I've recently studyed android by myself. and I tried Using Fragment by following my Textbook but I met an error even though I typed codes exactly the same as my textbook.
Can you guys explain to me what is wrong?
This is MainActivity.java
package com.example.ex_1;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public static class CounterFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// TODO Auto-generated method stub
View root = inflater.inflate(R.layout.counterfragment, container, false);
Button btnIncrease = (Button)root.findViewById(R.id.btnincrease);
final TextView textCounter = (TextView)root.findViewById(R.id.txtcounter);
btnIncrease.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
int count = Integer.parseInt(textCounter.getText().toString());
textCounter.setText(Integer.toString(count + 1));
}
});
return root;
}
}
}
This is activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/LinearLayout1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="${relativePackage}.${activityClass}" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="~~"/>
<fragment
android:name="com.example.ex_1.MainActivity$CounterFragment"
android:id="@+id/counterfragment"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
And the error is
09-24 07:40:08.329: E/AndroidRuntime(1794): FATAL EXCEPTION: main
09-24 07:40:08.329: E/AndroidRuntime(1794): Process: com.example.ex_1, PID: 1794
09-24 07:40:08.329: E/AndroidRuntime(1794): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.ex_1/com.example.ex_1.MainActivity}: android.view.InflateException: Binary XML file line #13: Error inflating class fragment
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.app.ActivityThread.access$800(ActivityThread.java:144)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.os.Handler.dispatchMessage(Handler.java:102)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.os.Looper.loop(Looper.java:135)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.app.ActivityThread.main(ActivityThread.java:5221)
09-24 07:40:08.329: E/AndroidRuntime(1794): at java.lang.reflect.Method.invoke(Native Method)
09-24 07:40:08.329: E/AndroidRuntime(1794): at java.lang.reflect.Method.invoke(Method.java:372)
09-24 07:40:08.329: E/AndroidRuntime(1794): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
09-24 07:40:08.329: E/AndroidRuntime(1794): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
09-24 07:40:08.329: E/AndroidRuntime(1794): Caused by: android.view.InflateException: Binary XML file line #13: Error inflating class fragment
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:763)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.view.LayoutInflater.rInflate(LayoutInflater.java:806)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.view.LayoutInflater.inflate(LayoutInflater.java:504)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
09-24 07:40:08.329: E/AndroidRuntime(1794): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:377)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.app.Activity.setContentView(Activity.java:2144)
09-24 07:40:08.329: E/AndroidRuntime(1794): at com.example.ex_1.MainActivity.onCreate(MainActivity.java:19)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.app.Activity.performCreate(Activity.java:5937)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
09-24 07:40:08.329: E/AndroidRuntime(1794): ... 10 more
09-24 07:40:08.329: E/AndroidRuntime(1794): Caused by: android.app.Fragment$InstantiationException: Trying to instantiate a class com.example.ex_1.MainActivity$CounterFragment that is not a Fragment
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.app.Fragment.instantiate(Fragment.java:606)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.app.Fragment.instantiate(Fragment.java:582)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2108)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.app.Activity.onCreateView(Activity.java:5286)
09-24 07:40:08.329: E/AndroidRuntime(1794): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:733)
09-24 07:40:08.329: E/AndroidRuntime(1794): ... 20 more
09-24 07:40:08.329: E/AndroidRuntime(1794): Caused by: java.lang.ClassCastException
09-24 07:40:08.329: E/AndroidRuntime(1794): ... 25 more
problem is that you set your api level too low, so it use "support" version of fragment, instead of "base" fragment
put "min api level" at 11 in your androidmanifest, remove dependency to "support" library, remove "import android.support.v4.app.Fragment" and replace it with "import android.app.fragment" and it should work