for循环在上一次迭代之前停止

Question

I've been programming an Android app which is supposed to add TextView s progrmatically. It is supposed to add 28 of them using a for loop. Below are the the important parts of the loop:

    for(int i = 0; i < 28; i++){
        Log.i("Creating round", "" + (i + 1));
        final int j = i;
        roundLayout[i] = new LinearLayout(getActivity());
        roundLayout[i].setOrientation(LinearLayout.HORIZONTAL);
        roundLayout[i].setBackgroundColor(Color.WHITE);
        roundLayout[i].setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                selectRound(j);
            }
        });
        layout.addView(roundLayout[i], lp);
        TextView title = new TextView(getActivity());
        title.setText("Round " + MainActivity.intFormat(i + 1, 2));
        title.setGravity(Gravity.CENTER);
        title.setTextSize(20);
        title.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
        roundLayout[i].addView(title, titleParams);

So as you can see, this loop, in each of its iterations, adds a roundLayout in the main layout , and in each of them adds a Textview title displaying the round number. However, while it is supposed to create 28 of them it only creates 27, but the logging goes till 28.

And here's what appears in the logcat:

    I/Creating round: 1
    I/Creating round: 2
    I/Creating round: 3
    I/Creating round: 4
    I/Creating round: 5
    I/Creating round: 6
    I/Creating round: 7
    I/Creating round: 8
    I/Creating round: 9
    I/Creating round: 10
    I/Creating round: 11
    I/Creating round: 12
    I/Creating round: 13
    I/Creating round: 14
    I/Creating round: 15
    I/Creating round: 16
    I/Creating round: 17
    I/Creating round: 18
    I/Creating round: 19
    I/Creating round: 20
    I/Creating round: 21
    I/Creating round: 22
    I/Creating round: 23
    I/Creating round: 24
    I/Creating round: 25
    I/Creating round: 26
    I/Creating round: 27
    I/Creating round: 28

EDIT: I've noticed that the container (which's width and height are set to match_parent) in which the layout is inflated may go past the screen (if that's even a thing). Have a look at the screenshots below:

The first screenshot shows the uppermost element of the component tree. We can clearly see the 4 blue lines delimiting it. However, the second screenshot shows the container in which the layout is inflated and we can't see the right nor the bottom line delimiting it. Here's the code for the layout:

    <?xml version="1.0" encoding="utf-8"?>
        <androidx.coordinatorlayout.widget.CoordinatorLayout 
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/main_content"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true"
        tools:context=".MainActivity">

        <com.google.android.material.appbar.AppBarLayout
            android:id="@+id/appbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:paddingTop="@dimen/appbar_padding_top"
            android:theme="@style/AppTheme.AppBarOverlay">

            <androidx.appcompat.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:layout_weight="1"
                android:background="?attr/colorPrimary"
                app:layout_scrollFlags="scroll|enterAlways"
                app:popupTheme="@style/AppTheme.PopupOverlay"
                app:title="@string/app_name">

            </androidx.appcompat.widget.Toolbar>

        </com.google.android.material.appbar.AppBarLayout>

        <androidx.viewpager.widget.ViewPager
            android:id="@+id/container"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            app:layout_behavior="@string/appbar_scrolling_view_behavior" />

     </androidx.coordinatorlayout.widget.CoordinatorLayout>

Thanks in advance!

Answer 1

The problem seems related to the view not the loop. Here I'm reproducing the views with your code and slightly modified it.

activity_main.xml layout:

<?xml version="1.0" encoding="utf-8"?>
<ScrollView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

  <LinearLayout
      android:id="@+id/parent_rly"
      android:layout_width="match_parent"
      android:orientation="vertical"
      android:layout_height="wrap_content"/>

</ScrollView>

MainActivity.java code:

public class MainActivity extends AppCompatActivity {
  private LinearLayout[] roundLayout;
  private LinearLayout layout;
  private LinearLayout.LayoutParams lp;
  private LinearLayout.LayoutParams titleParams;

  @Override protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    layout = findViewById(R.id.parent_rly);

    roundLayout = new LinearLayout[28];
    lp= new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
    titleParams= new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);

    addingTextViews();
  }

  private void addingTextViews() {
    for (int i = 0; i < 28; i++) {
      Log.i("Creating round", "" + (i + 1));
      roundLayout[i] = new LinearLayout(this);
      roundLayout[i].setOrientation(LinearLayout.HORIZONTAL);
      roundLayout[i].setBackgroundColor(Color.WHITE);

      layout.addView(roundLayout[i], lp);
      TextView title = new TextView(this);
      title.setText("Round " + (i + 1));
      title.setGravity(Gravity.CENTER);
      title.setTextSize(20);
      title.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
      roundLayout[i].addView(title, titleParams);
    }
  }
}

and it show the views correctly: