java 找不到符号“上下文”，android.content.Context
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Cannot find symbol 'Context', android.content.Context
提问by user3578847
I have the following code:
我有以下代码：
package com.androidtest.notification;
import android.app.Activity;
import android.os.Bundle;
import android.widget;
import android.widget.Toast;
import android.content.Context;
public class activityNotification extends Activity
{
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Context context = getApplicationContext();
CharSequence text = "Hello toast!";
int duration = Toast.LENGTH_SHORT;
Toast toast = Toast.makeText(context, text, duration);
toast.show();
}
}
I'm trying to compile it using ant on command line '$ ant build', but I keep getting the following error:
我正在尝试在命令行“$ ant build”上使用 ant 编译它，但我不断收到以下错误：
error: cannot find symbol
[javac] Context context = getApplicationContext();
[javac] ^
Any suggestions please? Thanks!
请问有什么建议吗？谢谢！
采纳答案by codemirror
Short answer: add this
简短回答：添加这个
import android.content.Context;
回答by Stefano Vuerich
Context in Activity is obtained by YourActivity.this or easier with this
Activity 中的上下文是通过 YourActivity.this 获得的，或者更容易使用 this
package com.androidtest.notification;
import android.app.Activity;
import android.os.Bundle;
import android.widget;
import android.widget.Toast;
import android.content.Context;
public class ActivityNotification extends Activity
{
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Context context = this; // or ActivityNotification.this
CharSequence text = "Hello toast!";
int duration = Toast.LENGTH_SHORT;
Toast toast = Toast.makeText(this, text, duration);
toast.show();
}
}
