按钮,触摸一下屏幕,都是事件。点击,键盘按键按下,鼠标滑过等等。
先看一个OnClick 安卓中的Button的点击事件:
activity_main.xml:android:onClick="Hello" 定义了一个Onclick的点击事件,点击之后,触发MainActivity中的Hello函数。
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:text="Button"
android:onClick="Hello" />
</RelativeLayout>
MainActivity.java:
package com.example.test.com;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.widget.Toast;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
}
/**
* 点击事件
* @param v
*/
public void Hello(View v) {
Toast.makeText(getBaseContext(), "YES!", Toast.LENGTH_SHORT).show(); //一个弹出框
}
}
效果图:
换一种方法:
上面这种方法有点笨拙,每次对一个按钮需要定义一些事件的时候,都需要去更改xml布局文件,这样做比较麻烦也不优雅。我们可以再Java代码端,给按钮添加事件监听。
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:text="Button"
/>
</RelativeLayout>
MainActivity.java:
package com.example.test.com;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
//获取Button对象
Button button1 = (Button) findViewById(R.id.button1);
//添加点击事件的监听
button1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(getBaseContext(), "YES!", Toast.LENGTH_SHORT).show();
}
});
}
}
OnTouch 点击拖动事件:
package com.example.test.com;
import android.app.Activity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.Window;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
//获取Button对象
Button button1 = (Button) findViewById(R.id.button1);
//Button OnTouch事件
button1.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
int iAction = event.getAction();
if (iAction == MotionEvent.ACTION_MOVE) {
Toast.makeText(getBaseContext(), "YES!", Toast.LENGTH_SHORT).show();
}
return false;
}
});
}
}
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:text="Button"
/>
</RelativeLayout>
安卓还有很多很多事件,这些事件具体的都需要自己在实战中去操作和积累经验。用法什么的 其实就和上面的一样的。