在Android中将Textview添加到相对布局

Question

So I have researched everywhere but no else seems to have this problem probably because they know how to program, but anyways I'm trying to add a TextView to a Relative Layout in my Android app, but no matter what I do I cannot get the text and the buttons I already have in the layout. Here is my code for the activity:

public class EnterApp extends Activity {
int marblesInJar=0;
int targetMarblesInJar=0;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Intent intent= getIntent();
    targetMarblesInJar= intent.getIntExtra("MESSAGE_marbles",0);

    RelativeLayout marble= new RelativeLayout(this);

    TextView textView = new TextView(getApplicationContext());

    textView.setTextSize(20);
    textView.setText("Your marble jar will be full when it has "+ targetMarblesInJar + " marbles. You have " + marblesInJar + " marbles.");
    textView.setTextColor(Color.BLACK);
    marble.addView(textView);

    this.setContentView(R.layout.activity_enter_app);


    // Show the Up button in the action bar.
    setupActionBar();
}

here is my code for the xml relative layout

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/relativeLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
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=".EnterApp" >

 <Button
 android:id="@+id/button1"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:layout_alignBaseline="@+id/button2"
 android:layout_alignBottom="@+id/button2"
 android:layout_marginRight="16dp"
 android:layout_toLeftOf="@+id/button2"
 android:onClick="addMarble"
 android:text="@string/addMarble" />

 <Button
 android:id="@+id/button2"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:layout_alignParentBottom="true"
 android:layout_alignParentRight="true"
 android:layout_marginBottom="82dp"
 android:layout_marginRight="22dp"
 android:onClick="lossMarble"
 android:text="@string/loseMarble" />



</RelativeLayout>

Answer 1

You already have the RelativeLayout so you don't need to do

 RelativeLayout marble= new RelativeLayout(this);

this creates a new RelativeLayout . Just create your TextView and add it to this layout after you inflate it with setContentView()

public class EnterApp extends Activity {
    int marblesInJar=0;
    int targetMarblesInJar=0;
    RelativeLayout marble;

@Override

public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  ...    
  setContentView(R.layout.activity_enter_app);     
  TextView textView = new TextView(this);

    textView.setTextSize(20);
    textView.setText("Your marble jar will be full when it has "+ targetMarblesInJar +     " marbles. You have " + marblesInJar + " marbles.");
    textView.setTextColor(Color.BLACK);
    marble = (RelativeLayout) findViewById(R.id.relativelayout); // id you gave your root layout
    marble.addView(textView);

Answer 2

In your onCreate() method you have the setContentView() method which sets the activity's view to the layout file defined in it. Right Now the parent view of your activity is the relative layout with id "relativeLayout". You need to add your textview to that relativeLayout for it to show up. The code for that is as follows:

RelativeLayout parent = (RelativeLayout) findViewById(R.id.relativeLayout);

parent.addView(textView);

It should show up now.