public class MainActivity extends Activity {
private TextView tx1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tx1= (TextView) findViewById(R.id.txtexample);
try{
tx1.setText("Hello testing");
Log.i("Correct","No error");
}
catch(Exception e){
Log.i("Error","Error here");
e.printStackTrace();
}
}
这有什么不对？
堆栈跟踪 :
08-21 06:19:43.713: E/Trace(3883): error opening trace file: No such file or directory (2)
08-21 06:19:43.892: I/Error(3883): Error here
08-21 06:19:43.902: W/System.err(3883): java.lang.NullPointerException
08-21 06:19:43.902: W/System.err(3883): at com.example.textview.MainActivity.onCreate(MainActivity.java:18)
08-21 06:19:43.902: W/System.err(3883): at android.app.Activity.performCreate(Activity.java:5104)
08-21 06:19:43.902: W/System.err(3883): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
08-21 06:19:43.902: W/System.err(3883): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
08-21 06:19:43.913: …