조각에서 활동 시작

조각에서 활동 시작

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두 조각에 버튼이 두 개 있습니다. 버튼을 누르면 새로운 활동을 시작하고 싶습니다. 그러나 나는 그것을 작동시킬 수 없습니다.

내가 받고있는 오류 : ERROR here : Type mismatch : cannot convert from mFragmentFavorite to Fragment

내가 도대체 ​​뭘 잘못하고있는 겁니까?

MyFragmentPagerAdapter

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;

public class MyFragmentPagerAdapter extends FragmentPagerAdapter{

    final int PAGE_COUNT = 3;

    /** Constructor of the class */
    public MyFragmentPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    /** This method will be invoked when a page is requested to create */
    @Override
    public Fragment getItem(int arg0) {

        switch(arg0){

        case 0:
            return new FavoriteActivity();
                    //ERROR: Type mismatch: cannot convert from FavoriteActivity to Fragment


        case 1:
            return new SettingsActivity();


        default:
            return null;

        }       
    }

    /** Returns the number of pages */
    @Override
    public int getCount() {
        return PAGE_COUNT;
    }
}

가장 좋아하는 활동

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;

public class FavoriteActivity extends Activity{

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.main_favorite, container, false);


        OnClickListener listnr=new OnClickListener() {
            @Override
            public void onClick(View v) {
                  Intent i= new Intent("aFavorite");
                  startActivity(i);
            }
        };

          Button btn =(Button) v.findViewById(R.id.mainFavorite);
          btn.setOnClickListener(listnr);

          return v;
    }
}

FavoriteActivity가 조각을 확장하면 오류가 사라지지만 findViewById(R.id.mainFavorite);오류가 발생하고 오류가 발생합니다.

findViewById (int) 메소드는 FavoriteActivity 유형에 대해 정의되지 않았습니다.

편집하다:

조각의 버튼을 눌러 활동을 시작하면 앱이 충돌합니다. 이것이 내 logcat입니다.

03-18 16:01:23.985: E/AndroidRuntime(1985): FATAL EXCEPTION: main
03-18 16:01:23.985: E/AndroidRuntime(1985): android.content.ActivityNotFoundException: No Activity found to handle Intent { act=FavoriteActivityList }
03-18 16:01:23.985: E/AndroidRuntime(1985):     at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1569)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at android.app.Instrumentation.execStartActivity(Instrumentation.java:1420)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at android.app.Activity.startActivityForResult(Activity.java:3446)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at android.app.Activity.startActivityForResult(Activity.java:3407)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at android.support.v4.app.FragmentActivity.startActivityFromFragment(FragmentActivity.java:826)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at android.support.v4.app.Fragment.startActivity(Fragment.java:838)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at com.example.spui.FavoriteActivity$1.onClick(FavoriteActivity.java:24)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at android.view.View.performClick(View.java:4211)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at android.view.View$PerformClick.run(View.java:17267)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at android.os.Handler.handleCallback(Handler.java:615)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at android.os.Handler.dispatchMessage(Handler.java:92)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at android.os.Looper.loop(Looper.java:137)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at android.app.ActivityThread.main(ActivityThread.java:4898)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at java.lang.reflect.Method.invokeNative(Native Method)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at java.lang.reflect.Method.invoke(Method.java:511)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
03-18 16:01:23.985: E/AndroidRuntime(1985):     at dalvik.system.NativeStart.main(Native Method)

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mFragmentFavorite in your code is a FragmentActivity which is not the same thing as a Fragment. That's why you're getting the type mismatch. Also, you should never call new on an Activity as that is not the proper way to start one.

If you want to start a new instance of mFragmentFavorite, you can do so via an Intent.

From a Fragment:

Intent intent = new Intent(getActivity(), mFragmentFavorite.class);
startActivity(intent);

From an Activity

Intent intent = new Intent(this, mFragmentFavorite.class);
startActivity(intent);

If you want to start aFavorite instead of mFragmentFavorite then you only need to change out their names in the created Intent.

Also, I recommend changing your class names to be more accurate. Calling something mFragmentFavorite is improper in that it's not a Fragment at all. Also, class declarations in Java typically start with a capital letter. You'd do well to name your class something like FavoriteActivity to be more accurate and conform to the language conventions. You will also need to rename the file to FavoriteActivity.java if you choose to do this since Java requires class names match the file name.

UPDATE

Also, it looks like you actually meant formFragmentFavorite to be a Fragment instead of a FragmentActivity based on your use of onCreateView. If you want mFragmentFavorite to be a Fragment then change the following line of code:

public class mFragmentFavorite extends FragmentActivity{

Make this instead read:

public class mFragmentFavorite extends Fragment {

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You should use getActivity() to launch activities from fragments

Intent intent = new Intent(getActivity(), mFragmentFavorite.class);
startActivity(intent);

Also, you should be naming classes with caps: MFragmentActivity instead of mFragmentActivity.

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I use this in my fragment.

Button btn1 = (Button) thisLayout
            .findViewById(R.id.btnDb1);

    btn1.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            Intent intent = new Intent(getActivity(), otherActivity.class);
            ((MainActivity) getActivity()).startActivity(intent);

        }
    });

    return thisLayout;
}

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If you are using getActivity() then you have to make sure that the calling activity is added already. If activity has not been added in such case so you may get null when you call getActivity()

in such cases getContext() is safe

then the code for starting the activity will be slightly changed like,

Intent intent = new Intent(getContext(), mFragmentFavorite.class);
startActivity(intent);

Activity, Service and Application extends ContextWrapper class so you can use this or getContext() or getApplicationContext() in the place of first argument.

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You may have to replace getActivity() with MainActivity.this for those that are having issues with this.

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Start new Activity From a Fragment:

Intent intent = new Intent(getActivity(), TargetActivity.class);
startActivity(intent);

Start new Activity From a Activity:

Intent intent = new Intent(this, TargetActivity.class);
startActivity(intent);

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with Kotlin I execute this code:

requireContext().startActivity<YourTargetActivity>()

참고URL : https://stackoverflow.com/questions/15478105/start-an-activity-from-a-fragment