我对Android非常陌生。我创建了一个示例项目,我可以显示一个Toast。现在我想在表格中显示一些数据。Android以编程方式创建TableLayout
我在onCreate方法(这里全法)尝试这样:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mNavigationDrawerFragment = (NavigationDrawerFragment) getSupportFragmentManager()
.findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
// Set up the drawer.
mNavigationDrawerFragment.setUp(R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
try {
TableLayout table = (TableLayout) findViewById(R.id.navigation_drawer);
TableRow tr = new TableRow(this);
TextView textview = new TextView(this);
textview.setText("Sup");
textview.setTextColor(Color.YELLOW);
tr.addView(textview);
table.addView(tr);
Toast.makeText(getApplicationContext(), "Well Done on getting the data", Toast.LENGTH_LONG).show();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
这里是我的fragment_main.xml文件:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/relLay"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity$PlaceholderFragment" >
<TextView
android:id="@+id/section_label"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/section_label"
android:layout_centerHorizontal="true"
android:text="Welcome!"
android:textAppearance="?android:attr/textAppearanceLarge" />
<TableLayout
android:id="@+id/MyLayout1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView1"
android:layout_below="@+id/section_label"
android:layout_marginLeft="18dp"
android:layout_marginTop="40dp" >
<TableRow
android:id="@+id/tableRow1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
</TableRow>
<TableRow
android:id="@+id/tableRow2"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
</TableRow>
<TableRow
android:id="@+id/tableRow3"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
</TableRow>
<TableRow
android:id="@+id/tableRow4"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
</TableRow>
</TableLayout>
是问题,当我运行应用程序我得到这个:
java.lang.NullPointerException
at com.example.helloworld.MainActivity.onCreate(MainActivity.java:115)
at android.app.Activity.performCreate(Activity.java:5431)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2269)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2363)
at android.app.ActivityThread.access$900(ActivityThread.java:161)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1265)
这是行115:
table.addView(tr);
为什么表空?为什么要得到一个简单的表格显示非常困难?请帮助我..
它是一个活动,或者你正在做的一个片段? – denizt
显示您的onCreate方法 – Suvitruf
检查setContentView方法。该布局必须包含TableLayout(MyLayout1)。 – Amsheer