Question

我有以下问题：我想创建按钮和textview而不在xml文件中声明它们。我需要的按钮数量总是可变的，我想使用按钮来打开和关闭文本视图。按钮和Textview应按照我创建它们的确切顺序在linearLayout中创建。希望你了解我

     final LinearLayout linL = (LinearLayout) findViewById (R.id.linearLayout1);


     TextView a1 = new TextView(this);
     a1.setText("Dynamic layouts ftw!");
     a1.setVisibility(View.VISIBLE);
     linL.addView(a1);

这是我到目前为止所尝试的：线性布局是在xml文件中创建的，并且allready包含一些元素。当我尝试运行它一切都很好，但只要我执行linL.addView（a1）即时获取空指针异常

欢呼声，克里斯托弗

Answer 1

使用setlayoutparams。可能会有所帮助

TextView txtTag = new TextView(this);
    txtTag.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
    txtTag.setText("Button " + (j + 1 + (i * 4));
    txtTag.setId(j + 1 + (i * 4));
    linL.addView(txtTag);

Answer 2

    try this structure whenever you want to create any thing dynamically.

    public class PhrasesActivity extends Activity {


        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.phrases);
            LinearLayout linearLayout = (LinearLayout) findViewById(R.id.LinearLayout1);

            LinearLayout L2 = new LinearLayout(this);
            L2.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));
            L2.setGravity(Gravity.CENTER);


            TextView a1 = new TextView(this);
            a1.setText("Dynamic layouts ftw!");
            a1.setVisibility(View.VISIBLE);

            Button b1 = new Button(this);
            b1.setText("SUBMIT");

            L2.addView(a1,(new LayoutParams(0,LayoutParams.WRAP_CONTENT,0.8f)));
            L2.addView(b1,(new LayoutParams(0,LayoutParams.WRAP_CONTENT,0.8f)));

            linearLayout.addView(L2);


        }
    }
Let me know you understand or not?

Answer 3

确保您的XML文件具有要添加按钮的视图设置（s）

<LinearLayout
android:id="@+id/myName">

在您键入的活动中：

LinearLayout ll = (LinearLayout) findViewById(R.id.myName);
Button extra = new Button(this);
extra.setText("extra");
ll.addView(extra);

如果需要，您现在可以创建一个循环来添加内容

Answer 4

您需要在XML文件中将ID添加到LinearLayout：

<LinearLayout android:id="@+id/linearLayout1" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_marginTop="@dimen/x5" android:orientation="vertical" >

创建一个按钮，没有xml的textview

4 个答案: