这个 Button.onClickListener 有什么问题,似乎不起作用
What is wrong with this Button.onClickListener which seems that is not working
我正在尝试实现 here 中的基本示例,并得到以下代码:
class MainActivity : AppCompatActivity() {
private lateinit var imageView: ImageView
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
val binding = ActivityMainBinding.inflate(layoutInflater)
imageView = binding.imageView
binding.button1.setOnClickListener {
this.dispatchTakePictureIntent()
}
setContentView(R.layout.activity_main)
}
private fun dispatchTakePictureIntent() {
val takePictureIntent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
try {
startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE)
} catch (e: ActivityNotFoundException) {
println(e.stackTrace)
}
}
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
super.onActivityResult(requestCode, resultCode, data)
if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
val imageBitmap = data?.extras?.get("data") as Bitmap
imageView.setImageBitmap(imageBitmap)
}
}
}
代码生成,我可以在我的 phone 中部署和 运行 应用程序,但是当我点击我设置点击监听器的按钮时,没有任何反应。谁能告诉我这里出了什么问题?
ps.: 这里是与activity相关的布局,如果需要的话:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<ImageView
android:id="@+id/imageView"
android:layout_width="348dp"
android:layout_height="177dp"
android:layout_marginStart="38dp"
android:layout_marginTop="151dp"
android:layout_marginEnd="25dp"
android:background="#0091EA"
android:contentDescription="@string/todo"
app:layout_constraintBottom_toTopOf="@+id/button4"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="158dp"
android:layout_marginTop="100dp"
android:layout_marginEnd="151dp"
android:layout_marginBottom="264dp"
android:text="@string/take_pic"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/button4" />
</androidx.constraintlayout.widget.ConstraintLayout>
您已经通过视图绑定扩充了一个布局,并且该布局中的按钮是您添加了点击侦听器的按钮。
但是,您从未使用过您扩充的布局。相反,你打电话给
setContentView(R.layout.activity_main)
它会扩充布局的新副本,但与您使用视图绑定扩充的实例无关。将此行替换为
setContentView(binding.root)
您是否授予应用程序读取存储的权限?
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
我正在尝试实现 here 中的基本示例,并得到以下代码:
class MainActivity : AppCompatActivity() {
private lateinit var imageView: ImageView
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
val binding = ActivityMainBinding.inflate(layoutInflater)
imageView = binding.imageView
binding.button1.setOnClickListener {
this.dispatchTakePictureIntent()
}
setContentView(R.layout.activity_main)
}
private fun dispatchTakePictureIntent() {
val takePictureIntent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
try {
startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE)
} catch (e: ActivityNotFoundException) {
println(e.stackTrace)
}
}
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
super.onActivityResult(requestCode, resultCode, data)
if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
val imageBitmap = data?.extras?.get("data") as Bitmap
imageView.setImageBitmap(imageBitmap)
}
}
}
代码生成,我可以在我的 phone 中部署和 运行 应用程序,但是当我点击我设置点击监听器的按钮时,没有任何反应。谁能告诉我这里出了什么问题?
ps.: 这里是与activity相关的布局,如果需要的话:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<ImageView
android:id="@+id/imageView"
android:layout_width="348dp"
android:layout_height="177dp"
android:layout_marginStart="38dp"
android:layout_marginTop="151dp"
android:layout_marginEnd="25dp"
android:background="#0091EA"
android:contentDescription="@string/todo"
app:layout_constraintBottom_toTopOf="@+id/button4"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="158dp"
android:layout_marginTop="100dp"
android:layout_marginEnd="151dp"
android:layout_marginBottom="264dp"
android:text="@string/take_pic"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/button4" />
</androidx.constraintlayout.widget.ConstraintLayout>
您已经通过视图绑定扩充了一个布局,并且该布局中的按钮是您添加了点击侦听器的按钮。
但是,您从未使用过您扩充的布局。相反,你打电话给
setContentView(R.layout.activity_main)
它会扩充布局的新副本,但与您使用视图绑定扩充的实例无关。将此行替换为
setContentView(binding.root)
您是否授予应用程序读取存储的权限?
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />