当我运行这段代码,它不工作和发送目录下载到我这条线: “add.setOnClickListener(新View.OnClickListener(){”安卓:logcat的显示上(.setOnClickListener)错误
这里是我的代码:
public class MainActivity extends ActionBarActivity {
int counter;
Button add, sub;
TextView display;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
counter =0;
add = (Button) findViewById(R.id.Badd);
sub = (Button) findViewById(R.id.Bsub);
display = (TextView) findViewById(R.id.TVmain);
add.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
counter++;
display.setText("Your Total is: " + counter);
}
});
activity_main.xml中:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.pluseonecalculator.MainActivity"
tools:ignore="MergeRootFrame" />
这是logcat的:
03-27 23:14:27.150:I /处理(408):发送信号。 PID:408 SIG:9 03-27 23:27:01.070:D/AndroidRuntime(420):关闭VM 03-27 23:27:01.070:W/dalvikvm(420):threadid = 1:未知的异常(group = 0x40015560) 03-27 23:27:01.090:E/AndroidRuntime(420):致命异常:主 03-27 23:27:01.090:E/AndroidRuntime(420):java.lang.RuntimeException :无法启动活动 ComponentInfo {com.example.pluseonecalculator/com.example.pluseonecalculator.MainActivity}: java.lang.NullPointerException 03-27 23:27:01.090:E/AndroidRuntime(420):at android.app (ActivityThread.java:1647) 03-27 23:27:01.090:E/AndroidRuntime(420) 03-27 23:27:01.090:E/AndroidRuntime(420):at android.app.ActivityThread.access $ 1500(ActivityThread.java:117) 03-27 23:27:01.090:E/AndroidRuntime(420):at android.app.ActivityThread $ H.handleMessage(ActivityThread.java:931) 03-27 23:27:01.090:E/AndroidRuntime(420):at android.os.Handler.dispatchMessage(Handler.java:99) 03 -27 23:27:01.090:E/AndroidRuntime(420):在android.os.Looper.loop(Looper.java:123) 03-27 23:27:01.090:E/AndroidRuntime(420):在android。 app.ActivityThread.main(ActivityThread.java:3683) 03-27 23:27:01.090:E/AndroidRuntime(420):at java.lang.reflect.Method.invokeNative(Native Method) 03-27 23:27 :01.090:E/AndroidRuntime(420):at java.lang.reflect.Method.invoke(Method.java:507) 03-27 23:27:01.090:E/AndroidRuntime(420):at com.android.int ernal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:839) 03-27 23:27:01.090:E/AndroidRuntime(420):at com.android.internal.os.ZygoteInit.main(ZygoteInit.java: 597) 03-27 23:27:01.090:E/AndroidRuntime(420):at dalvik.system.NativeStart.main(Native Method) 03-27 23:27:01.090:E/AndroidRuntime(420):由:java.lang.NullPointerException 03-27 23:27:01.090:E/AndroidRuntime(420):at com.example.pluseonecalculator.MainActivity.onCreate(MainActivity.java:34) 03-27 23:27:01.090: E/AndroidRuntime(420):在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 03-27 23:27:01.090:E/AndroidRuntime(420):at android.app.ActivityThread.performLaunchActivity(ActivityThread。 java:1611) 03-27 23:27:01.090:E/AndroidRuntime(420):... 11更多
logcat输出中的错误是什么? – csmckelvey
也发布activity_main.xml请 – donfuxx
检查出MainActivity中的第34行,“add”可能为空。如果你想改进格式,请确保你已经从你的布局 –