Java Android Studio - 应用程序已停止
声明:本页面是StackOverFlow热门问题的中英对照翻译,遵循CC BY-SA 4.0协议,如果您需要使用它,必须同样遵循CC BY-SA许可,注明原文地址和作者信息,同时你必须将它归于原作者(不是我):StackOverFlow
原文地址: http://stackoverflow.com/questions/21112627/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Android Studio - the application has stopped
提问by benLIVE
I'm trying Android Studio. I've created a simple app with a button with onClickLister()
to show a Toast message. I get the message "the application has stopped".
我正在尝试 Android Studio。我创建了一个带有按钮的简单应用程序,onClickLister()
用于显示 Toast 消息。我收到消息“应用程序已停止”。
-The same code works with Eclipse -I created more projects to try -tried on virtual and real device -Reinstalled Android Studio
- 相同的代码适用于 Eclipse - 我创建了更多的项目来尝试 - 在虚拟和真实设备上尝试 - 重新安装了 Android Studio
Any idea?
任何的想法?
XML:
XML:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context=".MainActivity$PlaceholderFragment">
<TextView
android:text="@string/hello_world"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/textView" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="New Button"
android:id="@+id/button"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
My Activity Class here :
我的活动课在这里:
public class MainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button mibtn = (Button)findViewById(R.id.button);
mibtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Toast.makeText(getApplicationContext(),"Apretado", Toast.LENGTH_LONG).show();
}
});
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment())
.commit();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
switch (item.getItemId()) {
case R.id.action_settings:
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
}
}
}
Logcat:
日志猫:
01-14 12:43:11.759 5651-5651/? W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x41538ba8)
01-14 12:43:11.759 5651-5651/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.omaxlive.myapplicationtest, PID: 5651
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.omaxlive.myapplicationtest/com.omaxlive.myapplicationtest.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access0(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.omaxlive.myapplicationtest.MainActivity.onCreate(MainActivity.java:25)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
????????????at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
????????????at android.app.ActivityThread.access0(ActivityThread.java:135)
????????????at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
????????????at android.os.Handler.dispatchMessage(Handler.java:102)
????????????at android.os.Looper.loop(Looper.java:136)
????????????at android.app.ActivityThread.main(ActivityThread.java:5017)
????????????at java.lang.reflect.Method.invokeNative(Native Method)
????????????at java.lang.reflect.Method.invoke(Method.java:515)
????????????at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
????????????at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
????????????at dalvik.system.NativeStart.main(Native Method)
采纳答案by pyus13
This Line shows that the Button you have created is in fragment_main.xml
此行显示您创建的 Button 位于 fragment_main.xml
tools:context=".MainActivity$PlaceholderFragment"
But you are finding your button in activity_main.xml
但是你正在找到你的按钮 activity_main.xml
Move your code from onCreate()
to onCreateView
of PlaceholderFragment like
将您的代码从PlaceholderFragment移动onCreate()
到onCreateView
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
Button mibtn = (Button)rootView.findViewById(R.id.button);
mibtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Toast.makeText(getApplicationContext(),"Apretado", Toast.LENGTH_LONG).show();
}
});
return rootView;
}
回答by vik
You are finding your layout on:
您在以下位置找到您的布局:
setContentView (R.layout.activity_main);
but your layout which you are using is fragment_main.xml
但是您使用的布局是 fragment_main.xml
so change setContentView(R.layout.activity_main);
to setContentView(R.layout.fragment_main);
所以setContentView(R.layout.activity_main);
改为setContentView(R.layout.fragment_main);
and secondly delete this code from your .java file
其次从您的 .java 文件中删除此代码
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment())
.commit();
}