未显示或未添加到LinearLayout中的TextVIew

Question

以下是main活动的代码。我在addJoke()方法中添加了TextView，但它没有出现在LinearLayout中。请解决。

package edu.calpoly.android.lab2;
import java.util.ArrayList;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnKeyListener;
import android.view.ViewGroup.LayoutParams;
import android.view.inputmethod.InputMethodManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;

public class AdvancedJokeList extends Activity {
    private static int i=0;
    //protected String m_strAuthorName;
    protected ArrayList<Joke> m_arrJokeList=new ArrayList<Joke>();
    //protected JokeListAdapter m_jokeAdapter;

    /**
     * ViewGroup used for maintaining a list of Views that each display Jokes.
     **/
    protected LinearLayout m_vwJokeLayout;
    protected EditText m_vwJokeEditText;
    protected Button m_vwJokeButton;
    protected int m_nDarkColor;
    protected int m_nLightColor;
    /**
     * Filter Options Submenu constants
     */
    protected static final int FILTER_OPTIONS = 1;
    protected static final int LIKE = Menu.FIRST + 1;
    protected static final int DISLIKE = Menu.FIRST + 2;
    protected static final int UNRATED = Menu.FIRST + 3;
    protected static final int SHOW_ALL = Menu.FIRST + 4;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        initLayout();
        String[] jokestring=getResources().getStringArray(R.array.jokeList);    
        for(String str : jokestring) 
        {
                Joke j=new Joke();
                j.setJoke(str);
                addJoke(j);
        }
        initAddJokeListeners();
    }

    protected void addJokeImplementation(){
        String strJoke=m_vwJokeEditText.getText().toString().trim();
        if(!strJoke.equals(""))
        {
        Joke joke=new Joke();
        joke.setJoke(strJoke);
        addJoke(joke);
        }
    }

    protected void initLayout() {
        setContentView(R.layout.advanced);
        m_vwJokeLayout=(LinearLayout)findViewById(R.id.jokeListViewGroup);
        m_vwJokeEditText=(EditText)findViewById(R.id.newJokeEditText);
        m_vwJokeButton=(Button)findViewById(R.id.addJokeButton);
    }

    protected void initAddJokeListeners() {
        // TODO
        m_vwJokeEditText.setOnKeyListener(new OnKeyListener(){
            @Override
            public boolean onKey(View v,int keyCOde, KeyEvent event){
                if(event.getAction()==KeyEvent.ACTION_DOWN)
                {
                    if(keyCOde==KeyEvent.KEYCODE_DPAD_CENTER)
                    {
                        addJokeImplementation();
                    }
                }
                return false;
            }

        });
        m_vwJokeButton.setOnClickListener(new OnClickListener() {
            @Override
        public void onClick(View view) {
        //Implement code to add a new joke here...
                addJokeImplementation();
            }
        });
    }

    protected void addJoke(Joke joke) {
         if(!m_arrJokeList.contains(joke))
          {
            m_arrJokeList.add(joke);
            //I also added textview here this one also
            //doesn't appear in Emulator layout, wondering whats wrong?;
            TextView TV=new TextView(this);
            TV.setLayoutParams(new LayoutParams(
                    LayoutParams.FILL_PARENT,
                    LayoutParams.WRAP_CONTENT));
            TV.setText(joke.toString());
            m_vwJokeLayout.addView(TV);
            m_nDarkColor=getResources().getColor(R.color.dark);
            m_nLightColor=getResources().getColor(R.color.light);       
            if(i==0)
            {
                TV.setBackgroundColor(m_nLightColor);
                i=1;
            }
            else
            {
                TV.setBackgroundColor(m_nDarkColor);
                i=0;
            }
            m_vwJokeEditText.setText("");
            InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);
            imm.hideSoftInputFromWindow(m_vwJokeEditText.getWindowToken(), 0);
          }
    }         

    /**
     * Method used to retrieve Jokes from online server. The getJoke script
     * takes a single optional parameter, which should be encode in "UTF-8".
     * This parameter allows tells script to only retrieve Jokes whose author
     * name matches the value in the parameter.
     * 
     * param-1) "author": The author of the joke.
     * 
     * URL: http://simexusa.com/aac/getJokes.php?
     * 
     */
    protected void getJokesFromServer() {
        // TODO
    }

    /**
     * This method uploads a single Joke to the server. This method should test
     * the response from the server and display success or failure to the user
     * via a Toast Notification
     * 
     * The addJoke script on the server requires two parameters, both of which
     * should be encode in "UTF-8":
     * 
     * param-1) "joke": The text of the joke.
     * 
     * param-2) "author": The author of the joke.
     * 
     * URL: http://simexusa.com/aac/addJoke.php?
     * 
     * @param joke
     *            The Joke to be uploaded to the server.
     * 
     */
    protected void uploadJokeToServer(Joke joke) {
        // TODO
    }

}         

这里是advanced.xml；

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    >
    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        >
        <Button
            android:id="@+id/addJokeButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Add Joke"
            />
        <EditText
            android:id="@+id/newJokeEditText"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:hint="Enter Joke"
            />
    </LinearLayout>
    <LinearLayout
        android:id="@+id/jokeListViewGroup"
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        >

    </LinearLayout>
</LinearLayout>

更新:稍微修改了代码，添加了Layout.params()，但TextView仍然没有出现。

Answer 1

问题解决了.

我很stupid....This太傻了……我忘了为代码的根添加android:orientation=“element..see”。

我太习惯Stackoverflow了……我变得懒惰

感谢所有伟大的开发人员，他们在每次我提出问题时都给出了一些很好的提示和答案。

Answer 2

有两个原因；您需要设置TV视图的高度和宽度，直接或使用布局参数，然后在完成此操作后，您需要再次调用setContentView，但由于添加它的布局是根布局的子布局，您可能需要获取根布局的引用，然后将TV视图添加到相应子布局，然后添加setContentView(根布局)。

Answer 3

如果你想检查你的视图是否存在，你会很乐意使用Hierarchy-viewer。检查这个：http://developer.android.com/guide/developing/tools/hierarchy-viewer.html

它显示了所有存在的视图，以及它们是如何放置的。这应该会对你进行这样的调试有很大帮助！