Question

我有这样的Android Activity布局：

<RelativeLayout 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" 
android:background="#184A64">

<ImageView
    android:id="@+id/logoTop"
    android:layout_width="fill_parent"
    android:layout_height="42dip"
    android:layout_alignParentTop="true"
    android:layout_gravity="center"
    android:background="#F1CF2F"
    android:contentDescription="@string/descLogoTop"
    android:padding="4dip"
    android:src="@drawable/logoTop" />

<ImageView
    android:id="@+id/logoBot"
    android:layout_width="fill_parent"
    android:layout_height="42dip"
    android:layout_alignParentBottom="true"
    android:layout_gravity="center"
    android:background="#F1CF2F"
    android:contentDescription="@string/descLogoBot"
    android:padding="4dip"
    android:src="@drawable/logoBot" />

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:padding="6dip" >

    <TextView
        android:id="@+id/data"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="left"
        android:text=""
        android:textColor="#FFFFFF"
        android:textSize="12sp"
        android:textStyle="normal" />

    <ImageView
        android:id="@+id/icon"
        android:layout_width="103dip"
        android:layout_height="62dip"
        android:layout_marginBottom="6dip"
        android:layout_marginRight="6dip"
        android:contentDescription="@string/descLogo"
        android:src="@drawable/ic_launcher" />

    <TextView
        android:id="@+id/toptext"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center_vertical"
        android:text=""
        android:textColor="#F1CF2F"
        android:textSize="12sp"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/bottomtext"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:singleLine="false"
        android:text=""
        android:textColor="#FFFFFF"
        android:textSize="12sp" />
</LinearLayout>

此xml定义了一个带有顶部矩形的布局，其中包含一个日志，还有一个带有徽标的底部矩形。这两个元素正确显示。但中间组件是带有TextView的线性布局，然后是图像，然后是2个TextView。此组件未显示。活动的Java代码如下：

public class NewsActivity extends Activity {

private ProgressDialog m_ProgressDialog = null; 
private Runnable viewNews;
private Bundle bundle;
private News m_news = null;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_news_activity);

     bundle = this.getIntent().getExtras();

    viewNews = new Runnable(){
        @Override
        public void run() {

            getNews();
        }
    };
    Thread thread =  new Thread(null, viewNews, "MagentoBackground");
    thread.start();
    m_ProgressDialog = ProgressDialog.show(NewsActivity.this,    
            this.getString(R.string.wait), this.getString(R.string.receiving, true));

}

public void getNews() {

    m_news = new News();
    m_news.setNewsTitle(bundle.getString("title"));
    m_news.setNewsText(bundle.getString("text"));
    m_news.setNewsDate(bundle.getString("date"));
    m_news.setNewsPhoto(bundle.getString("photo"));

    LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View v = vi.inflate(R.layout.activity_news_activity, null);

    try{
        ImageView iv = (ImageView) v.findViewById(R.id.icon);
        TextView tt = (TextView) v.findViewById(R.id.toptext);
        TextView bt = (TextView) v.findViewById(R.id.bottomtext);

        if (iv != null) {
            try{
                Bitmap bmp = Utils.getBitmapFromURL("http://www.myServer.com/IMG/" + m_news.getNewsPhoto());
                if (bmp == null){
                    Log.i("PHOTO ERROR", "http://www.myServer.com/IMG/" + m_news.getNewsPhoto());
                }
                iv.setImageBitmap(bmp);                     
            } catch (Exception e){
                Log.e("IMAGE ERROR", e.getMessage() + " - " + e.getStackTrace());
            }
        }
        if (tt != null) {
            tt.setText(m_news.getNewsTitle());
        }
        if(bt != null){
            bt.setText(m_news.getNewsText());
        }   
        TextView dt = (TextView) v.findViewById(R.id.data);         
        Date nd = new Date(Long.parseLong(m_news.getNewsDate())*1000);
        Calendar cal = Calendar.getInstance();
        cal.setTime(nd);
        dt.setText(cal.get(Calendar.DAY_OF_MONTH) + "/" + cal.get(Calendar.MONTH) + "/" + cal.get(Calendar.YEAR));

    } catch (Exception e){
        Log.e("ERROR NEWS", e.getMessage());
    }

    runOnUiThread(returnRes);
}
private Runnable returnRes = new Runnable() {

    @Override
    public void run() {
        m_ProgressDialog.dismiss();
    }
};
}

我在这里做的是从包中提取一些数据（它正常工作），然后将内容设置为TextViews和ImageView。但是，当我在模拟器上测试它时，Image和TextViews是空的。

我检查了电话

ImageView iv = (ImageView) v.findViewById(R.id.icon);
TextView tt = (TextView) v.findViewById(R.id.toptext);
TextView bt = (TextView) v.findViewById(R.id.bottomtext);

并且，显然，然后不要返回null。但如果做了

tt.setText("some random text here");

它不起作用。

我想我做的不对。有人可以帮帮我吗？

Answer 1

我认为问题在于您没有访问当前视图，但是您正在创建新视图：

LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View v = vi.inflate(R.layout.activity_news_activity, null);

您根本不需要这两行，因为您可以直接访问当前视图组件

ImageView iv = (ImageView) findViewById(R.id.icon);
TextView tt = (TextView) findViewById(R.id.toptext);
TextView bt = (TextView) findViewById(R.id.bottomtext);

然后设置值。

当然，由于非ui线程调用了getNews（）方法，因此必须通过runOnUiThread调用其中涉及UI的所有代码：

public void getNews() {
    // ...
    runOnUiThread(new Runnable() {
            @Override
            public void run() {

                ImageView iv = (ImageView) findViewById(R.id.icon);
                TextView tt = (TextView) findViewById(R.id.toptext);
                TextView bt = (TextView) findViewById(R.id.bottomtext);

                tt.setText("some random text here");
                //...
            }
        });
    //...

Answer 2

您应该指定LinearLayout在RelativeLayout内的位置。例如，您应该指定：

android:layout_below="@+id/logoTop"

此外，如果您希望LinearLayout中的项目垂直对齐，则需要设置

android:orientation="vertical"

这会使您的总LinearLayout声明看起来像：

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_below="@+id/logoTop"
    android:orientation="vertical"
    android:padding="6dip" >

Android View无法显示

2 个答案: