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

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

其他回答

在Kotlin中编写以下代码:-

 Handler().postDelayed({
            val mainIntent = Intent(this@SplashActivity, LoginActivity::class.java)
            startActivity(mainIntent)
            finish()
        }, 500)

希望这对你有所帮助,谢谢........

启动画面不应该从布局文件加载,加载时可能仍然有一些延迟。

最好的方法是为你的SplashScreenActivity创建一个主题,并设置android:windowBackground为一个可绘制的资源。

https://www.bignerdranch.com/blog/splash-screens-the-right-way/

简而言之:

在manifest中声明你的SplashScreenActivity:

<activity
        android:name=".activities.SplashScreenActivity"
        android:theme="@style/SplashTheme"
        android:screenOrientation="portrait">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

在SplashScreenActivity.java中:

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

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

}

接下来创建主题背景窗口的资源:

<style name="SplashTheme" parent="Theme.Bumpfie.Base">
    <item name="android:windowBackground">@drawable/splash</item>
</style>

可绘制文件splash.xml:

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@android:color/white"/>
    <item>
        <bitmap
            android:gravity="center"
            android:src="@drawable/app_logo"/>
    </item>
</layer-list>

注意这个解决方案不会让用户等待更长的时间:启动画面的延迟取决于应用程序的启动时间。

当你打开任何android应用程序时,默认情况下你会看到一个黑屏,上面是应用程序的标题和图标,你可以通过使用样式/主题来改变这种情况。

首先,在values文件夹中创建一个style.xml,并向其添加一个样式。

<style name="splashScreenTheme" parent="@android:style/Theme.DeviceDefault.Light.NoActionBar">
    <item name="android:windowBackground">@drawable/splash_screen</item>
</style>

而不是使用@android:style/Theme.DeviceDefault.Light。NoActionBar你可以使用任何其他主题作为父主题。

其次,在你的应用Manifest.xml中添加android:theme="@style/splashScreenTheme"到你的主活动。

<activity
        android:name="MainActivity"
        android:label="@string/app_name"
        android:theme="@style/splashScreenTheme" >

第三,在onCreate()启动活动中更新主题。

protected void onCreate(Bundle savedInstanceState) {
    // Make sure this is before calling super.onCreate
    setTheme(R.style.mainAppTheme);
    super.onCreate(savedInstanceState);
}

更新 看看这篇文章。

感谢@mat1h和@adelriosantiago

在Android Marshmallow之后,我想到的另一个有效使用启动画面的方法是在应用的启动画面中请求必要的Android权限。

似乎大多数应用程序都是这样处理权限请求的。

对话框是糟糕的ui,它们破坏了主要流程,让你决定运行时间,事实上,大多数用户甚至可能不在乎你的应用程序是否想在SD卡上写东西。他们中的一些人甚至不明白我们试图传达什么,直到我们用简单的英语翻译出来。 一次请求权限可以减少每次操作前的“if else”次数,使代码看起来不那么杂乱。

这是一个例子,你可以在你的splash活动中请求运行Android OS 23+的设备的权限。

如果所有权限都被授予或已经授予或应用程序正在Pre Marshmallow上运行,那么只需去显示主要内容,几乎半秒的延迟,以便用户可以欣赏我们在阅读这个问题时所付出的努力,并试图给予我们最好的。

import android.Manifest;
import android.annotation.TargetApi;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.widget.Toast;

import com.c2h5oh.beer.R;
import com.c2h5oh.beer.utils.Animatrix;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class SplashActivity extends AppCompatActivity {

    final private int REQUEST_CODE_ASK_MULTIPLE_PERMISSIONS = 124;

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

        //show animations 
        Animatrix.scale(findViewById(R.id.title_play), 100);
        Animatrix.scale(findViewById(R.id.title_edit), 100);
        Animatrix.scale(findViewById(R.id.title_record), 100);
        Animatrix.scale(findViewById(R.id.title_share), 100);

        if (Build.VERSION.SDK_INT >= 23) {

            // Marshmallow+ Permission APIs
            fuckMarshMallow();

        } else {

            // Pre-Marshmallow
            ///Display main contents
            displaySplashScreen();
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        switch (requestCode) {
            case REQUEST_CODE_ASK_MULTIPLE_PERMISSIONS: {
                Map<String, Integer> perms = new HashMap<String, Integer>();
                // Initial
                perms.put(Manifest.permission.READ_EXTERNAL_STORAGE, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.RECORD_AUDIO, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.MODIFY_AUDIO_SETTINGS, PackageManager.PERMISSION_GRANTED);
                perms.put(Manifest.permission.VIBRATE, PackageManager.PERMISSION_GRANTED);
                // Fill with results
                for (int i = 0; i < permissions.length; i++)
                    perms.put(permissions[i], grantResults[i]);

