Start an activity from a fragment
I have 2 fragments with on both fragments a button. When I press the button I'd like to start a new Activity. But I can't get it to work.
The error I'm getting: ERROR here: Type mismatch: cannot convert from mFragmentFavorite to Fragment
What am I doing wrong?
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;
}
}
FavoriteActivity
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;
}
}
If FavoriteActivity extends fragments, the error is gone but then I get an error at findViewById(R.id.mainFavorite);
and the error is
The method findViewById(int) is undefined for the type FavoriteActivity
EDIT:
When I press the button in the fragment to start the activity then the app crashes this is my logcat
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)
Solution 1:
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 {
Solution 2:
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
.
Solution 3:
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.
Solution 4:
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;
}
Solution 5:
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);