0
我对android
非常新。我有一些SomeActivity
计数器,但是当我到达对应SomeActivity
的页面,我的应用程序崩溃:在Android活动中添加计数器
final TextView counter = (TextView) findViewById(R.id.laws_counter);
ImageView handDown = (ImageView) findViewById(R.id.handViewDown);
counter.setText("" + 0);
我想,关于handown
的点击,计数器被-1
idented。这里是
handDown.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(NewsActivity.this,
"The favorite list would appear on clicking this icon",
Toast.LENGTH_LONG).show();
setDown();
}
private void setDown() {
String count = counter.getText().toString();
int now_count = Integer.parseInt(count) +1;
counter.setText(String.valueOf(now_count));
}
});
此编程是否正确?
更新:这里的logcat
10-22 00:18:05.579: ERROR/AndroidRuntime(378): FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.donnfelker.android.bootstrap/com.donnfelker.android.bootstrap.ui.NewsActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
at android.app.ActivityThread.access$1500(ActivityThread.java:117)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:3683)
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:839)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.donnfelker.android.bootstrap.ui.NewsActivity.onCreate(NewsActivity.java:41)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
... 11 more
从崩溃发布您的logcat。此代码来自两个不同的“活动”? – codeMagic
@codeMagic我更新了我的帖子 – user1611830
“NewsActivity”的第41行是什么?有些东西是'null'。在'Activity'中用'setContentView()'膨胀的xml中'View'的'counter'和'handViewDown'的id是什么? – codeMagic