Android App开发——添加APP启动界面

1.在创建的项目里面添加一个Empty Activit，我这里命名为BootScreen。

2.把启动时要显示的图像拖到res的mipmap目录下。

3.在BootScreen.java里面添加代码

public class BootScreen extends AppCompatActivity
{
    ProgressBar splashProgress;
    int SPLASH_TIME = 5000;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        //去掉导航栏
        getSupportActionBar().hide();
        setContentView(R.layout.activity_boot_screen);


        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            //透明状态栏
            getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            //透明导航栏
            getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
        }

        //进度条
        splashProgress = findViewById(R.id.splashProgress);
        playProgress();

        //启动和切换界面
        new Handler(getMainLooper()).postDelayed(new Runnable()
        {
            @Override
            public void run() {
                //切换到主界面
                Intent mySuperIntent = new Intent(BootScreen.this, MainActivity.class);
                startActivity(mySuperIntent);

                finish();

            }
        }, SPLASH_TIME);
    }

    private void playProgress() {
        ObjectAnimator.ofInt(splashProgress, "progress", 100)
                .setDuration(3000)
                .start();
    }
}

4.activity_boot_screen.xml布局文件

<?xml version="1.0" encoding="utf-8"?>
<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:background="@drawable/gard_bg"
    tools:context=".BootScreen">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:gravity="center"
        android:orientation="vertical">

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="180dp"
            android:paddingBottom="40dp"
            android:src="@mipmap/openapp" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Welcome You!"
            android:textColor="@android:color/white"
            style="@style/TextAppearance.MaterialComponents.Headline6"
            android:textStyle="bold" />

        <ProgressBar
            android:id="@+id/splashProgress"
            style="?android:attr/progressBarStyleHorizontal"
            android:layout_width="150dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="50dp" />

    </LinearLayout>

</RelativeLayout>

5.AndroidManifest.xml里面的启动顺序
5.1更改前

5.2 更改后

6.运行效果如下，这样一个简易的启动界面就完成了。