我按照Android的构建您的第一个应用程序指南进行操作。接下来，我尝试通过遵循多个教程（其中之一）添加启动器闪屏。当我在模拟器中运行应用程序时，它加载得非常快，以至于我无法确定闪屏是否起作用。有没有办法暂时减慢模拟器的速度以检查闪屏？此外，当单击“发送”按钮时，应用程序会崩溃，这是没有道理的，因为sendMessage函数存在于MainActivity中。
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)
我真的不确定出了什么问题，或者这个应用程序是否太小，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。因此，以下是所有代码。
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
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}
}
}
启动画面活动
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
<?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 styles.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>
编辑 - 在S T的帮助下更新了错误