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安卓编程新手。

我有一个布局 XML，我想向其中添加一个列表（包含数据库中的项目），格式为表格。

这是代码：

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.edit_cat);

        DatabaseHandler db = new DatabaseHandler(this);
        List<Category> allCategories = db.getAllCategories();

        //Get the main layout from XML
        LinearLayout mainLayout = (LinearLayout) findViewById(R.id.edit_cat);

        //Create table layout for the categories
        TableLayout catList = new TableLayout(this);

        //Iterate the categories, and organize in tables
        for (Category category : allCategories) {
            TableRow tr = new TableRow(this);

            //Display category name
            TextView name = new TextView(this);
            name.setLayoutParams(new LayoutParams(                      
                    LayoutParams.FILL_PARENT,
                    LayoutParams.WRAP_CONTENT));

            name.setText(category.getName());


            //Display category type
            TextView type = new TextView(this);
            type.setText(category.getType());
            type.setLayoutParams(new LayoutParams(
                    LayoutParams.FILL_PARENT,
                    LayoutParams.WRAP_CONTENT));

            //Display edit button
            Button btnEdit = new Button(this);
            btnEdit.setText(getResources().getString(R.string.edit));

            btnEdit.setLayoutParams(new LayoutParams(
                    LayoutParams.FILL_PARENT,
                    LayoutParams.WRAP_CONTENT));

            //Display delete button
            Button btnDelete = new Button(this);
            btnDelete.setText(getResources().getString(R.string.delete));

            btnDelete.setLayoutParams(new LayoutParams(
                    LayoutParams.FILL_PARENT,
                    LayoutParams.WRAP_CONTENT));


            tr.addView(name);
            tr.addView(type);
            tr.addView(btnEdit);
            tr.addView(btnDelete);

            catList.addView(tr, new TableLayout.LayoutParams(
                    LayoutParams.FILL_PARENT,
                    LayoutParams.WRAP_CONTENT));
        }

        mainLayout.addView(catList);


    }

这不会向布局添加任何内容。任何想法为什么这不起作用？

编辑：在此处添加了 xml 代码：

<?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/edit_cat"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1">

<TextView style="@style/pageHeader"
  android:text="@string/catEditor"/>

<Button
    android:id="@+id/btnNewCategory"
    android:text="@string/newCategory"
    android:textSize="11pt"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:onClick="onBtnClicked"/>
<Button
    android:id="@+id/back"
    android:text="@string/back"
    android:textSize="11pt"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:onClick="onBtnClicked"/>

</LinearLayout>
4

1 回答 1

5

好的，我想我有一个答案给你。

指定 LayoutParams 时需要更具体。虽然它不会引发编译异常，但如果您没有指定 LayoutParams 的正确父类，则不会显示任何内容。

当您指定布局参数时，您需要使用对象所在容器的类。如果您正在设置进入 LinearLayout 的 textview 的布局参数，new LinearLayout.LayoutParams(...)如果您正在创建一个进入 TableRow 的 textview，您将使用类似的方法，您需要使用TableRow.LayoutParams(...)

以下是经过少量修改的完整代码，因为我没有数据库设置。

    LinearLayout mainLayout = (LinearLayout) findViewById(R.id.edit_cat);

    //Create table layout for the categories        
    TableLayout catList = new TableLayout(this);

    //Set the table layout to Match parent for both width and height
    // Note: We use LinearLayout.LayoutParams because the TableLayout is going inside a LinearLayout

    catList.setLayoutParams(
        new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));


    //Iterate the categories, and organize in tables      
    for(int i = 0; i < 5; i++)
    {
        TableRow tr = new TableRow(this);
        /* Since the table row is going inside a table layout, we specify the parameters using TableLayout.LayoutParams */
        tr.setLayoutParams(new TableLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT));

        //Display category name
        TextView name = new TextView(this);

        /* Since the TextView is going inside a TableRow, we use new TableRow.LayoutParams ... */
        name.setLayoutParams(new TableRow.LayoutParams(
                TableRow.LayoutParams.FILL_PARENT,
                TableRow.LayoutParams.WRAP_CONTENT));

        name.setText("Test Row - " + i);
        name.setBackgroundColor(Color.RED);


        //Display category type
        TextView type = new TextView(this);
        type.setText("Type Row - " + i);
        type.setBackgroundColor(Color.GREEN);
        type.setLayoutParams(new TableRow.LayoutParams(
                TableRow.LayoutParams.FILL_PARENT,
                TableRow.LayoutParams.WRAP_CONTENT));

        //Display edit button
        Button btnEdit = new Button(this);
        btnEdit.setText("Edit");

        btnEdit.setLayoutParams(new TableRow.LayoutParams(
                TableRow.LayoutParams.FILL_PARENT,
                TableRow.LayoutParams.WRAP_CONTENT));

        //Display delete button
        Button btnDelete = new Button(this);
        btnDelete.setText("Delete");

        btnDelete.setLayoutParams(new TableRow.LayoutParams(
                 TableRow.LayoutParams.FILL_PARENT,
                 TableRow.LayoutParams.WRAP_CONTENT));


        tr.addView(name);
        tr.addView(type);
        tr.addView(btnEdit);
        tr.addView(btnDelete);

        catList.addView(tr);
    }


    mainLayout.addView(catList);
于 2012-04-23T19:49:39.947 回答