我想让我的应用看起来更专业,所以我决定添加一个启动画面。

我应该如何进行实现呢?


当前回答

public class MainActivity extends Activity {

@Override

public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Thread t=new Thread()
    {

        public void run()
        {   

            try {

                sleep(2000);
                finish();
                Intent cv=new Intent(MainActivity.this,HomeScreen.class/*otherclass*/);
                startActivity(cv);
            } 

            catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    };
    t.start();
}

其他回答

这是完整的代码

SplashActivity.java

public class SplashActivity extends AppCompatActivity {

private final int SPLASH_DISPLAY_DURATION = 1000;

@Override
public void onCreate(Bundle bundle) {
    super.onCreate(bundle);


    new Handler().postDelayed(new Runnable(){
        @Override
        public void run() {

            Intent mainIntent = new Intent(SplashActivity.this,MainActivity.class);
            SplashActivity.this.startActivity(mainIntent);
            SplashActivity.this.finish();
        }
    }, SPLASH_DISPLAY_DURATION);
}}

在drawables中创建bg_splash.xml

<?xml version="1.0" encoding="utf-8"?><layer-list xmlns:android="http://schemas.android.com/apk/res/android">

<item
    android:drawable="@color/app_color"/>

<item>
    <bitmap
        android:gravity="center"
        android:src="@drawable/ic_in_app_logo_big"/>
</item></layer-list>

在styles.xml中创建一个自定义主题

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

最后在AndroidManifest.xml中指定活动的主题

<activity
        android:name=".activities.SplashActivity"
        android:label="@string/app_name"
        android:screenOrientation="portrait"
        android:theme="@style/SplashTheme">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

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

欢呼。

有时用户打开SplashActivity并立即退出,但应用程序仍然在SPLASH_SCREEN_DISPLAY_LENGTH后转到MainActivity。

为了防止它:在SplashActivity中,你应该在移动到MainActivity之前检查SplashActivity是否结束

public class SplashActivity extends Activity {

    private final int SPLASH_SCREEN_DISPLAY_LENGTH = 2000;

    @Override
    public void onCreate(Bundle icicle) {
        ...
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {

                if (!isFinishing()) {//isFinishing(): If the activity is finishing, returns true; else returns false.
                    startActivity(new Intent(SplashActivity.this, MainActivity.class));
                    finish();
                }

            }, SPLASH_SCREEN_DISPLAY_LENGTH);
        }                             
   }                                
}

希望这对你有所帮助

进一步阅读:

应用发布时间和主题发布屏幕(Android Performance Patterns Season 6 Ep. 4) Android中的启动画面:正确的方法

旧的回答:

如何:简单的启动画面

这个答案会告诉你如何在应用启动时固定时间显示启动画面。例如,你可以选择显示3秒的启动画面。然而,如果你想要在可变的时间内(例如应用启动时间)显示飞溅屏幕,你应该看看Abdullah的答案https://stackoverflow.com/a/15832037/401025。但是要注意,应用程序在新设备上的启动速度可能非常快,所以用户只会看到一个flash,这是糟糕的用户体验。

首先,您需要在layout.xml文件中定义飞溅屏幕

  <?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">

          <ImageView android:id="@+id/splashscreen" android:layout_width="wrap_content"
                  android:layout_height="fill_parent"
                  android:src="@drawable/splash"
                  android:layout_gravity="center"/>

          <TextView android:layout_width="fill_parent"
                    android:layout_height="wrap_content"
                    android:text="Hello World, splash"/>

  </LinearLayout>

你的活动:

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

public class Splash extends Activity {

    /** Duration of wait **/
    private final int SPLASH_DISPLAY_LENGTH = 1000;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.splashscreen);

        /* New Handler to start the Menu-Activity 
         * and close this Splash-Screen after some seconds.*/
        new Handler().postDelayed(new Runnable(){
            @Override
            public void run() {
                /* Create an Intent that will start the Menu-Activity. */
                Intent mainIntent = new Intent(Splash.this,Menu.class);
                Splash.this.startActivity(mainIntent);
                Splash.this.finish();
            }
        }, SPLASH_DISPLAY_LENGTH);
    }
}

这就是全部;)

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();
    }

    ...
}

以上所有的答案都非常好。但是存在内存泄漏的问题。 这个问题在Android社区通常被称为“泄露活动”。这到底是什么意思呢?

当配置发生变化时,比如方向变化,Android会销毁Activity并重新创建它。通常,垃圾收集器只会清除旧Activity实例的已分配内存,一切正常。

“泄漏一个活动”指的是垃圾收集器无法清除旧活动实例的已分配内存的情况,因为它被(强)引用于一个活动实例外的对象。每个Android应用程序都分配了特定数量的内存。当垃圾回收器不能释放未使用的内存时,应用程序的性能将逐渐下降,最终崩溃并出现OutOfMemory错误。

如何确定应用程序是否泄漏内存?最快的方法是在Android Studio中打开内存选项卡,并在改变方向时注意分配的内存。 如果分配的内存一直在增加而不减少,那么就有内存泄漏。

1.当用户改变方向时内存泄漏。

首先,你需要在布局资源splashscreen.xml文件中定义启动画面

启动画面活动的示例代码。

public class Splash extends Activity {
 // 1. Create a static nested class that extends Runnable to start the main Activity
    private static class StartMainActivityRunnable implements Runnable {
        // 2. Make sure we keep the source Activity as a WeakReference (more on that later)
        private WeakReference mActivity;

        private StartMainActivityRunnable(Activity activity) {
         mActivity = new WeakReference(activity);
        }

        @Override
        public void run() {
         // 3. Check that the reference is valid and execute the code
            if (mActivity.get() != null) {
             Activity activity = mActivity.get();
             Intent mainIntent = new Intent(activity, MainActivity.class);
             activity.startActivity(mainIntent);
             activity.finish();
            }
        }
    }

    /** Duration of wait **/
    private final int SPLASH_DISPLAY_LENGTH = 1000;

    // 4. Declare the Handler as a member variable
    private Handler mHandler = new Handler();

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

        // 5. Pass a new instance of StartMainActivityRunnable with reference to 'this'.
        mHandler.postDelayed(new StartMainActivityRunnable(this), SPLASH_DISPLAY_LENGTH);
    }

    // 6. Override onDestroy()
    @Override
    public void onDestroy() {
     // 7. Remove any delayed Runnable(s) and prevent them from executing.
     mHandler.removeCallbacksAndMessages(null);

     // 8. Eagerly clear mHandler allocated memory
     mHandler = null;
    }
}

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