                // Check for ACCESS_FINE_LOCATION
                if (perms.get(Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED
                        && perms.get(Manifest.permission.RECORD_AUDIO) == PackageManager.PERMISSION_GRANTED
                        && perms.get(Manifest.permission.MODIFY_AUDIO_SETTINGS) == PackageManager.PERMISSION_GRANTED
                        && perms.get(Manifest.permission.VIBRATE) == PackageManager.PERMISSION_GRANTED) {
                    // All Permissions Granted

                    // Permission Denied
                    Toast.makeText(SplashActivity.this, "All Permission GRANTED !! Thank You :)", Toast.LENGTH_SHORT)
                            .show();

                    displaySplashScreen();

                } else {
                    // Permission Denied
                    Toast.makeText(SplashActivity.this, "One or More Permissions are DENIED Exiting App :(", Toast.LENGTH_SHORT)
                            .show();

                    finish();
                }
            }
            break;
            default:
                super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        }
    }


    @TargetApi(Build.VERSION_CODES.M)
    private void fuckMarshMallow() {
        List<String> permissionsNeeded = new ArrayList<String>();

        final List<String> permissionsList = new ArrayList<String>();
        if (!addPermission(permissionsList, Manifest.permission.READ_EXTERNAL_STORAGE))
            permissionsNeeded.add("Read SD Card");
        if (!addPermission(permissionsList, Manifest.permission.RECORD_AUDIO))
            permissionsNeeded.add("Record Audio");
        if (!addPermission(permissionsList, Manifest.permission.MODIFY_AUDIO_SETTINGS))
            permissionsNeeded.add("Equilizer");
        if (!addPermission(permissionsList, Manifest.permission.VIBRATE))
            permissionsNeeded.add("Vibrate");

        if (permissionsList.size() > 0) {
            if (permissionsNeeded.size() > 0) {

                // Need Rationale
                String message = "App need access to " + permissionsNeeded.get(0);

                for (int i = 1; i < permissionsNeeded.size(); i++)
                    message = message + ", " + permissionsNeeded.get(i);

                showMessageOKCancel(message,
                        new DialogInterface.OnClickListener() {

                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                requestPermissions(permissionsList.toArray(new String[permissionsList.size()]),
                                        REQUEST_CODE_ASK_MULTIPLE_PERMISSIONS);
                            }
                        });
                return;
            }
            requestPermissions(permissionsList.toArray(new String[permissionsList.size()]),
                    REQUEST_CODE_ASK_MULTIPLE_PERMISSIONS);
            return;
        }

        Toast.makeText(SplashActivity.this, "No new Permission Required- Launching App .You are Awesome!!", Toast.LENGTH_SHORT)
                .show();

        displaySplashScreen();
    }


    private void showMessageOKCancel(String message, DialogInterface.OnClickListener okListener) {
        new AlertDialog.Builder(SplashActivity.this)
                .setMessage(message)
                .setPositiveButton("OK", okListener)
                .setNegativeButton("Cancel", null)
                .create()
                .show();
    }

    @TargetApi(Build.VERSION_CODES.M)
    private boolean addPermission(List<String> permissionsList, String permission) {

        if (checkSelfPermission(permission) != PackageManager.PERMISSION_GRANTED) {
            permissionsList.add(permission);
            // Check for Rationale Option
            if (!shouldShowRequestPermissionRationale(permission))
                return false;
        }
        return true;
    }

    /**
     * Display main content with little delay just so that user can see
     * efforts I put to make this page
     */
    private void displaySplashScreen() {
        new Handler().postDelayed(new Runnable() {

        /*
         * Showing splash screen with a timer. This will be useful when you
         * want to show case your app logo / company
         */

            @Override
            public void run() {
                startActivity(new Intent(SplashActivity.this, AudioPlayerActivity.class));
                finish();
            }
        }, 500);
    }


}

Create an activity: Splash Create a layout XML file: splash.xml Put UI components in the splash.xml layout so it looks how you want your Splash.java may look like this: public class Splash extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.splash); int secondsDelayed = 1; new Handler().postDelayed(new Runnable() { public void run() { startActivity(new Intent(Splash.this, ActivityB.class)); finish(); } }, secondsDelayed * 1000); } } change ActivityB.class to whichever activity you want to start after the splash screen check your manifest file and it should look like

<活动 android: name = "。屏” android: label = " @string / app_name " > > < /活动 <活动 android: name = "。飞溅” android: label = " @string / title_activity_splash_screen " > <意图过滤器> <action android:name="android.intent.action. main " /> <category android:name="android.intent.category. launcher " /> < /意图过滤器> > < /活动