Android 以编程方式将RelativeLayout 添加到TableLayout
所以,我决定学习编写Android应用程序。我更喜欢通过编写代码来学习,因此我设置了环境并开始使用 Android!
并击中了我的头:)
我正在尝试将导入RelativeLayout作为TableRows添加到表视图中。
这是我想重复使用的表格布局,
<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/upload_list_table"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:stretchColumns="*" >
</TableLayout>
我将其包含在我的主要活动中
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/home_activity"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<include android:id="@+id/homeActivityUploadList" layout="@layout/upload_list_table" />
</LinearLayout>
,然后,我使用relativelayout创建了我的行,
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/upload_list_table_row_relative"
android:layout_width="fill_parent"
android:layout_height="?android:attr/listPreferredItemHeight"
android:padding="6dip" >
<ImageView
android:id="@+id/fileThumb"
android:layout_width="90px"
android:layout_height="fill_parent"
android:layout_alignParentTop="true"
android:layout_gravity="left"
android:padding="2px"
android:src="@drawable/nothumb" />
<TextView
android:id="@+id/fileDescription"
android:layout_width="fill_parent"
android:layout_height="26dip"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_toRightOf="@id/fileThumb"
android:ellipsize="marquee"
android:singleLine="true"
android:text="Desc" />
<TextView
android:id="@+id/fileTitle"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_above="@id/fileDescription"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:layout_alignWithParentIfMissing="true"
android:layout_toRightOf="@id/fileThumb"
android:gravity="center_vertical"
android:text="Title" />
</RelativeLayout>
现在,我正在尝试这个
public class HomeActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.home_activity);
TableLayout tbl = (TableLayout)findViewById(R.id.homeActivityUploadList);
RelativeLayout row = (RelativeLayout)findViewById(R.layout.upload_list_table_row_relative);
tbl.addView(row);
}
,但是,我得到了NullPointerException。找不到
RelativeLayout row = (RelativeLayout)findViewById(R.layout.upload_list_table_row_relative);
我也尝试过
RelativeLayout row = (RelativeLayout)findViewById(R.id.upload_list_table_row_relative);
我做错了什么?
谢谢
日志输出
01-24 11:30:15.757: D/dalvikvm(1625): GC_EXTERNAL_ALLOC freed 46K, 53% free 2539K/5379K, external 1625K/2137K, paused 68ms
01-24 11:30:15.877: D/dalvikvm(1625): GC_EXTERNAL_ALLOC 已释放 1K,53% 已释放 2538K/5379K,外部 2250K/2810K,暂停 58ms 01-24 11:30:15.967:D/AndroidRuntime(1625):关闭虚拟机 01-24 11:30:15.967:W/dalvikvm(1625):threadid = 1:线程因未捕获的异常而退出(组= 0x40015560) 01-24 11:30:15.977: E/AndroidRuntime(1625): 致命异常: main 01-24 11:30:15.977: E/AndroidRuntime(1625): java.lang.RuntimeException: 无法启动活动 ComponentInfo{com.*.HomeActivity}: java .lang.NullPointerException 01-24 11:30:15.977:E / AndroidRuntime(1625):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) 01-24 11:30:15.977:E / AndroidRuntime(1625):在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 01-24 11:30:15.977: E/AndroidRuntime(1625): 在 android.app.ActivityThread.access$1500(ActivityThread.java:117) 01-24 11:30:15.977: E/AndroidRuntime(1625): 在 android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 01-24 11:30:15.977: E/AndroidRuntime(1625): 在 android.os.Handler.dispatchMessage(Handler.java:99) 01-24 11:30:15.977:E / AndroidRuntime(1625):在android.os.Looper.loop(Looper.java:123) 01-24 11:30:15.977:E / AndroidRuntime(1625):在android.app.ActivityThread.main(ActivityThread.java:3683) 01-24 11:30:15.977:E / AndroidRuntime(1625):在java.lang.reflect.Method.invokeNative(本机方法) 01-24 11:30:15.977:E / AndroidRuntime(1625):在java.lang.reflect.Method.invoke(Method.java:507) 01-24 11:30:15.977: E/AndroidRuntime(1625): 在 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 01-24 11:30:15.977:E / AndroidRuntime(1625):在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 01-24 11:30:15.977:E / AndroidRuntime(1625):在dalvik.system.NativeStart.main(本机方法) 01-24 11:30:15.977:E / AndroidRuntime(1625):引起:java.lang.NullPointerException 01-24 11:30:15.977:E / AndroidRuntime(1625):在android.view.ViewGroup.addView(ViewGroup.java:1821) 01-24 11:30:15.977:E / AndroidRuntime(1625):在android.widget.TableLayout.addView(TableLayout.java:403) 01-24 11:30:15.977:E / AndroidRuntime(1625):在android.view.ViewGroup.addView(ViewGroup.java:1808) 01-24 11:30:15.977:E / AndroidRuntime(1625):在android.widget.TableLayout.addView(TableLayout.java:394) 01-24 11:30:15.977: E/AndroidRuntime(1625): 在 com.*.onCreate(HomeActivity.java:23) 01-24 11:30:15.977:E / AndroidRuntime(1625):在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 01-24 11:30:15.977:E / AndroidRuntime(1625):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 01-24 11:30:15.977: E/AndroidRuntime(1625): ... 11 更多
android:ellipsize=
So, I decided to learn to write Android apps. I prefer learning by writing code so I setup my environment and dived in to Android!
