在 Android Stud 中使用 Java 使表格行可滚动

Question

我尝试在相对布局中创建滚动视图以使表格布局可滚动，但我不断收到此错误：

02-02 19:29:10.116: E/AndroidRuntime(9400): 
java.lang.RuntimeException: Unable to start activity ComponentInfo{test.com.classmanagertest/test.com.classmanagertest.StudentsMasterList}: java.lang.IllegalStateException: 
The specified child already has a parent. You must call removeView() on the child's parent first.

这是我在数据库中显示字段的表格布局：

@Override
    public void onCreate(Bundle savedInstanceState)
    {

        super.onCreate(savedInstanceState);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.students_masterlist);
        db=openOrCreateDatabase("ClassManager",MODE_WORLD_WRITEABLE, null);


        Cursor c=db.rawQuery("SELECT StudPic, StudentID, LastName FROM MasterStudents", null);
        int count= c.getCount();
        c.moveToFirst();
        TableLayout tableLayout = new TableLayout(getApplicationContext());
        tableLayout.setVerticalScrollBarEnabled(true);
        TableRow tableRow;
        TextView textView, textView1;
        ImageView StudImageView;

        RelativeLayout rl=(RelativeLayout)findViewById(R.id.layout);
        ScrollView sv = new ScrollView(this);
        sv.addView(tableLayout);
        rl.addView(sv);

        for (Integer j = 0; j < count; j++)
        {
            tableRow = new TableRow(getApplicationContext());

            StudImageView = new ImageView(getApplicationContext());
            StudImageView.setPadding(20, 20, 20, 20);
            StudImage=c.getBlob(c.getColumnIndex("StudPic"));
            Bitmap b1= BitmapFactory.decodeByteArray(StudImage, 0, StudImage.length);
            StudImageView.setImageBitmap(b1);
            tableRow.addView(StudImageView);

            textView1 = new TextView(getApplicationContext());
            textView1.setText(c.getString(c.getColumnIndex("StudentID")));
            textView1.setPadding(20, 20, 20, 20);
            textView1.setTextColor(getResources().getColor(R.color.blueactionbar));
            textView1.setTextSize(TypedValue.COMPLEX_UNIT_DIP,25);
            textView1.setTypeface(null, Typeface.BOLD);
            tableRow.addView(textView1);

            textView = new TextView(getApplicationContext());
            textView.setText(c.getString(c.getColumnIndex("LastName")));
            textView.setPadding(20, 20, 20, 20);
            textView.setTextColor(getResources().getColor(R.color.blueactionbar));
            textView.setTextSize(TypedValue.COMPLEX_UNIT_DIP,25);
            textView.setTypeface(null, Typeface.BOLD);
            tableRow.addView(textView);
            tableLayout.addView(tableRow);

            c.moveToNext() ;
        }
        setContentView(tableLayout);
        db.close();
    }

这是我的 xml 文件：

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/white"
    android:layout_gravity="center_horizontal"
    android:scrollbars="vertical|horizontal"
    android:id="@+id/layout">



</RelativeLayout>

如何解决此错误？

任何帮助表示赞赏！非常感谢！

Answer 1

@Override
    public void onCreate(Bundle savedInstanceState)
    {

        super.onCreate(savedInstanceState);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.students_masterlist);
        db=openOrCreateDatabase("ClassManager",MODE_WORLD_WRITEABLE, null);


        Cursor c=db.rawQuery("SELECT StudPic, StudentID, LastName FROM MasterStudents", null);
        int count= c.getCount();
        c.moveToFirst();
        TableLayout tableLayout = new TableLayout(getApplicationContext());
        tableLayout.setVerticalScrollBarEnabled(true);
        TableRow tableRow;
        TextView textView, textView1;
        ImageView StudImageView;

        RelativeLayout rl=(RelativeLayout)findViewById(R.id.layout);
        ScrollView sv = new ScrollView(this);
        sv.addView(tableLayout);
        rl.addView(sv);
        for (Integer j = 0; j < count; j++)
        {
            tableRow = new TableRow(getApplicationContext());
            StudImageView = new ImageView(getApplicationContext());
            StudImageView.setPadding(20, 20, 20, 20);
            StudImage=c.getBlob(c.getColumnIndex("StudPic"));
            Bitmap b1= BitmapFactory.decodeByteArray(StudImage, 0, StudImage.length);
            StudImageView.setImageBitmap(b1);
            tableRow.addView(StudImageView);

            textView1 = new TextView(getApplicationContext());
            textView1.setText(c.getString(c.getColumnIndex("StudentID")));
            textView1.setPadding(20, 20, 20, 20);
            textView1.setTextColor(getResources().getColor(R.color.blueactionbar));
            textView1.setTextSize(TypedValue.COMPLEX_UNIT_DIP,25);
            textView1.setTypeface(null, Typeface.BOLD);
            tableRow.addView(textView1);

            textView = new TextView(getApplicationContext());
            textView.setText(c.getString(c.getColumnIndex("LastName")));
            textView.setPadding(20, 20, 20, 20);
            textView.setTextColor(getResources().getColor(R.color.blueactionbar));
            textView.setTextSize(TypedValue.COMPLEX_UNIT_DIP,25);
            textView.setTypeface(null, Typeface.BOLD);
            tableRow.addView(textView);
            tableLayout.addView(tableRow);
            c.moveToNext() ;
        }
        db.close();
        rl.requestLayout();

    }

第一个 setContentView 是使用 parenet 相对布局调用的，其中包含具有您的行的表布局。因此，您尝试将 setContentView 设置为包含在您已经 setContentView 到即的父级中的视图。

rl 包含 sv 包含 tableLayout。 但是您首先将活动视图设置为rl，然后再设置为tableLayout。

相反，您应该将内容视图设置为 rl。然后像您一样填充您的 tableLayout 并刷新布局。即在父视图上调用 requestLayout()。