<Fragment>的生命周期

最新推荐文章于 2025-08-23 11:54:15 发布

原创最新推荐文章于 2025-08-23 11:54:15 发布 · 236 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#Fragment

Android 专栏收录该内容

114 篇文章

订阅专栏

坚持住你的坚持，成功就在拐弯处。

/**
 * 生命周期的代码
 */
public class LifecycleFragment extends Fragment {

    public static final String TAG = "LifecycleFragment";

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);

        Log.d(TAG, "--onAttach--");

    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.d(TAG, "--onCreate--");
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        Log.d(TAG, "--onCreateView--");

        TextView tv = new TextView(getActivity());
        tv.setText("测试 fragment");
        tv.setGravity(Gravity.CENTER);
        tv.setTextSize(36);

        return tv;


    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        Log.d(TAG, "--onActivityCreated--");
    }

    @Override
    public void onStart() {
        super.onStart();

        Log.d(TAG, "--onStart--");
    }

    @Override
    public void onResume() {
        super.onResume();

        Log.d(TAG, "--onResume--");
    }

    @Override
    public void onPause() {
        super.onPause();
        Log.d(TAG, "--onPause--");
    }

    @Override
    public void onStop() {
        super.onStop();
        Log.d(TAG, "--onStop--");
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        Log.d(TAG, "--onDestroyView--");
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.d(TAG, "--onDestroy--");
    }

    @Override
    public void onDetach() {
        super.onDetach();
        Log.d(TAG, "--onDetach--");
    }


    public LifecycleFragment() {
    }


}

package com.test.lifecyclefragment.activity;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;

import com.test.lifecyclefragment.R;
import com.test.lifecyclefragment.fragment.LifecycleFragment;
import com.test.lifecyclefragment.fragment.SeconFragment;

/**
 * Fragment的生命周期
 *
 */
public class MainActivity extends AppCompatActivity {

    Button startActivity,addFragment,backFragment,replaceFragment,finish;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initView(); //初始化控件
        initListener(); //初始化监听事件

    }

    private void initListener() {
        startActivity.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //启动对话框风格Activity
                startActivity(new Intent(MainActivity.this,SecondActivity.class));
            }
        });

        //添加 Fragment
        addFragment.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                LifecycleFragment fragment = new LifecycleFragment();

                getFragmentManager().beginTransaction().replace(R.id.container,fragment).commit();
            }
        });

        //将替换前的Fragment 添加到 Back栈中
        backFragment.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                SeconFragment secFragment = new SeconFragment();
                getFragmentManager().beginTransaction()
                        .replace(R.id.container, secFragment)
                        .addToBackStack("aa")// 将替换前的Fragment添加到Back栈
                        .commit();
            }
        });

        //替换 Fragment
        replaceFragment.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                SeconFragment secFragment = new SeconFragment();
                getFragmentManager().beginTransaction().replace(R.id.container, secFragment).commit();
            }
        });

        // 为finish按钮绑定事件监听器
        finish.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View source)
            {
                // 结束该Activity
                MainActivity.this.finish();
            }
        });
    }

    private void initView() {
        startActivity = (Button) findViewById(R.id.start_dialog_activity);
        addFragment = (Button) findViewById(R.id.addFragment);
        backFragment = (Button) findViewById(R.id.backFragment);
        replaceFragment = (Button) findViewById(R.id.replaceFragment);
        finish = (Button) findViewById(R.id.finish);
    }
}

/**
 * 对话框风格 Activity
 */
public class SecondActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        TextView tv = new TextView(getApplication());
        tv.setText("对话框风格Activity");
        setContentView(tv);
    }
}

public class SeconFragment extends Fragment{
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        TextView tv = new TextView(getActivity());
        tv.setText("第二个 Fragment");
        tv.setGravity(Gravity.CENTER_HORIZONTAL);
        tv.setTextSize(36);
        tv.setTextColor(Color.BLUE);
        return  tv;

    }
}

点击加载目标Fragment 按钮时会执行 –onAttach–,–onCreate–, –onCreateView–,–onActivityCreated–,–onStart–,-onResume–方法.
接着点击启动对话框Activity的按钮当前的Activity会进入暂停状态,该 Fragment也会进入暂停状态,会执行 –onPause–方法. 点击返回键,关闭对话框Activity. Fragment会执行onResume()方法.

继续点击替换目标Fragment,并加入Back栈中的按钮
–onPause– –onStop– –onDestroyView–方法.

点击替换目标Fragment 按钮之后执行 –onPause–, –onStop–,–onDestroyView–, –onDestroy–,–onDetach– 该Fragment 将会被完全结束,Fragment将进入”销毁”状态.

Fragment 的生命周期中,如下方法被系统回调.

onAttach(Activity) 当Fragment被添加到 Activity时,被回调.该方法只会被调用一次.
onCreate(Bundle) 创建Fragment 时被回调,该方法只会被调用一次.
onCreateView(LayoutInflater, ViewGroup, Bundle) ;每次创建,绘制Fragment的View组件时回调该方法,Fragment将会显示该方法返回的view组件.
onActivityCreated(Bundle) 当Fragment所在的Activity 被启动完成后回调该方法.
onStart() 启动Fragment 时被回调.
onResume() 恢复Fragment时被回调, onStart()方法后一定会回调 onResume()方法.
onPause() 暂停时Fragment时被回调.
onStop(); 停止Fragment 时被回调.
onDestroyView() 销毁该Fragment 所包含的View 组件时调用.
onDestroy() 销毁 Fragment时被回调. 该方法只会调用一次.
onDetach() 将该 fragment 从Activity中被删除,被替换完成时,回调该方法. onDestroy方法后一定会回调 onDetach()方法.该方法只会调用一次.