Fragment newfragment =new MyFragment();
fragmentTransaction.replace(R.layout.activity_main,newfragment ).commit();
提示错误：The method replace(int, Fragment) in the type FragmentTransaction is not applicable for the arguments (int, MyFragment)
妈蛋，找了好久！一直以为子类对象不能赋值给父类引用。这部科学啊！
错误代码：
package com.example.testforfragment; import android.os.Bundle; import android.app.Activity; import android.app.FragmentManager; import android.app.FragmentTransaction; import android.support.v4.app.Fragment; import android.support.v4.app.Fragment.*; import android.view.Menu; public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); FragmentManager fragmentManager = getFragmentManager(); FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction(); Fragment newfragment =new MyFragment(); fragmentTransaction.replace(R.layout.activity_main,newfragment ).commit(); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } }
修改：
package com.example.testforfragment; import android.os.Bundle; import android.app.Activity; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentActivity; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentTransaction; import android.view.Menu; public class MainActivity extends FragmentActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); FragmentManager fragmentManager = getSupportFragmentManager(); FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction(); Fragment newfragment =new MyFragment(); fragmentTransaction.replace(R.layout.activity_main,newfragment ).commit(); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } }
1.导入的包
2.extends
3.getSurpport……