ViewBinding - 如何绑定包含的布局?
ViewBinding - how to get binding for included layouts?
在使用 ViewBinding 时,我遇到了一些未记录的案例。
第一:如何获取包含的通用视图布局部分的绑定,主绑定只能看到主布局中的项目?
其次:如何为包含的合并类型布局部分获取绑定,同样主绑定只能看到主布局中的项目?
如果是:
- 包含通用布局(不是合并节点),我们需要为包含的部分分配 ID,这样在绑定中我们将可以访问包含的子部分
<include
android:id="@+id/your_id"
layout="@layout/some_layout" />
在您的 activity 代码中这样:
private lateinit var exampleBinding: ActivityExampleBinding //activity_example.xml layout
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
exampleBinding = ActivityExampleBinding.inflate(layoutInflater)
setContentView(exampleBinding.root)
//we will be able to access included layouts view like this
val includedView: View = exampleBinding.yourId.idOfIncludedView
//[...]
}
- 在外部布局中包含合并块。我们不能给它添加 ID,因为合并块不是视图。
假设我们有这样的永恒合并布局(merge_layout.xm):
<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
tools:showIn="@layout/activity_example">
<TextView
android:id="@+id/some_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello World" />
</merge>
要正确绑定此类合并布局,我们需要:
在您的 activity 代码中:
private lateinit var exampleBinding: ActivityExampleBinding //activity_example.xml layout
private lateinit var mergeBinding: MergeLayoutBinding //merge_layout.xml layout
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
exampleBinding = ActivityExampleBinding.inflate(layoutInflater)
//we need to bind the root layout with our binder for external layout
mergeBinding = MergeLayoutBinding.bind(exampleBinding.root)
setContentView(exampleBinding.root)
//we will be able to access included in merge layout views like this
val mergedView: View = mergeBinding.someView
//[...]
}
您的第一个问题,即使用 ViewBinding 处理包含的布局可以很容易地解决。
这是一个示例 main_fragment.xml 文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recycler_view_main"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" />
<include
android:id="@+id/toolbar"
layout="@layout/toolbar" />
</LinearLayout>
而MainFragment.java可以这样
public class MeaningFragment extends Fragment {
private MainFragmentBinding binding;
private ToolbarBinding toolbarBinding;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
binding = MainFragmentBinding.inflate(inflater, container, false);
toolbarBinding = binding.toolbar;
return binding.getRoot();
}
@Override
public void onDestroy() {
super.onDestroy();
toolbarBinding = null;
binding = null;
}
}
现在,您有两个绑定。其中之一是默认设置,下一个来自包含的布局。
在包含布局中,您必须创建一个容器布局并将 id 放在这里。
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto">
<androidx.constraintlayout.widget.ConstraintLayout
android:id="@+id/example"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintTop_toTopOf="parent">
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
如果你想绑定包含的布局,
对于Activity
YourMainLayoutBinding mainLayoutBinding = MainLayoutBinding.inflate(getLayoutInflater);
View view = mainLayoutBinding.getRoot();
YourIncludedLayoutBinding includedLayoutBinding = YourIncludedLayoutBinding.bind(View);
对于片段
YourMainLayoutBinding mainLayoutBinding = MainLayoutBinding.inflate(inflater,container,false);
View view = mainLayoutBinding.getRoot();
YourIncludedLayoutBinding includedLayoutBinding = YourIncludedLayoutBinding.bind(View);
Make Sure if your main layout binding parent root is LinearLayout then,
includedLayoutBinding parent layout also be a linear layout
假设我在 activity_main.xml
文件中包含如下布局:
<include
android:id="@+id/ll_layout1"
layout="@layout/layout1"
android:visibility="gone" />
假设我想改变它的可见性。我可以这样做:
activityMainBinding.llLayout1.root.visibility = View.VISIBLE
使用数据绑定库。然后用 <layout>
标签
包装你的 XML 布局
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<layout>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
...
<include
android:id="@+id/toolbar"
layout="@layout/toolbar" />
...
</LinearLayout>
</layout>
toolbar.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ImageView
android:id="@+id/ivImage"
... />
<TextView
android:id="@+id/tvTitle"
... />
</LinearLayout>
MainActivity.kt
private lateinit var binding: ActivityMainBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = DataBindingUtil.setContentView(this, R.layout.activity_main)
// Access include layout views
binding.toolbar.rootView.ivImage.setImageResource(R.drawable.ic_back_arrow)
binding.toolbar.rootView.tvTitle.text = getString(R.string.home)
...
}
遵循以下步骤:-
private val binding : FragmentBinding
通过 viewBinding(FragmentBinding::bind)
确保在“onViewCreated(view: View, savedInstanceState: Bundle?)”