And hit my head :)
I am trying to add import RelativeLayout as TableRows to a Table view.
This is my table layout which I want to re-use,
<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/upload_list_table"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:stretchColumns="*" >
</TableLayout>
I included it i my my main activity with
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/home_activity"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<include android:id="@+id/homeActivityUploadList" layout="@layout/upload_list_table" />
</LinearLayout>
Then, I created my Row with RelativeLayout
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/upload_list_table_row_relative"
android:layout_width="fill_parent"
android:layout_height="?android:attr/listPreferredItemHeight"
android:padding="6dip" >
<ImageView
android:id="@+id/fileThumb"
android:layout_width="90px"
android:layout_height="fill_parent"
android:layout_alignParentTop="true"
android:layout_gravity="left"
android:padding="2px"
android:src="@drawable/nothumb" />
<TextView
android:id="@+id/fileDescription"
android:layout_width="fill_parent"
android:layout_height="26dip"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_toRightOf="@id/fileThumb"
android:ellipsize="marquee"
android:singleLine="true"
android:text="Desc" />
<TextView
android:id="@+id/fileTitle"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_above="@id/fileDescription"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:layout_alignWithParentIfMissing="true"
android:layout_toRightOf="@id/fileThumb"
android:gravity="center_vertical"
android:text="Title" />
</RelativeLayout>
Now, I am trying this
public class HomeActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.home_activity);
TableLayout tbl = (TableLayout)findViewById(R.id.homeActivityUploadList);
RelativeLayout row = (RelativeLayout)findViewById(R.layout.upload_list_table_row_relative);
tbl.addView(row);
}
But, i get NullPointerException. It can't find
RelativeLayout row = (RelativeLayout)findViewById(R.layout.upload_list_table_row_relative);
I've also tried
RelativeLayout row = (RelativeLayout)findViewById(R.id.upload_list_table_row_relative);
What am I doing wrong?
Thanks
Log output
01-24 11:30:15.757: D/dalvikvm(1625): GC_EXTERNAL_ALLOC freed 46K, 53% free 2539K/5379K, external 1625K/2137K, paused 68ms
01-24 11:30:15.877: D/dalvikvm(1625): GC_EXTERNAL_ALLOC freed 1K, 53% free 2538K/5379K, external 2250K/2810K, paused 58ms
01-24 11:30:15.967: D/AndroidRuntime(1625): Shutting down VM
01-24 11:30:15.967: W/dalvikvm(1625): threadid=1: thread exiting with uncaught exception (group=0x40015560)
01-24 11:30:15.977: E/AndroidRuntime(1625): FATAL EXCEPTION: main
01-24 11:30:15.977: E/AndroidRuntime(1625): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.*.HomeActivity}: java.lang.NullPointerException
01-24 11:30:15.977: E/AndroidRuntime(1625): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
01-24 11:30:15.977: E/AndroidRuntime(1625): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
01-24 11:30:15.977: E/AndroidRuntime(1625): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
01-24 11:30:15.977: E/AndroidRuntime(1625): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
01-24 11:30:15.977: E/AndroidRuntime(1625): at android.os.Handler.dispatchMessage(Handler.java:99)
01-24 11:30:15.977: E/AndroidRuntime(1625): at android.os.Looper.loop(Looper.java:123)
01-24 11:30:15.977: E/AndroidRuntime(1625): at android.app.ActivityThread.main(ActivityThread.java:3683)
01-24 11:30:15.977: E/AndroidRuntime(1625): at java.lang.reflect.Method.invokeNative(Native Method)
01-24 11:30:15.977: E/AndroidRuntime(1625): at java.lang.reflect.Method.invoke(Method.java:507)
01-24 11:30:15.977: E/AndroidRuntime(1625): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
01-24 11:30:15.977: E/AndroidRuntime(1625): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
01-24 11:30:15.977: E/AndroidRuntime(1625): at dalvik.system.NativeStart.main(Native Method)
01-24 11:30:15.977: E/AndroidRuntime(1625): Caused by: java.lang.NullPointerException
01-24 11:30:15.977: E/AndroidRuntime(1625): at android.view.ViewGroup.addView(ViewGroup.java:1821)
01-24 11:30:15.977: E/AndroidRuntime(1625): at android.widget.TableLayout.addView(TableLayout.java:403)
01-24 11:30:15.977: E/AndroidRuntime(1625): at android.view.ViewGroup.addView(ViewGroup.java:1808)
01-24 11:30:15.977: E/AndroidRuntime(1625): at android.widget.TableLayout.addView(TableLayout.java:394)
01-24 11:30:15.977: E/AndroidRuntime(1625): at com.*.onCreate(HomeActivity.java:23)
01-24 11:30:15.977: E/AndroidRuntime(1625): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
01-24 11:30:15.977: E/AndroidRuntime(1625): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
01-24 11:30:15.977: E/AndroidRuntime(1625): ... 11 more
android:ellipsize=
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你必须使用LayoutInflater
you must use LayoutInflater