Android如何使用样式创建半透明窗体

本示例介绍如何使用Android系统样式和自定义样式创建半透明界面。

1. 定义清单文件（AndroidManifest.xml）

<?xml version= "1.0" encoding= "utf-8"?>

<manifest xmlns:android= "http://schemas.android.com/apk/res/android"

      package= "my.andriod.test"

      android:versionCode= "1"

      android:versionName= "1.0">

    <application android:icon= "@drawable/icon" android:label= "@string/app_name">

        <!-- 使用自定义半透明主题样式  android:theme="@style/Theme.Translucent" -->

        <activity android:name= ".TranslucentActivity"

                  android:label= "@string/app_name"               

                  android:theme= "@style/Theme.Translucent">

            <intent-filter>

                <action android:name= "android.intent.action.MAIN" />

                <category android:name= "android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

        <!-- 使用 Android系统半透明主题样式

        <activity android:name=".TranslucentActivity"

                  android:label="@string/app_name"               

                  android:theme=" @android:style/Theme.Translucent">

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

         -->

    </application>

    <uses-sdk android:minSdkVersion= "9" />

</manifest>

2. 定义字符串资源（strings.xml）

<?xml version= "1.0" encoding= "utf-8"?>

<resources>

    <string name= "hello">Hello World, TranslucentActivity!</string>

    <string name= "app_name">TranslucentActivity</string>

    <string name= "activity_translucent"> App/Activity/Translucent</string>

    <string name= "translucent_background">Example of how you can make an

            activity have a translucent background, compositing over

            whatever is behind it.</string>

</resources>

3. 定义自定义样式（values/styles.xml）

<?xml version= "1.0" encoding= "utf-8"?>

<resources>

    <!-- 继承 Android系统的半透明主题样式，并指定半透明背景的颜色、隐藏窗口标题和前景色  -->

    <style name= "Theme.Translucent" parent= "android:style/Theme.Translucent">

        <item name= "android:windowBackground"> @drawable/translucent_background</item>

        <item name= "android:windowNoTitle">true</item>

        <item name= "android:colorForeground">#fff</item>

    </style>

</resources>

4. 定义半透明颜色（colors.xml）

<?xml version= "1.0" encoding= "utf-8"?>

<resources>

    <drawable name= "translucent_background">#e0000000</drawable>

</resources>

5. 定义布局文件（translucent_background.xml）

<?xml version= "1.0" encoding= "utf-8"?>

<!-- 在Activity中显示文本 -->

<TextView xmlns:android= "http://schemas.android.com/apk/res/android" android:id= "@+id/text"

    android:layout_width= "match_parent" android:layout_height= "match_parent"

    android:gravity= "center_vertical|center_horizontal"

    android:text= "@string/translucent_background"/>

6. 创建Activity（TranslucentActivity.java）

package my.andriod.test;

 

import android.app.Activity;

import android.os.Bundle;

 

publicclass TranslucentActivity extends Activity {

    /** Activity首次创建时，调用这个方法 */

    @Override

    publicvoid onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        //填充布局

        setContentView(R.layout. translucent_background);

    }

}