基本的 Android 启动器启动画面

问题描述

我是编写代码的新手，对于我猜测的可能是一个非常简单的问题，我深表歉意.我遵循了 Android 的构建您的第一个应用指南.接下来，我尝试按照一些教程(这是其中之一).当我在模拟器中运行应用程序时，它的加载速度如此之快，以至于我无法判断启动画面是否有效.有没有办法暂时减慢模拟器的速度以检查启动画面?此外，当单击发送按钮时应用程序崩溃，这是没有意义的，因为 sendMessage 函数存在于 MainActivity 中.

I'm new to writing code and apologize for what I am guessing is probably a very simple question. I followed Android's Build your first app guide. Next, I'm trying to add a launcher splash screen by following a number of tutorials (this being one of them). When I run the app in the emulator it loads so fast that I can't tell if the splash screen works. Is there a way to temporarily slow down the emulator to check the splash screen? Also the app crashes when the Send button is clicked which doesn't make sense because the sendMessage function exists in the MainActivity.

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.myfirstapp, PID: 9242
    java.lang.IllegalStateException: Could not find method sendMessage(View) in a parent or ancestor Context for android:onClick attribute defined on view class androidx.appcompat.widget.AppCompatButton with id 'button'
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:436)
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:393)
        at android.view.View.performClick(View.java:7125)
        at android.view.View.performClickInternal(View.java:7102)
        at android.view.View.access$3500(View.java:801)
        at android.view.View$PerformClick.run(View.java:27336)
        at android.os.Handler.handleCallback(Handler.java:883)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)

老实说，我不确定出了什么问题，或者应用程序是否太小以至于无法显示启动画面.我也不确定在这里分享我的项目的最佳方式.所以下面是所有的代码.

I'm honestly not sure what is wrong or if the app is just so small that a splash screen won't show. I'm also not sure the best way to share my project here. So below is all of the code.

AndroidManifest.xml

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.myfirstapp">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <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>
        </activity>

        <activity android:name=".DisplayMessageActivity"
                  android:parentActivityName=".MainActivity">
            <!-- For API 15 -->
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value=".MainActivity" />
        </activity>
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />
            </intent-filter>
        </activity>
    </application>
</manifest>

MainActivity.kt

MainActivity.kt

package com.example.myfirstapp

import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.EditText

const val EXTRA_MESSAGE = "come.example.myfirstapp.MESSAGE"

class MainActivity : AppCompatActivity()
{
    override fun onCreate(savedInstanceState: Bundle?)
    {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }

    //Called when user taps Send button
    fun sendMessage(view: View)
    {
        val editText = findViewById<EditText>(R.id.editTextTextPersonName)
        val message = editText.text.toString()
        val intent = Intent(this, DisplayMessageActivity::class.java).apply {putExtra(EXTRA_MESSAGE, message)}
        startActivity(intent)
    }
}

显示消息活动

package com.example.myfirstapp

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.TextView

class DisplayMessageActivity : AppCompatActivity()
{
    override fun onCreate(savedInstanceState: Bundle?)
    {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_display_message)

        //Get the Intent that started this activity and extract the string
        val message = intent.getStringExtra(EXTRA_MESSAGE)

        //Capture the layout's TextView and set the string as its text
        val text = findViewById<TextView>(R.id.textView).apply {text = message}
    }
}

SplashActivity

SplashActivity

package com.example.myfirstapp

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

class SplashActivity : AppCompatActivity()
{
    override fun onCreate(savedIntanceState: Bundle?)
    {
        setTheme(R.style.AppTheme)
        super.onCreate(savedIntanceState)
        setContentView(R.layout.activity_main)
    }
}

可绘制的 splash_background.xml

drawable splash_background.xml

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

值样式.xml

<resources>
    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>

    <!-- Splash Screen theme. -->
    <style name="SplashTheme" parent="Theme.AppCompat.NoActionBar">
        <item name="android:windowBackground">@drawable/splash_background</item>
    </style>
</resources>

对于新手问题很抱歉，我希望我发布它没有违反任何规则，但希望得到一些指导.谢谢！

Sorry for the novice question, and I hope I'm not breaking any rules by posting it, but would appreciate some guidance. Thanks!

编辑 - 在来自 S T

推荐答案

如果您想为首次发布添加教程，这里有很好的解释如何使用幻灯片创建介绍:https://www.androidhive.info/2016/05/android-build-intro-slider-app/

If you want to add a tutorial for the first launch there is well explained how to create an introduction with slides:https://www.androidhive.info/2016/05/android-build-intro-slider-app/

如果您只想在每次启动应用程序时出现一个简单的启动画面，请查看以下内容:https://android.jlelse.eu/the-complete-android-splash-screen-guide-c7db82bce565

If you want just a simple splash screen that appears each time the app is started see this:https://android.jlelse.eu/the-complete-android-splash-screen-guide-c7db82bce565

这篇关于基本的 Android 启动器启动画面的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！