Question

这里我引用了代码link

我必须添加多个textviews @ runtime并且可能它的工作但是textview没有显示，我必须在表格布局中添加表格行并显示textview。但它不起作用。

这是我的代码：

tx[i] = new TextView(S1.this);

                    tx[i].setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT));
                    tx[i].setText(name);

                    tr[i] = new TableRow(S1.this);
                    tr[i].setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT));
                    tr[i].addView(tx[i]);
                    rl.addView(tr[i]); // Exception

此处抛出异常，app停止工作。

这是我的logcat：

04-08 02:13:05.255: E/AndroidRuntime(1716): FATAL EXCEPTION: AsyncTask #1
04-08 02:13:05.255: E/AndroidRuntime(1716): Process: com.app.crossdine, PID: 1716
04-08 02:13:05.255: E/AndroidRuntime(1716): java.lang.RuntimeException: An error occured while executing doInBackground()
04-08 02:13:05.255: E/AndroidRuntime(1716):     at android.os.AsyncTask$3.done(AsyncTask.java:300)
04-08 02:13:05.255: E/AndroidRuntime(1716):     at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
04-08 02:13:05.255: E/AndroidRuntime(1716):     at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
04-08 02:13:05.255: E/AndroidRuntime(1716):     at java.util.concurrent.FutureTask.run(FutureTask.java:242)
04-08 02:13:05.255: E/AndroidRuntime(1716):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
04-08 02:13:05.255: E/AndroidRuntime(1716):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
04-08 02:13:05.255: E/AndroidRuntime(1716):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
04-08 02:13:05.255: E/AndroidRuntime(1716):     at java.lang.Thread.run(Thread.java:841)
04-08 02:13:05.255: E/AndroidRuntime(1716): Caused by: java.lang.NullPointerException
04-08 02:13:05.255: E/AndroidRuntime(1716):     at com.app.crossdine.S1$Getitems.doInBackground(S1.java:155)
04-08 02:13:05.255: E/AndroidRuntime(1716):     at com.app.crossdine.S1$Getitems.doInBackground(S1.java:1)
04-08 02:13:05.255: E/AndroidRuntime(1716):     at android.os.AsyncTask$2.call(AsyncTask.java:288)
 04-08 02:13:05.255: E/AndroidRuntime(1716):    at java.util.concurrent.FutureTask.run(FutureTask.java:237)

请指导我。

Answer 1

借助问题中提供的链接以及以下link，您可以像下面一样使用它（确保rl正确指向您要添加此内容的布局/视图表格）。

更新：因为您使用的是AsyncTask，所以无法修改此方法中的UI内容。我在onPostExecute方法中做了。此外，您应该使用TableRow.LayoutParams设置TextView的布局参数。我的工作代码如下

首先将以下内容添加到我的xml布局中的按钮

android:onClick="addTable"

然后添加以下java活动

public void addTable(View view){
    CreateTableTask mTask = new CreateTableTask();
    mTask.execute();
}

public class CreateTableTask extends AsyncTask<Void, Void, TableLayout> {
@Override
protected TableLayout doInBackground(Void... params) {
    LayoutParams params1 = new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT,
                    LayoutParams.WRAP_CONTENT);
    TableLayout layoutINNER = new TableLayout(MainActivity.this);
    layoutINNER.setLayoutParams(params1);
    TextView[] tx = new TextView[10];
    TableRow[] tr = new TableRow[10];
    for(int i=0; i<10; i++) {
        tx[i] = new TextView(MainActivity.this);
        tx[i].setLayoutParams(new TableRow.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
    tx[i].setText("Data");
    tr[i] = new TableRow(MainActivity.this);
    tr[i].setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
    tr[i].addView(tx[i]);
    // and then adding table row in tablelayout
    layoutINNER.addView(tr[i]);
    }
    return layoutINNER;
}

@Override
protected void onPostExecute(final TableLayout newTable) {
    if (newTable!=null) {
            // this rl is the layout where I want this table
        View rl= findViewById(R.id.mainlayout);
        ((ViewGroup) rl).addView(newTable);             
    } 
}       
}

如何在表格布局中添加表格行？

1 个答案: