AndroidStudio制作欢迎界面与应用图标

<?xml version="1.0" encoding="utf-8"?>
<!--添加一张欢迎界面的背景-->
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width = "match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/launch_bg">
    <!--显示版本号-->
    <TextView
        android:id="@+id/tv_version"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textColor="@android:color/white"
        android:textSize="14sp"
        android:layout_centerInParent="true"/>
</RelativeLayout>

package cn.edu.gdmec.android.androidstudiodemo;

import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;
import java.util.Timer;
import java.util.TimerTask;

public class SplashActivity extends AppCompatActivity{
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_splash);
        //设置此界面为
        // 竖屏
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
        init();
    }

    private void init() {
        TextView tv_version = findViewById(R.id.tv_version);
        try {
            PackageInfo packageInfo = getPackageManager().getPackageInfo(getPackageName(),0);
            tv_version.setText("version:"+packageInfo.versionName);
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
            tv_version.setText("version");
        }
        //利用timer让此界面延迟3秒后跳转，timer有一个线程，该线程不断执行task
        Timer timer = new Timer();
        TimerTask timerTask = new TimerTask() {
            @Override
            public void run() {
                //发送intent实现页面跳转，第一个参数为当前页面的context，第二个参数为要跳转的主页
                Intent intent = new Intent(SplashActivity.this,MainActivity.class);
                startActivity(intent);
                //跳转后关闭当前欢迎页面
                SplashActivity.this.finish();
            }
        };
        //调度执行timerTask，第二个参数传入延迟时间（毫秒）
        timer.schedule(timerTask,3000);
    }
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="cn.edu.gdmec.android.androidstudiodemo">
    <!--原为android:theme="@style/AppTheme"-->
    <!--去除ActionBar标题栏-->
    <!--添加应用图标，app_icon-->
    <application
        android:allowBackup="true"
        android:icon="@drawable/app_icon"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.AppCompat.NoActionBar">
        <activity android:name=".SplashActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <!--添加实现类-->
        <activity android:name=".MainActivity"></activity>
    </application>
</manifest>