在Android Studio上创建意图时出错

Question

使用import android.content.Intent; 来自Lompa的文件在主.java文件和清单上解决了我的问题，但在第二个.java文件中却解决了我的问题

这是代码：

package com.tutorial.helloworld;

import android.os.Bundle;
import android.util.Log;
import android.content.Intent;

public class SecondActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my);

        String varString = getIntent().getStringExtra("Test");
        Log.d("HelloWorld - Second Activity", varString);
    }
}

这里的错误：

G:\Crear_Apps\Projects\HelloWorld\app\src\main\java\com\tutorial\helloworld\SecondActivity.java

Error:(6, 37) error: cannot find symbol class Activity

Error:(8, 5) error: method does not override or implement a method from a supertype

Error:(10, 9) error: cannot find symbol variable super

Error:(11, 9) error: cannot find symbol method setContentView(int)

Error:(13, 28) error: cannot find symbol method getIntent()

---

我正在按照教程的步骤操作，并给我创建“意图”的错误，我搜索了解决方案，但没有任何效果，idk是由于Android Studio错误还是我的错误，我也重新启动了Android Studio，但没有任何反应。

MyActivity.java

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_my);
    Log.d("HelloWorld","onCreate");

    Intent i = new Intent(this, SecondActivity.class);
    i.putExtra("Test","true");

    startActivity(i);
}

SecondActivity.java

public class SecondActivity extends Activity{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my);

        String varString = getIntent().getStringExtra("Test");
        Log.d("HelloWorld - Second Activity",varString);
    }
}

AndroidManifest.xml中

        </activity>
            <activity android:name="com.tutorial.helloworld.SecondActivity">
            </activity>
    </application>

我得到的错误

G:\Crear_Apps\Projects\HelloWorld\app\src\main\java\com\tutorial\helloworld\MyActivity.java
Error:(20, 9) error: cannot find symbol class Intent
Error:(20, 24) error: cannot find symbol class Intent
G:\Crear_Apps\Projects\HelloWorld\app\src\main\java\com\tutorial\helloworld\SecondActivity.java
Error:(6, 37) error: cannot find symbol class Activity
Error:(8, 5) error: method does not override or implement a method from a supertype
Error:(10, 9) error: cannot find symbol variable super
Error:(11, 9) error: cannot find symbol method setContentView(int)
Error:(13, 28) error: cannot find symbol method getIntent()

Answer 1

改变这个

    </activity>
    <activity android:name="com.tutorial.helloworld.SecondActivity">
    </activity>
    </application>

对此

    </activity>
    <activity android:name=".SecondActivity">
    </activity>
    </application>

也尝试改变这个

    public class SecondActivity extends Activity

对此

    public class SecondActivity extends AppCompatActivity

进口

    import android.support.v7.app.AppCompatActivity;
    import android.content.Intent;

Answer 2

试试这个代码..您应该使用MyActivity.this而不是仅使用this还要同步一次android studio并清理您的项目并重建它。

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_my);
    Log.d("HelloWorld","onCreate");

    Intent i = new Intent(MyActivity.this, SecondActivity.class);
    i.putExtra("Test","true");

   startActivity(i);
}