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logact如何在android中設置複選框和按鈕的可見性？
05-04 17:53:15.820: E/AndroidRuntime(7709): FATAL EXCEPTION: main
05-04 17:53:15.820: E/AndroidRuntime(7709): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.registerscreen/com.example.registerscreen.FriendListActivity}: java.lang.NullPointerException
05-04 17:53:15.820: E/AndroidRuntime(7709): \t at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1815)
05-04 17:53:15.820: E/AndroidRuntime(7709): \t at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1831)
05-04 17:53:15.820: E/AndroidRuntime(7709): \t at android.app.ActivityThread.access$500(ActivityThread.java:122)
05-04 17:53:15.820: E/AndroidRuntime(7709): \t at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1024)
05-04 17:53:15.820: E/AndroidRuntime(7709): \t at android.os.Handler.dispatchMessage(Handler.java:99)
05-04 17:53:15.820: E/AndroidRuntime(7709): \t at android.os.Looper.loop(Looper.java:132)
05-04 17:53:15.820: E/AndroidRuntime(7709): \t at android.app.ActivityThread.main(ActivityThread.java:4123)
05-04 17:53:15.820: E/AndroidRuntime(7709): \t at java.lang.reflect.Method.invokeNative(Native Method)
05-04 17:53:15.820: E/AndroidRuntime(7709): \t at java.lang.reflect.Method.invoke(Method.java:491)
05-04 17:53:15.820: E/AndroidRuntime(7709): \t at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:844)
05-04 17:53:15.820: E/AndroidRuntime(7709): \t at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602)
05-04 17:53:15.820: E/AndroidRuntime(7709): \t at dalvik.system.NativeStart.main(Native Method)
05-04 17:53:15.820: E/AndroidRuntime(7709): Caused by: java.lang.NullPointerException
05-04 17:53:15.820: E/AndroidRuntime(7709): \t at com.example.registerscreen.FriendListActivity.onCreate(FriendListActivity.java:68)
05-04 17:53:15.820: E/AndroidRuntime(7709): \t at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1050)
05-04 17:53:15.820: E/AndroidRuntime(7709): \t at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1779)我能夠得到列表視圖我的電話接觸列表視圖的name.On右側我添加喜歡邀請button.Now我想要一個按鈕當我點擊這個按鈕時，這個按鈕就消失了，複選框出現了刻度標記。
我嘗試了很多東西，但我無法做到這一點。
public class FriendListActivity extends Activity {
SimpleCursorAdapter adapter;
ListView lvContacts;
Button b1;
CheckBox chk;
@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState) {
\t super.onCreate(savedInstanceState);
\t this.requestWindowFeature(Window.FEATURE_NO_TITLE);
\t setContentView(R.layout.activity_friend_listview);
\t
\t lvContacts = (ListView) findViewById(R.id.lv_friend_list);
\t ContentResolver cr = getContentResolver();
\t // Read Contacts
\t Cursor c = cr.query(ContactsContract.Contacts.CONTENT_URI,
\t new String[] { ContactsContract.Contacts._ID,ContactsContract.Contacts.DISPLAY_NAME }, null, null,
\t \t \t null);
\t // Attached with cursor with Adapter
\t adapter = new SimpleCursorAdapter(this, R.layout.activity_phonecontact,
\t \t \t c, new String[] { ContactsContract.Contacts.DISPLAY_NAME },
\t \t \t new int[] { R.id.tv_name });
\t lvContacts.setAdapter(adapter);
\t
\t
\t b1 = (Button)findViewById(R.id.btn_invite);
\t chk = (CheckBox)findViewById(R.id.chk_frnd);
\t b1.setOnClickListener(new OnClickListener()
\t {
\t
\t \t \t @Override
\t \t \t public void onClick(View arg0) {
\t \t \t b1.setVisibility(View.GONE);
\t \t \t chk.setVisibility(View.VISIBLE);
\t \t \t }
\t \t \t });
\t }
\t
\t
\t }
\t<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<ImageView
android:id="@+id/img_frnd_list"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/include1"
android:background="@null"
android:paddingLeft="10dp"
android:paddingTop="10dp"
android:contentDescription="@string/imageView_contact_image"
android:src="@drawable/contactimage" />
<TextView
android:id="@+id/tv_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/include1"
android:layout_toRightOf="@+id/img_frnd_list"
android:paddingLeft="10dp"
android:paddingTop="35dp"
android:textSize="@dimen/contact_text_size"
android:text="@string/Contact_Name" />
<Button
android:text="Play"
android:id="@+id/btn_invite"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:paddingTop="80dp"
android:visibility="visible"
android:layout_below="@+id/include1"
android:paddingRight="10dp" >
</Button>
<CheckBox
android:id="@+id/chk_frnd"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="gone"
android:layout_alignParentRight="true"
android:paddingTop="80dp"
android:layout_below="@+id/include1"
android:paddingRight="10dp" />
</RelativeLayout>
你有什麼試過？什麼事情沒有發生？ –
@PrerakSola我發佈了我的完整代碼，請給我看看...並告訴我我錯在哪裏...... –
你得到了什麼錯誤？任何力量關閉？ –