Question

I have been tweaking my main xml layout, adjusting the different views’ positions in my relative layout, and suddenly when I started it on my emulator, it crashed with the message:ClassCastException

My XML :

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center" >

 <com.example.bingbong.Render
    android:id="@+id/render"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    android:background="@color/pattern5"
    android:clickable="true" />

<TextView
    android:id="@+id/fps"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentRight="true"
    android:layout_alignParentTop="true"
    android:text="fpasds"
    android:textAppearance="?android:attr/textAppearanceLarge" />

<TextView
    android:id="@+id/score_top"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:text="asd"
    android:textAppearance="?android:attr/textAppearanceLarge" />

<TextView
    android:id="@+id/score_bot"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_alignParentBottom="true"
    android:text="asfa"
    android:textAppearance="?android:attr/textAppearanceLarge" />
</RelativeLayout>

The error log:

10-30 20:25:33.266: E/AndroidRuntime(269): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.bingbong/com.example.bingbong.Main_Activity}: java.lang.ClassCastException: android.widget.TextView
...
10-30 20:25:33.266: E/AndroidRuntime(269): Caused by: java.lang.ClassCastException: android.widget.TextView
10-30 20:25:33.266: E/AndroidRuntime(269):  at com.example.bingbong.Main_Activity.onCreate(Main_Activity.java:26)

The Main_Activity – where line 26 is :

 public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
                                WindowManager.LayoutParams.FLAG_FULLSCREEN);

        setContentView(R.layout.main_layout);
        r = (Render) findViewById(R.id.render);   // <--- Line 26.
        r.setView((TextView)findViewById(R.id.fps),(TextView)findViewById(R.id.score_top),(TextView)findViewById(R.id.score_bot));
    }

Answer 1

I get this occasionally if I am moving around views or changing the types of views (ie, a TextView change to a Button, or something like that). What usually fixes it for me is to do a clean build.

In the “Project” menu in Eclipse, select “Clean…” and either do all projects or select that particular project.