方向重新启动我的应用程序

Question

即时通讯编程新，我有一个带碎片的导航抽屉。当我旋转我的设备时，它会“重新启动应用程序”或调用Home片段。我不知道如何解决这个问题，它与super.onCreate（savedInstance）有关，但没有找到如何实现它。我也试着用我的清单上的onConfigurationChanged方法，但没有运气。我一直在复制来自不同教程的代码，以使我的应用程序工作，所以即时通讯不知道如果发布的代码应该是我应该发布的代码。谢谢。

public class MainActivity extends FragmentActivity { 


    private DrawerLayout mDrawerLayout; 
    ImageView home; 
    Fragment fragment = null; 
    TextView appname; 
    ExpandableListView expListView; 
    HashMap<String, List<String>> listDataChild; 
    ExpandableListAdapter listAdapter; 
    List<String> listDataHeader; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     String fontPath = "neue.ttf"; 
     setContentView(R.layout.activity_main); 
     home = (ImageView)findViewById(R.id.home); 
     home.setOnClickListener(homeOnclickListener); 
     appname = (TextView)findViewById(R.id.appname); 
     Typeface tf = Typeface.createFromAsset(this.getAssets(), fontPath); 
     appname.setTypeface(tf); 

     setUpDrawer(); 
    } 

    private void setUpDrawer() { 
     mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout); 
     mDrawerLayout.setScrimColor(getResources().getColor(android.R.color.transparent)); 
     mDrawerLayout.setDrawerListener(mDrawerListener); 
     expListView = (ExpandableListView) findViewById(R.id.lvExp); 
     prepareListData(); 
     listAdapter = new ExpandableListAdapter(this, listDataHeader, listDataChild); 
     expListView.setAdapter(listAdapter); 
     fragment = new Home(); 
     getSupportFragmentManager().beginTransaction().replace(R.id.content_frame, fragment).commit(); 
     mDrawerLayout.closeDrawer(expListView); 

     expListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() { 
           @Override 
           public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) { 
            switch (groupPosition) { 
             case 0: 
              switch (childPosition) { 
               case 0: 
                fragment = new 1(); 
                break; 
               case 1: 
                fragment = new 2(); 
                break; 
               case 2: 
                fragment = new 3(); 
                break; 
          ... 
         } 
         break; 

        case 1: 
         switch (childPosition) { 
          case 0: 
           fragment = new 4(); 
           break; 
          ... 
          default: 
           break; 
         } 
         break; 

        ... 
       } 
       getSupportFragmentManager().beginTransaction().replace(R.id.content_frame, fragment).commit(); 
       mDrawerLayout.closeDrawer(expListView); 
       return false; 
      } 
     }); 

    }... 

Answer 1

在设备旋转时，活动重新启动 - 这是明显的行为。如果您不希望重新创建活动，则应在您的Manifest文件中为该活动添加android:configChanges="orientation"。

否则，您可以防止调用setUpDrawer()当您的活动被通过检查savedInstanceState像这样重新启动 -

@Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     String fontPath = "neue.ttf"; 
     setContentView(R.layout.activity_main); 
     home = (ImageView)findViewById(R.id.home); 
     home.setOnClickListener(homeOnclickListener); 
     appname = (TextView)findViewById(R.id.appname); 
     Typeface tf = Typeface.createFromAsset(this.getAssets(), fontPath); 
     appname.setTypeface(tf); 

     if(savedInstanceState == null){ 
      setUpDrawer(); 
     } 
    }