中执行以下操作
val binding2 = binding.root.include_layout_id
例如val binding2 = binding.root.tool_bar_layout
现在访问您的包含布局,在此处查看。例如
binding2.textView.text = "your text"
在使用 ViewBinding 时,我遇到了一些未记录的案例。
第一:如何获取包含的通用视图布局部分的绑定,主绑定只能看到主布局中的项目?
其次:如何为包含的合并类型布局部分获取绑定,同样主绑定只能看到主布局中的项目?
如果是:
- 包含通用布局(不是合并节点),我们需要为包含的部分分配 ID,这样在绑定中我们将可以访问包含的子部分
<include
android:id="@+id/your_id"
layout="@layout/some_layout" />
在您的 activity 代码中这样:
private lateinit var exampleBinding: ActivityExampleBinding //activity_example.xml layout
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
exampleBinding = ActivityExampleBinding.inflate(layoutInflater)
setContentView(exampleBinding.root)
//we will be able to access included layouts view like this
val includedView: View = exampleBinding.yourId.idOfIncludedView
//[...]
}
- 在外部布局中包含合并块。我们不能给它添加 ID,因为合并块不是视图。 假设我们有这样的永恒合并布局(merge_layout.xm):
<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
tools:showIn="@layout/activity_example">
<TextView
android:id="@+id/some_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello World" />
</merge>
要正确绑定此类合并布局,我们需要:
在您的 activity 代码中:
private lateinit var exampleBinding: ActivityExampleBinding //activity_example.xml layout
private lateinit var mergeBinding: MergeLayoutBinding //merge_layout.xml layout
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
exampleBinding = ActivityExampleBinding.inflate(layoutInflater)
//we need to bind the root layout with our binder for external layout
mergeBinding = MergeLayoutBinding.bind(exampleBinding.root)
setContentView(exampleBinding.root)
//we will be able to access included in merge layout views like this
val mergedView: View = mergeBinding.someView
//[...]
}
您的第一个问题,即使用 ViewBinding 处理包含的布局可以很容易地解决。
这是一个示例 main_fragment.xml 文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recycler_view_main"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" />
<include
android:id="@+id/toolbar"
layout="@layout/toolbar" />
</LinearLayout>
而MainFragment.java可以这样
public class MeaningFragment extends Fragment {
private MainFragmentBinding binding;
private ToolbarBinding toolbarBinding;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
binding = MainFragmentBinding.inflate(inflater, container, false);
toolbarBinding = binding.toolbar;
return binding.getRoot();
}
@Override
public void onDestroy() {
super.onDestroy();
toolbarBinding = null;
binding = null;
}
}
现在,您有两个绑定。其中之一是默认设置,下一个来自包含的布局。
在包含布局中,您必须创建一个容器布局并将 id 放在这里。
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto">
<androidx.constraintlayout.widget.ConstraintLayout
android:id="@+id/example"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintTop_toTopOf="parent">
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
如果你想绑定包含的布局,
对于Activity
YourMainLayoutBinding mainLayoutBinding = MainLayoutBinding.inflate(getLayoutInflater);
View view = mainLayoutBinding.getRoot();
YourIncludedLayoutBinding includedLayoutBinding = YourIncludedLayoutBinding.bind(View);
对于片段
YourMainLayoutBinding mainLayoutBinding = MainLayoutBinding.inflate(inflater,container,false);
View view = mainLayoutBinding.getRoot();
YourIncludedLayoutBinding includedLayoutBinding = YourIncludedLayoutBinding.bind(View);
Make Sure if your main layout binding parent root is LinearLayout then, includedLayoutBinding parent layout also be a linear layout
假设我在 activity_main.xml
文件中包含如下布局:
<include
android:id="@+id/ll_layout1"
layout="@layout/layout1"
android:visibility="gone" />
假设我想改变它的可见性。我可以这样做:
activityMainBinding.llLayout1.root.visibility = View.VISIBLE
使用数据绑定库。然后用 <layout>
标签
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<layout>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
...
<include
android:id="@+id/toolbar"
layout="@layout/toolbar" />
...
</LinearLayout>
</layout>
toolbar.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<ImageView
android:id="@+id/ivImage"
... />
<TextView
android:id="@+id/tvTitle"
... />
</LinearLayout>
MainActivity.kt
private lateinit var binding: ActivityMainBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = DataBindingUtil.setContentView(this, R.layout.activity_main)
// Access include layout views
binding.toolbar.rootView.ivImage.setImageResource(R.drawable.ic_back_arrow)
binding.toolbar.rootView.tvTitle.text = getString(R.string.home)
...
}
遵循以下步骤:-
private val binding : FragmentBinding
通过viewBinding(FragmentBinding::bind)
确保在“onViewCreated(view: View, savedInstanceState: Bundle?)”
中执行以下操作val binding2 = binding.root.include_layout_id
例如val binding2 = binding.root.tool_bar_layout
现在访问您的包含布局,在此处查看。例如
binding2.textView.text = "your text"