以编程方式在 TableLayout 中添加行的问题

【问题标题】：Problem with adding rows in TableLayout programmatically以编程方式在 TableLayout 中添加行的问题
【发布时间】：2011-06-30 11:49:59
【问题描述】：

我正在尝试以编程方式在TableLayout 中添加行，并且我正在按照以下链接中给出的说明进行操作：

Dynamically Adding Rows to TableLayout 和 Creating Table Rows Inside A Table Layout Programmatically

我总是收到Application has stopped unexpectedly. Please try again. 错误。如果我在 XML 中定义整个 TableLayout，那么它可以正常工作，但是当我尝试以编程方式进行时，我总是会收到那个错误。

这是我的 XML 文件 (main.xml) 的代码：

<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:stretchColumns="1"
    android:id="@+id/maintable">
    <TableRow
        android:layout_width="fill_parent"
        android:layout_height="wrap_content">
        <TextView
            android:layout_column="1"
            android:text="Open..."
            android:padding="3dip" />
        <TextView
            android:text="Ctrl-O"
            android:gravity="right"
            android:padding="3dip" />
    </TableRow>
</TableLayout>

这是我在 .java 中完成的代码：

public class HelloTableLayout extends Activity {

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        /* Find Tablelayout defined in main.xml */
        TableLayout tl = (TableLayout)findViewById(R.id.maintable);
        /* Create a new row to be added. */
        TableRow tr = new TableRow(this);
        tr.setLayoutParams(new LayoutParams(
                        LayoutParams.FILL_PARENT,
                        LayoutParams.WRAP_CONTENT));
        /* Create a Button to be the row-content. */
        Button b = new Button(this);
        b.setText("Dynamic Button");
        b.setLayoutParams(new LayoutParams(
            LayoutParams.FILL_PARENT,
            LayoutParams.WRAP_CONTENT));
        /* Add Button to row. */
        tr.addView(b);
        /* Add row to TableLayout. */
        tl.addView(tr,new TableLayout.LayoutParams(
            LayoutParams.FILL_PARENT,
            LayoutParams.WRAP_CONTENT));
    }
}

