Android启动过程中背景图片显示

大部分Android App启动过程中，都会设置一个背景图片，直到App加载成功，图片消失。因此，这也是做Android App的基本技能之一。这个过程实现起来并不难。

总共需要以下内容：2个Activity，一张背景图，2个xml配置文件，String.xml，AndroidManifest写入配置信息。

1 准备一张背景图图片,命名为load,自己选择图片格式。放在drawable目录下

2  创建Load页面 LoadActivity.java及相关布局文件load.xml

LoadActivity.java

package com.timothy.load;import android.app.Activity;import android.os.Bundle;import android.content.Intent;import android.graphics.PixelFormat;import android.os.Handler;import android.view.WindowManager;public class LoadActivity extends Activity {    //time for picture display    private static final int LOAD_DISPLAY_TIME = 1500;        /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);                getWindow().setFormat(PixelFormat.RGBA_8888);        getWindow().addFlags(WindowManager.LayoutParams.FLAG_DITHER);        setContentView(R.layout.load);                new Handler().postDelayed(new Runnable() {            public void run() {                //Go to main activity, and finish load activity                Intent mainIntent = new Intent(LoadActivity.this, MainActivity.class);                LoadActivity.this.startActivity(mainIntent);                LoadActivity.this.finish();            }        }, LOAD_DISPLAY_TIME);     }}

load.xml

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:orientation="vertical"     android:gravity="center|center"     android:layout_width="fill_parent"     android:layout_height="fill_parent"     android:background="@drawable/load"> </LinearLayout>

3  创建主页面 MainActivity.java及相关布局文件main.xml 

MainActivity.java

package com.timothy.load;import android.app.Activity;import android.os.Bundle;public class MainActivity extends Activity {    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);    }}

main.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    ><TextView      android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="@string/hello"    /></LinearLayout>

4 配置strings.xml

<?xml version="1.0" encoding="utf-8"?><resources>    <string name="hello">Hello, this is a demo to picture before app start</string>    <string name="app_name">LoadPictureDemo</string>        <style name="MyTheme.NoTitleBar.CustomBackground" parent="@android:Theme.Black">          <item name="android:windowBackground">@drawable/load</item>          <item name="android:windowNoTitle">true</item>          <item name="android:windowFullscreen">true</item>          <item name="android:windowContentOverlay">@null</item>  </style></resources>

5 配置AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"      package="com.timothy.load"      android:versionCode="1"      android:versionName="1.0">    <uses-sdk android:minSdkVersion="8" />    <application android:icon="@drawable/icon" android:label="@string/app_name">                <activity android:name=".LoadActivity"                  android:configChanges="orientation|keyboardHidden"                  android:theme="@style/MyTheme.NoTitleBar.CustomBackground">            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>                <activity android:name=".MainActivity">        </activity>    </application></manifest>

6 OK, 编译运行

启动过程中：

完成启动：