使用浮動按鈕開始活動

Question

所以我有我的List類，它有一個浮動按鈕。我想做到這一點，當我點擊該按鈕時，它會進入我的另一個活動MainActivity。這是我的列表類的代碼。

public class List extends Activity { 
ImageButton floatButton; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_list); 
    populateUsersList(); 

    floatButton = (ImageButton) findViewById(R.id.imageButton); 
    floatButton.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      Intent barcodes = new Intent (List.this, MainActivity.class); 
      startActivity(barcodes); 
     } 
    }); 
} 

private void populateUsersList() { 
    // Construct the data source 
    ArrayList<User> arrayOfUsers = User.getUsers(); 
    // Create the adapter to convert the array to views 
    UserAdapter adapter = new UserAdapter(this, arrayOfUsers); 
    // Attach the adapter to a ListView 
    ListView listView = (ListView) findViewById(R.id.lvUsers); 
    listView.setAdapter(adapter); 
} 

它似乎應該工作，但每次我點擊按鈕，這個錯誤代碼彈出。

06-15 11:34:46.299 2971-2971/com.example.pethoalpar.zxingexample E/AndroidRuntime: FATAL EXCEPTION: main 
                       Process: com.example.pethoalpar.zxingexample, PID: 2971 
                       android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.pethoalpar.zxingexample/apn.keychains.MainActivity}; have you declared this activity in your AndroidManifest.xml? 
                        at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1777) 
                        at android.app.Instrumentation.execStartActivity(Instrumentation.java:1501) 
                        at android.app.Activity.startActivityForResult(Activity.java:3745) 
                        at android.app.Activity.startActivityForResult(Activity.java:3706) 
                        at android.app.Activity.startActivity(Activity.java:4016) 
                        at android.app.Activity.startActivity(Activity.java:3984) 
                        at apn.keychains.List$1.onClick(List.java:28) 
                        at android.view.View.performClick(View.java:4780) 
                        at android.view.View$PerformClick.run(View.java:19866) 
                        at android.os.Handler.handleCallback(Handler.java:739) 
                        at android.os.Handler.dispatchMessage(Handler.java:95) 
                        at android.os.Looper.loop(Looper.java:135) 
                        at android.app.ActivityThread.main(ActivityThread.java:5254) 
                        at java.lang.reflect.Method.invoke(Native Method) 
                        at java.lang.reflect.Method.invoke(Method.java:372) 
                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 

我該如何解決這個問題？

Answer 1

您需要在清單文件中聲明您的活動。

添加到您的清單：

<activity android:name=".MainActivity" android:screenOrientation="portrait" /> 

您所有的<activity... />標籤應<application.. />標籤下放置。