How to solve the problem with the location in the layout of your child SurfaceView?

Question

Android

He didn't seem to have done anything criminal. A default layout was created. I put an ImageView on it. Created the TouchView class.

package com.example.touchview;

import android.content.Context;
import android.view.SurfaceView;

public class TouchView extends SurfaceView{

  public TouchView(Context context) {
    super(context);
    
  }

}

Added a description of the object to the layout

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/rlMain"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".BlockerActivity" >

    

    <com.example.lookatme.TouchView
        android:id="@+id/tvPaint"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignTop="@+id/ivCenter"
        android:layout_marginTop="14dp" />
    <ImageView
        android:id="@+id/ivCenter"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:src="@drawable/ic_launcher" android:contentDescription="TODO"/>

</RelativeLayout>

so the app crashes at the moment setContentView(R.layout.activity_brocker) . There is nothing intelligible in LogCat:

10-23 18:02:03.442: W/dalvikvm(1964): threadid=1: thread exiting with uncaught exception (group=0xb57ef4f0)
10-23 18:02:03.442: E/AndroidRuntime(1964): FATAL EXCEPTION: main
10-23 18:02:03.442: E/AndroidRuntime(1964): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.lookatme/com.example.lookatme.BlockerActivity}: java.lang.ClassCastException: android.view.SurfaceView
10-23 18:02:03.442: E/AndroidRuntime(1964): 	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
10-23 18:02:03.442: E/AndroidRuntime(1964): 	at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
10-23 18:02:03.442: E/AndroidRuntime(1964): 	at android.app.ActivityThread.access$1500(ActivityThread.java:117)
10-23 18:02:03.442: E/AndroidRuntime(1964): 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
10-23 18:02:03.442: E/AndroidRuntime(1964): 	at android.os.Handler.dispatchMessage(Handler.java:99)
10-23 18:02:03.442: E/AndroidRuntime(1964): 	at android.os.Looper.loop(Looper.java:130)
10-23 18:02:03.442: E/AndroidRuntime(1964): 	at android.app.ActivityThread.main(ActivityThread.java:3683)
10-23 18:02:03.442: E/AndroidRuntime(1964): 	at java.lang.reflect.Method.invokeNative(Native Method)
10-23 18:02:03.442: E/AndroidRuntime(1964): 	at java.lang.reflect.Method.invoke(Method.java:507)
10-23 18:02:03.442: E/AndroidRuntime(1964): 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
10-23 18:02:03.442: E/AndroidRuntime(1964): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
10-23 18:02:03.442: E/AndroidRuntime(1964): 	at dalvik.system.NativeStart.main(Native Method)
10-23 18:02:03.442: E/AndroidRuntime(1964): Caused by: java.lang.ClassCastException: android.view.SurfaceView
10-23 18:02:03.442: E/AndroidRuntime(1964): 	at com.example.lookatme.BlockerActivity.onCreate(BlockerActivity.java:67)
10-23 18:02:03.442: E/AndroidRuntime(1964): 	at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
10-23 18:02:03.442: E/AndroidRuntime(1964): 	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
10-23 18:02:03.442: E/AndroidRuntime(1964): 	... 11 more
10-23 18:04:01.741: W/ActivityThread(2020): Application com.example.lookatme is waiting for the debugger on port 8100...

what is the reason for this fall? what am i doing wrong?
Without TouchView in the layout, everything runs fine.

Answer 1

The answer is here somewhere
It is also worth adding a constructor to the TouchView

public TouchView(Context context, AttributeSet attrs) {
        super(context, attrs);
        
    }