我正在写我教会的Android应用程序，我正在尝试使用ListView作为启动板来在线查看布道。 LV正确填充，但每个列表项中有两个未由游标填充的TextView - 它们在每个列表项中具有相同的文本。 （他们说准确地说“播放音频”和“播放视频”。）我需要一种方法来点击每个TextView并发送到某个网页。我正在尝试为每个TextView添加标签，但是当我尝试从我的ViewBinder访问它时，我得到一个NullPointerException。标签都有不同的值。
有谁知道如何为这些静态TextView分配标签？
SermonActivity.java
public class SermonActivity extends SherlockListActivity implements
OnClickListener, ViewBinder {
private Cursor cursor = null;
private SimpleCursorAdapter adapter = null;
private dbAdapter dba = null;
private ListView listView = null;
// Arrays
private static String[] FROM = { "title", "scripture", "speaker", "mdy",
"hour" };
private static int[] TO = { R.id.sermon_title, R.id.sermon_scripture,
R.id.sermon_speaker, R.id.sermon_date, R.id.sermon_time };
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sermon);
ActionBar actionBar = getSupportActionBar();
// Makes home button visible
actionBar.setHomeButtonEnabled(true);
// Allows home button to be used to navigate up
actionBar.setDisplayHomeAsUpEnabled(true);
}
@Override
protected void onDestroy() {
super.onPause();
dba.close();
cursor.close();
}
@Override
protected void onResume() {
super.onResume();
// Setting up the database adapter
dba = new dbAdapter(this);
dba.open();
// Getting the Cursor of the requested data
cursor = dba.read("sermons", null, null);
adapter = new SimpleCursorAdapter(this, R.layout.sermon_list, cursor,
FROM, TO, 0);
adapter.setViewBinder(this);
setListAdapter(adapter);
setTitle(R.string.title_activity_sermon);
}
/*
* To dynamically change the time of day displayed as well as adding the
* title and file tags to the play buttons
*/
@Override
public boolean setViewValue(View view, Cursor cursor, int columnIndex) {
// To set the sermon time
if (view.getId() == R.id.sermon_time) {
String time = cursor.getString(cursor.getColumnIndex("hour"));
if (time.contains("AM")) {
((TextView) view).setText("Sunday AM");
} else if (time.contains("PM")) {
((TextView) view).setText("Sunday PM");
}
// Adding tags for the title and file name to the "Play audio/video"
// buttons
***TextView playAudio = (TextView) findViewById(R.id.sermon_audio);*** //This is the line that throws the NullPointerException
playAudio.setTag(R.string.file_tag,
cursor.getString(cursor.getColumnIndex("file")));
playAudio.setTag(R.string.title_tag,
cursor.getString(cursor.getColumnIndex("title")));
TextView playVideo = (TextView) findViewById(R.id.sermon_video);
playVideo.setTag(R.string.file_tag,
cursor.getString(cursor.getColumnIndex("file")));
playVideo.setTag(R.string.title_tag,
cursor.getString(cursor.getColumnIndex("title")));
return true;
}
else {
return false;
}
}
@Override
public void onClick(View view) {
int id = view.getId();
// Starting WebActivity with needed data values
if (id == R.id.sermon_audio || id == R.id.sermon_video) {
Intent intent = new Intent(this, WebActivity.class);
intent.putExtra("file", (String) view.getTag(R.string.file_tag));
intent.putExtra("title", (String) view.getTag(R.string.title_tag));
String type = null;
if (id == R.id.sermon_audio) {
type = "audio";
} else if (id == R.id.sermon_video) {
type = "video";
}
intent.putExtra("type", type);
startActivity(intent);
}
}
}
sermon_list.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:clickable="false"
android:longClickable="false"
android:orientation="vertical" >
<ImageView
android:id="@+id/sermon_thumbnail"
style="@style/Thumbnail"
android:src="@drawable/sermon" />
<TextView
android:id="@+id/sermon_audio"
style="@style/FeedBody"
android:layout_alignParentLeft="true"
android:layout_below="@+id/sermon_speaker"
android:layout_marginTop="15dp"
android:clickable="true"
android:onClick="onClick"
android:paddingLeft="25dp"
android:text="Play audio"
android:textColor="@color/link" />
<TextView
android:id="@+id/sermon_video"
style="@style/FeedBody"
android:layout_alignBaseline="@+id/sermon_audio"
android:layout_alignBottom="@+id/sermon_audio"
android:layout_alignParentRight="true"
android:clickable="true"
android:onClick="onClick"
android:paddingRight="25dp"
android:text="Play video"
android:textColor="@color/link" />
<TextView
android:id="@+id/sermon_title"
style="@style/FeedTitle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_toRightOf="@id/sermon_thumbnail"
android:lines="2"
android:scrollHorizontally="false"
android:singleLine="false"
android:width="0dip" />
<TextView
android:id="@+id/sermon_scripture"
style="@style/FeedBody"
android:layout_alignParentLeft="true"
android:layout_below="@+id/sermon_thumbnail"
android:paddingLeft="3dp"
android:text="Scripture" />
<TextView
android:id="@+id/sermon_speaker"
style="@style/FeedBody"
android:layout_alignParentLeft="true"
android:layout_below="@+id/sermon_scripture"
android:paddingLeft="3dp"
android:text="Speaker" />
<TextView
android:id="@+id/sermon_time"
style="@style/FeedBody"
android:layout_alignBaseline="@+id/sermon_speaker"
android:layout_alignBottom="@+id/sermon_speaker"
android:layout_alignParentRight="true"
android:paddingRight="3dp"
android:paddingTop="5dp"
android:text="Time" />
<TextView
android:id="@+id/sermon_date"
style="@style/FeedBody"
android:layout_alignBaseline="@+id/sermon_scripture"
android:layout_alignBottom="@+id/sermon_scripture"
android:layout_alignParentRight="true"
android:paddingRight="3dp"
android:text="Date" />
</RelativeLayout>
堆栈跟踪
03-19 17:17:45.942: W/ActivityThread(21858): Application com.lakesidebaptist.lakesidelife is waiting for the debugger on port 8100...
