Question

我按照“How to get data from database in my android table view as columns”链接解决了我的问题但是出现没有数据的空白屏幕。单击按钮后，我编写了代码以从MS SQL DB中获取记录。

我的XML，出于布局目的，activity_display_result.xml：

<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/tab" >
</TableLayout>

来自 MainActivity.java的代码段：

@SuppressLint("NewApi") @Override
public void onCreate(Bundle b)
{
    super.onCreate(b);
    setContentView(R.layout.activity_main);

    if( Build.VERSION.SDK_INT >= 9)
    {
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy); 
    }

    initilize();

    button1.setOnClickListener(new OnClickListener() 
    {
        public void onClick(View v) 
        {
            List <Map<String,String>> dataList  = querySQL(e1.getText().toString(),e2.getText().toString(),e.getText().toString());

            StringBuilder builder = new StringBuilder();
            for (int i=0;i<dataList.size();i++)
            {               
               Log.i("onClick Method()", "UserName : "+dataList.get(i).get("UserName"));
               Log.i("onClick Method()", "Password : "+dataList.get(i).get("Password"));
               builder.append(dataList.get(i).get("UserName")).append(";").
               append(dataList.get(i).get("Password")).append("_");
            }

            builder.toString();

            String st = new String(builder);
            String[] rows =st.split("_");
            setContentView(R.layout.activity_display_result);
            TableLayout tableLayout =(TableLayout) findViewById(R.id.tab);
            tableLayout.removeAllViews();

            for(int i=0;i<rows.length;i++)
            {
                String row  = rows[i];
                TableRow tableRow = new TableRow(getApplicationContext());
                                                tableRow.setLayoutParams(new TableLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));

                final String[] cols = row.split(";");

                Log.i("MainActivity ","Column length :"+cols.length);

                //Handler handler = null;

                for (int j = 0; j < cols.length; j++) 
                {             
                    final String col = cols[j];                                 
                    TextView TextView11 = new TextView(getApplicationContext());
                    TextView11.setLayoutParams(new TableRow.LayoutParams(TableRow.LayoutParams.WRAP_CONTENT, TableRow.LayoutParams.WRAP_CONTENT));
                    TextView11.setTextColor(color.black);
                    //TextView11.setText(String.format("%7s", col));
                    TextView11.setText(col);
                    tableRow.addView(TextView11);
                }

                tableLayout.addView(tableRow);
                setContentView(R.layout.activity_display_result);
            }
        }
    });
}

声明所有

public void declere()
{
    e = (EditText)findViewById(R.id.editText3);
    e1 = (EditText)findViewById(R.id.editText1);
    e2 = (EditText)findViewById(R.id.editText2);
    button1=(Button)findViewById(R.id.button1);
}

//initializing 
public void initilize()
{
    Log.i("initilize() Method", "initilize() Method is called..Now Calling declere() method");
    declere();
    Log.i("initilize() Method", "declere() method is called ");
    Log.i("initilize() Method", "Before Calling CONN() method..");
    connect=CONN("sa","C!@C2@!2","RequestCenter");
    Log.i("initilize() Method", "CONN() method called Successfully..");

 }

我还添加了一个用于获取连接的CONN方法。任何人都可以帮我确定屏幕显示为空白的原因吗？

Answer 1

您正在onClick方法的末尾调用setContentView(R.layout.activity_display_result)，这会将视图重置为xml的内容，从而为您提供activity_display_result.xml中定义的空白屏幕。您需要删除该行并查看它是否有效。

Answer 2

有几件事：

您继续重置setContentView（R.layout.activity_display_result）;很多次（通过循环）。有原因吗？一旦将所有控件放入布局中，您可能只需在结尾处设置一次。我把它移到我认为应该在下面的代码中的位置。如果这不起作用，请重新考虑如上所述由2Dee

我自己理解的问题：为什么col设置为最终？这会不会阻止变量被赋予cols数组中的下一个值吗？谢谢！

    for(int i=0;i<rows.length;i++){
        String row  = rows[i];
        TableRow tableRow = new TableRow(getApplicationContext());
                                        tableRow.setLayoutParams(new     TableLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));

        final String[] cols = row.split(";");

        Log.i("MainActivity ","Column length :"+cols.length);

        //Handler handler = null;

        for (int j = 0; j < cols.length; j++) 
        {             
            final String col = cols[j];                                 
            TextView TextView11 = new TextView(getApplicationContext());
            TextView11.setLayoutParams(new TableRow.LayoutParams(TableRow.LayoutParams.WRAP_CONTENT, TableRow.LayoutParams.WRAP_CONTENT));
            TextView11.setTextColor(color.black);
            //TextView11.setText(String.format("%7s", col));
            TextView11.setText(col);
            tableRow.addView(TextView11);

        }

       tableLayout.addView(tableRow);
    }
    setContentView(R.layout.activity_display_result);

如何使用TableLayout显示数据库表记录

2 个答案: