How to change layout?

Question

Android

Comrades, there is such a code!
I absolutely understand that this is some kind of trifle, but nothing helps. The application does not start and writes Unfortunately has stopped!

public class MainActivity extends ActionBarActivity {

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

        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment())
                    .commit();
        }
    }

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="ololo"
        android:id="@+id/textView"
        android:layout_gravity="center_horizontal" />
</LinearLayout>

And in the logs I get

03-18 06:52:36.809    1384-1384/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.firstapp233.app/com.firstapp233.app.MainActivity}: java.lang.IllegalArgumentException: No view found for id 0x7f07003c (com.firstapp233.app:id/container) for fragment PlaceholderFragment{527476bc #0 id=0x7f07003c}
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
            at android.app.ActivityThread.access$600(ActivityThread.java:141)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:5103)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:525)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.IllegalArgumentException: No view found for id 0x7f07003c (com.firstapp233.app:id/container) for fragment PlaceholderFragment{527476bc #0 id=0x7f07003c}
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:919)
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
            at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
            at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1467)
            at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:570)
            at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1171)
            at android.app.Activity.performStart(Activity.java:5143)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
            at android.app.ActivityThread.access$600(ActivityThread.java:141)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:5103)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:525)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
            at dalvik.system.NativeStart.main(Native Method)

Answer 1

You forgot to put id in LinearLayout:
android:Id="@+id/container"