03-19 17:17:45.958: I/System.out(21858): Sending WAIT chunk
03-19 17:17:45.965: I/dalvikvm(21858): Debugger is active
03-19 17:17:46.161: I/System.out(21858): Debugger has connected
03-19 17:17:46.161: I/System.out(21858): waiting for debugger to settle...
03-19 17:17:46.364: I/System.out(21858): waiting for debugger to settle...
03-19 17:17:46.559: I/System.out(21858): waiting for debugger to settle...
03-19 17:17:46.762: I/System.out(21858): waiting for debugger to settle...
03-19 17:17:46.965: I/System.out(21858): waiting for debugger to settle...
03-19 17:17:47.161: I/System.out(21858): waiting for debugger to settle...
03-19 17:17:47.364: I/System.out(21858): debugger has settled (1300)
03-19 17:17:47.794: D/dalvikvm(21858): GC_CONCURRENT freed 186K, 3% free 10996K/11271K, paused 13ms+12ms, total 37ms
03-19 17:17:47.981: D/libEGL(21858): loaded /vendor/lib/egl/libEGL_POWERVR_SGX540_120.so
03-19 17:17:47.981: D/libEGL(21858): loaded /vendor/lib/egl/libGLESv1_CM_POWERVR_SGX540_120.so
03-19 17:17:47.981: D/libEGL(21858): loaded /vendor/lib/egl/libGLESv2_POWERVR_SGX540_120.so
03-19 17:17:48.036: D/OpenGLRenderer(21858): Enabling debug mode 0
03-19 17:17:51.848: D/dalvikvm(21858): GC_CONCURRENT freed 230K, 3% free 11206K/11527K, paused 14ms+13ms, total 54ms
03-19 17:17:51.903: I/none(21858): SELECT * FROM 'sermons';
03-19 17:17:51.903: I/none(21858): 20
03-19 17:17:55.731: D/dalvikvm(21858): Debugger has detached; object registry had 995 entries
03-19 17:17:55.731: D/AndroidRuntime(21858): Shutting down VM
03-19 17:17:55.731: W/dalvikvm(21858): threadid=1: thread exiting with uncaught exception (group=0x4182e300)
03-19 17:17:55.747: E/AndroidRuntime(21858): FATAL EXCEPTION: main
03-19 17:17:55.747: E/AndroidRuntime(21858): java.lang.NullPointerException
03-19 17:17:55.747: E/AndroidRuntime(21858): at com.lakesidebaptist.lakesidelife.ui.Content.SermonActivity.setViewValue(SermonActivity.java:90)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.support.v4.widget.SimpleCursorAdapter.bindView(SimpleCursorAdapter.java:131)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.support.v4.widget.CursorAdapter.getView(CursorAdapter.java:256)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.widget.AbsListView.obtainView(AbsListView.java:2267)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.widget.ListView.makeAndAddView(ListView.java:1769)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.widget.ListView.fillDown(ListView.java:672)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.widget.ListView.fillFromTop(ListView.java:733)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.widget.ListView.layoutChildren(ListView.java:1622)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.widget.AbsListView.onLayout(AbsListView.java:2102)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.View.layout(View.java:13754)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.ViewGroup.layout(ViewGroup.java:4362)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.widget.RelativeLayout.onLayout(RelativeLayout.java:948)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.View.layout(View.java:13754)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.ViewGroup.layout(ViewGroup.java:4362)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.View.layout(View.java:13754)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.ViewGroup.layout(ViewGroup.java:4362)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1649)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1507)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.widget.LinearLayout.onLayout(LinearLayout.java:1420)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.View.layout(View.java:13754)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.ViewGroup.layout(ViewGroup.java:4362)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.View.layout(View.java:13754)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.ViewGroup.layout(ViewGroup.java:4362)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1866)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1687)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:998)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4212)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.Choreographer.doCallbacks(Choreographer.java:555)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.Choreographer.doFrame(Choreographer.java:525)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.os.Handler.handleCallback(Handler.java:615)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.os.Handler.dispatchMessage(Handler.java:92)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.os.Looper.loop(Looper.java:137)
03-19 17:17:55.747: E/AndroidRuntime(21858): at android.app.ActivityThread.main(ActivityThread.java:4745)
03-19 17:17:55.747: E/AndroidRuntime(21858): at java.lang.reflect.Method.invokeNative(Native Method)
03-19 17:17:55.747: E/AndroidRuntime(21858): at java.lang.reflect.Method.invoke(Method.java:511)
03-19 17:17:55.747: E/AndroidRuntime(21858): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
03-19 17:17:55.747: E/AndroidRuntime(21858): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
03-19 17:17:55.747: E/AndroidRuntime(21858): at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：3)
尝试使用方法提供的视图并在其上查找视图，如下所示：
TextView playAudio = (TextView) view.findViewById(R.id.sermon_audio);
修改
您可能需要首先找到父视图，然后在其上使用findViewById，尝试这样的事情：
RelativeLayout parent = (RelativeLayout)view.getParent();
TextView playAudio = (TextView) parent.findViewById(R.id.sermon_audio);