setContentView(R.layout.new_layout) 更改布局，但 GoogleMap 片段为空白答案

【问题标题】：setContentView(R.layout.new_layout) to change layout, but then GoogleMap fragment is blanksetContentView(R.layout.new_layout) 更改布局，但 GoogleMap 片段为空白
【发布时间】：2022-01-13 00:41:07
【问题描述】：

我的应用成功显示了一个 GoogleMap 片段。但是当单击“展开”按钮加载新的布局 xml 文件时，地图现在是空白的。我可以为新布局加载一个新活动，但这会重复很多代码。理想情况下，我想单击展开按钮并使用相同的地图加载新布局，但减少屏幕上的混乱。

我不确定如何处理按钮点击。我最初尝试了setContentView(R.layout.activity_create_route_expanded);，但后来没有一个按钮是可点击的。我目前的尝试膨胀新布局，然后再次调用 onCreate
createRouteLayout = getLayoutInflater().inflate(R.layout.activity_create_route, null); 除了空白地图之外，一切正常。

这是我的代码的简化版本：

public class CreateRouteActivity extends FragmentActivity implements OnMapReadyCallback {

    private View createRouteLayout;
    private ViewModelCreateRoute viewModelCreateRoute; // Save variable state when changing the layout

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        // If user has changed to/from expanded view, use the saved layout. Otherwise default to activity_create_route
        if (createRouteLayout == null) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_create_route);
        } else {
            setContentView(createRouteLayout);
        }

        viewModelCreateRoute = new ViewModelProvider(this).get(ViewModelCreateRoute.class);
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.mapCreateRoute);
        mapFragment.getMapAsync(this); //See the callback below: onMapReady()

        findViewById(R.id.createRouteExpandButton).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (viewModelCreateRoute.isExpanded()) {
                    viewModelCreateRoute.toggleExpanded();
                    createRouteLayout = getLayoutInflater().inflate(R.layout.activity_create_route, null);
                } else {
                    viewModelCreateRoute.toggleExpanded();
                    createRouteLayout = getLayoutInflater().inflate(R.layout.activity_create_route_expanded, null);
                }
                onCreate(savedInstanceState);
            }
        });
    }

    @Override
    public void onMapReady(GoogleMap gMap) {
        viewModelCreateRoute.getMapDisplayContainer().setgMap(gMap);
        MapUtils.populateMap(viewModelCreateRoute.getMapDisplayContainer(), true, false);
    }
}

【问题讨论】：

我仍然找不到在显示地图时动态更改 ContentView 的方法，但我确实找到了一种更简单的方法来实现我的目标：

标签： android google-maps layout setcontentview

【解决方案1】：

我仍然找不到在显示地图时动态更改 ContentView 的方法，但我确实找到了一种更简单的方法来实现我的目标：

与其建立一个新的布局，不如动态地改变 ConstraintLayout：

在活动中：

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        Log.d(TAG, "CreateRouteActivity: onCreate: ");
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_create_route);

        findViewById(R.id.createRouteExpandButton).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                if(viewModelCreateRoute.isExpanded()){
                    viewModelCreateRoute.toggleExpanded();
                    shrinkLayout();

                } else {
                    viewModelCreateRoute.toggleExpanded();
                    expandLayout();
                }
            }
        });
    ...
    }

    private void expandLayout(){
        RecyclerView recyclerView = findViewById(R.id.createRouteRecycle);
        EditText raceInstructions = findViewById(R.id.raceInstructionsEditText);
        recyclerView.setVisibility(View.GONE);
        raceInstructions.setVisibility(View.GONE);

        ConstraintLayout constraintLayout = findViewById(R.id.createRouteConstraintLayout);
        ConstraintSet constraintSet = new ConstraintSet();
        constraintSet.clone(constraintLayout);
        constraintSet.connect(R.id.createRouteStartText,ConstraintSet.BOTTOM,R.id.saveRouteButton,ConstraintSet.TOP,0);
        constraintSet.applyTo(constraintLayout);
    }

    private void shrinkLayout(){
        RecyclerView recyclerView = findViewById(R.id.createRouteRecycle);
        EditText raceInstructions = findViewById(R.id.raceInstructionsEditText);
        recyclerView.setVisibility(View.VISIBLE);
        raceInstructions.setVisibility(View.VISIBLE);

        ConstraintLayout constraintLayout = findViewById(R.id.createRouteConstraintLayout);
        ConstraintSet constraintSet = new ConstraintSet();
        constraintSet.clone(constraintLayout);
        constraintSet.connect(R.id.createRouteStartText,ConstraintSet.BOTTOM,R.id.createRouteRecycle,ConstraintSet.TOP,0);
        constraintSet.applyTo(constraintLayout);
    }

【讨论】：