You need to override the onStop method which is called whenever the application goes in the background. Beware you need to add this to all your activities or it will only stop for that particular  activity.

@Override
public void onStop(){
    super.onStop();
    finish();
}

Just add these two lines and your activity will reload

finish();
startActivity(getIntent());

You basically need to parse.

button.setBackgroundColor(Color.parseColor("#bdbdbd"));

OR
textView1.setTextColor(Color.parseColor("#bdbdbd"));

You can only set the maximum value in android directly.

Select the Seekbar in the XML and add this line to it

android:max="VALUE"

It should look something like this

<SeekBar android:id="@+id/SeekBar01"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:max="255"/>

Here the seek bar value is not from 0 - 255.

 

If you want your android app not to change orientation when the user changes the orientation.

You can do it both programatically or updating the manifest file.

1) Updating the Manifest.

Just add this line to the activity that you want for a particular activity

android:screenOrientation="portrait"

It would look like 
 <activity
            android:name="com.example.Activity"
            android:label="Example" 
            android:screenOrientation="portrait">
        </activity>