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

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();
}

其他回答

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;
    }
}

欲了解更多信息,请点击此链接

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();
  }
}

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;)

     - Add in SplashActivity 

   public class SplashActivity extends Activity {

       private ProgressBar progressBar;
       int i=0;
       Context context;
       private GoogleApiClient googleApiClient;

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

           new Handler().postDelayed(new Runnable() {
               @Override
               public void run() {
                   startActivity(new Intent(Splash.this, LoginActivity.class));
                   finish();
               }
           }, 2000);

       }

   }

  - Add in activity_splash.xml

   <RelativeLayout
   xmlns:android="http://schemas.android.com/apk/res/android"
       xmlns:tools="http://schemas.android.com/tools"
       xmlns:custom="http://schemas.android.com/apk/res-auto"
       android:background="@color/colorAccent"
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       tools:context=".Splash">

       <ImageView
           android:id="@+id/ivLogo"
           android:layout_width="match_parent"
           android:layout_height="match_parent"
           android:src="@mipmap/icon_splash"
           android:layout_centerHorizontal="true"
           android:layout_centerVertical="true"/>


       <ProgressBar
           android:id="@+id/circle_progress"
           style="?android:attr/progressBarStyleHorizontal"
           android:layout_width="fill_parent"
           android:layout_height="wrap_content"
           android:layout_alignParentBottom="true"
           android:layout_marginBottom="5dp"
           android:max="100"
           android:progressTint="@color/green"
           android:visibility="visible" />

   </RelativeLayout>

  - Add in AndroidManifest.xml

    <activity android:name="ex.com.SplashActivity">
               <intent-filter>
                   <action android:name="android.intent.action.MAIN" />

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

Create an Activity SplashScreen.java public class SplashScreen extends Activity { protected boolean _active = true; protected int _splashTime = 3000; // time to display the splash screen in ms @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.splashscreen); Thread splashTread = new Thread() { @Override public void run() { try { int waited = 0; while (_active && (waited < _splashTime)) { sleep(100); if (_active) { waited += 100; } } } catch (Exception e) { } finally { startActivity(new Intent(SplashScreen.this, MainActivity.class)); finish(); } }; }; splashTread.start(); } } splashscreen.xml will be like this <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="600px" android:layout_height="1024px" android:background="#FF0000"> </RelativeLayout>