Activity及Fragment之间的跳转

Posted 2022-07-19 ihrthk

Activity及Fragment之间的跳转

直接跳转

基本使用方法

public class MainActivity extends AppCompatActivity 

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

    public void jump(View view) 
        Intent intent = new Intent(this, VideoPlayActivity.class);
        intent.putExtra("video_id", "1");
        startActivity(intent);
    

public class VideoPlayActivity extends Activity 
    @Override
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_video_play);

        Intent intent = getIntent();
    

借助工具类

然而并没什么卵用

public static void startActivity(Context context, Class clazz,Bundle data) 
    Intent intent = new Intent(context, clazz);
    if(data != null)
        intent.putExtras(data);
    
    context.startActivity(intent);

推荐方案

1. 把new Intent()放在目标Activity,这样可以onCreate里的getIntent形成对应
2. 更容易理解和管理一个出口，多个入口的情况
3. 较方便维护传递数据的key和value（即key由目标Activity来定义，value是实际的来源）

public class MainActivity extends AppCompatActivity 

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

    public void jump(View view) 
        startActivity(VideoPlayActivity.newIntent(this, "1"));
    

public class VideoPlayActivity extends Activity 
    @Override
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_video_play);

    

    public static Intent newIntent(Context context, String vid) 
        Intent intent = new Intent(context, VideoPlayActivity.class);
        intent.putExtra("video_id", vid);
        return intent;
    

Fragment跳转

1. 首先需要一个空的构造方法，Fragment恢复重建要使用。
2. 使用newInstance代替构造方法传参
3. 在Fragment.onCreate方法获取实参

public class MainFragment

    public MainFragment() 
        // Required empty public constructor
    

    public static MainFragment newInstance(int pos) 
        MainFragment fragment = new MainFragment();
        Bundle args = new Bundle();
        args.putInt("pos", pos);
        fragment.setArguments(args);
        return fragment;
    

    @Override
    public void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        if (getArguments() != null) 
            pos = getArguments().getInt("pos");