阿卜杜拉的回答很好。但我想在我的回答中补充一些细节。

实现启动画面

正确执行闪屏的方法与你想象的略有不同。您所看到的splash视图必须立即准备好，甚至在您可以在splash活动中膨胀布局文件之前。

所以你不会使用布局文件。相反，指定启动画面的背景作为活动的主题背景。为此，首先在res/drawable中创建一个XML drawable。

background_splash.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- Background Color -->
    <item
        android:drawable="@color/gray"/>

    <!-- Logo -->
    <item>
        <bitmap
            android:gravity="center"
            android:src="@mipmap/ic_launcher"/>
    </item>

</layer-list>

它只是一个层列表与标志在中心背景色与它。

现在打开styles.xml并添加这个样式

<style name="SplashTheme" parent="Theme.AppCompat.NoActionBar">
        <item name="android:windowBackground">@drawable/background_splash</item>
</style>

这个主题将没有动作栏和我们刚才创建的背景。

在manifest中，你需要将SplashTheme设置为你想要用作splash的活动。

<activity
android:name=".SplashActivity"
android:theme="@style/SplashTheme">
<intent-filter>
    <action android:name="android.intent.action.MAIN" />

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

然后在你的活动代码中，使用意图引导用户进入特定的屏幕。

public class SplashActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Intent intent = new Intent(this, MainActivity.class);
        startActivity(intent);
        finish();
    }
}

这才是正确的做法。我用这些参考来回答。

https://material.google.com/patterns/launch-screens.html https://www.bignerdranch.com/blog/splash-screens-the-right-way/ 感谢这些人把我推向正确的方向。我想要帮助其他人，因为公认的答案并不是做启动画面的建议。

另一种方法是使用CountDownTimer实现

@Override
public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.splashscreen);

 new CountDownTimer(5000, 1000) { //5 seconds
      public void onTick(long millisUntilFinished) {
          mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);
      }

     public void onFinish() {
          startActivity(new Intent(SplashActivity.this, MainActivity.class));
          finish();
     }

  }.start();
}

public class SplashActivity extends Activity {

  Context ctx;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      ctx = this;
      setContentView(R.layout.activity_splash);

      Thread thread = new Thread(){
          public void run(){
              try {
                  sleep(3000);
              } catch (InterruptedException e) {
                  e.printStackTrace();
              }

              Intent in = new Intent(ctx,MainActivity.class);
              startActivity(in);
              finish();
          }
      };
      thread.start();
  }
}

启动画面示例:

public class MainActivity extends Activity {
    private ImageView splashImageView;
    boolean splashloading = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        splashImageView = new ImageView(this);
        splashImageView.setScaleType(ScaleType.FIT_XY);
        splashImageView.setImageResource(R.drawable.ic_launcher);
        setContentView(splashImageView);
        splashloading = true;
        Handler h = new Handler();
        h.postDelayed(new Runnable() {
            public void run() {
                splashloading = false;
                setContentView(R.layout.activity_main);
            }

        }, 3000);

    }

}

在Android中，启动画面是一个有点不可用的对象:为了隐藏主活动启动的延迟，它不能尽快加载。使用它有两个原因:广告和网络运营。

实现为对话框使跳跃没有延迟从启动画面到主UI的活动。

public class SplashDialog extends Dialog {
    ImageView splashscreen;
    SplashLoader loader;
    int splashTime = 4000;

    public SplashDialog(Context context, int theme) {
        super(context, theme);
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_splash);
        setCancelable(false);

        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                cancel();
            }
        }, splashTime);

    }
}

布局:

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

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@color/white">

    <ImageView
        android:id="@+id/splashscreen"
        android:layout_width="190dp"
        android:layout_height="190dp"
        android:background="@drawable/whistle"
        android:layout_centerInParent="true" />

</RelativeLayout>

并开始:

public class MyActivity extends ActionBarActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (getIntent().getCategories() != null &&  getIntent().getCategories().contains("android.intent.category.LAUNCHER")) {
            showSplashScreen();
        }
    }

    protected Dialog splashDialog;
    protected void showSplashScreen() {
        splashDialog = new SplashDialog(this, R.style.SplashScreen);
        splashDialog.show();
    }

    ...
}

这里有一个简单的!

~卢诺克斯

MainActivity.java

package com.example.splashscreen;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

splashscreen.java

package com.example.splashscreen;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;

public class splashscreen extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.splashscreen);

        //Splash Screen duration
        int secondsDelayed = 1;
        new Handler().postDelayed(new Runnable() {
            public void run() {
                startActivity(new Intent(splashscreen.this, MainActivity.class));
                finish();
            }
        }, secondsDelayed * 3000);
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

splashscreen.xml

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

    />

splashlogo.png

splashlogo.png

GitHub

SplashScreen