我试图解决我的项目活动的一个问题,所以在谷歌搜索后我找到了 单选复选框的例子
我应用了它,但是当运行它时它会关闭,任何解决问题的帮助将不胜感激,
多谢 。
SingleSelectionCheckBox 类
public class SingleSelectionCheckBox extends Activity {
CheckBox cbActivate ;
CheckBox cbAll ;
CheckBox cbFilter ;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
cbActivate = (CheckBox)findViewById(R.id.cbActivate);
cbActivate.setOnCheckedChangeListener(listener);
cbAll = (CheckBox)findViewById(R.id.cbAll);
cbAll.setOnCheckedChangeListener(listener);
cbFilter = (CheckBox)findViewById(R.id.cbFilter);
cbFilter.setOnCheckedChangeListener(listener);
}
private OnCheckedChangeListener listener = new OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton arg0, boolean isChecked) {
if(isChecked){
switch(arg0.getId())
{
case R.id.cbActivate:
cbActivate.setChecked(true);
cbAll.setChecked(false);
cbFilter.setChecked(false);
break;
case R.id.cbAll:
cbAll.setChecked(true);
cbFilter.setChecked(false);
cbActivate.setChecked(false);
break;
case R.id.cbFilter:
cbFilter.setChecked(true);
cbAll.setChecked(false);
cbActivate.setChecked(false);
break;
}
}
}
};}
主xml
<CheckBox
android:id="@+id/cbActivate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="50dp"
android:text="ActivateMe" />
<CheckBox
android:id="@+id/cbAll"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="50dp"
android:text="ApplyAll" />
<CheckBox
android:id="@+id/cbFilter"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="50dp"
android:text="ApplyFilter" />
日志猫
java.lang.RuntimeException: Unable to start activity
ComponentInfo{com.test.demo/com.test.demo.SingleSelectionCheckBox}:
java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1651)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
at android.app.ActivityThread.access$1500(ActivityThread.java:117)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:130)
at android.app.ActivityThread.main(ActivityThread.java:3687)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.test.demo.SingleSelectionCheckBox.onCreate(SingleSelectionCheckBox.java:19)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615)