第十课，本课中您将学习到如何添加按钮到用户界面和编写点击它的代码 ，运行程序显示一个简单的文本
package com.aide.trainer.myapp;
import android.app.*;
import android.os.*;
public class MainActivity extends Activity
{
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Set main.xml as user interface layout
setContentView(R.layout.main);
}
}
在这个XML文件的“TextView”元素下面添加一个“Button”元素，也可以用UI设计器实现
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="30dp"
android:text="Hi World"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"/>
</LinearLayout>
请确认“Button”元素的属性“android:layout_width”和“android:layout_height”的值为“wrap_content”，这些都是强制性的，对每个视图都需要指定它的大小
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="30dp"
android:text="Hi World"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"/>
</LinearLayout>
设置“Button”的元素属性“android:text”为“Exit”
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="30dp"
android:text="Hi World"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Exit"/>
</LinearLayout>
为“Button”元素添加属性“android:onClick”为“onExitButtonClick”，点击按钮时这个Java方法将被调用
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="30dp"
android:text="Hi World"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Exit"
android:onClick="onExitButtonClick"/>
</LinearLayout>
我们已经在下面的MainActivity类中添加了Java方法“onExitButtonClick”
package com.aide.trainer.myapp;
import android.app.*;
import android.os.*;
import android.view.*;
public class MainActivity extends Activity
{
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Set main.xml as user interface layout
setContentView(R.layout.main);
}
/** Called when the new exit button is clicked. */
public void onExitButtonClick(View view)
{
}
}
现在在“onExitButtonClick”中调用“finish()”方法退出应用程序
package com.aide.trainer.myapp;
import android.app.*;
import android.os.*;
import android.view.*;
public class MainActivity extends Activity
{
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Set main.xml as user interface layout
setContentView(R.layout.main);
}
/** Called when the new exit button is clicked. */
public void onExitButtonClick(View view)
{
finish();
}
}
现在在“Exit”按钮下面添加第二个按钮“Drop”
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="30dp"
android:text="Hi World"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="onExitButtonClick"
android:text="Exit"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Drop"/>
</LinearLayout>
添加属性“android:onClick”到“Drop”按钮，值为“onDropButtonClick”
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="30dp"
android:text="Hi World"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="onExitButtonClick"
android:text="Exit"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Drop"
android:onClick="onDropButtonClick"/>
</LinearLayout>
我们已经添加了Java方法“onDropButtonClick”，运行应用程序并查看结果
package com.aide.trainer.myapp;
import android.app.*;
import android.os.*;
import android.view.*;
import android.view.animation.*;
public class MainActivity extends Activity
{
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Set main.xml as user interface layout
setContentView(R.layout.main);
}
/** Called when the new exit button is clicked. */
public void onExitButtonClick(View view)
{
finish();
}
/** Called when the new drop button is clicked. */
public void onDropButtonClick(View view)
{
// Do some fancy animation...
TranslateAnimation animation = new TranslateAnimation(0, 0, 0, 1000);
animation.setDuration(1000);
view.startAnimation(animation);
}
}
欢迎加入AIDE教程网官方交流群：758110864
版权声明：本文为AIDE教程网原创文章，转载请附上原文出处链接和本声明。
本文链接：https://www.aidemx.cn/1856.html
.jpg)
.jpg)
.jpg)