这是解决问题的 LogCat：

04-04 13:56:21.161: DEBUG/AndroidRuntime(502): >>>>>>>>>>>>>> AndroidRuntime START <<<<<<<<<<<<<<
04-04 13:56:21.171: DEBUG/AndroidRuntime(502): CheckJNI is ON
04-04 13:56:21.441: DEBUG/AndroidRuntime(502): --- registering native functions ---
04-04 13:56:21.871: DEBUG/ddm-heap(502): Got feature list request
04-04 13:56:22.411: DEBUG/AndroidRuntime(502): Shutting down VM
04-04 13:56:22.411: DEBUG/dalvikvm(502): DestroyJavaVM waiting for non-daemon threads to exit
04-04 13:56:22.411: DEBUG/dalvikvm(502): DestroyJavaVM shutting VM down
04-04 13:56:22.421: DEBUG/dalvikvm(502): HeapWorker thread shutting down
04-04 13:56:22.421: DEBUG/dalvikvm(502): HeapWorker thread has shut down
04-04 13:56:22.431: DEBUG/jdwp(502): JDWP shutting down net...
04-04 13:56:22.431: ERROR/AndroidRuntime(502): ERROR: thread attach failed
04-04 13:56:22.441: INFO/dalvikvm(502): Debugger has detached; object registry had 1 entries
04-04 13:56:22.451: DEBUG/dalvikvm(502): VM cleaning up
04-04 13:56:22.481: DEBUG/dalvikvm(502): LinearAlloc 0x0 used 629532 of 5242880 (12%)
04-04 13:56:23.111: DEBUG/AndroidRuntime(510): >>>>>>>>>>>>>> AndroidRuntime START <<<<<<<<<<<<<<
04-04 13:56:23.121: DEBUG/AndroidRuntime(510): CheckJNI is ON
04-04 13:56:23.391: DEBUG/AndroidRuntime(510): --- registering native functions ---
04-04 13:56:23.821: DEBUG/ddm-heap(510): Got feature list request
04-04 13:56:24.401: INFO/ActivityManager(35): Starting activity: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.vision.HelloLinearLayout/.HelloLinearLayout }
04-04 13:56:24.471: DEBUG/AndroidRuntime(510): Shutting down VM
04-04 13:56:24.491: DEBUG/dalvikvm(510): DestroyJavaVM waiting for non-daemon threads to exit
04-04 13:56:24.521: DEBUG/dalvikvm(510): DestroyJavaVM shutting VM down
04-04 13:56:24.521: DEBUG/dalvikvm(510): HeapWorker thread shutting down
04-04 13:56:24.547: ERROR/AndroidRuntime(510): ERROR: thread attach failed
04-04 13:56:24.571: DEBUG/dalvikvm(510): HeapWorker thread has shut down
04-04 13:56:24.591: DEBUG/jdwp(510): JDWP shutting down net...
04-04 13:56:24.611: INFO/dalvikvm(510): Debugger has detached; object registry had 1 entries
04-04 13:56:24.611: DEBUG/dalvikvm(510): VM cleaning up
04-04 13:56:24.761: INFO/ActivityManager(35): Start proc com.vision.HelloLinearLayout for activity com.vision.HelloLinearLayout/.HelloLinearLayout: pid=517 uid=10028 gids={3003}
04-04 13:56:24.771: DEBUG/dalvikvm(510): LinearAlloc 0x0 used 639500 of 5242880 (12%)
04-04 13:56:25.041: DEBUG/ddm-heap(517): Got feature list request
04-04 13:56:25.651: DEBUG/AndroidRuntime(517): Shutting down VM
04-04 13:56:25.661: WARN/dalvikvm(517): threadid=3: thread exiting with uncaught exception (group=0x4001b188)
04-04 13:56:25.661: ERROR/AndroidRuntime(517): Uncaught handler: thread main exiting due to uncaught exception
04-04 13:56:25.692: ERROR/AndroidRuntime(517): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.vision.HelloLinearLayout/com.vision.HelloLinearLayout.HelloLinearLayout}: java.lang.NullPointerException
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     at android.app.ActivityThread.access$2200(ActivityThread.java:119)
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     at android.os.Looper.loop(Looper.java:123)
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     at android.app.ActivityThread.main(ActivityThread.java:4363)
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     at java.lang.reflect.Method.invokeNative(Native Method)
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     at java.lang.reflect.Method.invoke(Method.java:521)
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     at dalvik.system.NativeStart.main(Native Method)
04-04 13:56:25.692: ERROR/AndroidRuntime(517): Caused by: java.lang.NullPointerException
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     at com.vision.HelloLinearLayout.HelloLinearLayout.onCreate(HelloLinearLayout.java:35)
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
04-04 13:56:25.692: ERROR/AndroidRuntime(517):     ... 11 more
04-04 13:56:25.731: INFO/Process(35): Sending signal. PID: 517 SIG: 3
04-04 13:56:25.741: INFO/dalvikvm(517): threadid=7: reacting to signal 3
04-04 13:56:25.741: INFO/dalvikvm(517): Wrote stack trace to '/data/anr/traces.txt'
04-04 13:56:34.527: WARN/ActivityManager(35): Launch timeout has expired, giving up wake lock!
04-04 13:56:35.244: WARN/ActivityManager(35): Activity idle timeout for HistoryRecord{43cb3358 com.vision.HelloLinearLayout/.HelloLinearLayout}
04-04 13:56:40.471: DEBUG/dalvikvm(98): GC freed 184 objects / 7888 bytes in 185ms
04-04 13:56:42.241: INFO/Process(517): Sending signal. PID: 517 SIG: 9
04-04 13:56:42.281: INFO/ActivityManager(35): Process com.vision.HelloLinearLayout (pid 517) has died.
04-04 13:56:42.361: INFO/UsageStats(35): Unexpected resume of com.android.launcher while already resumed in com.vision.HelloLinearLayout
04-04 13:56:42.461: ERROR/gralloc(35): [unregister] handle 0x342e08 still locked (state=40000001)
04-04 13:56:42.471: WARN/InputManagerService(35): Window already focused, ignoring focus gain of: com.android.internal.view.IInputMethodClient$Stub$Proxy@43cd6e30
04-04 13:57:04.991: DEBUG/dalvikvm(94): GC freed 13267 objects / 589160 bytes in 124ms
04-04 14:14:44.061: DEBUG/dalvikvm(35): threadid=15: bogus mon 1+0>0; adjusting

请帮我解决这个问题并指导我做错了什么。

【问题讨论】：

  • 这段代码的哪一行抛出了使你的应用程序停止的异常？什么是异常？
  • 请发布 logCat 输出！否则可能很难找到解决方案！
  • 你的 main.xml 是一个 TableRow（没有表格？R.id.maintable 在哪里
  • 抱歉，发布 main.xml 代码时出现问题，这里是完整代码：schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:stretchColumns="1" android:id="@+id/maintable">
  • 如何检查哪一行代码使应用程序停止？我的意思是如何调试？

标签： android tablelayout tablerow


【解决方案1】：

您要查看的行是这一行：

错误/AndroidRuntime(517)：由以下原因引起： java.lang.NullPointerException 04-04 13:56:25.692: 错误/AndroidRuntime（517）：在 com.vision.HelloLinearLayout.HelloLinearLayout.onCreate(HelloLinearLayout.java:35) 04-04 13:56:25.692: 错误/AndroidRuntime(517)：在

我猜这是第 35 行：

tl.addView(tr,new TableLayout.LayoutParams(

这意味着你的电话在这里：

 TableLayout tl = (TableLayout)findViewById(R.id.maintable);

返回NULL？

【讨论】：

  • 如果您的意思是在我的 main.xml 中没有使用此 id 的控件，请再次查看问题。之前，它没有正确显示我的 main.xml 代码，但我只是编辑了我的问题以使其看起来正确。请现在再次查看问题。谢谢。
  • 好吧，不是真的。这可能是问题所在：但错误表明第 35 行有一个空指针。如果我猜对了这一行，就我所见，唯一可以在那里抛出空指针的是 tl。与 tl 相关的唯一另一行是使用 findViewById 的调用。所以不管是什么原因，这似乎是返回 NULL，除非我弄错了。
  • 我不知道，但只是为了检查一下，我更改了表的 ID 并再次尝试，它对我有用。所以，我猜你的猜测可能是对的。那个id有问题吗？谁能详细说明一下？
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