findViewById returns null in android 4.4.4 only

Question

I used findViewById() in Android 4.4.4 / 4.4.2 / 5.0.2 .

But 4.4.4 only has error 'NullpointException'.

This is my code in MainActivity.

FrameLayout fl = (FrameLayout) this.findViewById(Util.StringToResourceID(this, "id", "main_map_fl"));

All android has no error, but only returns null in 4.4.4.

However,

Util.StringToResourceID(this, "id", "main_map_fl")

It returns value. Not null.

I tried setContentView before that code.

I tried clean project first, too.

I don't know why the error caused. Please help me.

+)

Here is my .xml code that has 'main_map_fl'.

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/main_rl"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >

<include
    android:id="@+id/main_tbt_ll"
    android:layout_width="200dp"
    android:layout_height="fill_parent"
    android:layout_alignParentRight="true"
    layout="@layout/layout_sub_tbt"
    android:visibility="visible" />

<FrameLayout
    android:id="@+id/main_map_fl"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent
    android:layout_toLeftOf="@+id/main_tbt_ll"
    android:background="#ffff0000" >
</FrameLayout>

<ImageView
    android:id="@+id/main_tbt_shadow_iv"
    android:layout_width="wrap_content"
    android:layout_height="fill_parent"
    android:layout_toLeftOf="@+id/main_tbt_ll"
    android:background="@drawable/shadow_w" />
<LinearLayout
    android:id="@+id/main_action_ll"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:orientation="vertical">
    <TextView 
        android:id="@+id/main_action_set_admin_tv"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:padding="5dp"
        android:gravity="center"
        android:background="#b2333333"
        style="@style/font_31p_255_255_255"/>
    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="@drawable/bottom_bar_bg" >
        <ImageButton
            android:background="@drawable/btn_main_actionbar_back"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/main_action_back_ib"
            android:layout_gravity="center_vertical"/> ...... 
    </LinearLayout>
</LinearLayout>

++)

Util.StringToResourceID

It is packagename and class String to int, I think.

public static int StringToResourceID(Context context, String _class, String _field) {
    int rval = 0;
    String a = context.getPackageName() + ".R$" + _class;

    try {
        Class Ra = Class.forName(a);

        try {
            rval = Ra.getField(_field).getInt(Ra);
        } catch (IllegalArgumentException var7) {
            ...........
    return rval;
}

Answer 1

You only want to get the resourceId based on name, is that correct? How about this?

public static int StringToResourceID(Context context, String _class, String _field) {
    return context.getResources().getIdentifier(_field, _class, context.getPackageName());
}