Android Fragment和FragmentActivity用法

待我称王封你为后i 2022-08-24 00:50 179阅读 0赞

Android Fragment是Android4.0以上才有的；而FragmentActivity是为了兼容4.0以下版本的Fragment使用的。

所以如果你想兼容4.0以下Android版本使用Fragment的话，框架Activity需要继承FragmentActivity，FragmentActivity这个类是在android.support.v4.app.FragmentActivity里的。

下面介绍2种用法：

1、继承Activity的。

（这个只针对4.0以上的Android平台使用Fragment）。

框架Activity：

package com.tandong.fragment;
    
    import android.app.Activity;
    import android.app.Fragment;
    import android.app.FragmentManager;
    import android.app.FragmentTransaction;
    import android.os.Bundle;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    
    /**
     * 不兼容4.0以下模式Fragment
     * 
     * @author tandong
     * 
     */
    
    public class Mt_Activity extends Activity implements OnClickListener {
    	private Button btn_first, btn_second;
    	private Fragment Fragment_first, Fragment_Second;
    	private FragmentTransaction fragmentTransaction;
    	private FragmentManager fragmentManager;
    
    	@Override
    	protected void onCreate(Bundle savedInstanceState) {
    		// TODO Auto-generated method stub
    		super.onCreate(savedInstanceState);
    		setContentView(R.layout.fragment);
    		initView();
    
    		Fragment_Second = new Fragment_Second();
    		fragmentManager = this.getFragmentManager();
    		fragmentTransaction = fragmentManager.beginTransaction();
    		fragmentTransaction.replace(R.id.main_fragment_layout, Fragment_Second,"second_Fragment").commit();
    	}
    
    	private void initView() {
    		btn_first = (Button) this.findViewById(R.id.btn_first);
    		btn_second = (Button) this.findViewById(R.id.btn_second);
    		btn_first.setOnClickListener(this);
    		btn_second.setOnClickListener(this);
    	}
    
    	@Override
    	public void onClick(View arg0) {
    		switch (arg0.getId()) {
    		case R.id.btn_first:
    			// 加载不同的Fragment
    			if (null == Fragment_first) {
    				Fragment_first = new Fragment_first();
    			}
    			fragmentTransaction = fragmentManager.beginTransaction();
    			fragmentTransaction.replace(R.id.main_fragment_layout, Fragment_first, "fist_Fragment");
    			fragmentTransaction.commit();
    			break;
    		case R.id.btn_second:
    			if (null == Fragment_Second) {
    				Fragment_Second = new Fragment_Second();
    			}
    			fragmentTransaction = fragmentManager.beginTransaction();
    			fragmentTransaction.replace(R.id.main_fragment_layout, Fragment_Second, "second_Fragment");
    			fragmentTransaction.commit();
    			break;
    		default:
    			break;
    		}
    
    	}
    
    }

Fragment代码：

package com.tandong.fragment;
    
    import android.app.Fragment;
    import android.os.Bundle;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    
    public class Fragment_Second extends Fragment {
          private View rootView;
    	@Override
    	public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    		// TODO Auto-generated method stub
    if(container==null)
    return null;
    		rootView=inflater.inflate(R.layout.fragment_two, container,false);
    		
    		return rootView;
    	}
    
    }

2.继承FragmentActivity的（向下兼容4.0以下版本使用Fragment，导入的是android.support.v4包里的内容）

框架Activity：

package com.tandong.fragment;
    
    import android.os.Bundle;
    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.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    
    /**
     * 兼容4.0以下模式Fragment
     * 
     * @author tandong
     * 
     */
    
    public class Mt_Activity extends FragmentActivity implements OnClickListener {
    	private Button btn_first, btn_second;
    	private Fragment Fragment_first, Fragment_Second;
    	private FragmentTransaction fragmentTransaction;
    	private FragmentManager fragmentManager;
    
    	@Override
    	protected void onCreate(Bundle savedInstanceState) {
    		// TODO Auto-generated method stub
    		super.onCreate(savedInstanceState);
    		setContentView(R.layout.fragment);
    		initView();
    
    		Fragment_first = new Fragment_first();
    		fragmentManager = this.getSupportFragmentManager();
    		fragmentTransaction = fragmentManager.beginTransaction();
    		fragmentTransaction.replace(R.id.main_fragment_layout, Fragment_first,"first_Fragment").commit();
    	}
    
    	private void initView() {
    		btn_first = (Button) this.findViewById(R.id.btn_first);
    		btn_second = (Button) this.findViewById(R.id.btn_second);
    		btn_first.setOnClickListener(this);
    		btn_second.setOnClickListener(this);
    	}
    
    	@Override
    	public void onClick(View arg0) {
    		switch (arg0.getId()) {
    		case R.id.btn_first:
    			// 加载不同的Fragment
    			if (null == Fragment_first) {
    				Fragment_first = new Fragment_first();
    			}
    			fragmentTransaction = fragmentManager.beginTransaction();
    			fragmentTransaction.replace(R.id.main_fragment_layout, Fragment_first, "fist_Fragment");
    			fragmentTransaction.commit();
    			break;
    		case R.id.btn_second:
    			if (null == Fragment_Second) {
    				Fragment_Second = new Fragment_Second();
    			}
    			fragmentTransaction = fragmentManager.beginTransaction();
    			fragmentTransaction.replace(R.id.main_fragment_layout, Fragment_Second, "second_Fragment");
    			fragmentTransaction.commit();
    			break;
    		default:
    			break;
    		}
    
    	}
    
    }

Fragment代码：

package com.tandong.fragment;
    
    import android.os.Bundle;
    import android.support.v4.app.Fragment;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    
    public class Fragment_first extends Fragment {
    	private View rootView;
    
    	@Override
    	public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    if(container==null)
       return null;
    		rootView = inflater.inflate(R.layout.fragment_first, container,false);
    
    		return rootView;
    	}
    }

原著：[http://www.aplesson.com/?p=377][http_www.aplesson.com_p_377]

[http_www.aplesson.com_p_377]: http://www.aplesson.com/?p=377